Patch series "mm: introduce shrinker debugfs interface", v5.
The only existing debugging mechanism is a couple of tracepoints in
do_shrink_slab(): mm_shrink_slab_start and mm_shrink_slab_end. They
aren't covering everything though: shrinkers which report 0 objects will
never show up, there is no support for memcg-aware shrinkers. Shrinkers
are identified by their scan function, which is not always enough (e.g.
hard to guess which super block's shrinker it is having only
"super_cache_scan").
To provide a better visibility and debug options for memory shrinkers this
patchset introduces a /sys/kernel/debug/shrinker interface, to some extent
similar to /sys/kernel/slab.
For each shrinker registered in the system a directory is created. As
now, the directory will contain only a "scan" file, which allows to get
the number of managed objects for each memory cgroup (for memcg-aware
shrinkers) and each numa node (for numa-aware shrinkers on a numa
machine). Other interfaces might be added in the future.
To make debugging more pleasant, the patchset also names all shrinkers, so
that debugfs entries can have meaningful names.
This patch (of 5):
Shrinker debugfs requires a way to represent memory cgroups without using
full paths, both for displaying information and getting input from a user.
Cgroup inode number is a perfect way, already used by bpf.
This commit adds a couple of helper functions which will be used to handle
memcg-aware shrinkers.
Link: https://lkml.kernel.org/r/20220601032227.4076670-1-roman.gushchin@linux.dev
Link: https://lkml.kernel.org/r/20220601032227.4076670-2-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Currently mem_cgroup_from_obj() is not working properly with objects
allocated using vmalloc(). It creates problems in some cases, when it's
called for static objects belonging to modules or generally allocated
using vmalloc().
This patch makes mem_cgroup_from_obj() safe to be called on objects
allocated using vmalloc().
It also introduces mem_cgroup_from_slab_obj(), which is a faster version
to use in places when we know the object is either a slab object or a
generic slab page (e.g. when adding an object to a lru list).
Link: https://lkml.kernel.org/r/20220610180310.1725111-1-roman.gushchin@linux.dev
Suggested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Acked-by: Shakeel Butt <shakeelb@google.com>
Tested-by: Vasily Averin <vvs@openvz.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: Qian Cai <quic_qiancai@quicinc.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Florian Westphal <fw@strlen.de>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There are already statistics of {pgscan,pgsteal}_kswapd and
{pgscan,pgsteal}_direct of memcg event here, but now only the sum of the
two is displayed in memory.stat of cgroup v2.
In order to obtain more accurate information during monitoring and
debugging, and to align with the display in /proc/vmstat, it better to
display {pgscan,pgsteal}_kswapd and {pgscan,pgsteal}_direct separately.
Also, for forward compatibility, we still display pgscan and pgsteal items
so that it won't break existing applications.
[zhengqi.arch@bytedance.com: add comment for memcg_vm_event_stat (suggested by Michal)]
Link: https://lkml.kernel.org/r/20220606154028.55030-1-zhengqi.arch@bytedance.com
[zhengqi.arch@bytedance.com: fix the doc, thanks to Johannes]
Link: https://lkml.kernel.org/r/20220607064803.79363-1-zhengqi.arch@bytedance.com
Link: https://lkml.kernel.org/r/20220604082209.55174-1-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There is no slabinfo.py in tools/cgroup, but has memcg_slabinfo.py instead.
Link: https://lkml.kernel.org/r/20220610024451.744135-1-yang.yang29@zte.com.cn
Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Applications can currently escape their cgroup memory containment when
zswap is enabled. This patch adds per-cgroup tracking and limiting of
zswap backend memory to rectify this.
The existing cgroup2 memory.stat file is extended to show zswap statistics
analogous to what's in meminfo and vmstat. Furthermore, two new control
files, memory.zswap.current and memory.zswap.max, are added to allow
tuning zswap usage on a per-workload basis. This is important since not
all workloads benefit from zswap equally; some even suffer compared to
disk swap when memory contents don't compress well. The optimal size of
the zswap pool, and the threshold for writeback, also depends on the size
of the workload's warm set.
The implementation doesn't use a traditional page_counter transaction.
zswap is unconventional as a memory consumer in that we only know the
amount of memory to charge once expensive compression has occurred. If
zwap is disabled or the limit is already exceeded we obviously don't want
to compress page upon page only to reject them all. Instead, the limit is
checked against current usage, then we compress and charge. This allows
some limit overrun, but not enough to matter in practice.
