linux-sg2042/mm/internal.h

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/* internal.h: mm/ internal definitions
*
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef __MM_INTERNAL_H
#define __MM_INTERNAL_H
#include <linux/fs.h>
#include <linux/mm.h>
thp: reintroduce split_huge_page() This patch adds implementation of split_huge_page() for new refcountings. Unlike previous implementation, new split_huge_page() can fail if somebody holds GUP pin on the page. It also means that pin on page would prevent it from bening split under you. It makes situation in many places much cleaner. The basic scheme of split_huge_page(): - Check that sum of mapcounts of all subpage is equal to page_count() plus one (caller pin). Foll off with -EBUSY. This way we can avoid useless PMD-splits. - Freeze the page counters by splitting all PMD and setup migration PTEs. - Re-check sum of mapcounts against page_count(). Page's counts are stable now. -EBUSY if page is pinned. - Split compound page. - Unfreeze the page by removing migration entries. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-16 08:54:10 +08:00
#include <linux/pagemap.h>
mm, printk: introduce new format string for flags In mm we use several kinds of flags bitfields that are sometimes printed for debugging purposes, or exported to userspace via sysfs. To make them easier to interpret independently on kernel version and config, we want to dump also the symbolic flag names. So far this has been done with repeated calls to pr_cont(), which is unreliable on SMP, and not usable for e.g. sysfs export. To get a more reliable and universal solution, this patch extends printk() format string for pointers to handle the page flags (%pGp), gfp_flags (%pGg) and vma flags (%pGv). Existing users of dump_flag_names() are converted and simplified. It would be possible to pass flags by value instead of pointer, but the %p format string for pointers already has extensions for various kernel structures, so it's a good fit, and the extra indirection in a non-critical path is negligible. [linux@rasmusvillemoes.dk: lots of good implementation suggestions] Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-16 05:55:56 +08:00
#include <linux/tracepoint-defs.h>
/*
* The set of flags that only affect watermark checking and reclaim
* behaviour. This is used by the MM to obey the caller constraints
* about IO, FS and watermark checking while ignoring placement
* hints such as HIGHMEM usage.
*/
#define GFP_RECLAIM_MASK (__GFP_RECLAIM|__GFP_HIGH|__GFP_IO|__GFP_FS|\
mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic __GFP_REPEAT was designed to allow retry-but-eventually-fail semantic to the page allocator. This has been true but only for allocations requests larger than PAGE_ALLOC_COSTLY_ORDER. It has been always ignored for smaller sizes. This is a bit unfortunate because there is no way to express the same semantic for those requests and they are considered too important to fail so they might end up looping in the page allocator for ever, similarly to GFP_NOFAIL requests. Now that the whole tree has been cleaned up and accidental or misled usage of __GFP_REPEAT flag has been removed for !costly requests we can give the original flag a better name and more importantly a more useful semantic. Let's rename it to __GFP_RETRY_MAYFAIL which tells the user that the allocator would try really hard but there is no promise of a success. This will work independent of the order and overrides the default allocator behavior. Page allocator users have several levels of guarantee vs. cost options (take GFP_KERNEL as an example) - GFP_KERNEL & ~__GFP_RECLAIM - optimistic allocation without _any_ attempt to free memory at all. The most light weight mode which even doesn't kick the background reclaim. Should be used carefully because it might deplete the memory and the next user might hit the more aggressive reclaim - GFP_KERNEL & ~__GFP_DIRECT_RECLAIM (or GFP_NOWAIT)- optimistic allocation without any attempt to free memory from the current context but can wake kswapd to reclaim memory if the zone is below the low watermark. Can be used from either atomic contexts or when the request is a performance optimization and there is another fallback for a slow path. - (GFP_KERNEL|__GFP_HIGH) & ~__GFP_DIRECT_RECLAIM (aka GFP_ATOMIC) - non sleeping allocation with an expensive fallback so it can access some portion of memory reserves. Usually used from interrupt/bh context with an expensive slow path fallback. - GFP_KERNEL - both background and direct reclaim are allowed and the _default_ page allocator behavior is used. That means that !costly allocation requests are basically nofail but there is no guarantee of that behavior so failures have to be checked properly by callers (e.g. OOM killer victim is allowed to fail currently). - GFP_KERNEL | __GFP_NORETRY - overrides the default allocator behavior and all allocation requests fail early rather than cause disruptive reclaim (one round of reclaim in this implementation). The OOM killer is not invoked. - GFP_KERNEL | __GFP_RETRY_MAYFAIL - overrides the default allocator behavior and all allocation requests try really hard. The request will fail if the reclaim cannot make any progress. The OOM killer won't be triggered. - GFP_KERNEL | __GFP_NOFAIL - overrides the default allocator behavior and all allocation requests will loop endlessly until they succeed. This might be really dangerous especially for larger orders. Existing users of __GFP_REPEAT are changed to __GFP_RETRY_MAYFAIL because they already had their semantic. No new users are added. __alloc_pages_slowpath is changed to bail out for __GFP_RETRY_MAYFAIL if there is no progress and we have already passed the OOM point. This means that all the reclaim opportunities have been exhausted except the most disruptive one (the OOM killer) and a user defined fallback behavior is more sensible than keep retrying in the page allocator. [akpm@linux-foundation.org: fix arch/sparc/kernel/mdesc.c] [mhocko@suse.com: semantic fix] Link: http://lkml.kernel.org/r/20170626123847.GM11534@dhcp22.suse.cz [mhocko@kernel.org: address other thing spotted by Vlastimil] Link: http://lkml.kernel.org/r/20170626124233.GN11534@dhcp22.suse.cz Link: http://lkml.kernel.org/r/20170623085345.11304-3-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Alex Belits <alex.belits@cavium.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: David Daney <david.daney@cavium.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: NeilBrown <neilb@suse.com> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-13 05:36:45 +08:00
__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_NOFAIL|\
__GFP_NORETRY|__GFP_MEMALLOC|__GFP_NOMEMALLOC|\
__GFP_ATOMIC)
/* The GFP flags allowed during early boot */
#define GFP_BOOT_MASK (__GFP_BITS_MASK & ~(__GFP_RECLAIM|__GFP_IO|__GFP_FS))
/* Control allocation cpuset and node placement constraints */
#define GFP_CONSTRAINT_MASK (__GFP_HARDWALL|__GFP_THISNODE)
/* Do not use these with a slab allocator */
#define GFP_SLAB_BUG_MASK (__GFP_DMA32|__GFP_HIGHMEM|~__GFP_BITS_MASK)
2016-12-25 11:00:30 +08:00
void page_writeback_init(void);
int do_swap_page(struct vm_fault *vmf);
mm: make swapin readahead to improve thp collapse rate This patch makes swapin readahead to improve thp collapse rate. When khugepaged scanned pages, there can be a few of the pages in swap area. With the patch THP can collapse 4kB pages into a THP when there are up to max_ptes_swap swap ptes in a 2MB range. The patch was tested with a test program that allocates 400B of memory, writes to it, and then sleeps. I force the system to swap out all. Afterwards, the test program touches the area by writing, it skips a page in each 20 pages of the area. Without the patch, system did not swap in readahead. THP rate was %65 of the program of the memory, it did not change over time. With this patch, after 10 minutes of waiting khugepaged had collapsed %99 of the program's memory. [kirill.shutemov@linux.intel.com: trivial cleanup of exit path of the function] [kirill.shutemov@linux.intel.com: __collapse_huge_page_swapin(): drop unused 'pte' parameter] [kirill.shutemov@linux.intel.com: do not hold anon_vma lock during swap in] Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com> Acked-by: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Xie XiuQi <xiexiuqi@huawei.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: David Rientjes <rientjes@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-27 06:25:03 +08:00
void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
unsigned long floor, unsigned long ceiling);
static inline bool can_madv_dontneed_vma(struct vm_area_struct *vma)
{
return !(vma->vm_flags & (VM_LOCKED|VM_HUGETLB|VM_PFNMAP));
}
mm, oom: introduce oom reaper This patch (of 5): This is based on the idea from Mel Gorman discussed during LSFMM 2015 and independently brought up by Oleg Nesterov. The OOM killer currently allows to kill only a single task in a good hope that the task will terminate in a reasonable time and frees up its memory. Such a task (oom victim) will get an access to memory reserves via mark_oom_victim to allow a forward progress should there be a need for additional memory during exit path. It has been shown (e.g. by Tetsuo Handa) that it is not that hard to construct workloads which break the core assumption mentioned above and the OOM victim might take unbounded amount of time to exit because it might be blocked in the uninterruptible state waiting for an event (e.g. lock) which is blocked by another task looping in the page allocator. This patch reduces the probability of such a lockup by introducing a specialized kernel thread (oom_reaper) which tries to reclaim additional memory by preemptively reaping the anonymous or swapped out memory owned by the oom victim under an assumption that such a memory won't be needed when its owner is killed and kicked from the userspace anyway. There is one notable exception to this, though, if the OOM victim was in the process of coredumping the result would be incomplete. This is considered a reasonable constrain because the overall system health is more important than debugability of a particular application. A kernel thread has been chosen because we need a reliable way of invocation so workqueue context is not appropriate because all the workers might be busy (e.g. allocating memory). Kswapd which sounds like another good fit is not appropriate as well because it might get blocked on locks during reclaim as well. oom_reaper has to take mmap_sem on the target task for reading so the solution is not 100% because the semaphore might be held or blocked for write but the probability is reduced considerably wrt. basically any lock blocking forward progress as described above. In order to prevent from blocking on the lock without any forward progress we are using only a trylock and retry 10 times with a short sleep in between. Users of mmap_sem which need it for write should be carefully reviewed to use _killable waiting as much as possible and reduce allocations requests done with the lock held to absolute minimum to reduce the risk even further. The API between oom killer and oom reaper is quite trivial. wake_oom_reaper updates mm_to_reap with cmpxchg to guarantee only NULL->mm transition and oom_reaper clear this atomically once it is done with the work. This means that only a single mm_struct can be reaped at the time. As the operation is potentially disruptive we are trying to limit it to the ncessary minimum and the reaper blocks any updates while it operates on an mm. mm_struct is pinned by mm_count to allow parallel exit_mmap and a race is detected by atomic_inc_not_zero(mm_users). Signed-off-by: Michal Hocko <mhocko@suse.com> Suggested-by: Oleg Nesterov <oleg@redhat.com> Suggested-by: Mel Gorman <mgorman@suse.de> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Andrea Argangeli <andrea@kernel.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-26 05:20:24 +08:00
void unmap_page_range(struct mmu_gather *tlb,
struct vm_area_struct *vma,
unsigned long addr, unsigned long end,
struct zap_details *details);
extern int __do_page_cache_readahead(struct address_space *mapping,
struct file *filp, pgoff_t offset, unsigned long nr_to_read,
unsigned long lookahead_size);
/*
* Submit IO for the read-ahead request in file_ra_state.
*/
static inline unsigned long ra_submit(struct file_ra_state *ra,
struct address_space *mapping, struct file *filp)
{
return __do_page_cache_readahead(mapping, filp,
ra->start, ra->size, ra->async_size);
}
/*
* Turn a non-refcounted page (->_refcount == 0) into refcounted with
* a count of one.
*/
static inline void set_page_refcounted(struct page *page)
{
VM_BUG_ON_PAGE(PageTail(page), page);
2016-03-18 05:19:26 +08:00
VM_BUG_ON_PAGE(page_ref_count(page), page);
set_page_count(page, 1);
}
extern unsigned long highest_memmap_pfn;
mm: fix 100% CPU kswapd busyloop on unreclaimable nodes Patch series "mm: kswapd spinning on unreclaimable nodes - fixes and cleanups". Jia reported a scenario in which the kswapd of a node indefinitely spins at 100% CPU usage. We have seen similar cases at Facebook. The kernel's current method of judging its ability to reclaim a node (or whether to back off and sleep) is based on the amount of scanned pages in proportion to the amount of reclaimable pages. In Jia's and our scenarios, there are no reclaimable pages in the node, however, and the condition for backing off is never met. Kswapd busyloops in an attempt to restore the watermarks while having nothing to work with. This series reworks the definition of an unreclaimable node based not on scanning but on whether kswapd is able to actually reclaim pages in MAX_RECLAIM_RETRIES (16) consecutive runs. This is the same criteria the page allocator uses for giving up on direct reclaim and invoking the OOM killer. If it cannot free any pages, kswapd will go to sleep and leave further attempts to direct reclaim invocations, which will either make progress and re-enable kswapd, or invoke the OOM killer. Patch #1 fixes the immediate problem Jia reported, the remainder are smaller fixlets, cleanups, and overall phasing out of the old method. Patch #6 is the odd one out. It's a nice cleanup to get_scan_count(), and directly related to #5, but in itself not relevant to the series. If the whole series is too ambitious for 4.11, I would consider the first three patches fixes, the rest cleanups. This patch (of 9): Jia He reports a problem with kswapd spinning at 100% CPU when requesting more hugepages than memory available in the system: $ echo 4000 >/proc/sys/vm/nr_hugepages top - 13:42:59 up 3:37, 1 user, load average: 1.09, 1.03, 1.01 Tasks: 1 total, 1 running, 0 sleeping, 0 stopped, 0 zombie %Cpu(s): 0.0 us, 12.5 sy, 0.0 ni, 85.5 id, 2.0 wa, 0.0 hi, 0.0 si, 0.0 st KiB Mem: 31371520 total, 30915136 used, 456384 free, 320 buffers KiB Swap: 6284224 total, 115712 used, 6168512 free. 48192 cached Mem PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 76 root 20 0 0 0 0 R 100.0 0.000 217:17.29 kswapd3 At that time, there are no reclaimable pages left in the node, but as kswapd fails to restore the high watermarks it refuses to go to sleep. Kswapd needs to back away from nodes that fail to balance. Up until commit 1d82de618ddd ("mm, vmscan: make kswapd reclaim in terms of nodes") kswapd had such a mechanism. It considered zones whose theoretically reclaimable pages it had reclaimed six times over as unreclaimable and backed away from them. This guard was erroneously removed as the patch changed the definition of a balanced node. However, simply restoring this code wouldn't help in the case reported here: there *are* no reclaimable pages that could be scanned until the threshold is met. Kswapd would stay awake anyway. Introduce a new and much simpler way of backing off. If kswapd runs through MAX_RECLAIM_RETRIES (16) cycles without reclaiming a single page, make it back off from the node. This is the same number of shots direct reclaim takes before declaring OOM. Kswapd will go to sleep on that node until a direct reclaimer manages to reclaim some pages, thus proving the node reclaimable again. [hannes@cmpxchg.org: check kswapd failure against the cumulative nr_reclaimed count] Link: http://lkml.kernel.org/r/20170306162410.GB2090@cmpxchg.org [shakeelb@google.com: fix condition for throttle_direct_reclaim] Link: http://lkml.kernel.org/r/20170314183228.20152-1-shakeelb@google.com Link: http://lkml.kernel.org/r/20170228214007.5621-2-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Shakeel Butt <shakeelb@google.com> Reported-by: Jia He <hejianet@gmail.com> Tested-by: Jia He <hejianet@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-04 05:51:51 +08:00
/*
* Maximum number of reclaim retries without progress before the OOM
* killer is consider the only way forward.
*/
#define MAX_RECLAIM_RETRIES 16
Unevictable LRU Infrastructure When the system contains lots of mlocked or otherwise unevictable pages, the pageout code (kswapd) can spend lots of time scanning over these pages. Worse still, the presence of lots of unevictable pages can confuse kswapd into thinking that more aggressive pageout modes are required, resulting in all kinds of bad behaviour. Infrastructure to manage pages excluded from reclaim--i.e., hidden from vmscan. Based on a patch by Larry Woodman of Red Hat. Reworked to maintain "unevictable" pages on a separate per-zone LRU list, to "hide" them from vmscan. Kosaki Motohiro added the support for the memory controller unevictable lru list. Pages on the unevictable list have both PG_unevictable and PG_lru set. Thus, PG_unevictable is analogous to and mutually exclusive with PG_active--it specifies which LRU list the page is on. The unevictable infrastructure is enabled by a new mm Kconfig option [CONFIG_]UNEVICTABLE_LRU. A new function 'page_evictable(page, vma)' in vmscan.c tests whether or not a page may be evictable. Subsequent patches will add the various !evictable tests. We'll want to keep these tests light-weight for use in shrink_active_list() and, possibly, the fault path. To avoid races between tasks putting pages [back] onto an LRU list and tasks that might be moving the page from non-evictable to evictable state, the new function 'putback_lru_page()' -- inverse to 'isolate_lru_page()' -- tests the "evictability" of a page after placing it on the LRU, before dropping the reference. If the page has become unevictable, putback_lru_page() will redo the 'putback', thus moving the page to the unevictable list. This way, we avoid "stranding" evictable pages on the unevictable list. [akpm@linux-foundation.org: fix fallout from out-of-order merge] [riel@redhat.com: fix UNEVICTABLE_LRU and !PROC_PAGE_MONITOR build] [nishimura@mxp.nes.nec.co.jp: remove redundant mapping check] [kosaki.motohiro@jp.fujitsu.com: unevictable-lru-infrastructure: putback_lru_page()/unevictable page handling rework] [kosaki.motohiro@jp.fujitsu.com: kill unnecessary lock_page() in vmscan.c] [kosaki.motohiro@jp.fujitsu.com: revert migration change of unevictable lru infrastructure] [kosaki.motohiro@jp.fujitsu.com: revert to unevictable-lru-infrastructure-kconfig-fix.patch] [kosaki.motohiro@jp.fujitsu.com: restore patch failure of vmstat-unevictable-and-mlocked-pages-vm-events.patch] Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Debugged-by: Benjamin Kidwell <benjkidwell@yahoo.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 11:26:39 +08:00
/*
* in mm/vmscan.c:
*/
vmscan: move isolate_lru_page() to vmscan.c On large memory systems, the VM can spend way too much time scanning through pages that it cannot (or should not) evict from memory. Not only does it use up CPU time, but it also provokes lock contention and can leave large systems under memory presure in a catatonic state. This patch series improves VM scalability by: 1) putting filesystem backed, swap backed and unevictable pages onto their own LRUs, so the system only scans the pages that it can/should evict from memory 2) switching to two handed clock replacement for the anonymous LRUs, so the number of pages that need to be scanned when the system starts swapping is bound to a reasonable number 3) keeping unevictable pages off the LRU completely, so the VM does not waste CPU time scanning them. ramfs, ramdisk, SHM_LOCKED shared memory segments and mlock()ed VMA pages are keept on the unevictable list. This patch: isolate_lru_page logically belongs to be in vmscan.c than migrate.c. It is tough, because we don't need that function without memory migration so there is a valid argument to have it in migrate.c. However a subsequent patch needs to make use of it in the core mm, so we can happily move it to vmscan.c. Also, make the function a little more generic by not requiring that it adds an isolated page to a given list. Callers can do that. Note that we now have '__isolate_lru_page()', that does something quite different, visible outside of vmscan.c for use with memory controller. Methinks we need to rationalize these names/purposes. --lts [akpm@linux-foundation.org: fix mm/memory_hotplug.c build] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 11:26:09 +08:00
extern int isolate_lru_page(struct page *page);
Unevictable LRU Infrastructure When the system contains lots of mlocked or otherwise unevictable pages, the pageout code (kswapd) can spend lots of time scanning over these pages. Worse still, the presence of lots of unevictable pages can confuse kswapd into thinking that more aggressive pageout modes are required, resulting in all kinds of bad behaviour. Infrastructure to manage pages excluded from reclaim--i.e., hidden from vmscan. Based on a patch by Larry Woodman of Red Hat. Reworked to maintain "unevictable" pages on a separate per-zone LRU list, to "hide" them from vmscan. Kosaki Motohiro added the support for the memory controller unevictable lru list. Pages on the unevictable list have both PG_unevictable and PG_lru set. Thus, PG_unevictable is analogous to and mutually exclusive with PG_active--it specifies which LRU list the page is on. The unevictable infrastructure is enabled by a new mm Kconfig option [CONFIG_]UNEVICTABLE_LRU. A new function 'page_evictable(page, vma)' in vmscan.c tests whether or not a page may be evictable. Subsequent patches will add the various !evictable tests. We'll want to keep these tests light-weight for use in shrink_active_list() and, possibly, the fault path. To avoid races between tasks putting pages [back] onto an LRU list and tasks that might be moving the page from non-evictable to evictable state, the new function 'putback_lru_page()' -- inverse to 'isolate_lru_page()' -- tests the "evictability" of a page after placing it on the LRU, before dropping the reference. If the page has become unevictable, putback_lru_page() will redo the 'putback', thus moving the page to the unevictable list. This way, we avoid "stranding" evictable pages on the unevictable list. [akpm@linux-foundation.org: fix fallout from out-of-order merge] [riel@redhat.com: fix UNEVICTABLE_LRU and !PROC_PAGE_MONITOR build] [nishimura@mxp.nes.nec.co.jp: remove redundant mapping check] [kosaki.motohiro@jp.fujitsu.com: unevictable-lru-infrastructure: putback_lru_page()/unevictable page handling rework] [kosaki.motohiro@jp.fujitsu.com: kill unnecessary lock_page() in vmscan.c] [kosaki.motohiro@jp.fujitsu.com: revert migration change of unevictable lru infrastructure] [kosaki.motohiro@jp.fujitsu.com: revert to unevictable-lru-infrastructure-kconfig-fix.patch] [kosaki.motohiro@jp.fujitsu.com: restore patch failure of vmstat-unevictable-and-mlocked-pages-vm-events.patch] Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Debugged-by: Benjamin Kidwell <benjkidwell@yahoo.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 11:26:39 +08:00
extern void putback_lru_page(struct page *page);
vmscan: move isolate_lru_page() to vmscan.c On large memory systems, the VM can spend way too much time scanning through pages that it cannot (or should not) evict from memory. Not only does it use up CPU time, but it also provokes lock contention and can leave large systems under memory presure in a catatonic state. This patch series improves VM scalability by: 1) putting filesystem backed, swap backed and unevictable pages onto their own LRUs, so the system only scans the pages that it can/should evict from memory 2) switching to two handed clock replacement for the anonymous LRUs, so the number of pages that need to be scanned when the system starts swapping is bound to a reasonable number 3) keeping unevictable pages off the LRU completely, so the VM does not waste CPU time scanning them. ramfs, ramdisk, SHM_LOCKED shared memory segments and mlock()ed VMA pages are keept on the unevictable list. This patch: isolate_lru_page logically belongs to be in vmscan.c than migrate.c. It is tough, because we don't need that function without memory migration so there is a valid argument to have it in migrate.c. However a subsequent patch needs to make use of it in the core mm, so we can happily move it to vmscan.c. Also, make the function a little more generic by not requiring that it adds an isolated page to a given list. Callers can do that. Note that we now have '__isolate_lru_page()', that does something quite different, visible outside of vmscan.c for use with memory controller. Methinks we need to rationalize these names/purposes. --lts [akpm@linux-foundation.org: fix mm/memory_hotplug.c build] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 11:26:09 +08:00
/*
* in mm/rmap.c:
*/
extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address);
Unevictable LRU Infrastructure When the system contains lots of mlocked or otherwise unevictable pages, the pageout code (kswapd) can spend lots of time scanning over these pages. Worse still, the presence of lots of unevictable pages can confuse kswapd into thinking that more aggressive pageout modes are required, resulting in all kinds of bad behaviour. Infrastructure to manage pages excluded from reclaim--i.e., hidden from vmscan. Based on a patch by Larry Woodman of Red Hat. Reworked to maintain "unevictable" pages on a separate per-zone LRU list, to "hide" them from vmscan. Kosaki Motohiro added the support for the memory controller unevictable lru list. Pages on the unevictable list have both PG_unevictable and PG_lru set. Thus, PG_unevictable is analogous to and mutually exclusive with PG_active--it specifies which LRU list the page is on. The unevictable infrastructure is enabled by a new mm Kconfig option [CONFIG_]UNEVICTABLE_LRU. A new function 'page_evictable(page, vma)' in vmscan.c tests whether or not a page may be evictable. Subsequent patches will add the various !evictable tests. We'll want to keep these tests light-weight for use in shrink_active_list() and, possibly, the fault path. To avoid races between tasks putting pages [back] onto an LRU list and tasks that might be moving the page from non-evictable to evictable state, the new function 'putback_lru_page()' -- inverse to 'isolate_lru_page()' -- tests the "evictability" of a page after placing it on the LRU, before dropping the reference. If the page has become unevictable, putback_lru_page() will redo the 'putback', thus moving the page to the unevictable list. This way, we avoid "stranding" evictable pages on the unevictable list. [akpm@linux-foundation.org: fix fallout from out-of-order merge] [riel@redhat.com: fix UNEVICTABLE_LRU and !PROC_PAGE_MONITOR build] [nishimura@mxp.nes.nec.co.jp: remove redundant mapping check] [kosaki.motohiro@jp.fujitsu.com: unevictable-lru-infrastructure: putback_lru_page()/unevictable page handling rework] [kosaki.motohiro@jp.fujitsu.com: kill unnecessary lock_page() in vmscan.c] [kosaki.motohiro@jp.fujitsu.com: revert migration change of unevictable lru infrastructure] [kosaki.motohiro@jp.fujitsu.com: revert to unevictable-lru-infrastructure-kconfig-fix.patch] [kosaki.motohiro@jp.fujitsu.com: restore patch failure of vmstat-unevictable-and-mlocked-pages-vm-events.patch] Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Debugged-by: Benjamin Kidwell <benjkidwell@yahoo.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 11:26:39 +08:00
/*
* in mm/page_alloc.c
*/
mm/page_alloc: restrict max order of merging on isolated pageblock Current pageblock isolation logic could isolate each pageblock individually. This causes freepage accounting problem if freepage with pageblock order on isolate pageblock is merged with other freepage on normal pageblock. We can prevent merging by restricting max order of merging to pageblock order if freepage is on isolate pageblock. A side-effect of this change is that there could be non-merged buddy freepage even if finishing pageblock isolation, because undoing pageblock isolation is just to move freepage from isolate buddy list to normal buddy list rather than to consider merging. So, the patch also makes undoing pageblock isolation consider freepage merge. When un-isolation, freepage with more than pageblock order and it's buddy are checked. If they are on normal pageblock, instead of just moving, we isolate the freepage and free it in order to get merged. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Heesub Shin <heesub.shin@samsung.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Ritesh Harjani <ritesh.list@gmail.com> Cc: Gioh Kim <gioh.kim@lge.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-11-14 07:19:21 +08:00
/*
* Structure for holding the mostly immutable allocation parameters passed
* between functions involved in allocations, including the alloc_pages*
* family of functions.