[hannes@cmpxchg.org: fix for CONFIG_SLOB builds]
Link: https://lkml.kernel.org/r/YnwD14zxYjUJPc2w@cmpxchg.org
[hannes@cmpxchg.org: opt out of cgroups v1]
Link: https://lkml.kernel.org/r/Yn6it9mBYFA+/lTb@cmpxchg.org
Link: https://lkml.kernel.org/r/20220510152847.230957-7-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We run a lot of automated tests when building our software and run into
OOM scenarios when the tests run unbounded. v1 memcg exports
memcg->watermark as "memory.max_usage_in_bytes" in sysfs. We use this
metric to heuristically limit the number of tests that can run in parallel
based on per test historical data.
This metric is currently not exported for v2 memcg and there is no other
easy way of getting this information. getrusage() syscall returns
"ru_maxrss" which can be used as an approximation but that's the max RSS
of a single child process across all children instead of the aggregated
max for all child processes. The only work around is to periodically poll
"memory.current" but that's not practical for short-lived one-off cgroups.
Hence, expose memcg->watermark as "memory.peak" for v2 memcg.
Link: https://lkml.kernel.org/r/20220507050916.GA13577@us192.sjc.aristanetworks.com
Signed-off-by: Ganesan Rajagopal <rganesan@arista.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This removes an assumption that a large folio is HPAGE_PMD_NR pages
in size.
Link: https://lkml.kernel.org/r/20220504182857.4013401-8-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This patch still does not use pte marker in any way, however it teaches
the core mm about the pte marker idea.
For example, handle_pte_marker() is introduced that will parse and handle
all the pte marker faults.
Many of the places are more about commenting it up - so that we know
there's the possibility of pte marker showing up, and why we don't need
special code for the cases.
[peterx@redhat.com: userfaultfd.c needs swapops.h]
Link: https://lkml.kernel.org/r/YmRlVj3cdizYJsr0@xz-m1.local
Link: https://lkml.kernel.org/r/20220405014833.14015-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "MM changes to improve swap-over-NFS support".
Assorted improvements for swap-via-filesystem.
This is a resend of these patches, rebased on current HEAD. The only
substantial changes is that swap_dirty_folio has replaced
swap_set_page_dirty.
Currently swap-via-fs (SWP_FS_OPS) doesn't work for any filesystem. It
has previously worked for NFS but that broke a few releases back. This
series changes to use a new ->swap_rw rather than ->readpage and
->direct_IO. It also makes other improvements.
There is a companion series already in linux-next which fixes various
issues with NFS. Once both series land, a final patch is needed which
changes NFS over to use ->swap_rw.
This patch (of 10):
Many functions declared in include/linux/swap.h are only used within mm/
Create a new "mm/swap.h" and move some of these declarations there.
Remove the redundant 'extern' from the function declarations.
[akpm@linux-foundation.org: mm/memory-failure.c needs mm/swap.h]
Link: https://lkml.kernel.org/r/164859751830.29473.5309689752169286816.stgit@noble.brown
Link: https://lkml.kernel.org/r/164859778120.29473.11725907882296224053.stgit@noble.brown
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: David Howells <dhowells@redhat.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This patch series adds a memory.reclaim proactive reclaim interface.
The rationale behind the interface and how it works are in the first
patch.
This patch (of 4):
Introduce a memcg interface to trigger memory reclaim on a memory cgroup.
Use case: Proactive Reclaim
---------------------------
A userspace proactive reclaimer can continuously probe the memcg to
reclaim a small amount of memory. This gives more accurate and up-to-date
workingset estimation as the LRUs are continuously sorted and can
potentially provide more deterministic memory overcommit behavior. The
memory overcommit controller can provide more proactive response to the
changing behavior of the running applications instead of being reactive.
A userspace reclaimer's purpose in this case is not a complete replacement
for kswapd or direct reclaim, it is to proactively identify memory savings
opportunities and reclaim some amount of cold pages set by the policy to
free up the memory for more demanding jobs or scheduling new jobs.
A user space proactive reclaimer is used in Google data centers.
Additionally, Meta's TMO paper recently referenced a very similar
interface used for user space proactive reclaim:
https://dl.acm.org/doi/pdf/10.1145/3503222.3507731
Benefits of a user space reclaimer:
-----------------------------------
1) More flexible on who should be charged for the cpu of the memory
reclaim. For proactive reclaim, it makes more sense to be centralized.
2) More flexible on dedicating the resources (like cpu). The memory
overcommit controller can balance the cost between the cpu usage and
the memory reclaimed.
3) Provides a way to the applications to keep their LRUs sorted, so,
under memory pressure better reclaim candidates are selected. This
also gives more accurate and uptodate notion of working set for an
application.
Why memory.high is not enough?
------------------------------
- memory.high can be used to trigger reclaim in a memcg and can
potentially be used for proactive reclaim. However there is a big
downside in using memory.high. It can potentially introduce high
reclaim stalls in the target application as the allocations from the
processes or the threads of the application can hit the temporary
memory.high limit.
- Userspace proactive reclaimers usually use feedback loops to decide
how much memory to proactively reclaim from a workload. The metrics
used for this are usually either refaults or PSI, and these metrics will
become messy if the application gets throttled by hitting the high
limit.
- memory.high is a stateful interface, if the userspace proactive
reclaimer crashes for any reason while triggering reclaim it can leave
the application in a bad state.
- If a workload is rapidly expanding, setting memory.high to proactively
reclaim memory can result in actually reclaiming more memory than
intended.
The benefits of such interface and shortcomings of existing interface were
further discussed in this RFC thread:
https://lore.kernel.org/linux-mm/5df21376-7dd1-bf81-8414-32a73cea45dd@google.com/
Interface:
----------
Introducing a very simple memcg interface 'echo 10M > memory.reclaim' to
trigger reclaim in the target memory cgroup.
The interface is introduced as a nested-keyed file to allow for future
optional arguments to be easily added to configure the behavior of
reclaim.
Possible Extensions:
--------------------
- This interface can be extended with an additional parameter or flags
to allow specifying one or more types of memory to reclaim from (e.g.
file, anon, ..).
- The interface can also be extended with a node mask to reclaim from
specific nodes. This has use cases for reclaim-based demotion in memory
tiering systens.
- A similar per-node interface can also be added to support proactive
reclaim and reclaim-based demotion in systems without memcg.
- Add a timeout parameter to make it easier for user space to call the
interface without worrying about being blocked for an undefined amount
of time.
For now, let's keep things simple by adding the basic functionality.
[yosryahmed@google.com: worked on versions v2 onwards, refreshed to
current master, updated commit message based on recent
discussions and use cases]
Link: https://lkml.kernel.org/r/20220425190040.2475377-1-yosryahmed@google.com
Link: https://lkml.kernel.org/r/20220425190040.2475377-2-yosryahmed@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Co-developed-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Wei Xu <weixugc@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Chen Wandun <chenwandun@huawei.com>
Cc: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: "Michal Koutn" <mkoutny@suse.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There is no use for the private value, __OOM_TYPE and OOM notifier
OOM_CONTROL. Therefore remove them to make the code clean.
Link: https://lkml.kernel.org/r/20220421122755.40899-1-lujialin4@huawei.com
Signed-off-by: Lu Jialin <lujialin4@huawei.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
cgroup_memory_noswap is only used in mm/memcontrol.c, therefore just make
it static, and remove export in include/linux/memcontrol.h
Link: https://lkml.kernel.org/r/20220421124736.62180-1-lujialin4@huawei.com
Signed-off-by: Lu Jialin <lujialin4@huawei.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
After commit bef8620cd8 ("mm: memcg: deprecate the non-hierarchical
mode"), we won't have a NULL parent except root_mem_cgroup. And this case
is handled when (memcg == root).
Link: https://lkml.kernel.org/r/20220403020833.26164-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
For each round-trip, we assign generation on first invocation and compare
it on subsequent invocations.
Let's move them together to make it more self-explaining. Also this
reduce a check on prev.
[hannes@cmpxchg.org: better comment to explain reclaim model]
Link: https://lkml.kernel.org/r/20220330234719.18340-4-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
During mem_cgroup_iter, there are two ways to get iteration position:
reclaim vs non-reclaim mode.
Let's do it explicitly for reclaim vs non-reclaim mode.
Link: https://lkml.kernel.org/r/20220330234719.18340-3-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/memcg: some cleanup for mem_cgroup_iter()", v2.
No functional change, try to make it more readable.
This patch (of 3):
Instead of resetting memcg when css is either not verified or not got
reference, we can set it after these process.
No functional change, just simplified the code a little.
Link: https://lkml.kernel.org/r/20220330234719.18340-1-richard.weiyang@gmail.com
Link: https://lkml.kernel.org/r/20220330234719.18340-2-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When mz is not NULL, it means mz can either come from
mem_cgroup_largest_soft_limit_node or
__mem_cgroup_largest_soft_limit_node. And both of them have removed this
node by __mem_cgroup_remove_exceeded().