*
* nodemask, migratetype and high_zoneidx are initialized only once in
* __alloc_pages_nodemask() and then never change.
*
* zonelist, preferred_zone and classzone_idx are set first in
* __alloc_pages_nodemask() for the fast path, and might be later changed
* in __alloc_pages_slowpath(). All other functions pass the whole strucure
* by a const pointer.
*/
struct alloc_context {
struct zonelist *zonelist;
nodemask_t *nodemask;
struct zoneref *preferred_zoneref;
int migratetype;
enum zone_type high_zoneidx;
bool spread_dirty_pages;
};
#define ac_classzone_idx(ac) zonelist_zone_idx(ac->preferred_zoneref)
mm/page_alloc: restrict max order of merging on isolated pageblock Current pageblock isolation logic could isolate each pageblock individually. This causes freepage accounting problem if freepage with pageblock order on isolate pageblock is merged with other freepage on normal pageblock. We can prevent merging by restricting max order of merging to pageblock order if freepage is on isolate pageblock. A side-effect of this change is that there could be non-merged buddy freepage even if finishing pageblock isolation, because undoing pageblock isolation is just to move freepage from isolate buddy list to normal buddy list rather than to consider merging. So, the patch also makes undoing pageblock isolation consider freepage merge. When un-isolation, freepage with more than pageblock order and it's buddy are checked. If they are on normal pageblock, instead of just moving, we isolate the freepage and free it in order to get merged. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Heesub Shin <heesub.shin@samsung.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Ritesh Harjani <ritesh.list@gmail.com> Cc: Gioh Kim <gioh.kim@lge.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-11-14 07:19:21 +08:00
/*
* Locate the struct page for both the matching buddy in our
* pair (buddy1) and the combined O(n+1) page they form (page).
*
* 1) Any buddy B1 will have an order O twin B2 which satisfies
* the following equation:
* B2 = B1 ^ (1 << O)
* For example, if the starting buddy (buddy2) is #8 its order
* 1 buddy is #10:
* B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
*
* 2) Any buddy B will have an order O+1 parent P which
* satisfies the following equation:
* P = B & ~(1 << O)
*
* Assumption: *_mem_map is contiguous at least up to MAX_ORDER
*/
static inline unsigned long
__find_buddy_pfn(unsigned long page_pfn, unsigned int order)
mm/page_alloc: restrict max order of merging on isolated pageblock Current pageblock isolation logic could isolate each pageblock individually. This causes freepage accounting problem if freepage with pageblock order on isolate pageblock is merged with other freepage on normal pageblock. We can prevent merging by restricting max order of merging to pageblock order if freepage is on isolate pageblock. A side-effect of this change is that there could be non-merged buddy freepage even if finishing pageblock isolation, because undoing pageblock isolation is just to move freepage from isolate buddy list to normal buddy list rather than to consider merging. So, the patch also makes undoing pageblock isolation consider freepage merge. When un-isolation, freepage with more than pageblock order and it's buddy are checked. If they are on normal pageblock, instead of just moving, we isolate the freepage and free it in order to get merged. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Heesub Shin <heesub.shin@samsung.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Ritesh Harjani <ritesh.list@gmail.com> Cc: Gioh Kim <gioh.kim@lge.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-11-14 07:19:21 +08:00
{
return page_pfn ^ (1 << order);
mm/page_alloc: restrict max order of merging on isolated pageblock Current pageblock isolation logic could isolate each pageblock individually. This causes freepage accounting problem if freepage with pageblock order on isolate pageblock is merged with other freepage on normal pageblock. We can prevent merging by restricting max order of merging to pageblock order if freepage is on isolate pageblock. A side-effect of this change is that there could be non-merged buddy freepage even if finishing pageblock isolation, because undoing pageblock isolation is just to move freepage from isolate buddy list to normal buddy list rather than to consider merging. So, the patch also makes undoing pageblock isolation consider freepage merge. When un-isolation, freepage with more than pageblock order and it's buddy are checked. If they are on normal pageblock, instead of just moving, we isolate the freepage and free it in order to get merged. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Heesub Shin <heesub.shin@samsung.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Ritesh Harjani <ritesh.list@gmail.com> Cc: Gioh Kim <gioh.kim@lge.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-11-14 07:19:21 +08:00
}
mm/compaction: speed up pageblock_pfn_to_page() when zone is contiguous There is a performance drop report due to hugepage allocation and in there half of cpu time are spent on pageblock_pfn_to_page() in compaction [1]. In that workload, compaction is triggered to make hugepage but most of pageblocks are un-available for compaction due to pageblock type and skip bit so compaction usually fails. Most costly operations in this case is to find valid pageblock while scanning whole zone range. To check if pageblock is valid to compact, valid pfn within pageblock is required and we can obtain it by calling pageblock_pfn_to_page(). This function checks whether pageblock is in a single zone and return valid pfn if possible. Problem is that we need to check it every time before scanning pageblock even if we re-visit it and this turns out to be very expensive in this workload. Although we have no way to skip this pageblock check in the system where hole exists at arbitrary position, we can use cached value for zone continuity and just do pfn_to_page() in the system where hole doesn't exist. This optimization considerably speeds up in above workload. Before vs After Max: 1096 MB/s vs 1325 MB/s Min: 635 MB/s 1015 MB/s Avg: 899 MB/s 1194 MB/s Avg is improved by roughly 30% [2]. [1]: http://www.spinics.net/lists/linux-mm/msg97378.html [2]: https://lkml.org/lkml/2015/12/9/23 [akpm@linux-foundation.org: don't forget to restore zone->contiguous on error path, per Vlastimil] Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Reported-by: Aaron Lu <aaron.lu@intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Aaron Lu <aaron.lu@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-16 05:57:51 +08:00
extern struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
unsigned long end_pfn, struct zone *zone);
static inline struct page *pageblock_pfn_to_page(unsigned long start_pfn,
unsigned long end_pfn, struct zone *zone)
{
if (zone->contiguous)
return pfn_to_page(start_pfn);
return __pageblock_pfn_to_page(start_pfn, end_pfn, zone);
}
mm/page_alloc: restrict max order of merging on isolated pageblock Current pageblock isolation logic could isolate each pageblock individually. This causes freepage accounting problem if freepage with pageblock order on isolate pageblock is merged with other freepage on normal pageblock. We can prevent merging by restricting max order of merging to pageblock order if freepage is on isolate pageblock. A side-effect of this change is that there could be non-merged buddy freepage even if finishing pageblock isolation, because undoing pageblock isolation is just to move freepage from isolate buddy list to normal buddy list rather than to consider merging. So, the patch also makes undoing pageblock isolation consider freepage merge. When un-isolation, freepage with more than pageblock order and it's buddy are checked. If they are on normal pageblock, instead of just moving, we isolate the freepage and free it in order to get merged. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Heesub Shin <heesub.shin@samsung.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Ritesh Harjani <ritesh.list@gmail.com> Cc: Gioh Kim <gioh.kim@lge.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-11-14 07:19:21 +08:00
extern int __isolate_free_page(struct page *page, unsigned int order);
extern void __free_pages_bootmem(struct page *page, unsigned long pfn,
unsigned int order);
extern void prep_compound_page(struct page *page, unsigned int order);
mm/page_alloc: introduce post allocation processing on page allocator This patch is motivated from Hugh and Vlastimil's concern [1]. There are two ways to get freepage from the allocator. One is using normal memory allocation API and the other is __isolate_free_page() which is internally used for compaction and pageblock isolation. Later usage is rather tricky since it doesn't do whole post allocation processing done by normal API. One problematic thing I already know is that poisoned page would not be checked if it is allocated by __isolate_free_page(). Perhaps, there would be more. We could add more debug logic for allocated page in the future and this separation would cause more problem. I'd like to fix this situation at this time. Solution is simple. This patch commonize some logic for newly allocated page and uses it on all sites. This will solve the problem. [1] http://marc.info/?i=alpine.LSU.2.11.1604270029350.7066%40eggly.anvils%3E [iamjoonsoo.kim@lge.com: mm-page_alloc-introduce-post-allocation-processing-on-page-allocator-v3] Link: http://lkml.kernel.org/r/1464230275-25791-7-git-send-email-iamjoonsoo.kim@lge.com Link: http://lkml.kernel.org/r/1466150259-27727-9-git-send-email-iamjoonsoo.kim@lge.com Link: http://lkml.kernel.org/r/1464230275-25791-7-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Minchan Kim <minchan@kernel.org> Cc: Alexander Potapenko <glider@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-27 06:23:58 +08:00
extern void post_alloc_hook(struct page *page, unsigned int order,
gfp_t gfp_flags);
extern int user_min_free_kbytes;
mm: introduce PageHuge() for testing huge/gigantic pages A series of patches to enhance the /proc/pagemap interface and to add a userspace executable which can be used to present the pagemap data. Export 10 more flags to end users (and more for kernel developers): 11. KPF_MMAP (pseudo flag) memory mapped page 12. KPF_ANON (pseudo flag) memory mapped page (anonymous) 13. KPF_SWAPCACHE page is in swap cache 14. KPF_SWAPBACKED page is swap/RAM backed 15. KPF_COMPOUND_HEAD (*) 16. KPF_COMPOUND_TAIL (*) 17. KPF_HUGE hugeTLB pages 18. KPF_UNEVICTABLE page is in the unevictable LRU list 19. KPF_HWPOISON hardware detected corruption 20. KPF_NOPAGE (pseudo flag) no page frame at the address (*) For compound pages, exporting _both_ head/tail info enables users to tell where a compound page starts/ends, and its order. a simple demo of the page-types tool # ./page-types -h page-types [options] -r|--raw Raw mode, for kernel developers -a|--addr addr-spec Walk a range of pages -b|--bits bits-spec Walk pages with specified bits -l|--list Show page details in ranges -L|--list-each Show page details one by one -N|--no-summary Don't show summay info -h|--help Show this usage message addr-spec: N one page at offset N (unit: pages) N+M pages range from N to N+M-1 N,M pages range from N to M-1 N, pages range from N to end ,M pages range from 0 to M bits-spec: bit1,bit2 (flags & (bit1|bit2)) != 0 bit1,bit2=bit1 (flags & (bit1|bit2)) == bit1 bit1,~bit2 (flags & (bit1|bit2)) == bit1 =bit1,bit2 flags == (bit1|bit2) bit-names: locked error referenced uptodate dirty lru active slab writeback reclaim buddy mmap anonymous swapcache swapbacked compound_head compound_tail huge unevictable hwpoison nopage reserved(r) mlocked(r) mappedtodisk(r) private(r) private_2(r) owner_private(r) arch(r) uncached(r) readahead(o) slob_free(o) slub_frozen(o) slub_debug(o) (r) raw mode bits (o) overloaded bits # ./page-types flags page-count MB symbolic-flags long-symbolic-flags 0x0000000000000000 487369 1903 _________________________________ 0x0000000000000014 5 0 __R_D____________________________ referenced,dirty 0x0000000000000020 1 0 _____l___________________________ lru 0x0000000000000024 34 0 __R__l___________________________ referenced,lru 0x0000000000000028 3838 14 ___U_l___________________________ uptodate,lru 0x0001000000000028 48 0 ___U_l_______________________I___ uptodate,lru,readahead 0x000000000000002c 6478 25 __RU_l___________________________ referenced,uptodate,lru 0x000100000000002c 47 0 __RU_l_______________________I___ referenced,uptodate,lru,readahead 0x0000000000000040 8344 32 ______A__________________________ active 0x0000000000000060 1 0 _____lA__________________________ lru,active 0x0000000000000068 348 1 ___U_lA__________________________ uptodate,lru,active 0x0001000000000068 12 0 ___U_lA______________________I___ uptodate,lru,active,readahead 0x000000000000006c 988 3 __RU_lA__________________________ referenced,uptodate,lru,active 0x000100000000006c 48 0 __RU_lA______________________I___ referenced,uptodate,lru,active,readahead 0x0000000000004078 1 0 ___UDlA_______b__________________ uptodate,dirty,lru,active,swapbacked 0x000000000000407c 34 0 __RUDlA_______b__________________ referenced,uptodate,dirty,lru,active,swapbacked 0x0000000000000400 503 1 __________B______________________ buddy 0x0000000000000804 1 0 __R________M_____________________ referenced,mmap 0x0000000000000828 1029 4 ___U_l_____M_____________________ uptodate,lru,mmap 0x0001000000000828 43 0 ___U_l_____M_________________I___ uptodate,lru,mmap,readahead 0x000000000000082c 382 1 __RU_l_____M_____________________ referenced,uptodate,lru,mmap 0x000100000000082c 12 0 __RU_l_____M_________________I___ referenced,uptodate,lru,mmap,readahead 0x0000000000000868 192 0 ___U_lA____M_____________________ uptodate,lru,active,mmap 0x0001000000000868 12 0 ___U_lA____M_________________I___ uptodate,lru,active,mmap,readahead 0x000000000000086c 800 3 __RU_lA____M_____________________ referenced,uptodate,lru,active,mmap 0x000100000000086c 31 0 __RU_lA____M_________________I___ referenced,uptodate,lru,active,mmap,readahead 0x0000000000004878 2 0 ___UDlA____M__b__________________ uptodate,dirty,lru,active,mmap,swapbacked 0x0000000000001000 492 1 ____________a____________________ anonymous 0x0000000000005808 4 0 ___U_______Ma_b__________________ uptodate,mmap,anonymous,swapbacked 0x0000000000005868 2839 11 ___U_lA____Ma_b__________________ uptodate,lru,active,mmap,anonymous,swapbacked 0x000000000000586c 30 0 __RU_lA____Ma_b__________________ referenced,uptodate,lru,active,mmap,anonymous,swapbacked total 513968 2007 # ./page-types -r flags page-count MB symbolic-flags long-symbolic-flags 0x0000000000000000 468002 1828 _________________________________ 0x0000000100000000 19102 74 _____________________r___________ reserved 0x0000000000008000 41 0 _______________H_________________ compound_head 0x0000000000010000 188 0 ________________T________________ compound_tail 0x0000000000008014 1 0 __R_D__________H_________________ referenced,dirty,compound_head 0x0000000000010014 4 0 __R_D___________T________________ referenced,dirty,compound_tail 0x0000000000000020 1 0 _____l___________________________ lru 0x0000000800000024 34 0 __R__l__________________P________ referenced,lru,private 0x0000000000000028 3794 14 ___U_l___________________________ uptodate,lru 0x0001000000000028 46 0 ___U_l_______________________I___ uptodate,lru,readahead 0x0000000400000028 44 0 ___U_l_________________d_________ uptodate,lru,mappedtodisk 0x0001000400000028 2 0 ___U_l_________________d_____I___ uptodate,lru,mappedtodisk,readahead 0x000000000000002c 6434 25 __RU_l___________________________ referenced,uptodate,lru 0x000100000000002c 47 0 __RU_l_______________________I___ referenced,uptodate,lru,readahead 0x000000040000002c 14 0 __RU_l_________________d_________ referenced,uptodate,lru,mappedtodisk 0x000000080000002c 30 0 __RU_l__________________P________ referenced,uptodate,lru,private 0x0000000800000040 8124 31 ______A_________________P________ active,private 0x0000000000000040 219 0 ______A__________________________ active 0x0000000800000060 1 0 _____lA_________________P________ lru,active,private 0x0000000000000068 322 1 ___U_lA__________________________ uptodate,lru,active 0x0001000000000068 12 0 ___U_lA______________________I___ uptodate,lru,active,readahead 0x0000000400000068 13 0 ___U_lA________________d_________ uptodate,lru,active,mappedtodisk 0x0000000800000068 12 0 ___U_lA_________________P________ uptodate,lru,active,private 0x000000000000006c 977 3 __RU_lA__________________________ referenced,uptodate,lru,active 0x000100000000006c 48 0 __RU_lA______________________I___ referenced,uptodate,lru,active,readahead 0x000000040000006c 5 0 __RU_lA________________d_________ referenced,uptodate,lru,active,mappedtodisk 0x000000080000006c 3 0 __RU_lA_________________P________ referenced,uptodate,lru,active,private 0x0000000c0000006c 3 0 __RU_lA________________dP________ referenced,uptodate,lru,active,mappedtodisk,private 0x0000000c00000068 1 0 ___U_lA________________dP________ uptodate,lru,active,mappedtodisk,private 0x0000000000004078 1 0 ___UDlA_______b__________________ uptodate,dirty,lru,active,swapbacked 0x000000000000407c 34 0 __RUDlA_______b__________________ referenced,uptodate,dirty,lru,active,swapbacked 0x0000000000000400 538 2 __________B______________________ buddy 0x0000000000000804 1 0 __R________M_____________________ referenced,mmap 0x0000000000000828 1029 4 ___U_l_____M_____________________ uptodate,lru,mmap 0x0001000000000828 43 0 ___U_l_____M_________________I___ uptodate,lru,mmap,readahead 0x000000000000082c 382 1 __RU_l_____M_____________________ referenced,uptodate,lru,mmap 0x000100000000082c 12 0 __RU_l_____M_________________I___ referenced,uptodate,lru,mmap,readahead 0x0000000000000868 192 0 ___U_lA____M_____________________ uptodate,lru,active,mmap 0x0001000000000868 12 0 ___U_lA____M_________________I___ uptodate,lru,active,mmap,readahead 0x000000000000086c 800 3 __RU_lA____M_____________________ referenced,uptodate,lru,active,mmap 0x000100000000086c 31 0 __RU_lA____M_________________I___ referenced,uptodate,lru,active,mmap,readahead 0x0000000000004878 2 0 ___UDlA____M__b__________________ uptodate,dirty,lru,active,mmap,swapbacked 0x0000000000001000 492 1 ____________a____________________ anonymous 0x0000000000005008 2 0 ___U________a_b__________________ uptodate,anonymous,swapbacked 0x0000000000005808 4 0 ___U_______Ma_b__________________ uptodate,mmap,anonymous,swapbacked 0x000000000000580c 1 0 __RU_______Ma_b__________________ referenced,uptodate,mmap,anonymous,swapbacked 0x0000000000005868 2839 11 ___U_lA____Ma_b__________________ uptodate,lru,active,mmap,anonymous,swapbacked 0x000000000000586c 29 0 __RU_lA____Ma_b__________________ referenced,uptodate,lru,active,mmap,anonymous,swapbacked total 513968 2007 # ./page-types --raw --list --no-summary --bits reserved offset count flags 0 15 _____________________r___________ 31 4 _____________________r___________ 159 97 _____________________r___________ 4096 2067 _____________________r___________ 6752 2390 _____________________r___________ 9355 3 _____________________r___________ 9728 14526 _____________________r___________ This patch: Introduce PageHuge(), which identifies huge/gigantic pages by their dedicated compound destructor functions. Also move prep_compound_gigantic_page() to hugetlb.c and make __free_pages_ok() non-static. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-17 06:32:22 +08:00
#if defined CONFIG_COMPACTION || defined CONFIG_CMA
/*
* in mm/compaction.c
*/
/*
* compact_control is used to track pages being migrated and the free pages
* they are being migrated to during memory compaction. The free_pfn starts
* at the end of a zone and migrate_pfn begins at the start. Movable pages
* are moved to the end of a zone during a compaction run and the run
* completes when free_pfn <= migrate_pfn
*/
struct compact_control {
struct list_head freepages; /* List of free pages to migrate to */
struct list_head migratepages; /* List of pages being migrated */