Not necessary to call __mem_cgroup_remove_exceeded() again.
[mhocko@suse.com: refine changelog]
Link: https://lkml.kernel.org/r/20220314233030.12334-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The local variable nr_scanned is unneeded as mem_cgroup_soft_reclaim
always does *total_scanned += nr_scanned. So we can pass total_scanned
directly to the mem_cgroup_soft_reclaim to simplify the code and save some
cpu cycles of adding nr_scanned to total_scanned.
Link: https://lkml.kernel.org/r/20220328114144.53389-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Daniel Dao has reported [1] a regression on workloads that may trigger a
lot of refaults (anon and file). The underlying issue is that flushing
rstat is expensive. Although rstat flush are batched with (nr_cpus *
MEMCG_BATCH) stat updates, it seems like there are workloads which
genuinely do stat updates larger than batch value within short amount of
time. Since the rstat flush can happen in the performance critical
codepaths like page faults, such workload can suffer greatly.
This patch fixes this regression by making the rstat flushing
conditional in the performance critical codepaths. More specifically,
the kernel relies on the async periodic rstat flusher to flush the stats
and only if the periodic flusher is delayed by more than twice the
amount of its normal time window then the kernel allows rstat flushing
from the performance critical codepaths.
Now the question: what are the side-effects of this change? The worst
that can happen is the refault codepath will see 4sec old lruvec stats
and may cause false (or missed) activations of the refaulted page which
may under-or-overestimate the workingset size. Though that is not very
concerning as the kernel can already miss or do false activations.
There are two more codepaths whose flushing behavior is not changed by
this patch and we may need to come to them in future. One is the
writeback stats used by dirty throttling and second is the deactivation
heuristic in the reclaim. For now keeping an eye on them and if there
is report of regression due to these codepaths, we will reevaluate then.
Link: https://lore.kernel.org/all/CA+wXwBSyO87ZX5PVwdHm-=dBjZYECGmfnydUicUyrQqndgX2MQ@mail.gmail.com [1]
Link: https://lkml.kernel.org/r/20220304184040.1304781-1-shakeelb@google.com
Fixes: 1f828223b7 ("memcg: flush lruvec stats in the refault")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reported-by: Daniel Dao <dqminh@cloudflare.com>
Tested-by: Ivan Babrou <ivan@cloudflare.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Frank Hofmann <fhofmann@cloudflare.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This set of changes removes tracehook.h, moves modification of all of
the ptrace fields inside of siglock to remove races, adds a missing
permission check to ptrace.c
The removal of tracehook.h is quite significant as it has been a major
source of confusion in recent years. Much of that confusion was
around task_work and TIF_NOTIFY_SIGNAL (which I have now decoupled
making the semantics clearer).
For people who don't know tracehook.h is a vestiage of an attempt to
implement uprobes like functionality that was never fully merged, and
was later superseeded by uprobes when uprobes was merged. For many
years now we have been removing what tracehook functionaly a little
bit at a time. To the point where now anything left in tracehook.h is
some weird strange thing that is difficult to understand.
Eric W. Biederman (15):
ptrace: Move ptrace_report_syscall into ptrace.h
ptrace/arm: Rename tracehook_report_syscall report_syscall
ptrace: Create ptrace_report_syscall_{entry,exit} in ptrace.h
ptrace: Remove arch_syscall_{enter,exit}_tracehook
ptrace: Remove tracehook_signal_handler
task_work: Remove unnecessary include from posix_timers.h
task_work: Introduce task_work_pending
task_work: Call tracehook_notify_signal from get_signal on all architectures
task_work: Decouple TIF_NOTIFY_SIGNAL and task_work
signal: Move set_notify_signal and clear_notify_signal into sched/signal.h
resume_user_mode: Remove #ifdef TIF_NOTIFY_RESUME in set_notify_resume
resume_user_mode: Move to resume_user_mode.h
tracehook: Remove tracehook.h
ptrace: Move setting/clearing ptrace_message into ptrace_stop
ptrace: Return the signal to continue with from ptrace_stop
Jann Horn (1):
ptrace: Check PTRACE_O_SUSPEND_SECCOMP permission on PTRACE_SEIZE
Yang Li (1):
ptrace: Remove duplicated include in ptrace.c
MAINTAINERS | 1 -
arch/Kconfig | 5 +-
arch/alpha/kernel/ptrace.c | 5 +-
arch/alpha/kernel/signal.c | 4 +-
arch/arc/kernel/ptrace.c | 5 +-
arch/arc/kernel/signal.c | 4 +-
arch/arm/kernel/ptrace.c | 12 +-
arch/arm/kernel/signal.c | 4 +-
arch/arm64/kernel/ptrace.c | 14 +--
arch/arm64/kernel/signal.c | 4 +-
arch/csky/kernel/ptrace.c | 5 +-
arch/csky/kernel/signal.c | 4 +-
arch/h8300/kernel/ptrace.c | 5 +-
arch/h8300/kernel/signal.c | 4 +-
arch/hexagon/kernel/process.c | 4 +-
arch/hexagon/kernel/signal.c | 1 -
arch/hexagon/kernel/traps.c | 6 +-
arch/ia64/kernel/process.c | 4 +-
arch/ia64/kernel/ptrace.c | 6 +-
arch/ia64/kernel/signal.c | 1 -
arch/m68k/kernel/ptrace.c | 5 +-
arch/m68k/kernel/signal.c | 4 +-
arch/microblaze/kernel/ptrace.c | 5 +-
arch/microblaze/kernel/signal.c | 4 +-
arch/mips/kernel/ptrace.c | 5 +-
arch/mips/kernel/signal.c | 4 +-
arch/nds32/include/asm/syscall.h | 2 +-
arch/nds32/kernel/ptrace.c | 5 +-
arch/nds32/kernel/signal.c | 4 +-
arch/nios2/kernel/ptrace.c | 5 +-
arch/nios2/kernel/signal.c | 4 +-
arch/openrisc/kernel/ptrace.c | 5 +-
arch/openrisc/kernel/signal.c | 4 +-
arch/parisc/kernel/ptrace.c | 7 +-
arch/parisc/kernel/signal.c | 4 +-
arch/powerpc/kernel/ptrace/ptrace.c | 8 +-
arch/powerpc/kernel/signal.c | 4 +-
arch/riscv/kernel/ptrace.c | 5 +-
arch/riscv/kernel/signal.c | 4 +-
arch/s390/include/asm/entry-common.h | 1 -
arch/s390/kernel/ptrace.c | 1 -
arch/s390/kernel/signal.c | 5 +-
arch/sh/kernel/ptrace_32.c | 5 +-
arch/sh/kernel/signal_32.c | 4 +-
arch/sparc/kernel/ptrace_32.c | 5 +-
arch/sparc/kernel/ptrace_64.c | 5 +-
arch/sparc/kernel/signal32.c | 1 -
arch/sparc/kernel/signal_32.c | 4 +-
arch/sparc/kernel/signal_64.c | 4 +-
arch/um/kernel/process.c | 4 +-
arch/um/kernel/ptrace.c | 5 +-
arch/x86/kernel/ptrace.c | 1 -
arch/x86/kernel/signal.c | 5 +-
arch/x86/mm/tlb.c | 1 +
arch/xtensa/kernel/ptrace.c | 5 +-
arch/xtensa/kernel/signal.c | 4 +-
block/blk-cgroup.c | 2 +-
fs/coredump.c | 1 -
fs/exec.c | 1 -
fs/io-wq.c | 6 +-
fs/io_uring.c | 11 +-
fs/proc/array.c | 1 -
fs/proc/base.c | 1 -
include/asm-generic/syscall.h | 2 +-
include/linux/entry-common.h | 47 +-------
include/linux/entry-kvm.h | 2 +-
include/linux/posix-timers.h | 1 -
include/linux/ptrace.h | 81 ++++++++++++-
include/linux/resume_user_mode.h | 64 ++++++++++
include/linux/sched/signal.h | 17 +++
include/linux/task_work.h | 5 +
include/linux/tracehook.h | 226 -----------------------------------
include/uapi/linux/ptrace.h | 2 +-
kernel/entry/common.c | 19 +--
kernel/entry/kvm.c | 9 +-
kernel/exit.c | 3 +-
kernel/livepatch/transition.c | 1 -
kernel/ptrace.c | 47 +++++---
kernel/seccomp.c | 1 -
kernel/signal.c | 62 +++++-----
kernel/task_work.c | 4 +-
kernel/time/posix-cpu-timers.c | 1 +
mm/memcontrol.c | 2 +-
security/apparmor/domain.c | 1 -
security/selinux/hooks.c | 1 -
85 files changed, 372 insertions(+), 495 deletions(-)
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Merge tag 'ptrace-cleanups-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull ptrace cleanups from Eric Biederman:
"This set of changes removes tracehook.h, moves modification of all of
the ptrace fields inside of siglock to remove races, adds a missing
permission check to ptrace.c
The removal of tracehook.h is quite significant as it has been a major
source of confusion in recent years. Much of that confusion was around
task_work and TIF_NOTIFY_SIGNAL (which I have now decoupled making the
semantics clearer).