mm, compaction: reorder fields in struct compact_control Patch series "try to reduce fragmenting fallbacks", v3. Last year, Johannes Weiner has reported a regression in page mobility grouping [1] and while the exact cause was not found, I've come up with some ways to improve it by reducing the number of allocations falling back to different migratetype and causing permanent fragmentation. The series was tested with mmtests stress-highalloc modified to do GFP_KERNEL order-4 allocations, on 4.9 with "mm, vmscan: fix zone balance check in prepare_kswapd_sleep" (without that, kcompactd indeed wasn't woken up) on UMA machine with 4GB memory. There were 5 repeats of each run, as the extfrag stats are quite volatile (note the stats below are sums, not averages, as it was less perl hacking for me). Success rate are the same, already high due to the low allocation order used, so I'm not including them. Compaction stats: (the patches are stacked, and I haven't measured the non-functional-changes patches separately) patch 1 patch 2 patch 3 patch 4 patch 7 patch 8 Compaction stalls 22449 24680 24846 19765 22059 17480 Compaction success 12971 14836 14608 10475 11632 8757 Compaction failures 9477 9843 10238 9290 10426 8722 Page migrate success 3109022 3370438 3312164 1695105 1608435 2111379 Page migrate failure 911588 1149065 1028264 1112675 1077251 1026367 Compaction pages isolated 7242983 8015530 7782467 4629063 4402787 5377665 Compaction migrate scanned 980838938 987367943 957690188 917647238 947155598 1018922197 Compaction free scanned 557926893 598946443 602236894 594024490 541169699 763651731 Compaction cost 10243 10578 10304 8286 8398 9440 Compaction stats are mostly within noise until patch 4, which decreases the number of compactions, and migrations. Part of that could be due to more pageblocks marked as unmovable, and async compaction skipping those. This changes a bit with patch 7, but not so much. Patch 8 increases free scanner stats and migrations, which comes from the changed termination criteria. Interestingly number of compactions decreases - probably the fully compacted pageblock satisfies multiple subsequent allocations, so it amortizes. Next comes the extfrag tracepoint, where "fragmenting" means that an allocation had to fallback to a pageblock of another migratetype which wasn't fully free (which is almost all of the fallbacks). I have locally added another tracepoint for "Page steal" into steal_suitable_fallback() which triggers in situations where we are allowed to do move_freepages_block(). If we decide to also do set_pageblock_migratetype(), it's "Pages steal with pageblock" with break down for which allocation migratetype we are stealing and from which fallback migratetype. The last part "due to counting" comes from patch 4 and counts the events where the counting of movable pages allowed us to change pageblock's migratetype, while the number of free pages alone wouldn't be enough to cross the threshold. patch 1 patch 2 patch 3 patch 4 patch 7 patch 8 Page alloc extfrag event 10155066 8522968 10164959 15622080 13727068 13140319 Extfrag fragmenting 10149231 8517025 10159040 15616925 13721391 13134792 Extfrag fragmenting for unmovable 159504 168500 184177 97835 70625 56948 Extfrag fragmenting unmovable placed with movable 153613 163549 172693 91740 64099 50917 Extfrag fragmenting unmovable placed with reclaim. 5891 4951 11484 6095 6526 6031 Extfrag fragmenting for reclaimable 4738 4829 6345 4822 5640 5378 Extfrag fragmenting reclaimable placed with movable 1836 1902 1851 1579 1739 1760 Extfrag fragmenting reclaimable placed with unmov. 2902 2927 4494 3243 3901 3618 Extfrag fragmenting for movable 9984989 8343696 9968518 15514268 13645126 13072466 Pages steal 179954 192291 210880 123254 94545 81486 Pages steal with pageblock 22153 18943 20154 33562 29969 33444 Pages steal with pageblock for unmovable 14350 12858 13256 20660 19003 20852 Pages steal with pageblock for unmovable from mov. 12812 11402 11683 19072 17467 19298 Pages steal with pageblock for unmovable from recl. 1538 1456 1573 1588 1536 1554 Pages steal with pageblock for movable 7114 5489 5965 11787 10012 11493 Pages steal with pageblock for movable from unmov. 6885 5291 5541 11179 9525 10885 Pages steal with pageblock for movable from recl. 229 198 424 608 487 608 Pages steal with pageblock for reclaimable 689 596 933 1115 954 1099 Pages steal with pageblock for reclaimable from unmov. 273 219 537 658 547 667 Pages steal with pageblock for reclaimable from mov. 416 377 396 457 407 432 Pages steal with pageblock due to counting 11834 10075 7530 ... for unmovable 8993 7381 4616 ... for movable 2792 2653 2851 ... for reclaimable 49 41 63 What we can see is that "Extfrag fragmenting for unmovable" and "... placed with movable" drops with almost each patch, which is good as we are polluting less movable pageblocks with unmovable pages. The most significant change is patch 4 with movable page counting. On the other hand it increases "Extfrag fragmenting for movable" by 50%. "Pages steal" drops though, so these movable allocation fallbacks find only small free pages and are not allowed to steal whole pageblocks back. "Pages steal with pageblock" raises, because the patch increases the chances of pageblock migratetype changes to happen. This affects all migratetypes. The summary is that patch 4 is not a clear win wrt these stats, but I believe that the tradeoff it makes is a good one. There's less pollution of movable pageblocks by unmovable allocations. There's less stealing between pageblock, and those that remain have higher chance of changing migratetype also the pageblock itself, so it should more faithfully reflect the migratetype of the pages within the pageblock. The increase of movable allocations falling back to unmovable pageblock might look dramatic, but those allocations can be migrated by compaction when needed, and other patches in the series (7-9) improve that aspect. Patches 7 and 8 continue the trend of reduced unmovable fallbacks and also reduce the impact on movable fallbacks from patch 4. [1] https://www.spinics.net/lists/linux-mm/msg114237.html This patch (of 8): While currently there are (mostly by accident) no holes in struct compact_control (on x86_64), but we are going to add more bool flags, so place them all together to the end of the structure. While at it, just order all fields from largest to smallest. Link: http://lkml.kernel.org/r/20170307131545.28577-2-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-09 06:54:30 +08:00
struct zone *zone;
unsigned long nr_freepages; /* Number of isolated free pages */
unsigned long nr_migratepages; /* Number of pages to migrate */
unsigned long total_migrate_scanned;
unsigned long total_free_scanned;
unsigned long free_pfn; /* isolate_freepages search base */
unsigned long migrate_pfn; /* isolate_migratepages search base */
unsigned long last_migrated_pfn;/* Not yet flushed page being freed */
mm, compaction: reorder fields in struct compact_control Patch series "try to reduce fragmenting fallbacks", v3. Last year, Johannes Weiner has reported a regression in page mobility grouping [1] and while the exact cause was not found, I've come up with some ways to improve it by reducing the number of allocations falling back to different migratetype and causing permanent fragmentation. The series was tested with mmtests stress-highalloc modified to do GFP_KERNEL order-4 allocations, on 4.9 with "mm, vmscan: fix zone balance check in prepare_kswapd_sleep" (without that, kcompactd indeed wasn't woken up) on UMA machine with 4GB memory. There were 5 repeats of each run, as the extfrag stats are quite volatile (note the stats below are sums, not averages, as it was less perl hacking for me). Success rate are the same, already high due to the low allocation order used, so I'm not including them. Compaction stats: (the patches are stacked, and I haven't measured the non-functional-changes patches separately) patch 1 patch 2 patch 3 patch 4 patch 7 patch 8 Compaction stalls 22449 24680 24846 19765 22059 17480 Compaction success 12971 14836 14608 10475 11632 8757 Compaction failures 9477 9843 10238 9290 10426 8722 Page migrate success 3109022 3370438 3312164 1695105 1608435 2111379 Page migrate failure 911588 1149065 1028264 1112675 1077251 1026367 Compaction pages isolated 7242983 8015530 7782467 4629063 4402787 5377665 Compaction migrate scanned 980838938 987367943 957690188 917647238 947155598 1018922197 Compaction free scanned 557926893 598946443 602236894 594024490 541169699 763651731 Compaction cost 10243 10578 10304 8286 8398 9440 Compaction stats are mostly within noise until patch 4, which decreases the number of compactions, and migrations. Part of that could be due to more pageblocks marked as unmovable, and async compaction skipping those. This changes a bit with patch 7, but not so much. Patch 8 increases free scanner stats and migrations, which comes from the changed termination criteria. Interestingly number of compactions decreases - probably the fully compacted pageblock satisfies multiple subsequent allocations, so it amortizes. Next comes the extfrag tracepoint, where "fragmenting" means that an allocation had to fallback to a pageblock of another migratetype which wasn't fully free (which is almost all of the fallbacks). I have locally added another tracepoint for "Page steal" into steal_suitable_fallback() which triggers in situations where we are allowed to do move_freepages_block(). If we decide to also do set_pageblock_migratetype(), it's "Pages steal with pageblock" with break down for which allocation migratetype we are stealing and from which fallback migratetype. The last part "due to counting" comes from patch 4 and counts the events where the counting of movable pages allowed us to change pageblock's migratetype, while the number of free pages alone wouldn't be enough to cross the threshold. patch 1 patch 2 patch 3 patch 4 patch 7 patch 8 Page alloc extfrag event 10155066 8522968 10164959 15622080 13727068 13140319 Extfrag fragmenting 10149231 8517025 10159040 15616925 13721391 13134792 Extfrag fragmenting for unmovable 159504 168500 184177 97835 70625 56948 Extfrag fragmenting unmovable placed with movable 153613 163549 172693 91740 64099 50917 Extfrag fragmenting unmovable placed with reclaim. 5891 4951 11484 6095 6526 6031 Extfrag fragmenting for reclaimable 4738 4829 6345 4822 5640 5378 Extfrag fragmenting reclaimable placed with movable 1836 1902 1851 1579 1739 1760 Extfrag fragmenting reclaimable placed with unmov. 2902 2927 4494 3243 3901 3618 Extfrag fragmenting for movable 9984989 8343696 9968518 15514268 13645126 13072466 Pages steal 179954 192291 210880 123254 94545 81486 Pages steal with pageblock 22153 18943 20154 33562 29969 33444 Pages steal with pageblock for unmovable 14350 12858 13256 20660 19003 20852 Pages steal with pageblock for unmovable from mov. 12812 11402 11683 19072 17467 19298 Pages steal with pageblock for unmovable from recl. 1538 1456 1573 1588 1536 1554 Pages steal with pageblock for movable 7114 5489 5965 11787 10012 11493 Pages steal with pageblock for movable from unmov. 6885 5291 5541 11179 9525 10885 Pages steal with pageblock for movable from recl. 229 198 424 608 487 608 Pages steal with pageblock for reclaimable 689 596 933 1115 954 1099 Pages steal with pageblock for reclaimable from unmov. 273 219 537 658 547 667 Pages steal with pageblock for reclaimable from mov. 416 377 396 457 407 432 Pages steal with pageblock due to counting 11834 10075 7530 ... for unmovable 8993 7381 4616 ... for movable 2792 2653 2851 ... for reclaimable 49 41 63 What we can see is that "Extfrag fragmenting for unmovable" and "... placed with movable" drops with almost each patch, which is good as we are polluting less movable pageblocks with unmovable pages. The most significant change is patch 4 with movable page counting. On the other hand it increases "Extfrag fragmenting for movable" by 50%. "Pages steal" drops though, so these movable allocation fallbacks find only small free pages and are not allowed to steal whole pageblocks back. "Pages steal with pageblock" raises, because the patch increases the chances of pageblock migratetype changes to happen. This affects all migratetypes. The summary is that patch 4 is not a clear win wrt these stats, but I believe that the tradeoff it makes is a good one. There's less pollution of movable pageblocks by unmovable allocations. There's less stealing between pageblock, and those that remain have higher chance of changing migratetype also the pageblock itself, so it should more faithfully reflect the migratetype of the pages within the pageblock. The increase of movable allocations falling back to unmovable pageblock might look dramatic, but those allocations can be migrated by compaction when needed, and other patches in the series (7-9) improve that aspect. Patches 7 and 8 continue the trend of reduced unmovable fallbacks and also reduce the impact on movable fallbacks from patch 4. [1] https://www.spinics.net/lists/linux-mm/msg114237.html This patch (of 8): While currently there are (mostly by accident) no holes in struct compact_control (on x86_64), but we are going to add more bool flags, so place them all together to the end of the structure. While at it, just order all fields from largest to smallest. Link: http://lkml.kernel.org/r/20170307131545.28577-2-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-09 06:54:30 +08:00
const gfp_t gfp_mask; /* gfp mask of a direct compactor */
int order; /* order a direct compactor needs */
int migratetype; /* migratetype of direct compactor */
mm, compaction: reorder fields in struct compact_control Patch series "try to reduce fragmenting fallbacks", v3. Last year, Johannes Weiner has reported a regression in page mobility grouping [1] and while the exact cause was not found, I've come up with some ways to improve it by reducing the number of allocations falling back to different migratetype and causing permanent fragmentation. The series was tested with mmtests stress-highalloc modified to do GFP_KERNEL order-4 allocations, on 4.9 with "mm, vmscan: fix zone balance check in prepare_kswapd_sleep" (without that, kcompactd indeed wasn't woken up) on UMA machine with 4GB memory. There were 5 repeats of each run, as the extfrag stats are quite volatile (note the stats below are sums, not averages, as it was less perl hacking for me). Success rate are the same, already high due to the low allocation order used, so I'm not including them. Compaction stats: (the patches are stacked, and I haven't measured the non-functional-changes patches separately) patch 1 patch 2 patch 3 patch 4 patch 7 patch 8 Compaction stalls 22449 24680 24846 19765 22059 17480 Compaction success 12971 14836 14608 10475 11632 8757 Compaction failures 9477 9843 10238 9290 10426 8722 Page migrate success 3109022 3370438 3312164 1695105 1608435 2111379 Page migrate failure 911588 1149065 1028264 1112675 1077251 1026367 Compaction pages isolated 7242983 8015530 7782467 4629063 4402787 5377665 Compaction migrate scanned 980838938 987367943 957690188 917647238 947155598 1018922197 Compaction free scanned 557926893 598946443 602236894 594024490 541169699 763651731 Compaction cost 10243 10578 10304 8286 8398 9440 Compaction stats are mostly within noise until patch 4, which decreases the number of compactions, and migrations. Part of that could be due to more pageblocks marked as unmovable, and async compaction skipping those. This changes a bit with patch 7, but not so much. Patch 8 increases free scanner stats and migrations, which comes from the changed termination criteria. Interestingly number of compactions decreases - probably the fully compacted pageblock satisfies multiple subsequent allocations, so it amortizes. Next comes the extfrag tracepoint, where "fragmenting" means that an allocation had to fallback to a pageblock of another migratetype which wasn't fully free (which is almost all of the fallbacks). I have locally added another tracepoint for "Page steal" into steal_suitable_fallback() which triggers in situations where we are allowed to do move_freepages_block(). If we decide to also do set_pageblock_migratetype(), it's "Pages steal with pageblock" with break down for which allocation migratetype we are stealing and from which fallback migratetype. The last part "due to counting" comes from patch 4 and counts the events where the counting of movable pages allowed us to change pageblock's migratetype, while the number of free pages alone wouldn't be enough to cross the threshold. patch 1 patch 2 patch 3 patch 4 patch 7 patch 8 Page alloc extfrag event 10155066 8522968 10164959 15622080 13727068 13140319 Extfrag fragmenting 10149231 8517025 10159040 15616925 13721391 13134792 Extfrag fragmenting for unmovable 159504 168500 184177 97835 70625 56948 Extfrag fragmenting unmovable placed with movable 153613 163549 172693 91740 64099 50917 Extfrag fragmenting unmovable placed with reclaim. 5891 4951 11484 6095 6526 6031 Extfrag fragmenting for reclaimable 4738 4829 6345 4822 5640 5378 Extfrag fragmenting reclaimable placed with movable 1836 1902 1851 1579 1739 1760 Extfrag fragmenting reclaimable placed with unmov. 2902 2927 4494 3243 3901 3618 Extfrag fragmenting for movable 9984989 8343696 9968518 15514268 13645126 13072466 Pages steal 179954 192291 210880 123254 94545 81486 Pages steal with pageblock 22153 18943 20154 33562 29969 33444 Pages steal with pageblock for unmovable 14350 12858 13256 20660 19003 20852 Pages steal with pageblock for unmovable from mov. 12812 11402 11683 19072 17467 19298 Pages steal with pageblock for unmovable from recl. 1538 1456 1573 1588 1536 1554 Pages steal with pageblock for movable 7114 5489 5965 11787 10012 11493 Pages steal with pageblock for movable from unmov. 6885 5291 5541 11179 9525 10885 Pages steal with pageblock for movable from recl. 229 198 424 608 487 608 Pages steal with pageblock for reclaimable 689 596 933 1115 954 1099 Pages steal with pageblock for reclaimable from unmov. 273 219 537 658 547 667 Pages steal with pageblock for reclaimable from mov. 416 377 396 457 407 432 Pages steal with pageblock due to counting 11834 10075 7530 ... for unmovable 8993 7381 4616 ... for movable 2792 2653 2851 ... for reclaimable 49 41 63 What we can see is that "Extfrag fragmenting for unmovable" and "... placed with movable" drops with almost each patch, which is good as we are polluting less movable pageblocks with unmovable pages. The most significant change is patch 4 with movable page counting. On the other hand it increases "Extfrag fragmenting for movable" by 50%. "Pages steal" drops though, so these movable allocation fallbacks find only small free pages and are not allowed to steal whole pageblocks back. "Pages steal with pageblock" raises, because the patch increases the chances of pageblock migratetype changes to happen. This affects all migratetypes. The summary is that patch 4 is not a clear win wrt these stats, but I believe that the tradeoff it makes is a good one. There's less pollution of movable pageblocks by unmovable allocations. There's less stealing between pageblock, and those that remain have higher chance of changing migratetype also the pageblock itself, so it should more faithfully reflect the migratetype of the pages within the pageblock. The increase of movable allocations falling back to unmovable pageblock might look dramatic, but those allocations can be migrated by compaction when needed, and other patches in the series (7-9) improve that aspect. Patches 7 and 8 continue the trend of reduced unmovable fallbacks and also reduce the impact on movable fallbacks from patch 4. [1] https://www.spinics.net/lists/linux-mm/msg114237.html This patch (of 8): While currently there are (mostly by accident) no holes in struct compact_control (on x86_64), but we are going to add more bool flags, so place them all together to the end of the structure. While at it, just order all fields from largest to smallest. Link: http://lkml.kernel.org/r/20170307131545.28577-2-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-09 06:54:30 +08:00
const unsigned int alloc_flags; /* alloc flags of a direct compactor */
const int classzone_idx; /* zone index of a direct compactor */
enum migrate_mode mode; /* Async or sync migration mode */
mm: compaction: cache if a pageblock was scanned and no pages were isolated When compaction was implemented it was known that scanning could potentially be excessive. The ideal was that a counter be maintained for each pageblock but maintaining this information would incur a severe penalty due to a shared writable cache line. It has reached the point where the scanning costs are a serious problem, particularly on long-lived systems where a large process starts and allocates a large number of THPs at the same time. Instead of using a shared counter, this patch adds another bit to the pageblock flags called PG_migrate_skip. If a pageblock is scanned by either migrate or free scanner and 0 pages were isolated, the pageblock is marked to be skipped in the future. When scanning, this bit is checked before any scanning takes place and the block skipped if set. The main difficulty with a patch like this is "when to ignore the cached information?" If it's ignored too often, the scanning rates will still be excessive. If the information is too stale then allocations will fail that might have otherwise succeeded. In this patch o CMA always ignores the information o If the migrate and free scanner meet then the cached information will be discarded if it's at least 5 seconds since the last time the cache was discarded o If there are a large number of allocation failures, discard the cache. The time-based heuristic is very clumsy but there are few choices for a better event. Depending solely on multiple allocation failures still allows excessive scanning when THP allocations are failing in quick succession due to memory pressure. Waiting until memory pressure is relieved would cause compaction to continually fail instead of using reclaim/compaction to try allocate the page. The time-based mechanism is clumsy but a better option is not obvious. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Cc: Richard Davies <richard@arachsys.com> Cc: Shaohua Li <shli@kernel.org> Cc: Avi Kivity <avi@redhat.com> Acked-by: Rafael Aquini <aquini@redhat.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 07:32:41 +08:00
bool ignore_skip_hint; /* Scan blocks even if marked skip */
bool no_set_skip_hint; /* Don't mark blocks for skipping */
2016-10-08 08:00:37 +08:00
bool ignore_block_suitable; /* Scan blocks considered unsuitable */