For people who don't know tracehook.h is a vestiage of an attempt to
implement uprobes like functionality that was never fully merged, and
was later superseeded by uprobes when uprobes was merged. For many
years now we have been removing what tracehook functionaly a little
bit at a time. To the point where anything left in tracehook.h was
some weird strange thing that was difficult to understand"
* tag 'ptrace-cleanups-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
ptrace: Remove duplicated include in ptrace.c
ptrace: Check PTRACE_O_SUSPEND_SECCOMP permission on PTRACE_SEIZE
ptrace: Return the signal to continue with from ptrace_stop
ptrace: Move setting/clearing ptrace_message into ptrace_stop
tracehook: Remove tracehook.h
resume_user_mode: Move to resume_user_mode.h
resume_user_mode: Remove #ifdef TIF_NOTIFY_RESUME in set_notify_resume
signal: Move set_notify_signal and clear_notify_signal into sched/signal.h
task_work: Decouple TIF_NOTIFY_SIGNAL and task_work
task_work: Call tracehook_notify_signal from get_signal on all architectures
task_work: Introduce task_work_pending
task_work: Remove unnecessary include from posix_timers.h
ptrace: Remove tracehook_signal_handler
ptrace: Remove arch_syscall_{enter,exit}_tracehook
ptrace: Create ptrace_report_syscall_{entry,exit} in ptrace.h
ptrace/arm: Rename tracehook_report_syscall report_syscall
ptrace: Move ptrace_report_syscall into ptrace.h
- Rewrite how munlock works to massively reduce the contention
on i_mmap_rwsem (Hugh Dickins):
https://lore.kernel.org/linux-mm/8e4356d-9622-a7f0-b2c-f116b5f2efea@google.com/
- Sort out the page refcount mess for ZONE_DEVICE pages (Christoph Hellwig):
https://lore.kernel.org/linux-mm/20220210072828.2930359-1-hch@lst.de/
- Convert GUP to use folios and make pincount available for order-1
pages. (Matthew Wilcox)
- Convert a few more truncation functions to use folios (Matthew Wilcox)
- Convert page_vma_mapped_walk to use PFNs instead of pages (Matthew Wilcox)
- Convert rmap_walk to use folios (Matthew Wilcox)
- Convert most of shrink_page_list() to use a folio (Matthew Wilcox)
- Add support for creating large folios in readahead (Matthew Wilcox)
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Merge tag 'folio-5.18c' of git://git.infradead.org/users/willy/pagecache
Pull folio updates from Matthew Wilcox:
- Rewrite how munlock works to massively reduce the contention on
i_mmap_rwsem (Hugh Dickins):
https://lore.kernel.org/linux-mm/8e4356d-9622-a7f0-b2c-f116b5f2efea@google.com/
- Sort out the page refcount mess for ZONE_DEVICE pages (Christoph
Hellwig):
https://lore.kernel.org/linux-mm/20220210072828.2930359-1-hch@lst.de/
- Convert GUP to use folios and make pincount available for order-1
pages. (Matthew Wilcox)
- Convert a few more truncation functions to use folios (Matthew
Wilcox)
- Convert page_vma_mapped_walk to use PFNs instead of pages (Matthew
Wilcox)
- Convert rmap_walk to use folios (Matthew Wilcox)
- Convert most of shrink_page_list() to use a folio (Matthew Wilcox)
- Add support for creating large folios in readahead (Matthew Wilcox)
* tag 'folio-5.18c' of git://git.infradead.org/users/willy/pagecache: (114 commits)
mm/damon: minor cleanup for damon_pa_young
selftests/vm/transhuge-stress: Support file-backed PMD folios
mm/filemap: Support VM_HUGEPAGE for file mappings
mm/readahead: Switch to page_cache_ra_order
mm/readahead: Align file mappings for non-DAX
mm/readahead: Add large folio readahead
mm: Support arbitrary THP sizes
mm: Make large folios depend on THP
mm: Fix READ_ONLY_THP warning
mm/filemap: Allow large folios to be added to the page cache
mm: Turn can_split_huge_page() into can_split_folio()
mm/vmscan: Convert pageout() to take a folio
mm/vmscan: Turn page_check_references() into folio_check_references()
mm/vmscan: Account large folios correctly
mm/vmscan: Optimise shrink_page_list for non-PMD-sized folios
mm/vmscan: Free non-shmem folios without splitting them
mm/rmap: Constify the rmap_walk_control argument
mm/rmap: Convert rmap_walk() to take a folio
mm: Turn page_anon_vma() into folio_anon_vma()
mm/rmap: Turn page_lock_anon_vma_read() into folio_lock_anon_vma_read()
...
alloc_mem_cgroup_per_node_info is allocated for each possible node and
this used to be a problem because !node_online nodes didn't have
appropriate data structure allocated. This has changed by "mm: handle
uninitialized numa nodes gracefully" so we can drop the special casing
here.
Link: https://lkml.kernel.org/r/20220127085305.20890-7-mhocko@kernel.org
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Alexey Makhalov <amakhalov@vmware.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Rafael Aquini <raquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The idr_alloc() does not include @max ID. So in the current
implementation, the maximum memcg ID is 65534 instead of 65535. It
seems a bug. So fix this.
Link: https://lkml.kernel.org/r/20220228122126.37293-15-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kari Argillander <kari.argillander@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are two idrs being used by memory cgroup, one is for kmem ID,
another is for memory cgroup ID. The maximum ID of both is 64Ki. Both
of them can limit the total number of memory cgroups. Actually, we can
reuse memory cgroup ID for kmem ID to simplify the code.
Link: https://lkml.kernel.org/r/20220228122126.37293-14-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kari Argillander <kari.argillander@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If we run 10k containers in the system, the size of the
list_lru_memcg->lrus can be ~96KB per list_lru. When we decrease the
number containers, the size of the array will not be shrinked. It is
not scalable. The xarray is a good choice for this case. We can save a
lot of memory when there are tens of thousands continers in the system.
If we use xarray, we also can remove the logic code of resizing array,
which can simplify the code.
[akpm@linux-foundation.org: remove unused local]
Link: https://lkml.kernel.org/r/20220228122126.37293-13-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kari Argillander <kari.argillander@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The purpose of the memcg_drain_all_list_lrus() is list_lrus reparenting.
It is very similar to memcg_reparent_objcgs(). Rename it to
memcg_reparent_list_lrus() so that the name can more consistent with
memcg_reparent_objcgs().
Link: https://lkml.kernel.org/r/20220228122126.37293-12-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kari Argillander <kari.argillander@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In our server, we found a suspected memory leak problem. The kmalloc-32
consumes more than 6GB of memory. Other kmem_caches consume less than
2GB memory.
After our in-depth analysis, the memory consumption of kmalloc-32 slab
cache is the cause of list_lru_one allocation.
crash> p memcg_nr_cache_ids
memcg_nr_cache_ids = $2 = 24574
memcg_nr_cache_ids is very large and memory consumption of each list_lru
can be calculated with the following formula.
num_numa_node * memcg_nr_cache_ids * 32 (kmalloc-32)
There are 4 numa nodes in our system, so each list_lru consumes ~3MB.
crash> list super_blocks | wc -l
952
Every mount will register 2 list lrus, one is for inode, another is for
dentry. There are 952 super_blocks. So the total memory is 952 * 2 * 3
MB (~5.6GB). But the number of memory cgroup is less than 500. So I
guess more than 12286 containers have been deployed on this machine (I do
not know why there are so many containers, it may be a user's bug or the
user really want to do that). And memcg_nr_cache_ids has not been reduced
to a suitable value. This can waste a lot of memory.
Now the infrastructure for dynamic list_lru_one allocation is ready, so
remove statically allocated memory code to save memory.
Link: https://lkml.kernel.org/r/20220228122126.37293-11-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kari Argillander <kari.argillander@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It will simplify the code if moving memcg_online_kmem() to
mem_cgroup_css_online() and do not need to set ->kmemcg_id to -1 to
indicate the memcg is offline. In the next patch, ->kmemcg_id will be
used to sync list lru reparenting which requires not to change
->kmemcg_id.
Link: https://lkml.kernel.org/r/20220228122126.37293-10-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Alex Shi <alexs@kernel.org>
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kari Argillander <kari.argillander@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We currently allocate scope for every memcg to be able to tracked on
every superblock instantiated in the system, regardless of whether that
superblock is even accessible to that memcg.
These huge memcg counts come from container hosts where memcgs are
confined to just a small subset of the total number of superblocks that
instantiated at any given point in time.