mm, kswapd: replace kswapd compaction with waking up kcompactd Similarly to direct reclaim/compaction, kswapd attempts to combine reclaim and compaction to attempt making memory allocation of given order available. The details differ from direct reclaim e.g. in having high watermark as a goal. The code involved in kswapd's reclaim/compaction decisions has evolved to be quite complex. Testing reveals that it doesn't actually work in at least one scenario, and closer inspection suggests that it could be greatly simplified without compromising on the goal (make high-order page available) or efficiency (don't reclaim too much). The simplification relieas of doing all compaction in kcompactd, which is simply woken up when high watermarks are reached by kswapd's reclaim. The scenario where kswapd compaction doesn't work was found with mmtests test stress-highalloc configured to attempt order-9 allocations without direct reclaim, just waking up kswapd. There was no compaction attempt from kswapd during the whole test. Some added instrumentation shows what happens: - balance_pgdat() sets end_zone to Normal, as it's not balanced - reclaim is attempted on DMA zone, which sets nr_attempted to 99, but it cannot reclaim anything, so sc.nr_reclaimed is 0 - for zones DMA32 and Normal, kswapd_shrink_zone uses testorder=0, so it merely checks if high watermarks were reached for base pages. This is true, so no reclaim is attempted. For DMA, testorder=0 wasn't used, as compaction_suitable() returned COMPACT_SKIPPED - even though the pgdat_needs_compaction flag wasn't set to false, no compaction happens due to the condition sc.nr_reclaimed > nr_attempted being false (as 0 < 99) - priority-- due to nr_reclaimed being 0, repeat until priority reaches 0 pgdat_balanced() is false as only the small zone DMA appears balanced (curiously in that check, watermark appears OK and compaction_suitable() returns COMPACT_PARTIAL, because a lower classzone_idx is used there) Now, even if it was decided that reclaim shouldn't be attempted on the DMA zone, the scenario would be the same, as (sc.nr_reclaimed=0 > nr_attempted=0) is also false. The condition really should use >= as the comment suggests. Then there is a mismatch in the check for setting pgdat_needs_compaction to false using low watermark, while the rest uses high watermark, and who knows what other subtlety. Hopefully this demonstrates that this is unsustainable. Luckily we can simplify this a lot. The reclaim/compaction decisions make sense for direct reclaim scenario, but in kswapd, our primary goal is to reach high watermark in order-0 pages. Afterwards we can attempt compaction just once. Unlike direct reclaim, we don't reclaim extra pages (over the high watermark), the current code already disallows it for good reasons. After this patch, we simply wake up kcompactd to process the pgdat, after we have either succeeded or failed to reach the high watermarks in kswapd, which goes to sleep. We pass kswapd's order and classzone_idx, so kcompactd can apply the same criteria to determine which zones are worth compacting. Note that we use the classzone_idx from wakeup_kswapd(), not balanced_classzone_idx which can include higher zones that kswapd tried to balance too, but didn't consider them in pgdat_balanced(). Since kswapd now cannot create high-order pages itself, we need to adjust how it determines the zones to be balanced. The key element here is adding a "highorder" parameter to zone_balanced, which, when set to false, makes it consider only order-0 watermark instead of the desired higher order (this was done previously by kswapd_shrink_zone(), but not elsewhere). This false is passed for example in pgdat_balanced(). Importantly, wakeup_kswapd() uses true to make sure kswapd and thus kcompactd are woken up for a high-order allocation failure. The last thing is to decide what to do with pageblock_skip bitmap handling. Compaction maintains a pageblock_skip bitmap to record pageblocks where isolation recently failed. This bitmap can be reset by three ways: 1) direct compaction is restarting after going through the full deferred cycle 2) kswapd goes to sleep, and some other direct compaction has previously finished scanning the whole zone and set zone->compact_blockskip_flush. Note that a successful direct compaction clears this flag. 3) compaction was invoked manually via trigger in /proc The case 2) is somewhat fuzzy to begin with, but after introducing kcompactd we should update it. The check for direct compaction in 1), and to set the flush flag in 2) use current_is_kswapd(), which doesn't work for kcompactd. Thus, this patch adds bool direct_compaction to compact_control to use in 2). For the case 1) we remove the check completely - unlike the former kswapd compaction, kcompactd does use the deferred compaction functionality, so flushing tied to restarting from deferred compaction makes sense here. Note that when kswapd goes to sleep, kcompactd is woken up, so it will see the flushed pageblock_skip bits. This is different from when the former kswapd compaction observed the bits and I believe it makes more sense. Kcompactd can afford to be more thorough than a direct compaction trying to limit allocation latency, or kswapd whose primary goal is to reclaim. For testing, I used stress-highalloc configured to do order-9 allocations with GFP_NOWAIT|__GFP_HIGH|__GFP_COMP, so they relied just on kswapd/kcompactd reclaim/compaction (the interfering kernel builds in phases 1 and 2 work as usual): stress-highalloc 4.5-rc1+before 4.5-rc1+after -nodirect -nodirect Success 1 Min 1.00 ( 0.00%) 5.00 (-66.67%) Success 1 Mean 1.40 ( 0.00%) 6.20 (-55.00%) Success 1 Max 2.00 ( 0.00%) 7.00 (-16.67%) Success 2 Min 1.00 ( 0.00%) 5.00 (-66.67%) Success 2 Mean 1.80 ( 0.00%) 6.40 (-52.38%) Success 2 Max 3.00 ( 0.00%) 7.00 (-16.67%) Success 3 Min 34.00 ( 0.00%) 62.00 ( 1.59%) Success 3 Mean 41.80 ( 0.00%) 63.80 ( 1.24%) Success 3 Max 53.00 ( 0.00%) 65.00 ( 2.99%) User 3166.67 3181.09 System 1153.37 1158.25 Elapsed 1768.53 1799.37 4.5-rc1+before 4.5-rc1+after -nodirect -nodirect Direct pages scanned 32938 32797 Kswapd pages scanned 2183166 2202613 Kswapd pages reclaimed 2152359 2143524 Direct pages reclaimed 32735 32545 Percentage direct scans 1% 1% THP fault alloc 579 612 THP collapse alloc 304 316 THP splits 0 0 THP fault fallback 793 778 THP collapse fail 11 16 Compaction stalls 1013 1007 Compaction success 92 67 Compaction failures 920 939 Page migrate success 238457 721374 Page migrate failure 23021 23469 Compaction pages isolated 504695 1479924 Compaction migrate scanned 661390 8812554 Compaction free scanned 13476658 84327916 Compaction cost 262 838 After this patch we see improvements in allocation success rate (especially for phase 3) along with increased compaction activity. The compaction stalls (direct compaction) in the interfering kernel builds (probably THP's) also decreased somewhat thanks to kcompactd activity, yet THP alloc successes improved a bit. Note that elapsed and user time isn't so useful for this benchmark, because of the background interference being unpredictable. It's just to quickly spot some major unexpected differences. System time is somewhat more useful and that didn't increase. Also (after adjusting mmtests' ftrace monitor): Time kswapd awake 2547781 2269241 Time kcompactd awake 0 119253 Time direct compacting 939937 557649 Time kswapd compacting 0 0 Time kcompactd compacting 0 119099 The decrease of overal time spent compacting appears to not match the increased compaction stats. I suspect the tasks get rescheduled and since the ftrace monitor doesn't see that, the reported time is wall time, not CPU time. But arguably direct compactors care about overall latency anyway, whether busy compacting or waiting for CPU doesn't matter. And that latency seems to almost halved. It's also interesting how much time kswapd spent awake just going through all the priorities and failing to even try compacting, over and over. We can also configure stress-highalloc to perform both direct reclaim/compaction and wakeup kswapd/kcompactd, by using GFP_KERNEL|__GFP_HIGH|__GFP_COMP: stress-highalloc 4.5-rc1+before 4.5-rc1+after -direct -direct Success 1 Min 4.00 ( 0.00%) 9.00 (-50.00%) Success 1 Mean 8.00 ( 0.00%) 10.00 (-19.05%) Success 1 Max 12.00 ( 0.00%) 11.00 ( 15.38%) Success 2 Min 4.00 ( 0.00%) 9.00 (-50.00%) Success 2 Mean 8.20 ( 0.00%) 10.00 (-16.28%) Success 2 Max 13.00 ( 0.00%) 11.00 ( 8.33%) Success 3 Min 75.00 ( 0.00%) 74.00 ( 1.33%) Success 3 Mean 75.60 ( 0.00%) 75.20 ( 0.53%) Success 3 Max 77.00 ( 0.00%) 76.00 ( 0.00%) User 3344.73 3246.04 System 1194.24 1172.29 Elapsed 1838.04 1836.76 4.5-rc1+before 4.5-rc1+after -direct -direct Direct pages scanned 125146 120966 Kswapd pages scanned 2119757 2135012 Kswapd pages reclaimed 2073183 2108388 Direct pages reclaimed 124909 120577 Percentage direct scans 5% 5% THP fault alloc 599 652 THP collapse alloc 323 354 THP splits 0 0 THP fault fallback 806 793 THP collapse fail 17 16 Compaction stalls 2457 2025 Compaction success 906 518 Compaction failures 1551 1507 Page migrate success 2031423 2360608 Page migrate failure 32845 40852 Compaction pages isolated 4129761 4802025 Compaction migrate scanned 11996712 21750613 Compaction free scanned 214970969 344372001 Compaction cost 2271 2694 In this scenario, this patch doesn't change the overall success rate as direct compaction already tries all it can. There's however significant reduction in direct compaction stalls (that is, the number of allocations that went into direct compaction). The number of successes (i.e. direct compaction stalls that ended up with successful allocation) is reduced by the same number. This means the offload to kcompactd is working as expected, and direct compaction is reduced either due to detecting contention, or compaction deferred by kcompactd. In the previous version of this patchset there was some apparent reduction of success rate, but the changes in this version (such as using sync compaction only), new baseline kernel, and/or averaging results from 5 executions (my bet), made this go away. Ftrace-based stats seem to roughly agree: Time kswapd awake 2532984 2326824 Time kcompactd awake 0 257916 Time direct compacting 864839 735130 Time kswapd compacting 0 0 Time kcompactd compacting 0 257585 Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: David Rientjes <rientjes@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-18 05:18:15 +08:00
bool direct_compaction; /* False from kcompactd or /proc/... */
mm, compaction: make whole_zone flag ignore cached scanner positions Patch series "make direct compaction more deterministic") This is mostly a followup to Michal's oom detection rework, which highlighted the need for direct compaction to provide better feedback in reclaim/compaction loop, so that it can reliably recognize when compaction cannot make further progress, and allocation should invoke OOM killer or fail. We've discussed this at LSF/MM [1] where I proposed expanding the async/sync migration mode used in compaction to more general "priorities". This patchset adds one new priority that just overrides all the heuristics and makes compaction fully scan all zones. I don't currently think that we need more fine-grained priorities, but we'll see. Other than that there's some smaller fixes and cleanups, mainly related to the THP-specific hacks. I've tested this with stress-highalloc in GFP_KERNEL order-4 and THP-like order-9 scenarios. There's some improvement for compaction stats for the order-4, which is likely due to the better watermarks handling. In the previous version I reported mostly noise wrt compaction stats, and decreased direct reclaim - now the reclaim is without difference. I believe this is due to the less aggressive compaction priority increase in patch 6. "before" is a mmotm tree prior to 4.7 release plus the first part of the series that was sent and merged separately before after order-4: Compaction stalls 27216 30759 Compaction success 19598 25475 Compaction failures 7617 5283 Page migrate success 370510 464919 Page migrate failure 25712 27987 Compaction pages isolated 849601 1041581 Compaction migrate scanned 143146541 101084990 Compaction free scanned 208355124 144863510 Compaction cost 1403 1210 order-9: Compaction stalls 7311 7401 Compaction success 1634 1683 Compaction failures 5677 5718 Page migrate success 194657 183988 Page migrate failure 4753 4170 Compaction pages isolated 498790 456130 Compaction migrate scanned 565371 524174 Compaction free scanned 4230296 4250744 Compaction cost 215 203 [1] https://lwn.net/Articles/684611/ This patch (of 11): A recent patch has added whole_zone flag that compaction sets when scanning starts from the zone boundary, in order to report that zone has been fully scanned in one attempt. For allocations that want to try really hard or cannot fail, we will want to introduce a mode where scanning whole zone is guaranteed regardless of the cached positions. This patch reuses the whole_zone flag in a way that if it's already passed true to compaction, the cached scanner positions are ignored. Employing this flag during reclaim/compaction loop will be done in the next patch. This patch however converts compaction invoked from userspace via procfs to use this flag. Before this patch, the cached positions were first reset to zone boundaries and then read back from struct zone, so there was a window where a parallel compaction could replace the reset values, making the manual compaction less effective. Using the flag instead of performing reset is more robust. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20160810091226.6709-2-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Lorenzo Stoakes <lstoakes@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-08 07:57:35 +08:00
bool whole_zone; /* Whole zone should/has been scanned */
mm, compaction: simplify contended compaction handling Async compaction detects contention either due to failing trylock on zone->lock or lru_lock, or by need_resched(). Since 1f9efdef4f3f ("mm, compaction: khugepaged should not give up due to need_resched()") the code got quite complicated to distinguish these two up to the __alloc_pages_slowpath() level, so different decisions could be taken for khugepaged allocations. After the recent changes, khugepaged allocations don't check for contended compaction anymore, so we again don't need to distinguish lock and sched contention, and simplify the current convoluted code a lot. However, I believe it's also possible to simplify even more and completely remove the check for contended compaction after the initial async compaction for costly orders, which was originally aimed at THP page fault allocations. There are several reasons why this can be done now: - with the new defaults, THP page faults no longer do reclaim/compaction at all, unless the system admin has overridden the default, or application has indicated via madvise that it can benefit from THP's. In both cases, it means that the potential extra latency is expected and worth the benefits. - even if reclaim/compaction proceeds after this patch where it previously wouldn't, the second compaction attempt is still async and will detect the contention and back off, if the contention persists - there are still heuristics like deferred compaction and pageblock skip bits in place that prevent excessive THP page fault latencies Link: http://lkml.kernel.org/r/20160721073614.24395-9-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-29 06:49:30 +08:00
bool contended; /* Signal lock or sched contention */
mm, compaction: finish whole pageblock to reduce fragmentation The main goal of direct compaction is to form a high-order page for allocation, but it should also help against long-term fragmentation when possible. Most lower-than-pageblock-order compactions are for non-movable allocations, which means that if we compact in a movable pageblock and terminate as soon as we create the high-order page, it's unlikely that the fallback heuristics will claim the whole block. Instead there might be a single unmovable page in a pageblock full of movable pages, and the next unmovable allocation might pick another pageblock and increase long-term fragmentation. To help against such scenarios, this patch changes the termination criteria for compaction so that the current pageblock is finished even though the high-order page already exists. Note that it might be possible that the high-order page formed elsewhere in the zone due to parallel activity, but this patch doesn't try to detect that. This is only done with sync compaction, because async compaction is limited to pageblock of the same migratetype, where it cannot result in a migratetype fallback. (Async compaction also eagerly skips order-aligned blocks where isolation fails, which is against the goal of migrating away as much of the pageblock as possible.) As a result of this patch, long-term memory fragmentation should be reduced. In testing based on 4.9 kernel with stress-highalloc from mmtests configured for order-4 GFP_KERNEL allocations, this patch has reduced the number of unmovable allocations falling back to movable pageblocks by 20%. The number Link: http://lkml.kernel.org/r/20170307131545.28577-9-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-09 06:54:52 +08:00
bool finishing_block; /* Finishing current pageblock */
};
unsigned long
mm: compaction: cache if a pageblock was scanned and no pages were isolated When compaction was implemented it was known that scanning could potentially be excessive. The ideal was that a counter be maintained for each pageblock but maintaining this information would incur a severe penalty due to a shared writable cache line. It has reached the point where the scanning costs are a serious problem, particularly on long-lived systems where a large process starts and allocates a large number of THPs at the same time. Instead of using a shared counter, this patch adds another bit to the pageblock flags called PG_migrate_skip. If a pageblock is scanned by either migrate or free scanner and 0 pages were isolated, the pageblock is marked to be skipped in the future. When scanning, this bit is checked before any scanning takes place and the block skipped if set. The main difficulty with a patch like this is "when to ignore the cached information?" If it's ignored too often, the scanning rates will still be excessive. If the information is too stale then allocations will fail that might have otherwise succeeded. In this patch o CMA always ignores the information o If the migrate and free scanner meet then the cached information will be discarded if it's at least 5 seconds since the last time the cache was discarded o If there are a large number of allocation failures, discard the cache. The time-based heuristic is very clumsy but there are few choices for a better event. Depending solely on multiple allocation failures still allows excessive scanning when THP allocations are failing in quick succession due to memory pressure. Waiting until memory pressure is relieved would cause compaction to continually fail instead of using reclaim/compaction to try allocate the page. The time-based mechanism is clumsy but a better option is not obvious. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Cc: Richard Davies <richard@arachsys.com> Cc: Shaohua Li <shli@kernel.org> Cc: Avi Kivity <avi@redhat.com> Acked-by: Rafael Aquini <aquini@redhat.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 07:32:41 +08:00
isolate_freepages_range(struct compact_control *cc,
unsigned long start_pfn, unsigned long end_pfn);
unsigned long
mm, compaction: move pageblock checks up from isolate_migratepages_range() isolate_migratepages_range() is the main function of the compaction scanner, called either on a single pageblock by isolate_migratepages() during regular compaction, or on an arbitrary range by CMA's __alloc_contig_migrate_range(). It currently perfoms two pageblock-wide compaction suitability checks, and because of the CMA callpath, it tracks if it crossed a pageblock boundary in order to repeat those checks. However, closer inspection shows that those checks are always true for CMA: - isolation_suitable() is true because CMA sets cc->ignore_skip_hint to true - migrate_async_suitable() check is skipped because CMA uses sync compaction We can therefore move the compaction-specific checks to isolate_migratepages() and simplify isolate_migratepages_range(). Furthermore, we can mimic the freepage scanner family of functions, which has isolate_freepages_block() function called both by compaction from isolate_freepages() and by CMA from isolate_freepages_range(), where each use-case adds own specific glue code. This allows further code simplification. Thus, we rename isolate_migratepages_range() to isolate_migratepages_block() and limit its functionality to a single pageblock (or its subset). For CMA, a new different isolate_migratepages_range() is created as a CMA-specific wrapper for the _block() function. The checks specific to compaction are moved to isolate_migratepages(). As part of the unification of these two families of functions, we remove the redundant zone parameter where applicable, since zone pointer is already passed in cc->zone. Furthermore, going back to compact_zone() and compact_finished() when pageblock is found unsuitable (now by isolate_migratepages()) is wasteful - the checks are meant to skip pageblocks quickly. The patch therefore also introduces a simple loop into isolate_migratepages() so that it does not return immediately on failed pageblock checks, but keeps going until isolate_migratepages_range() gets called once. Similarily to isolate_freepages(), the function periodically checks if it needs to reschedule or abort async compaction. [iamjoonsoo.kim@lge.com: fix isolated page counting bug in compaction] Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Minchan Kim <minchan@kernel.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Christoph Lameter <cl@linux.com> Cc: Rik van Riel <riel@redhat.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 06:27:09 +08:00
isolate_migratepages_range(struct compact_control *cc,
unsigned long low_pfn, unsigned long end_pfn);
mm/compaction: enhance compaction finish condition Compaction has anti fragmentation algorithm. It is that freepage should be more than pageblock order to finish the compaction if we don't find any freepage in requested migratetype buddy list. This is for mitigating fragmentation, but, there is a lack of migratetype consideration and it is too excessive compared to page allocator's anti fragmentation algorithm. Not considering migratetype would cause premature finish of compaction. For example, if allocation request is for unmovable migratetype, freepage with CMA migratetype doesn't help that allocation and compaction should not be stopped. But, current logic regards this situation as compaction is no longer needed, so finish the compaction. Secondly, condition is too excessive compared to page allocator's logic. We can steal freepage from other migratetype and change pageblock migratetype on more relaxed conditions in page allocator. This is designed to prevent fragmentation and we can use it here. Imposing hard constraint only to the compaction doesn't help much in this case since page allocator would cause fragmentation again. To solve these problems, this patch borrows anti fragmentation logic from page allocator. It will reduce premature compaction finish in some cases and reduce excessive compaction work. stress-highalloc test in mmtests with non movable order 7 allocation shows considerable increase of compaction success rate. Compaction success rate (Compaction success * 100 / Compaction stalls, %) 31.82 : 42.20 I tested it on non-reboot 5 runs stress-highalloc benchmark and found that there is no more degradation on allocation success rate than before. That roughly means that this patch doesn't result in more fragmentations. Vlastimil suggests additional idea that we only test for fallbacks when migration scanner has scanned a whole pageblock. It looked good for fragmentation because chance of stealing increase due to making more free pages in certain pageblock. So, I tested it, but, it results in decreased compaction success rate, roughly 38.00. I guess the reason that if system is low memory condition, watermark check could be failed due to not enough order 0 free page and so, sometimes, we can't reach a fallback check although migrate_pfn is aligned to pageblock_nr_pages. I can insert code to cope with this situation but it makes code more complicated so I don't include his idea at this patch. [akpm@linux-foundation.org: fix CONFIG_CMA=n build] Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15 06:45:21 +08:00
int find_suitable_fallback(struct free_area *area, unsigned int order,
int migratetype, bool only_stealable, bool *can_steal);
#endif
/*
* This function returns the order of a free page in the buddy system. In
* general, page_zone(page)->lock must be held by the caller to prevent the
* page from being allocated in parallel and returning garbage as the order.
* If a caller does not hold page_zone(page)->lock, it must guarantee that the
mm, compaction: skip buddy pages by their order in the migrate scanner The migration scanner skips PageBuddy pages, but does not consider their order as checking page_order() is generally unsafe without holding the zone->lock, and acquiring the lock just for the check wouldn't be a good tradeoff. Still, this could avoid some iterations over the rest of the buddy page, and if we are careful, the race window between PageBuddy() check and page_order() is small, and the worst thing that can happen is that we skip too much and miss some isolation candidates. This is not that bad, as compaction can already fail for many other reasons like parallel allocations, and those have much larger race window. This patch therefore makes the migration scanner obtain the buddy page order and use it to skip the whole buddy page, if the order appears to be in the valid range. It's important that the page_order() is read only once, so that the value used in the checks and in the pfn calculation is the same. But in theory the compiler can replace the local variable by multiple inlines of page_order(). Therefore, the patch introduces page_order_unsafe() that uses ACCESS_ONCE to prevent this. Testing with stress-highalloc from mmtests shows a 15% reduction in number of pages scanned by migration scanner. The reduction is >60% with __GFP_NO_KSWAPD allocations, along with success rates better by few percent. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Christoph Lameter <cl@linux.com> Cc: Rik van Riel <riel@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 06:27:23 +08:00
* page cannot be allocated or merged in parallel. Alternatively, it must
* handle invalid values gracefully, and use page_order_unsafe() below.
*/
static inline unsigned int page_order(struct page *page)
{
/* PageBuddy() must be checked by the caller */
return page_private(page);
}
Solve section mismatch for free_area_init_core. WARNING: vmlinux.o(.meminit.text+0x649): Section mismatch in reference from the function free_area_init_core() to the function .init.text:setup_usemap() The function __meminit free_area_init_core() references a function __init setup_usemap(). If free_area_init_core is only used by setup_usemap then annotate free_area_init_core with a matching annotation. The warning is covers this stack of functions in mm/page_alloc.c: alloc_bootmem_node must be marked __init. alloc_bootmem_node is used by setup_usemap, if !SPARSEMEM. (usemap_size is only used by setup_usemap, if !SPARSEMEM.) setup_usemap is only used by free_area_init_core. free_area_init_core is only used by free_area_init_node. free_area_init_node is used by: arch/alpha/mm/numa.c: __init paging_init() arch/arm/mm/init.c: __init bootmem_init_node() arch/avr32/mm/init.c: __init paging_init() arch/cris/arch-v10/mm/init.c: __init paging_init() arch/cris/arch-v32/mm/init.c: __init paging_init() arch/m32r/mm/discontig.c: __init zone_sizes_init() arch/m32r/mm/init.c: __init zone_sizes_init() arch/m68k/mm/motorola.c: __init paging_init() arch/m68k/mm/sun3mmu.c: __init paging_init() arch/mips/sgi-ip27/ip27-memory.c: __init paging_init() arch/parisc/mm/init.c: __init paging_init() arch/sparc/mm/srmmu.c: __init srmmu_paging_init() arch/sparc/mm/sun4c.c: __init sun4c_paging_init() arch/sparc64/mm/init.c: __init paging_init() mm/page_alloc.c: __init free_area_init_nodes() mm/page_alloc.c: __init free_area_init() and mm/memory_hotplug.c: hotadd_new_pgdat() hotadd_new_pgdat can not be an __init function, but: It is compiled for MEMORY_HOTPLUG configurations only MEMORY_HOTPLUG depends on SPARSEMEM || X86_64_ACPI_NUMA X86_64_ACPI_NUMA depends on X86_64 ARCH_FLATMEM_ENABLE depends on X86_32 ARCH_DISCONTIGMEM_ENABLE depends on X86_32 So X86_64_ACPI_NUMA implies SPARSEMEM, right? So we can mark the stack of functions __init for !SPARSEMEM, but we must mark them __meminit for SPARSEMEM configurations. This is ok, because then the calls to alloc_bootmem_node are also avoided. Compile-tested on: silly minimal config defconfig x86_32 defconfig x86_64 defconfig x86_64 -HIBERNATION +MEMORY_HOTPLUG Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-24 07:24:06 +08:00
mm, compaction: skip buddy pages by their order in the migrate scanner The migration scanner skips PageBuddy pages, but does not consider their order as checking page_order() is generally unsafe without holding the zone->lock, and acquiring the lock just for the check wouldn't be a good tradeoff. Still, this could avoid some iterations over the rest of the buddy page, and if we are careful, the race window between PageBuddy() check and page_order() is small, and the worst thing that can happen is that we skip too much and miss some isolation candidates. This is not that bad, as compaction can already fail for many other reasons like parallel allocations, and those have much larger race window. This patch therefore makes the migration scanner obtain the buddy page order and use it to skip the whole buddy page, if the order appears to be in the valid range. It's important that the page_order() is read only once, so that the value used in the checks and in the pfn calculation is the same. But in theory the compiler can replace the local variable by multiple inlines of page_order(). Therefore, the patch introduces page_order_unsafe() that uses ACCESS_ONCE to prevent this. Testing with stress-highalloc from mmtests shows a 15% reduction in number of pages scanned by migration scanner. The reduction is >60% with __GFP_NO_KSWAPD allocations, along with success rates better by few percent. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Christoph Lameter <cl@linux.com> Cc: Rik van Riel <riel@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 06:27:23 +08:00
/*
* Like page_order(), but for callers who cannot afford to hold the zone lock.
* PageBuddy() should be checked first by the caller to minimize race window,
* and invalid values must be handled gracefully.
*
* READ_ONCE is used so that if the caller assigns the result into a local
mm, compaction: skip buddy pages by their order in the migrate scanner The migration scanner skips PageBuddy pages, but does not consider their order as checking page_order() is generally unsafe without holding the zone->lock, and acquiring the lock just for the check wouldn't be a good tradeoff. Still, this could avoid some iterations over the rest of the buddy page, and if we are careful, the race window between PageBuddy() check and page_order() is small, and the worst thing that can happen is that we skip too much and miss some isolation candidates. This is not that bad, as compaction can already fail for many other reasons like parallel allocations, and those have much larger race window. This patch therefore makes the migration scanner obtain the buddy page order and use it to skip the whole buddy page, if the order appears to be in the valid range. It's important that the page_order() is read only once, so that the value used in the checks and in the pfn calculation is the same. But in theory the compiler can replace the local variable by multiple inlines of page_order(). Therefore, the patch introduces page_order_unsafe() that uses ACCESS_ONCE to prevent this. Testing with stress-highalloc from mmtests shows a 15% reduction in number of pages scanned by migration scanner. The reduction is >60% with __GFP_NO_KSWAPD allocations, along with success rates better by few percent. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Christoph Lameter <cl@linux.com> Cc: Rik van Riel <riel@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 06:27:23 +08:00
* variable and e.g. tests it for valid range before using, the compiler cannot
* decide to remove the variable and inline the page_private(page) multiple
* times, potentially observing different values in the tests and the actual
* use of the result.
*/
#define page_order_unsafe(page) READ_ONCE(page_private(page))
mm, compaction: skip buddy pages by their order in the migrate scanner The migration scanner skips PageBuddy pages, but does not consider their order as checking page_order() is generally unsafe without holding the zone->lock, and acquiring the lock just for the check wouldn't be a good tradeoff. Still, this could avoid some iterations over the rest of the buddy page, and if we are careful, the race window between PageBuddy() check and page_order() is small, and the worst thing that can happen is that we skip too much and miss some isolation candidates. This is not that bad, as compaction can already fail for many other reasons like parallel allocations, and those have much larger race window. This patch therefore makes the migration scanner obtain the buddy page order and use it to skip the whole buddy page, if the order appears to be in the valid range. It's important that the page_order() is read only once, so that the value used in the checks and in the pfn calculation is the same. But in theory the compiler can replace the local variable by multiple inlines of page_order(). Therefore, the patch introduces page_order_unsafe() that uses ACCESS_ONCE to prevent this. Testing with stress-highalloc from mmtests shows a 15% reduction in number of pages scanned by migration scanner. The reduction is >60% with __GFP_NO_KSWAPD allocations, along with success rates better by few percent. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Christoph Lameter <cl@linux.com> Cc: Rik van Riel <riel@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-10 06:27:23 +08:00
static inline bool is_cow_mapping(vm_flags_t flags)
{
return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
}
/*
* These three helpers classifies VMAs for virtual memory accounting.
*/
/*
* Executable code area - executable, not writable, not stack
*/
mm: warn about VmData over RLIMIT_DATA This patch provides a way of working around a slight regression introduced by commit 84638335900f ("mm: rework virtual memory accounting"). Before that commit RLIMIT_DATA have control only over size of the brk region. But that change have caused problems with all existing versions of valgrind, because it set RLIMIT_DATA to zero. This patch fixes rlimit check (limit actually in bytes, not pages) and by default turns it into warning which prints at first VmData misuse: "mmap: top (795): VmData 516096 exceed data ulimit 512000. Will be forbidden soon." Behavior is controlled by boot param ignore_rlimit_data=y/n and by sysfs /sys/module/kernel/parameters/ignore_rlimit_data. For now it set to "y". [akpm@linux-foundation.org: tweak kernel-parameters.txt text[ Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Link: http://lkml.kernel.org/r/20151228211015.GL2194@uranus Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Kees Cook <keescook@google.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-03 08:57:43 +08:00
static inline bool is_exec_mapping(vm_flags_t flags)
{
return (flags & (VM_EXEC | VM_WRITE | VM_STACK)) == VM_EXEC;
mm: warn about VmData over RLIMIT_DATA This patch provides a way of working around a slight regression introduced by commit 84638335900f ("mm: rework virtual memory accounting"). Before that commit RLIMIT_DATA have control only over size of the brk region. But that change have caused problems with all existing versions of valgrind, because it set RLIMIT_DATA to zero. This patch fixes rlimit check (limit actually in bytes, not pages) and by default turns it into warning which prints at first VmData misuse: "mmap: top (795): VmData 516096 exceed data ulimit 512000. Will be forbidden soon." Behavior is controlled by boot param ignore_rlimit_data=y/n and by sysfs /sys/module/kernel/parameters/ignore_rlimit_data. For now it set to "y". [akpm@linux-foundation.org: tweak kernel-parameters.txt text[ Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Link: http://lkml.kernel.org/r/20151228211015.GL2194@uranus Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Kees Cook <keescook@google.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-03 08:57:43 +08:00
}
/*
* Stack area - atomatically grows in one direction
*
* VM_GROWSUP / VM_GROWSDOWN VMAs are always private anonymous:
* do_mmap() forbids all other combinations.
*/
mm: warn about VmData over RLIMIT_DATA This patch provides a way of working around a slight regression introduced by commit 84638335900f ("mm: rework virtual memory accounting"). Before that commit RLIMIT_DATA have control only over size of the brk region. But that change have caused problems with all existing versions of valgrind, because it set RLIMIT_DATA to zero. This patch fixes rlimit check (limit actually in bytes, not pages) and by default turns it into warning which prints at first VmData misuse: "mmap: top (795): VmData 516096 exceed data ulimit 512000. Will be forbidden soon." Behavior is controlled by boot param ignore_rlimit_data=y/n and by sysfs /sys/module/kernel/parameters/ignore_rlimit_data. For now it set to "y". [akpm@linux-foundation.org: tweak kernel-parameters.txt text[ Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Link: http://lkml.kernel.org/r/20151228211015.GL2194@uranus Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Kees Cook <keescook@google.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-03 08:57:43 +08:00
static inline bool is_stack_mapping(vm_flags_t flags)
{
return (flags & VM_STACK) == VM_STACK;
mm: warn about VmData over RLIMIT_DATA This patch provides a way of working around a slight regression introduced by commit 84638335900f ("mm: rework virtual memory accounting"). Before that commit RLIMIT_DATA have control only over size of the brk region. But that change have caused problems with all existing versions of valgrind, because it set RLIMIT_DATA to zero. This patch fixes rlimit check (limit actually in bytes, not pages) and by default turns it into warning which prints at first VmData misuse: "mmap: top (795): VmData 516096 exceed data ulimit 512000. Will be forbidden soon." Behavior is controlled by boot param ignore_rlimit_data=y/n and by sysfs /sys/module/kernel/parameters/ignore_rlimit_data. For now it set to "y". [akpm@linux-foundation.org: tweak kernel-parameters.txt text[ Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Link: http://lkml.kernel.org/r/20151228211015.GL2194@uranus Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Kees Cook <keescook@google.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-03 08:57:43 +08:00
}
/*
* Data area - private, writable, not stack
*/
mm: warn about VmData over RLIMIT_DATA This patch provides a way of working around a slight regression introduced by commit 84638335900f ("mm: rework virtual memory accounting"). Before that commit RLIMIT_DATA have control only over size of the brk region. But that change have caused problems with all existing versions of valgrind, because it set RLIMIT_DATA to zero. This patch fixes rlimit check (limit actually in bytes, not pages) and by default turns it into warning which prints at first VmData misuse: "mmap: top (795): VmData 516096 exceed data ulimit 512000. Will be forbidden soon." Behavior is controlled by boot param ignore_rlimit_data=y/n and by sysfs /sys/module/kernel/parameters/ignore_rlimit_data. For now it set to "y". [akpm@linux-foundation.org: tweak kernel-parameters.txt text[ Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Link: http://lkml.kernel.org/r/20151228211015.GL2194@uranus Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Kees Cook <keescook@google.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-03 08:57:43 +08:00
static inline bool is_data_mapping(vm_flags_t flags)
{
return (flags & (VM_WRITE | VM_SHARED | VM_STACK)) == VM_WRITE;
mm: warn about VmData over RLIMIT_DATA This patch provides a way of working around a slight regression introduced by commit 84638335900f ("mm: rework virtual memory accounting"). Before that commit RLIMIT_DATA have control only over size of the brk region. But that change have caused problems with all existing versions of valgrind, because it set RLIMIT_DATA to zero. This patch fixes rlimit check (limit actually in bytes, not pages) and by default turns it into warning which prints at first VmData misuse: "mmap: top (795): VmData 516096 exceed data ulimit 512000. Will be forbidden soon." Behavior is controlled by boot param ignore_rlimit_data=y/n and by sysfs /sys/module/kernel/parameters/ignore_rlimit_data. For now it set to "y". [akpm@linux-foundation.org: tweak kernel-parameters.txt text[ Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Link: http://lkml.kernel.org/r/20151228211015.GL2194@uranus Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Kees Cook <keescook@google.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-03 08:57:43 +08:00
}
mm: nommu: sort mm->mmap list properly When I was reading nommu code, I found that it handles the vma list/tree in an unusual way. IIUC, because there can be more than one identical/overrapped vmas in the list/tree, it sorts the tree more strictly and does a linear search on the tree. But it doesn't applied to the list (i.e. the list could be constructed in a different order than the tree so that we can't use the list when finding the first vma in that order). Since inserting/sorting a vma in the tree and link is done at the same time, we can easily construct both of them in the same order. And linear searching on the tree could be more costly than doing it on the list, it can be converted to use the list. Also, after the commit 297c5eee3724 ("mm: make the vma list be doubly linked") made the list be doubly linked, there were a couple of code need to be fixed to construct the list properly. Patch 1/6 is a preparation. It maintains the list sorted same as the tree and construct doubly-linked list properly. Patch 2/6 is a simple optimization for the vma deletion. Patch 3/6 and 4/6 convert tree traversal to list traversal and the rest are simple fixes and cleanups. This patch: @vma added into @mm should be sorted by start addr, end addr and VMA struct addr in that order because we may get identical VMAs in the @mm. However this was true only for the rbtree, not for the list. This patch fixes this by remembering 'rb_prev' during the tree traversal like find_vma_prepare() does and linking the @vma via __vma_link_list(). After this patch, we can iterate the whole VMAs in correct order simply by using @mm->mmap list. [akpm@linux-foundation.org: avoid duplicating __vma_link_list()] Signed-off-by: Namhyung Kim <namhyung@gmail.com> Acked-by: Greg Ungerer <gerg@uclinux.org> Cc: David Howells <dhowells@redhat.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:11:22 +08:00
/* mm/util.c */
void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
struct vm_area_struct *prev, struct rb_node *rb_parent);
#ifdef CONFIG_MMU
extern long populate_vma_page_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end, int *nonblocking);
extern void munlock_vma_pages_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end);
static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
{
munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
}
mlock: mlocked pages are unevictable Make sure that mlocked pages also live on the unevictable LRU, so kswapd will not scan them over and over again. This is achieved through various strategies: 1) add yet another page flag--PG_mlocked--to indicate that the page is locked for efficient testing in vmscan and, optionally, fault path. This allows early culling of unevictable pages, preventing them from getting to page_referenced()/try_to_unmap(). Also allows separate accounting of mlock'd pages, as Nick's original patch did. Note: Nick's original mlock patch used a PG_mlocked flag. I had removed this in favor of the PG_unevictable flag + an mlock_count [new page struct member]. I restored the PG_mlocked flag to eliminate the new count field. 2) add the mlock/unevictable infrastructure to mm/mlock.c, with internal APIs in mm/internal.h. This is a rework of Nick's original patch to these files, taking into account that mlocked pages are now kept on unevictable LRU list. 3) update vmscan.c:page_evictable() to check PageMlocked() and, if vma passed in, the vm_flags. Note that the vma will only be passed in for new pages in the fault path; and then only if the "cull unevictable pages in fault path" patch is included. 4) add try_to_unlock() to rmap.c to walk a page's rmap and ClearPageMlocked() if no other vmas have it mlocked. Reuses as much of try_to_unmap() as possible. This effectively replaces the use of one of the lru list links as an mlock count. If this mechanism let's pages in mlocked vmas leak through w/o PG_mlocked set [I don't know that it does], we should catch them later in try_to_unmap(). One hopes this will be rare, as it will be relatively expensive. Original mm/internal.h, mm/rmap.c and mm/mlock.c changes: Signed-off-by: Nick Piggin <npiggin@suse.de> splitlru: introduce __get_user_pages(): New munlock processing need to GUP_FLAGS_IGNORE_VMA_PERMISSIONS. because current get_user_pages() can't grab PROT_NONE pages theresore it cause PROT_NONE pages can't munlock. [akpm@linux-foundation.org: fix this for pagemap-pass-mm-into-pagewalkers.patch] [akpm@linux-foundation.org: untangle patch interdependencies] [akpm@linux-foundation.org: fix things after out-of-order merging] [hugh@veritas.com: fix page-flags mess] [lee.schermerhorn@hp.com: fix munlock page table walk - now requires 'mm'] [kosaki.motohiro@jp.fujitsu.com: build fix] [kosaki.motohiro@jp.fujitsu.com: fix truncate race and sevaral comments] [kosaki.motohiro@jp.fujitsu.com: splitlru: introduce __get_user_pages()] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 11:26:44 +08:00
/*
* must be called with vma's mmap_sem held for read or write, and page locked.
mlock: mlocked pages are unevictable Make sure that mlocked pages also live on the unevictable LRU, so kswapd will not scan them over and over again. This is achieved through various strategies: 1) add yet another page flag--PG_mlocked--to indicate that the page is locked for efficient testing in vmscan and, optionally, fault path. This allows early culling of unevictable pages, preventing them from getting to page_referenced()/try_to_unmap(). Also allows separate accounting of mlock'd pages, as Nick's original patch did. Note: Nick's original mlock patch used a PG_mlocked flag. I had removed this in favor of the PG_unevictable flag + an mlock_count [new page struct member]. I restored the PG_mlocked flag to eliminate the new count field. 2) add the mlock/unevictable infrastructure to mm/mlock.c, with internal APIs in mm/internal.h. This is a rework of Nick's original patch to these files, taking into account that mlocked pages are now kept on unevictable LRU list. 3) update vmscan.c:page_evictable() to check PageMlocked() and, if vma passed in, the vm_flags. Note that the vma will only be passed in for new pages in the fault path; and then only if the "cull unevictable pages in fault path" patch is included. 4) add try_to_unlock() to rmap.c to walk a page's rmap and ClearPageMlocked() if no other vmas have it mlocked. Reuses as much of try_to_unmap() as possible. This effectively replaces the use of one of the lru list links as an mlock count. If this mechanism let's pages in mlocked vmas leak through w/o PG_mlocked set [I don't know that it does], we should catch them later in try_to_unmap(). One hopes this will be rare, as it will be relatively expensive. Original mm/internal.h, mm/rmap.c and mm/mlock.c changes: Signed-off-by: Nick Piggin <npiggin@suse.de> splitlru: introduce __get_user_pages(): New munlock processing need to GUP_FLAGS_IGNORE_VMA_PERMISSIONS. because current get_user_pages() can't grab PROT_NONE pages theresore it cause PROT_NONE pages can't munlock. [akpm@linux-foundation.org: fix this for pagemap-pass-mm-into-pagewalkers.patch] [akpm@linux-foundation.org: untangle patch interdependencies] [akpm@linux-foundation.org: fix things after out-of-order merging] [hugh@veritas.com: fix page-flags mess] [lee.schermerhorn@hp.com: fix munlock page table walk - now requires 'mm'] [kosaki.motohiro@jp.fujitsu.com: build fix] [kosaki.motohiro@jp.fujitsu.com: fix truncate race and sevaral comments] [kosaki.motohiro@jp.fujitsu.com: splitlru: introduce __get_user_pages()] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 11:26:44 +08:00
*/
extern void mlock_vma_page(struct page *page);
extern unsigned int munlock_vma_page(struct page *page);
mlock: mlocked pages are unevictable Make sure that mlocked pages also live on the unevictable LRU, so kswapd will not scan them over and over again. This is achieved through various strategies: 1) add yet another page flag--PG_mlocked--to indicate that the page is locked for efficient testing in vmscan and, optionally, fault path. This allows early culling of unevictable pages, preventing them from getting to page_referenced()/try_to_unmap(). Also allows separate accounting of mlock'd pages, as Nick's original patch did. Note: Nick's original mlock patch used a PG_mlocked flag. I had removed this in favor of the PG_unevictable flag + an mlock_count [new page struct member]. I restored the PG_mlocked flag to eliminate the new count field. 2) add the mlock/unevictable infrastructure to mm/mlock.c, with internal APIs in mm/internal.h. This is a rework of Nick's original patch to these files, taking into account that mlocked pages are now kept on unevictable LRU list. 3) update vmscan.c:page_evictable() to check PageMlocked() and, if vma passed in, the vm_flags. Note that the vma will only be passed in for new pages in the fault path; and then only if the "cull unevictable pages in fault path" patch is included. 4) add try_to_unlock() to rmap.c to walk a page's rmap and ClearPageMlocked() if no other vmas have it mlocked. Reuses as much of try_to_unmap() as possible. This effectively replaces the use of one of the lru list links as an mlock count. If this mechanism let's pages in mlocked vmas leak through w/o PG_mlocked set [I don't know that it does], we should catch them later in try_to_unmap(). One hopes this will be rare, as it will be relatively expensive. Original mm/internal.h, mm/rmap.c and mm/mlock.c changes: Signed-off-by: Nick Piggin <npiggin@suse.de> splitlru: introduce __get_user_pages(): New munlock processing need to GUP_FLAGS_IGNORE_VMA_PERMISSIONS. because current get_user_pages() can't grab PROT_NONE pages theresore it cause PROT_NONE pages can't munlock. [akpm@linux-foundation.org: fix this for pagemap-pass-mm-into-pagewalkers.patch] [akpm@linux-foundation.org: untangle patch interdependencies] [akpm@linux-foundation.org: fix things after out-of-order merging] [hugh@veritas.com: fix page-flags mess] [lee.schermerhorn@hp.com: fix munlock page table walk - now requires 'mm'] [kosaki.motohiro@jp.fujitsu.com: build fix] [kosaki.motohiro@jp.fujitsu.com: fix truncate race and sevaral comments] [kosaki.motohiro@jp.fujitsu.com: splitlru: introduce __get_user_pages()] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 11:26:44 +08:00
/*
* Clear the page's PageMlocked(). This can be useful in a situation where
* we want to unconditionally remove a page from the pagecache -- e.g.,
* on truncation or freeing.
*
* It is legal to call this function for any page, mlocked or not.
* If called for a page that is still mapped by mlocked vmas, all we do
* is revert to lazy LRU behaviour -- semantics are not broken.
*/
mm: use clear_page_mlock() in page_remove_rmap() We had thought that pages could no longer get freed while still marked as mlocked; but Johannes Weiner posted this program to demonstrate that truncating an mlocked private file mapping containing COWed pages is still mishandled: #include <sys/types.h> #include <sys/mman.h> #include <sys/stat.h> #include <stdlib.h> #include <unistd.h> #include <fcntl.h> #include <stdio.h> int main(void) { char *map; int fd; system("grep mlockfreed /proc/vmstat"); fd = open("chigurh", O_CREAT|O_EXCL|O_RDWR); unlink("chigurh"); ftruncate(fd, 4096); map = mmap(NULL, 4096, PROT_WRITE, MAP_PRIVATE, fd, 0); map[0] = 11; mlock(map, sizeof(fd)); ftruncate(fd, 0); close(fd); munlock(map, sizeof(fd)); munmap(map, 4096); system("grep mlockfreed /proc/vmstat"); return 0; } The anon COWed pages are not caught by truncation's clear_page_mlock() of the pagecache pages; but unmap_mapping_range() unmaps them, so we ought to look out for them there in page_remove_rmap(). Indeed, why should truncation or invalidation be doing the clear_page_mlock() when removing from pagecache? mlock is a property of mapping in userspace, not a property of pagecache: an mlocked unmapped page is nonsensical. Reported-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Rik van Riel <riel@redhat.com> Cc: Michel Lespinasse <walken@google.com> Cc: Ying Han <yinghan@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 07:33:19 +08:00
extern void clear_page_mlock(struct page *page);
mlock: mlocked pages are unevictable Make sure that mlocked pages also live on the unevictable LRU, so kswapd will not scan them over and over again. This is achieved through various strategies: 1) add yet another page flag--PG_mlocked--to indicate that the page is locked for efficient testing in vmscan and, optionally, fault path. This allows early culling of unevictable pages, preventing them from getting to page_referenced()/try_to_unmap(). Also allows separate accounting of mlock'd pages, as Nick's original patch did. Note: Nick's original mlock patch used a PG_mlocked flag. I had removed this in favor of the PG_unevictable flag + an mlock_count [new page struct member]. I restored the PG_mlocked flag to eliminate the new count field. 2) add the mlock/unevictable infrastructure to mm/mlock.c, with internal APIs in mm/internal.h. This is a rework of Nick's original patch to these files, taking into account that mlocked pages are now kept on unevictable LRU list. 3) update vmscan.c:page_evictable() to check PageMlocked() and, if vma passed in, the vm_flags. Note that the vma will only be passed in for new pages in the fault path; and then only if the "cull unevictable pages in fault path" patch is included. 4) add try_to_unlock() to rmap.c to walk a page's rmap and ClearPageMlocked() if no other vmas have it mlocked. Reuses as much of try_to_unmap() as possible. This effectively replaces the use of one of the lru list links as an mlock count. If this mechanism let's pages in mlocked vmas leak through w/o PG_mlocked set [I don't know that it does], we should catch them later in try_to_unmap(). One hopes this will be rare, as it will be relatively expensive. Original mm/internal.h, mm/rmap.c and mm/mlock.c changes: Signed-off-by: Nick Piggin <npiggin@suse.de> splitlru: introduce __get_user_pages(): New munlock processing need to GUP_FLAGS_IGNORE_VMA_PERMISSIONS. because current get_user_pages() can't grab PROT_NONE pages theresore it cause PROT_NONE pages can't munlock. [akpm@linux-foundation.org: fix this for pagemap-pass-mm-into-pagewalkers.patch] [akpm@linux-foundation.org: untangle patch interdependencies] [akpm@linux-foundation.org: fix things after out-of-order merging] [hugh@veritas.com: fix page-flags mess] [lee.schermerhorn@hp.com: fix munlock page table walk - now requires 'mm'] [kosaki.motohiro@jp.fujitsu.com: build fix] [kosaki.motohiro@jp.fujitsu.com: fix truncate race and sevaral comments] [kosaki.motohiro@jp.fujitsu.com: splitlru: introduce __get_user_pages()] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 11:26:44 +08:00
/*
mm: page migration fix PageMlocked on migrated pages Commit e6c509f85455 ("mm: use clear_page_mlock() in page_remove_rmap()") in v3.7 inadvertently made mlock_migrate_page() impotent: page migration unmaps the page from userspace before migrating, and that commit clears PageMlocked on the final unmap, leaving mlock_migrate_page() with nothing to do. Not a serious bug, the next attempt at reclaiming the page would fix it up; but a betrayal of page migration's intent - the new page ought to emerge as PageMlocked. I don't see how to fix it for mlock_migrate_page() itself; but easily fixed in remove_migration_pte(), by calling mlock_vma_page() when the vma is VM_LOCKED - under pte lock as in try_to_unmap_one(). Delete mlock_migrate_page()? Not quite, it does still serve a purpose for migrate_misplaced_transhuge_page(): where we could replace it by a test, clear_page_mlock(), mlock_vma_page() sequence; but would that be an improvement? mlock_migrate_page() is fairly lean, and let's make it leaner by skipping the irq save/restore now clearly not needed. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Rik van Riel <riel@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 10:49:37 +08:00
* mlock_migrate_page - called only from migrate_misplaced_transhuge_page()
* (because that does not go through the full procedure of migration ptes):
* to migrate the Mlocked page flag; update statistics.
mlock: mlocked pages are unevictable Make sure that mlocked pages also live on the unevictable LRU, so kswapd will not scan them over and over again. This is achieved through various strategies: 1) add yet another page flag--PG_mlocked--to indicate that the page is locked for efficient testing in vmscan and, optionally, fault path. This allows early culling of unevictable pages, preventing them from getting to page_referenced()/try_to_unmap(). Also allows separate accounting of mlock'd pages, as Nick's original patch did. Note: Nick's original mlock patch used a PG_mlocked flag. I had removed this in favor of the PG_unevictable flag + an mlock_count [new page struct member]. I restored the PG_mlocked flag to eliminate the new count field. 2) add the mlock/unevictable infrastructure to mm/mlock.c, with internal APIs in mm/internal.h. This is a rework of Nick's original patch to these files, taking into account that mlocked pages are now kept on unevictable LRU list. 3) update vmscan.c:page_evictable() to check PageMlocked() and, if vma passed in, the vm_flags. Note that the vma will only be passed in for new pages in the fault path; and then only if the "cull unevictable pages in fault path" patch is included. 4) add try_to_unlock() to rmap.c to walk a page's rmap and ClearPageMlocked() if no other vmas have it mlocked. Reuses as much of try_to_unmap() as possible. This effectively replaces the use of one of the lru list links as an mlock count. If this mechanism let's pages in mlocked vmas leak through w/o PG_mlocked set [I don't know that it does], we should catch them later in try_to_unmap(). One hopes this will be rare, as it will be relatively expensive. Original mm/internal.h, mm/rmap.c and mm/mlock.c changes: Signed-off-by: Nick Piggin <npiggin@suse.de> splitlru: introduce __get_user_pages(): New munlock processing need to GUP_FLAGS_IGNORE_VMA_PERMISSIONS. because current get_user_pages() can't grab PROT_NONE pages theresore it cause PROT_NONE pages can't munlock. [akpm@linux-foundation.org: fix this for pagemap-pass-mm-into-pagewalkers.patch] [akpm@linux-foundation.org: untangle patch interdependencies] [akpm@linux-foundation.org: fix things after out-of-order merging] [hugh@veritas.com: fix page-flags mess] [lee.schermerhorn@hp.com: fix munlock page table walk - now requires 'mm'] [kosaki.motohiro@jp.fujitsu.com: build fix] [kosaki.motohiro@jp.fujitsu.com: fix truncate race and sevaral comments] [kosaki.motohiro@jp.fujitsu.com: splitlru: introduce __get_user_pages()] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 11:26:44 +08:00
*/
static inline void mlock_migrate_page(struct page *newpage, struct page *page)
{
if (TestClearPageMlocked(page)) {
int nr_pages = hpage_nr_pages(page);
mm: page migration fix PageMlocked on migrated pages Commit e6c509f85455 ("mm: use clear_page_mlock() in page_remove_rmap()") in v3.7 inadvertently made mlock_migrate_page() impotent: page migration unmaps the page from userspace before migrating, and that commit clears PageMlocked on the final unmap, leaving mlock_migrate_page() with nothing to do. Not a serious bug, the next attempt at reclaiming the page would fix it up; but a betrayal of page migration's intent - the new page ought to emerge as PageMlocked. I don't see how to fix it for mlock_migrate_page() itself; but easily fixed in remove_migration_pte(), by calling mlock_vma_page() when the vma is VM_LOCKED - under pte lock as in try_to_unmap_one(). Delete mlock_migrate_page()? Not quite, it does still serve a purpose for migrate_misplaced_transhuge_page(): where we could replace it by a test, clear_page_mlock(), mlock_vma_page() sequence; but would that be an improvement? mlock_migrate_page() is fairly lean, and let's make it leaner by skipping the irq save/restore now clearly not needed. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Rik van Riel <riel@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 10:49:37 +08:00
/* Holding pmd lock, no change in irq context: __mod is safe */
__mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
mlock: mlocked pages are unevictable Make sure that mlocked pages also live on the unevictable LRU, so kswapd will not scan them over and over again. This is achieved through various strategies: 1) add yet another page flag--PG_mlocked--to indicate that the page is locked for efficient testing in vmscan and, optionally, fault path. This allows early culling of unevictable pages, preventing them from getting to page_referenced()/try_to_unmap(). Also allows separate accounting of mlock'd pages, as Nick's original patch did. Note: Nick's original mlock patch used a PG_mlocked flag. I had removed this in favor of the PG_unevictable flag + an mlock_count [new page struct member]. I restored the PG_mlocked flag to eliminate the new count field. 2) add the mlock/unevictable infrastructure to mm/mlock.c, with internal APIs in mm/internal.h. This is a rework of Nick's original patch to these files, taking into account that mlocked pages are now kept on unevictable LRU list. 3) update vmscan.c:page_evictable() to check PageMlocked() and, if vma passed in, the vm_flags. Note that the vma will only be passed in for new pages in the fault path; and then only if the "cull unevictable pages in fault path" patch is included. 4) add try_to_unlock() to rmap.c to walk a page's rmap and ClearPageMlocked() if no other vmas have it mlocked. Reuses as much of try_to_unmap() as possible. This effectively replaces the use of one of the lru list links as an mlock count. If this mechanism let's pages in mlocked vmas leak through w/o PG_mlocked set [I don't know that it does], we should catch them later in try_to_unmap(). One hopes this will be rare, as it will be relatively expensive. Original mm/internal.h, mm/rmap.c and mm/mlock.c changes: Signed-off-by: Nick Piggin <npiggin@suse.de> splitlru: introduce __get_user_pages(): New munlock processing need to GUP_FLAGS_IGNORE_VMA_PERMISSIONS. because current get_user_pages() can't grab PROT_NONE pages theresore it cause PROT_NONE pages can't munlock. [akpm@linux-foundation.org: fix this for pagemap-pass-mm-into-pagewalkers.patch] [akpm@linux-foundation.org: untangle patch interdependencies] [akpm@linux-foundation.org: fix things after out-of-order merging] [hugh@veritas.com: fix page-flags mess] [lee.schermerhorn@hp.com: fix munlock page table walk - now requires 'mm'] [kosaki.motohiro@jp.fujitsu.com: build fix] [kosaki.motohiro@jp.fujitsu.com: fix truncate race and sevaral comments] [kosaki.motohiro@jp.fujitsu.com: splitlru: introduce __get_user_pages()] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 11:26:44 +08:00
SetPageMlocked(newpage);
__mod_zone_page_state(page_zone(newpage), NR_MLOCK, nr_pages);
}
mlock: mlocked pages are unevictable Make sure that mlocked pages also live on the unevictable LRU, so kswapd will not scan them over and over again. This is achieved through various strategies: 1) add yet another page flag--PG_mlocked--to indicate that the page is locked for efficient testing in vmscan and, optionally, fault path. This allows early culling of unevictable pages, preventing them from getting to page_referenced()/try_to_unmap(). Also allows separate accounting of mlock'd pages, as Nick's original patch did. Note: Nick's original mlock patch used a PG_mlocked flag. I had removed this in favor of the PG_unevictable flag + an mlock_count [new page struct member]. I restored the PG_mlocked flag to eliminate the new count field. 2) add the mlock/unevictable infrastructure to mm/mlock.c, with internal APIs in mm/internal.h. This is a rework of Nick's original patch to these files, taking into account that mlocked pages are now kept on unevictable LRU list. 3) update vmscan.c:page_evictable() to check PageMlocked() and, if vma passed in, the vm_flags. Note that the vma will only be passed in for new pages in the fault path; and then only if the "cull unevictable pages in fault path" patch is included. 4) add try_to_unlock() to rmap.c to walk a page's rmap and ClearPageMlocked() if no other vmas have it mlocked. Reuses as much of try_to_unmap() as possible. This effectively replaces the use of one of the lru list links as an mlock count. If this mechanism let's pages in mlocked vmas leak through w/o PG_mlocked set [I don't know that it does], we should catch them later in try_to_unmap(). One hopes this will be rare, as it will be relatively expensive. Original mm/internal.h, mm/rmap.c and mm/mlock.c changes: Signed-off-by: Nick Piggin <npiggin@suse.de> splitlru: introduce __get_user_pages(): New munlock processing need to GUP_FLAGS_IGNORE_VMA_PERMISSIONS. because current get_user_pages() can't grab PROT_NONE pages theresore it cause PROT_NONE pages can't munlock. [akpm@linux-foundation.org: fix this for pagemap-pass-mm-into-pagewalkers.patch] [akpm@linux-foundation.org: untangle patch interdependencies] [akpm@linux-foundation.org: fix things after out-of-order merging] [hugh@veritas.com: fix page-flags mess] [lee.schermerhorn@hp.com: fix munlock page table walk - now requires 'mm'] [kosaki.motohiro@jp.fujitsu.com: build fix] [kosaki.motohiro@jp.fujitsu.com: fix truncate race and sevaral comments] [kosaki.motohiro@jp.fujitsu.com: splitlru: introduce __get_user_pages()] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 11:26:44 +08:00
}
extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
thp: reintroduce split_huge_page() This patch adds implementation of split_huge_page() for new refcountings. Unlike previous implementation, new split_huge_page() can fail if somebody holds GUP pin on the page. It also means that pin on page would prevent it from bening split under you. It makes situation in many places much cleaner. The basic scheme of split_huge_page(): - Check that sum of mapcounts of all subpage is equal to page_count() plus one (caller pin). Foll off with -EBUSY. This way we can avoid useless PMD-splits. - Freeze the page counters by splitting all PMD and setup migration PTEs. - Re-check sum of mapcounts against page_count(). Page's counts are stable now. -EBUSY if page is pinned. - Split compound page. - Unfreeze the page by removing migration entries. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-16 08:54:10 +08:00
/*
* At what user virtual address is page expected in @vma?
*/
static inline unsigned long
__vma_address(struct page *page, struct vm_area_struct *vma)
{
pgoff_t pgoff = page_to_pgoff(page);
return vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
}
static inline unsigned long
vma_address(struct page *page, struct vm_area_struct *vma)
{
unsigned long start, end;
start = __vma_address(page, vma);
end = start + PAGE_SIZE * (hpage_nr_pages(page) - 1);
thp: reintroduce split_huge_page() This patch adds implementation of split_huge_page() for new refcountings. Unlike previous implementation, new split_huge_page() can fail if somebody holds GUP pin on the page. It also means that pin on page would prevent it from bening split under you. It makes situation in many places much cleaner. The basic scheme of split_huge_page(): - Check that sum of mapcounts of all subpage is equal to page_count() plus one (caller pin). Foll off with -EBUSY. This way we can avoid useless PMD-splits. - Freeze the page counters by splitting all PMD and setup migration PTEs. - Re-check sum of mapcounts against page_count(). Page's counts are stable now. -EBUSY if page is pinned. - Split compound page. - Unfreeze the page by removing migration entries. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-16 08:54:10 +08:00
/* page should be within @vma mapping range */
VM_BUG_ON_VMA(end < vma->vm_start || start >= vma->vm_end, vma);
thp: reintroduce split_huge_page() This patch adds implementation of split_huge_page() for new refcountings. Unlike previous implementation, new split_huge_page() can fail if somebody holds GUP pin on the page. It also means that pin on page would prevent it from bening split under you. It makes situation in many places much cleaner. The basic scheme of split_huge_page(): - Check that sum of mapcounts of all subpage is equal to page_count() plus one (caller pin). Foll off with -EBUSY. This way we can avoid useless PMD-splits. - Freeze the page counters by splitting all PMD and setup migration PTEs. - Re-check sum of mapcounts against page_count(). Page's counts are stable now. -EBUSY if page is pinned. - Split compound page. - Unfreeze the page by removing migration entries. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-16 08:54:10 +08:00
return max(start, vma->vm_start);
thp: reintroduce split_huge_page() This patch adds implementation of split_huge_page() for new refcountings. Unlike previous implementation, new split_huge_page() can fail if somebody holds GUP pin on the page. It also means that pin on page would prevent it from bening split under you. It makes situation in many places much cleaner. The basic scheme of split_huge_page(): - Check that sum of mapcounts of all subpage is equal to page_count() plus one (caller pin). Foll off with -EBUSY. This way we can avoid useless PMD-splits. - Freeze the page counters by splitting all PMD and setup migration PTEs. - Re-check sum of mapcounts against page_count(). Page's counts are stable now. -EBUSY if page is pinned. - Split compound page. - Unfreeze the page by removing migration entries. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-16 08:54:10 +08:00
}
#else /* !CONFIG_MMU */
mlock: mlocked pages are unevictable Make sure that mlocked pages also live on the unevictable LRU, so kswapd will not scan them over and over again. This is achieved through various strategies: 1) add yet another page flag--PG_mlocked--to indicate that the page is locked for efficient testing in vmscan and, optionally, fault path. This allows early culling of unevictable pages, preventing them from getting to page_referenced()/try_to_unmap(). Also allows separate accounting of mlock'd pages, as Nick's original patch did. Note: Nick's original mlock patch used a PG_mlocked flag. I had removed this in favor of the PG_unevictable flag + an mlock_count [new page struct member]. I restored the PG_mlocked flag to eliminate the new count field. 2) add the mlock/unevictable infrastructure to mm/mlock.c, with internal APIs in mm/internal.h. This is a rework of Nick's original patch to these files, taking into account that mlocked pages are now kept on unevictable LRU list. 3) update vmscan.c:page_evictable() to check PageMlocked() and, if vma passed in, the vm_flags. Note that the vma will only be passed in for new pages in the fault path; and then only if the "cull unevictable pages in fault path" patch is included. 4) add try_to_unlock() to rmap.c to walk a page's rmap and ClearPageMlocked() if no other vmas have it mlocked. Reuses as much of try_to_unmap() as possible. This effectively replaces the use of one of the lru list links as an mlock count. If this mechanism let's pages in mlocked vmas leak through w/o PG_mlocked set [I don't know that it does], we should catch them later in try_to_unmap(). One hopes this will be rare, as it will be relatively expensive. Original mm/internal.h, mm/rmap.c and mm/mlock.c changes: Signed-off-by: Nick Piggin <npiggin@suse.de> splitlru: introduce __get_user_pages(): New munlock processing need to GUP_FLAGS_IGNORE_VMA_PERMISSIONS. because current get_user_pages() can't grab PROT_NONE pages theresore it cause PROT_NONE pages can't munlock. [akpm@linux-foundation.org: fix this for pagemap-pass-mm-into-pagewalkers.patch] [akpm@linux-foundation.org: untangle patch interdependencies] [akpm@linux-foundation.org: fix things after out-of-order merging] [hugh@veritas.com: fix page-flags mess] [lee.schermerhorn@hp.com: fix munlock page table walk - now requires 'mm'] [kosaki.motohiro@jp.fujitsu.com: build fix] [kosaki.motohiro@jp.fujitsu.com: fix truncate race and sevaral comments] [kosaki.motohiro@jp.fujitsu.com: splitlru: introduce __get_user_pages()] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 11:26:44 +08:00
static inline void clear_page_mlock(struct page *page) { }
static inline void mlock_vma_page(struct page *page) { }
static inline void mlock_migrate_page(struct page *new, struct page *old) { }
#endif /* !CONFIG_MMU */
Unevictable LRU Infrastructure When the system contains lots of mlocked or otherwise unevictable pages, the pageout code (kswapd) can spend lots of time scanning over these pages. Worse still, the presence of lots of unevictable pages can confuse kswapd into thinking that more aggressive pageout modes are required, resulting in all kinds of bad behaviour. Infrastructure to manage pages excluded from reclaim--i.e., hidden from vmscan. Based on a patch by Larry Woodman of Red Hat. Reworked to maintain "unevictable" pages on a separate per-zone LRU list, to "hide" them from vmscan. Kosaki Motohiro added the support for the memory controller unevictable lru list. Pages on the unevictable list have both PG_unevictable and PG_lru set. Thus, PG_unevictable is analogous to and mutually exclusive with PG_active--it specifies which LRU list the page is on. The unevictable infrastructure is enabled by a new mm Kconfig option [CONFIG_]UNEVICTABLE_LRU. A new function 'page_evictable(page, vma)' in vmscan.c tests whether or not a page may be evictable. Subsequent patches will add the various !evictable tests. We'll want to keep these tests light-weight for use in shrink_active_list() and, possibly, the fault path. To avoid races between tasks putting pages [back] onto an LRU list and tasks that might be moving the page from non-evictable to evictable state, the new function 'putback_lru_page()' -- inverse to 'isolate_lru_page()' -- tests the "evictability" of a page after placing it on the LRU, before dropping the reference. If the page has become unevictable, putback_lru_page() will redo the 'putback', thus moving the page to the unevictable list. This way, we avoid "stranding" evictable pages on the unevictable list. [akpm@linux-foundation.org: fix fallout from out-of-order merge] [riel@redhat.com: fix UNEVICTABLE_LRU and !PROC_PAGE_MONITOR build] [nishimura@mxp.nes.nec.co.jp: remove redundant mapping check] [kosaki.motohiro@jp.fujitsu.com: unevictable-lru-infrastructure: putback_lru_page()/unevictable page handling rework] [kosaki.motohiro@jp.fujitsu.com: kill unnecessary lock_page() in vmscan.c] [kosaki.motohiro@jp.fujitsu.com: revert migration change of unevictable lru infrastructure] [kosaki.motohiro@jp.fujitsu.com: revert to unevictable-lru-infrastructure-kconfig-fix.patch] [kosaki.motohiro@jp.fujitsu.com: restore patch failure of vmstat-unevictable-and-mlocked-pages-vm-events.patch] Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Debugged-by: Benjamin Kidwell <benjkidwell@yahoo.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19 11:26:39 +08:00
/*
* Return the mem_map entry representing the 'offset' subpage within
* the maximally aligned gigantic page 'base'. Handle any discontiguity
* in the mem_map at MAX_ORDER_NR_PAGES boundaries.
*/
static inline struct page *mem_map_offset(struct page *base, int offset)
{
if (unlikely(offset >= MAX_ORDER_NR_PAGES))
return nth_page(base, offset);
return base + offset;
}
/*
* Iterator over all subpages within the maximally aligned gigantic
* page 'base'. Handle any discontiguity in the mem_map.
*/
static inline struct page *mem_map_next(struct page *iter,
struct page *base, int offset)
{
if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) {
unsigned long pfn = page_to_pfn(base) + offset;
if (!pfn_valid(pfn))
return NULL;
return pfn_to_page(pfn);
}
return iter + 1;
}
Solve section mismatch for free_area_init_core. WARNING: vmlinux.o(.meminit.text+0x649): Section mismatch in reference from the function free_area_init_core() to the function .init.text:setup_usemap() The function __meminit free_area_init_core() references a function __init setup_usemap(). If free_area_init_core is only used by setup_usemap then annotate free_area_init_core with a matching annotation. The warning is covers this stack of functions in mm/page_alloc.c: alloc_bootmem_node must be marked __init. alloc_bootmem_node is used by setup_usemap, if !SPARSEMEM. (usemap_size is only used by setup_usemap, if !SPARSEMEM.) setup_usemap is only used by free_area_init_core. free_area_init_core is only used by free_area_init_node. free_area_init_node is used by: arch/alpha/mm/numa.c: __init paging_init() arch/arm/mm/init.c: __init bootmem_init_node() arch/avr32/mm/init.c: __init paging_init() arch/cris/arch-v10/mm/init.c: __init paging_init() arch/cris/arch-v32/mm/init.c: __init paging_init() arch/m32r/mm/discontig.c: __init zone_sizes_init() arch/m32r/mm/init.c: __init zone_sizes_init() arch/m68k/mm/motorola.c: __init paging_init() arch/m68k/mm/sun3mmu.c: __init paging_init() arch/mips/sgi-ip27/ip27-memory.c: __init paging_init() arch/parisc/mm/init.c: __init paging_init() arch/sparc/mm/srmmu.c: __init srmmu_paging_init() arch/sparc/mm/sun4c.c: __init sun4c_paging_init() arch/sparc64/mm/init.c: __init paging_init() mm/page_alloc.c: __init free_area_init_nodes() mm/page_alloc.c: __init free_area_init() and mm/memory_hotplug.c: hotadd_new_pgdat() hotadd_new_pgdat can not be an __init function, but: It is compiled for MEMORY_HOTPLUG configurations only MEMORY_HOTPLUG depends on SPARSEMEM || X86_64_ACPI_NUMA X86_64_ACPI_NUMA depends on X86_64 ARCH_FLATMEM_ENABLE depends on X86_32 ARCH_DISCONTIGMEM_ENABLE depends on X86_32 So X86_64_ACPI_NUMA implies SPARSEMEM, right? So we can mark the stack of functions __init for !SPARSEMEM, but we must mark them __meminit for SPARSEMEM configurations. This is ok, because then the calls to alloc_bootmem_node are also avoided. Compile-tested on: silly minimal config defconfig x86_32 defconfig x86_64 defconfig x86_64 -HIBERNATION +MEMORY_HOTPLUG Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-24 07:24:06 +08:00
/*
* FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
* so all functions starting at paging_init should be marked __init
* in those cases. SPARSEMEM, however, allows for memory hotplug,
* and alloc_bootmem_node is not used.
*/
#ifdef CONFIG_SPARSEMEM
#define __paginginit __meminit
#else
#define __paginginit __init
#endif
/* Memory initialisation debug and verification */
enum mminit_level {
MMINIT_WARNING,
MMINIT_VERIFY,
MMINIT_TRACE
};
#ifdef CONFIG_DEBUG_MEMORY_INIT
extern int mminit_loglevel;
#define mminit_dprintk(level, prefix, fmt, arg...) \
do { \
if (level < mminit_loglevel) { \
if (level <= MMINIT_WARNING) \
pr_warn("mminit::" prefix " " fmt, ##arg); \
else \
printk(KERN_DEBUG "mminit::" prefix " " fmt, ##arg); \
} \
} while (0)
extern void mminit_verify_pageflags_layout(void);
extern void mminit_verify_zonelist(void);
#else
static inline void mminit_dprintk(enum mminit_level level,
const char *prefix, const char *fmt, ...)
{
}
static inline void mminit_verify_pageflags_layout(void)
{
}
static inline void mminit_verify_zonelist(void)
{
}
#endif /* CONFIG_DEBUG_MEMORY_INIT */
/* mminit_validate_memmodel_limits is independent of CONFIG_DEBUG_MEMORY_INIT */
#if defined(CONFIG_SPARSEMEM)
extern void mminit_validate_memmodel_limits(unsigned long *start_pfn,
unsigned long *end_pfn);
#else
static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn,
unsigned long *end_pfn)
{
}
#endif /* CONFIG_SPARSEMEM */
#define NODE_RECLAIM_NOSCAN -2
#define NODE_RECLAIM_FULL -1
#define NODE_RECLAIM_SOME 0
#define NODE_RECLAIM_SUCCESS 1
extern int hwpoison_filter(struct page *p);
extern u32 hwpoison_filter_dev_major;
extern u32 hwpoison_filter_dev_minor;
extern u64 hwpoison_filter_flags_mask;
extern u64 hwpoison_filter_flags_value;
HWPOISON: add memory cgroup filter The hwpoison test suite need to inject hwpoison to a collection of selected task pages, and must not touch pages not owned by them and thus kill important system processes such as init. (But it's OK to mis-hwpoison free/unowned pages as well as shared clean pages. Mis-hwpoison of shared dirty pages will kill all tasks, so the test suite will target all or non of such tasks in the first place.) The memory cgroup serves this purpose well. We can put the target processes under the control of a memory cgroup, and tell the hwpoison injection code to only kill pages associated with some active memory cgroup. The prerequisite for doing hwpoison stress tests with mem_cgroup is, the mem_cgroup code tracks task pages _accurately_ (unless page is locked). Which we believe is/should be true. The benefits are simplification of hwpoison injector code. Also the mem_cgroup code will automatically be tested by hwpoison test cases. The alternative interfaces pin-pfn/unpin-pfn can also delegate the (process and page flags) filtering functions reliably to user space. However prototype implementation shows that this scheme adds more complexity than we wanted. Example test case: mkdir /cgroup/hwpoison usemem -m 100 -s 1000 & echo `jobs -p` > /cgroup/hwpoison/tasks memcg_ino=$(ls -id /cgroup/hwpoison | cut -f1 -d' ') echo $memcg_ino > /debug/hwpoison/corrupt-filter-memcg page-types -p `pidof init` --hwpoison # shall do nothing page-types -p `pidof usemem` --hwpoison # poison its pages [AK: Fix documentation] [Add fix for problem noticed by Li Zefan <lizf@cn.fujitsu.com>; dentry in the css could be NULL] CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> CC: Hugh Dickins <hugh.dickins@tiscali.co.uk> CC: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> CC: Balbir Singh <balbir@linux.vnet.ibm.com> CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> CC: Li Zefan <lizf@cn.fujitsu.com> CC: Paul Menage <menage@google.com> CC: Nick Piggin <npiggin@suse.de> CC: Andi Kleen <andi@firstfloor.org> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-12-16 19:19:59 +08:00
extern u64 hwpoison_filter_memcg;
extern u32 hwpoison_filter_enable;
mm: make mmap_sem for write waits killable for mm syscalls This is a follow up work for oom_reaper [1]. As the async OOM killing depends on oom_sem for read we would really appreciate if a holder for write didn't stood in the way. This patchset is changing many of down_write calls to be killable to help those cases when the writer is blocked and waiting for readers to release the lock and so help __oom_reap_task to process the oom victim. Most of the patches are really trivial because the lock is help from a shallow syscall paths where we can return EINTR trivially and allow the current task to die (note that EINTR will never get to the userspace as the task has fatal signal pending). Others seem to be easy as well as the callers are already handling fatal errors and bail and return to userspace which should be sufficient to handle the failure gracefully. I am not familiar with all those code paths so a deeper review is really appreciated. As this work is touching more areas which are not directly connected I have tried to keep the CC list as small as possible and people who I believed would be familiar are CCed only to the specific patches (all should have received the cover though). This patchset is based on linux-next and it depends on down_write_killable for rw_semaphores which got merged into tip locking/rwsem branch and it is merged into this next tree. I guess it would be easiest to route these patches via mmotm because of the dependency on the tip tree but if respective maintainers prefer other way I have no objections. I haven't covered all the mmap_write(mm->mmap_sem) instances here $ git grep "down_write(.*\<mmap_sem\>)" next/master | wc -l 98 $ git grep "down_write(.*\<mmap_sem\>)" | wc -l 62 I have tried to cover those which should be relatively easy to review in this series because this alone should be a nice improvement. Other places can be changed on top. [0] http://lkml.kernel.org/r/1456752417-9626-1-git-send-email-mhocko@kernel.org [1] http://lkml.kernel.org/r/1452094975-551-1-git-send-email-mhocko@kernel.org [2] http://lkml.kernel.org/r/1456750705-7141-1-git-send-email-mhocko@kernel.org This patch (of 18): This is the first step in making mmap_sem write waiters killable. It focuses on the trivial ones which are taking the lock early after entering the syscall and they are not changing state before. Therefore it is very easy to change them to use down_write_killable and immediately return with -EINTR. This will allow the waiter to pass away without blocking the mmap_sem which might be required to make a forward progress. E.g. the oom reaper will need the lock for reading to dismantle the OOM victim address space. The only tricky function in this patch is vm_mmap_pgoff which has many call sites via vm_mmap. To reduce the risk keep vm_mmap with the original non-killable semantic for now. vm_munmap callers do not bother checking the return value so open code it into the munmap syscall path for now for simplicity. Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-24 07:25:27 +08:00
extern unsigned long __must_check vm_mmap_pgoff(struct file *, unsigned long,
unsigned long, unsigned long,
unsigned long, unsigned long);
mm: setup pageblock_order before it's used by sparsemem On architectures with CONFIG_HUGETLB_PAGE_SIZE_VARIABLE set, such as Itanium, pageblock_order is a variable with default value of 0. It's set to the right value by set_pageblock_order() in function free_area_init_core(). But pageblock_order may be used by sparse_init() before free_area_init_core() is called along path: sparse_init() ->sparse_early_usemaps_alloc_node() ->usemap_size() ->SECTION_BLOCKFLAGS_BITS ->((1UL << (PFN_SECTION_SHIFT - pageblock_order)) * NR_PAGEBLOCK_BITS) The uninitialized pageblock_size will cause memory wasting because usemap_size() returns a much bigger value then it's really needed. For example, on an Itanium platform, sparse_init() pageblock_order=0 usemap_size=24576 free_area_init_core() before pageblock_order=0, usemap_size=24576 free_area_init_core() after pageblock_order=12, usemap_size=8 That means 24K memory has been wasted for each section, so fix it by calling set_pageblock_order() from sparse_init(). Signed-off-by: Xishi Qiu <qiuxishi@huawei.com> Signed-off-by: Jiang Liu <liuj97@gmail.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: Keping Chen <chenkeping@huawei.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-08-01 07:43:19 +08:00
extern void set_pageblock_order(void);
unsigned long reclaim_clean_pages_from_list(struct zone *zone,
struct list_head *page_list);
/* The ALLOC_WMARK bits are used as an index to zone->watermark */
#define ALLOC_WMARK_MIN WMARK_MIN
#define ALLOC_WMARK_LOW WMARK_LOW
#define ALLOC_WMARK_HIGH WMARK_HIGH
#define ALLOC_NO_WATERMARKS 0x04 /* don't check watermarks at all */
/* Mask to get the watermark bits */
#define ALLOC_WMARK_MASK (ALLOC_NO_WATERMARKS-1)
mm, oom: do not rely on TIF_MEMDIE for memory reserves access For ages we have been relying on TIF_MEMDIE thread flag to mark OOM victims and then, among other things, to give these threads full access to memory reserves. There are few shortcomings of this implementation, though. First of all and the most serious one is that the full access to memory reserves is quite dangerous because we leave no safety room for the system to operate and potentially do last emergency steps to move on. Secondly this flag is per task_struct while the OOM killer operates on mm_struct granularity so all processes sharing the given mm are killed. Giving the full access to all these task_structs could lead to a quick memory reserves depletion. We have tried to reduce this risk by giving TIF_MEMDIE only to the main thread and the currently allocating task but that doesn't really solve this problem while it surely opens up a room for corner cases - e.g. GFP_NO{FS,IO} requests might loop inside the allocator without access to memory reserves because a particular thread was not the group leader. Now that we have the oom reaper and that all oom victims are reapable after 1b51e65eab64 ("oom, oom_reaper: allow to reap mm shared by the kthreads") we can be more conservative and grant only partial access to memory reserves because there are reasonable chances of the parallel memory freeing. We still want some access to reserves because we do not want other consumers to eat up the victim's freed memory. oom victims will still contend with __GFP_HIGH users but those shouldn't be so aggressive to starve oom victims completely. Introduce ALLOC_OOM flag and give all tsk_is_oom_victim tasks access to the half of the reserves. This makes the access to reserves independent on which task has passed through mark_oom_victim. Also drop any usage of TIF_MEMDIE from the page allocator proper and replace it by tsk_is_oom_victim as well which will make page_alloc.c completely TIF_MEMDIE free finally. CONFIG_MMU=n doesn't have oom reaper so let's stick to the original ALLOC_NO_WATERMARKS approach. There is a demand to make the oom killer memcg aware which will imply many tasks killed at once. This change will allow such a usecase without worrying about complete memory reserves depletion. Link: http://lkml.kernel.org/r/20170810075019.28998-2-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-07 07:24:50 +08:00
/*
* Only MMU archs have async oom victim reclaim - aka oom_reaper so we
* cannot assume a reduced access to memory reserves is sufficient for
* !MMU
*/
#ifdef CONFIG_MMU
#define ALLOC_OOM 0x08
#else
#define ALLOC_OOM ALLOC_NO_WATERMARKS
#endif
#define ALLOC_HARDER 0x10 /* try to alloc harder */
#define ALLOC_HIGH 0x20 /* __GFP_HIGH set */
#define ALLOC_CPUSET 0x40 /* check for correct cpuset */
#define ALLOC_CMA 0x80 /* allow allocations from CMA areas */
mm: send one IPI per CPU to TLB flush all entries after unmapping pages An IPI is sent to flush remote TLBs when a page is unmapped that was potentially accesssed by other CPUs. There are many circumstances where this happens but the obvious one is kswapd reclaiming pages belonging to a running process as kswapd and the task are likely running on separate CPUs. On small machines, this is not a significant problem but as machine gets larger with more cores and more memory, the cost of these IPIs can be high. This patch uses a simple structure that tracks CPUs that potentially have TLB entries for pages being unmapped. When the unmapping is complete, the full TLB is flushed on the assumption that a refill cost is lower than flushing individual entries. Architectures wishing to do this must give the following guarantee. If a clean page is unmapped and not immediately flushed, the architecture must guarantee that a write to that linear address from a CPU with a cached TLB entry will trap a page fault. This is essentially what the kernel already depends on but the window is much larger with this patch applied and is worth highlighting. The architecture should consider whether the cost of the full TLB flush is higher than sending an IPI to flush each individual entry. An additional architecture helper called flush_tlb_local is required. It's a trivial wrapper with some accounting in the x86 case. The impact of this patch depends on the workload as measuring any benefit requires both mapped pages co-located on the LRU and memory pressure. The case with the biggest impact is multiple processes reading mapped pages taken from the vm-scalability test suite. The test case uses NR_CPU readers of mapped files that consume 10*RAM. Linear mapped reader on a 4-node machine with 64G RAM and 48 CPUs 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 Ops lru-file-mmap-read-elapsed 159.62 ( 0.00%) 120.68 ( 24.40%) Ops lru-file-mmap-read-time_range 30.59 ( 0.00%) 2.80 ( 90.85%) Ops lru-file-mmap-read-time_stddv 6.70 ( 0.00%) 0.64 ( 90.38%) 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 User 581.00 611.43 System 5804.93 4111.76 Elapsed 161.03 122.12 This is showing that the readers completed 24.40% faster with 29% less system CPU time. From vmstats, it is known that the vanilla kernel was interrupted roughly 900K times per second during the steady phase of the test and the patched kernel was interrupts 180K times per second. The impact is lower on a single socket machine. 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 Ops lru-file-mmap-read-elapsed 25.33 ( 0.00%) 20.38 ( 19.54%) Ops lru-file-mmap-read-time_range 0.91 ( 0.00%) 1.44 (-58.24%) Ops lru-file-mmap-read-time_stddv 0.28 ( 0.00%) 0.47 (-65.34%) 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 User 58.09 57.64 System 111.82 76.56 Elapsed 27.29 22.55 It's still a noticeable improvement with vmstat showing interrupts went from roughly 500K per second to 45K per second. The patch will have no impact on workloads with no memory pressure or have relatively few mapped pages. It will have an unpredictable impact on the workload running on the CPU being flushed as it'll depend on how many TLB entries need to be refilled and how long that takes. Worst case, the TLB will be completely cleared of active entries when the target PFNs were not resident at all. [sasha.levin@oracle.com: trace tlb flush after disabling preemption in try_to_unmap_flush] Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Dave Hansen <dave.hansen@intel.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-05 06:47:32 +08:00
enum ttu_flags;
struct tlbflush_unmap_batch;
mm: move pcp and lru-pcp draining into single wq We currently have 2 specific WQ_RECLAIM workqueues in the mm code. vmstat_wq for updating pcp stats and lru_add_drain_wq dedicated to drain per cpu lru caches. This seems more than necessary because both can run on a single WQ. Both do not block on locks requiring a memory allocation nor perform any allocations themselves. We will save one rescuer thread this way. On the other hand drain_all_pages() queues work on the system wq which doesn't have rescuer and so this depend on memory allocation (when all workers are stuck allocating and new ones cannot be created). Initially we thought this would be more of a theoretical problem but Hugh Dickins has reported: : 4.11-rc has been giving me hangs after hours of swapping load. At : first they looked like memory leaks ("fork: Cannot allocate memory"); : but for no good reason I happened to do "cat /proc/sys/vm/stat_refresh" : before looking at /proc/meminfo one time, and the stat_refresh stuck : in D state, waiting for completion of flush_work like many kworkers. : kthreadd waiting for completion of flush_work in drain_all_pages(). This worker should be using WQ_RECLAIM as well in order to guarantee a forward progress. We can reuse the same one as for lru draining and vmstat. Link: http://lkml.kernel.org/r/20170307131751.24936-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@suse.de> Tested-by: Yang Li <pku.leo@gmail.com> Tested-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-04-08 07:05:05 +08:00
/*
* only for MM internal work items which do not depend on
* any allocations or locks which might depend on allocations
*/
extern struct workqueue_struct *mm_percpu_wq;
mm: send one IPI per CPU to TLB flush all entries after unmapping pages An IPI is sent to flush remote TLBs when a page is unmapped that was potentially accesssed by other CPUs. There are many circumstances where this happens but the obvious one is kswapd reclaiming pages belonging to a running process as kswapd and the task are likely running on separate CPUs. On small machines, this is not a significant problem but as machine gets larger with more cores and more memory, the cost of these IPIs can be high. This patch uses a simple structure that tracks CPUs that potentially have TLB entries for pages being unmapped. When the unmapping is complete, the full TLB is flushed on the assumption that a refill cost is lower than flushing individual entries. Architectures wishing to do this must give the following guarantee. If a clean page is unmapped and not immediately flushed, the architecture must guarantee that a write to that linear address from a CPU with a cached TLB entry will trap a page fault. This is essentially what the kernel already depends on but the window is much larger with this patch applied and is worth highlighting. The architecture should consider whether the cost of the full TLB flush is higher than sending an IPI to flush each individual entry. An additional architecture helper called flush_tlb_local is required. It's a trivial wrapper with some accounting in the x86 case. The impact of this patch depends on the workload as measuring any benefit requires both mapped pages co-located on the LRU and memory pressure. The case with the biggest impact is multiple processes reading mapped pages taken from the vm-scalability test suite. The test case uses NR_CPU readers of mapped files that consume 10*RAM. Linear mapped reader on a 4-node machine with 64G RAM and 48 CPUs 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 Ops lru-file-mmap-read-elapsed 159.62 ( 0.00%) 120.68 ( 24.40%) Ops lru-file-mmap-read-time_range 30.59 ( 0.00%) 2.80 ( 90.85%) Ops lru-file-mmap-read-time_stddv 6.70 ( 0.00%) 0.64 ( 90.38%) 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 User 581.00 611.43 System 5804.93 4111.76 Elapsed 161.03 122.12 This is showing that the readers completed 24.40% faster with 29% less system CPU time. From vmstats, it is known that the vanilla kernel was interrupted roughly 900K times per second during the steady phase of the test and the patched kernel was interrupts 180K times per second. The impact is lower on a single socket machine. 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 Ops lru-file-mmap-read-elapsed 25.33 ( 0.00%) 20.38 ( 19.54%) Ops lru-file-mmap-read-time_range 0.91 ( 0.00%) 1.44 (-58.24%) Ops lru-file-mmap-read-time_stddv 0.28 ( 0.00%) 0.47 (-65.34%) 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 User 58.09 57.64 System 111.82 76.56 Elapsed 27.29 22.55 It's still a noticeable improvement with vmstat showing interrupts went from roughly 500K per second to 45K per second. The patch will have no impact on workloads with no memory pressure or have relatively few mapped pages. It will have an unpredictable impact on the workload running on the CPU being flushed as it'll depend on how many TLB entries need to be refilled and how long that takes. Worst case, the TLB will be completely cleared of active entries when the target PFNs were not resident at all. [sasha.levin@oracle.com: trace tlb flush after disabling preemption in try_to_unmap_flush] Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Dave Hansen <dave.hansen@intel.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-05 06:47:32 +08:00
#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
void try_to_unmap_flush(void);
void try_to_unmap_flush_dirty(void);
mm, mprotect: flush TLB if potentially racing with a parallel reclaim leaving stale TLB entries Nadav Amit identified a theoritical race between page reclaim and mprotect due to TLB flushes being batched outside of the PTL being held. He described the race as follows: CPU0 CPU1 ---- ---- user accesses memory using RW PTE [PTE now cached in TLB] try_to_unmap_one() ==> ptep_get_and_clear() ==> set_tlb_ubc_flush_pending() mprotect(addr, PROT_READ) ==> change_pte_range() ==> [ PTE non-present - no flush ] user writes using cached RW PTE ... try_to_unmap_flush() The same type of race exists for reads when protecting for PROT_NONE and also exists for operations that can leave an old TLB entry behind such as munmap, mremap and madvise. For some operations like mprotect, it's not necessarily a data integrity issue but it is a correctness issue as there is a window where an mprotect that limits access still allows access. For munmap, it's potentially a data integrity issue although the race is massive as an munmap, mmap and return to userspace must all complete between the window when reclaim drops the PTL and flushes the TLB. However, it's theoritically possible so handle this issue by flushing the mm if reclaim is potentially currently batching TLB flushes. Other instances where a flush is required for a present pte should be ok as either the page lock is held preventing parallel reclaim or a page reference count is elevated preventing a parallel free leading to corruption. In the case of page_mkclean there isn't an obvious path that userspace could take advantage of without using the operations that are guarded by this patch. Other users such as gup as a race with reclaim looks just at PTEs. huge page variants should be ok as they don't race with reclaim. mincore only looks at PTEs. userfault also should be ok as if a parallel reclaim takes place, it will either fault the page back in or read some of the data before the flush occurs triggering a fault. Note that a variant of this patch was acked by Andy Lutomirski but this was for the x86 parts on top of his PCID work which didn't make the 4.13 merge window as expected. His ack is dropped from this version and there will be a follow-on patch on top of PCID that will include his ack. [akpm@linux-foundation.org: tweak comments] [akpm@linux-foundation.org: fix spello] Link: http://lkml.kernel.org/r/20170717155523.emckq2esjro6hf3z@suse.de Reported-by: Nadav Amit <nadav.amit@gmail.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: <stable@vger.kernel.org> [v4.4+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-03 04:31:52 +08:00
void flush_tlb_batched_pending(struct mm_struct *mm);
mm: send one IPI per CPU to TLB flush all entries after unmapping pages An IPI is sent to flush remote TLBs when a page is unmapped that was potentially accesssed by other CPUs. There are many circumstances where this happens but the obvious one is kswapd reclaiming pages belonging to a running process as kswapd and the task are likely running on separate CPUs. On small machines, this is not a significant problem but as machine gets larger with more cores and more memory, the cost of these IPIs can be high. This patch uses a simple structure that tracks CPUs that potentially have TLB entries for pages being unmapped. When the unmapping is complete, the full TLB is flushed on the assumption that a refill cost is lower than flushing individual entries. Architectures wishing to do this must give the following guarantee. If a clean page is unmapped and not immediately flushed, the architecture must guarantee that a write to that linear address from a CPU with a cached TLB entry will trap a page fault. This is essentially what the kernel already depends on but the window is much larger with this patch applied and is worth highlighting. The architecture should consider whether the cost of the full TLB flush is higher than sending an IPI to flush each individual entry. An additional architecture helper called flush_tlb_local is required. It's a trivial wrapper with some accounting in the x86 case. The impact of this patch depends on the workload as measuring any benefit requires both mapped pages co-located on the LRU and memory pressure. The case with the biggest impact is multiple processes reading mapped pages taken from the vm-scalability test suite. The test case uses NR_CPU readers of mapped files that consume 10*RAM. Linear mapped reader on a 4-node machine with 64G RAM and 48 CPUs 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 Ops lru-file-mmap-read-elapsed 159.62 ( 0.00%) 120.68 ( 24.40%) Ops lru-file-mmap-read-time_range 30.59 ( 0.00%) 2.80 ( 90.85%) Ops lru-file-mmap-read-time_stddv 6.70 ( 0.00%) 0.64 ( 90.38%) 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 User 581.00 611.43 System 5804.93 4111.76 Elapsed 161.03 122.12 This is showing that the readers completed 24.40% faster with 29% less system CPU time. From vmstats, it is known that the vanilla kernel was interrupted roughly 900K times per second during the steady phase of the test and the patched kernel was interrupts 180K times per second. The impact is lower on a single socket machine. 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 Ops lru-file-mmap-read-elapsed 25.33 ( 0.00%) 20.38 ( 19.54%) Ops lru-file-mmap-read-time_range 0.91 ( 0.00%) 1.44 (-58.24%) Ops lru-file-mmap-read-time_stddv 0.28 ( 0.00%) 0.47 (-65.34%) 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 User 58.09 57.64 System 111.82 76.56 Elapsed 27.29 22.55 It's still a noticeable improvement with vmstat showing interrupts went from roughly 500K per second to 45K per second. The patch will have no impact on workloads with no memory pressure or have relatively few mapped pages. It will have an unpredictable impact on the workload running on the CPU being flushed as it'll depend on how many TLB entries need to be refilled and how long that takes. Worst case, the TLB will be completely cleared of active entries when the target PFNs were not resident at all. [sasha.levin@oracle.com: trace tlb flush after disabling preemption in try_to_unmap_flush] Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Dave Hansen <dave.hansen@intel.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-05 06:47:32 +08:00
#else
static inline void try_to_unmap_flush(void)
{
}
static inline void try_to_unmap_flush_dirty(void)
{
}
mm, mprotect: flush TLB if potentially racing with a parallel reclaim leaving stale TLB entries Nadav Amit identified a theoritical race between page reclaim and mprotect due to TLB flushes being batched outside of the PTL being held. He described the race as follows: CPU0 CPU1 ---- ---- user accesses memory using RW PTE [PTE now cached in TLB] try_to_unmap_one() ==> ptep_get_and_clear() ==> set_tlb_ubc_flush_pending() mprotect(addr, PROT_READ) ==> change_pte_range() ==> [ PTE non-present - no flush ] user writes using cached RW PTE ... try_to_unmap_flush() The same type of race exists for reads when protecting for PROT_NONE and also exists for operations that can leave an old TLB entry behind such as munmap, mremap and madvise. For some operations like mprotect, it's not necessarily a data integrity issue but it is a correctness issue as there is a window where an mprotect that limits access still allows access. For munmap, it's potentially a data integrity issue although the race is massive as an munmap, mmap and return to userspace must all complete between the window when reclaim drops the PTL and flushes the TLB. However, it's theoritically possible so handle this issue by flushing the mm if reclaim is potentially currently batching TLB flushes. Other instances where a flush is required for a present pte should be ok as either the page lock is held preventing parallel reclaim or a page reference count is elevated preventing a parallel free leading to corruption. In the case of page_mkclean there isn't an obvious path that userspace could take advantage of without using the operations that are guarded by this patch. Other users such as gup as a race with reclaim looks just at PTEs. huge page variants should be ok as they don't race with reclaim. mincore only looks at PTEs. userfault also should be ok as if a parallel reclaim takes place, it will either fault the page back in or read some of the data before the flush occurs triggering a fault. Note that a variant of this patch was acked by Andy Lutomirski but this was for the x86 parts on top of his PCID work which didn't make the 4.13 merge window as expected. His ack is dropped from this version and there will be a follow-on patch on top of PCID that will include his ack. [akpm@linux-foundation.org: tweak comments] [akpm@linux-foundation.org: fix spello] Link: http://lkml.kernel.org/r/20170717155523.emckq2esjro6hf3z@suse.de Reported-by: Nadav Amit <nadav.amit@gmail.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: <stable@vger.kernel.org> [v4.4+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-03 04:31:52 +08:00
static inline void flush_tlb_batched_pending(struct mm_struct *mm)
{
}
mm: send one IPI per CPU to TLB flush all entries after unmapping pages An IPI is sent to flush remote TLBs when a page is unmapped that was potentially accesssed by other CPUs. There are many circumstances where this happens but the obvious one is kswapd reclaiming pages belonging to a running process as kswapd and the task are likely running on separate CPUs. On small machines, this is not a significant problem but as machine gets larger with more cores and more memory, the cost of these IPIs can be high. This patch uses a simple structure that tracks CPUs that potentially have TLB entries for pages being unmapped. When the unmapping is complete, the full TLB is flushed on the assumption that a refill cost is lower than flushing individual entries. Architectures wishing to do this must give the following guarantee. If a clean page is unmapped and not immediately flushed, the architecture must guarantee that a write to that linear address from a CPU with a cached TLB entry will trap a page fault. This is essentially what the kernel already depends on but the window is much larger with this patch applied and is worth highlighting. The architecture should consider whether the cost of the full TLB flush is higher than sending an IPI to flush each individual entry. An additional architecture helper called flush_tlb_local is required. It's a trivial wrapper with some accounting in the x86 case. The impact of this patch depends on the workload as measuring any benefit requires both mapped pages co-located on the LRU and memory pressure. The case with the biggest impact is multiple processes reading mapped pages taken from the vm-scalability test suite. The test case uses NR_CPU readers of mapped files that consume 10*RAM. Linear mapped reader on a 4-node machine with 64G RAM and 48 CPUs 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 Ops lru-file-mmap-read-elapsed 159.62 ( 0.00%) 120.68 ( 24.40%) Ops lru-file-mmap-read-time_range 30.59 ( 0.00%) 2.80 ( 90.85%) Ops lru-file-mmap-read-time_stddv 6.70 ( 0.00%) 0.64 ( 90.38%) 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 User 581.00 611.43 System 5804.93 4111.76 Elapsed 161.03 122.12 This is showing that the readers completed 24.40% faster with 29% less system CPU time. From vmstats, it is known that the vanilla kernel was interrupted roughly 900K times per second during the steady phase of the test and the patched kernel was interrupts 180K times per second. The impact is lower on a single socket machine. 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 Ops lru-file-mmap-read-elapsed 25.33 ( 0.00%) 20.38 ( 19.54%) Ops lru-file-mmap-read-time_range 0.91 ( 0.00%) 1.44 (-58.24%) Ops lru-file-mmap-read-time_stddv 0.28 ( 0.00%) 0.47 (-65.34%) 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 User 58.09 57.64 System 111.82 76.56 Elapsed 27.29 22.55 It's still a noticeable improvement with vmstat showing interrupts went from roughly 500K per second to 45K per second. The patch will have no impact on workloads with no memory pressure or have relatively few mapped pages. It will have an unpredictable impact on the workload running on the CPU being flushed as it'll depend on how many TLB entries need to be refilled and how long that takes. Worst case, the TLB will be completely cleared of active entries when the target PFNs were not resident at all. [sasha.levin@oracle.com: trace tlb flush after disabling preemption in try_to_unmap_flush] Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Dave Hansen <dave.hansen@intel.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-05 06:47:32 +08:00
#endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */
mm, printk: introduce new format string for flags In mm we use several kinds of flags bitfields that are sometimes printed for debugging purposes, or exported to userspace via sysfs. To make them easier to interpret independently on kernel version and config, we want to dump also the symbolic flag names. So far this has been done with repeated calls to pr_cont(), which is unreliable on SMP, and not usable for e.g. sysfs export. To get a more reliable and universal solution, this patch extends printk() format string for pointers to handle the page flags (%pGp), gfp_flags (%pGg) and vma flags (%pGv). Existing users of dump_flag_names() are converted and simplified. It would be possible to pass flags by value instead of pointer, but the %p format string for pointers already has extensions for various kernel structures, so it's a good fit, and the extra indirection in a non-critical path is negligible. [linux@rasmusvillemoes.dk: lots of good implementation suggestions] Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-16 05:55:56 +08:00
extern const struct trace_print_flags pageflag_names[];
extern const struct trace_print_flags vmaflag_names[];
extern const struct trace_print_flags gfpflag_names[];
static inline bool is_migrate_highatomic(enum migratetype migratetype)
{
return migratetype == MIGRATE_HIGHATOMIC;
}
static inline bool is_migrate_highatomic_page(struct page *page)
{
return get_pageblock_migratetype(page) == MIGRATE_HIGHATOMIC;
}
void setup_zone_pageset(struct zone *zone);
#endif /* __MM_INTERNAL_H */