For these systems with huge container counts, list_lru does not need the
capability of tracking every memcg on every superblock. What it comes
down to is that adding the memcg to the list_lru at the first insert.
So introduce kmem_cache_alloc_lru to allocate objects and its list_lru.
In the later patch, we will convert all inode and dentry allocation from
kmem_cache_alloc to kmem_cache_alloc_lru.
Link: https://lkml.kernel.org/r/20220228122126.37293-3-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kari Argillander <kari.argillander@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Before the for-each-CPU loop, preemption is disabled so that so that
drain_local_stock() can be invoked directly instead of scheduling a
worker. Ensuring that drain_local_stock() completed on the local CPU is
not correctness problem. It _could_ be that the charging path will be
forced to reclaim memory because cached charges are still waiting for
their draining.
Disabling preemption before invoking drain_local_stock() is problematic
on PREEMPT_RT due to the sleeping locks involved. To ensure that no CPU
migrations happens across for_each_online_cpu() it is enouhg to use
migrate_disable() which disables migration and keeps context preemptible
to a sleeping lock can be acquired. A race with CPU hotplug is not a
problem because pcp data is not going away. In the worst case we just
schedule draining of an empty stock.
Use migrate_disable() instead of get_cpu() around the
for_each_online_cpu() loop.
Link: https://lkml.kernel.org/r/20220226204144.1008339-7-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: kernel test robot <oliver.sang@intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The members of the per-CPU structure memcg_stock_pcp are protected by
disabling interrupts. This is not working on PREEMPT_RT because it
creates atomic context in which actions are performed which require
preemptible context. One example is obj_cgroup_release().
The IRQ-disable sections can be replaced with local_lock_t which
preserves the explicit disabling of interrupts while keeps the code
preemptible on PREEMPT_RT.
drain_obj_stock() drops a reference on obj_cgroup which leads to an
invocat= ion of obj_cgroup_release() if it is the last object. This in
turn leads to recursive locking of the local_lock_t. To avoid this,
obj_cgroup_release() = is invoked outside of the locked section.
obj_cgroup_uncharge_pages() can be invoked with the local_lock_t
acquired a= nd without it. This will lead later to a recursion in
refill_stock(). To avoid the locking recursion provide
obj_cgroup_uncharge_pages_locked() which uses the locked version of
refill_stock().
- Replace disabling interrupts for memcg_stock with a local_lock_t.
- Let drain_obj_stock() return the old struct obj_cgroup which is
passed to obj_cgroup_put() outside of the locked section.
- Provide obj_cgroup_uncharge_pages_locked() which uses the locked
version of refill_stock() to avoid recursive locking in
drain_obj_stock().
Link: https://lkml.kernel.org/r/20220209014709.GA26885@xsang-OptiPlex-9020
Link: https://lkml.kernel.org/r/20220226204144.1008339-6-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reported-by: kernel test robot <oliver.sang@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Provide the inner part of refill_stock() as __refill_stock() without
disabling interrupts. This eases the integration of local_lock_t where
recursive locking must be avoided.
Open code obj_cgroup_uncharge_pages() in drain_obj_stock() and use
__refill_stock(). The caller of drain_obj_stock() already disables
interrupts.
[bigeasy@linutronix.de: patch body around Johannes' diff]
Link: https://lkml.kernel.org/r/20220226204144.1008339-5-bigeasy@linutronix.de
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: kernel test robot <oliver.sang@intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The per-CPU counter are modified with the non-atomic modifier. The
consistency is ensured by disabling interrupts for the update. On non
PREEMPT_RT configuration this works because acquiring a spinlock_t typed
lock with the _irq() suffix disables interrupts. On PREEMPT_RT
configurations the RMW operation can be interrupted.
Another problem is that mem_cgroup_swapout() expects to be invoked with
disabled interrupts because the caller has to acquire a spinlock_t which
is acquired with disabled interrupts. Since spinlock_t never disables
interrupts on PREEMPT_RT the interrupts are never disabled at this
point.
The code is never called from in_irq() context on PREEMPT_RT therefore
disabling preemption during the update is sufficient on PREEMPT_RT. The
sections which explicitly disable interrupts can remain on PREEMPT_RT
because the sections remain short and they don't involve sleeping locks
(memcg_check_events() is doing nothing on PREEMPT_RT).
Disable preemption during update of the per-CPU variables which do not
explicitly disable interrupts.
Link: https://lkml.kernel.org/r/20220226204144.1008339-4-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: kernel test robot <oliver.sang@intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
During the integration of PREEMPT_RT support, the code flow around
memcg_check_events() resulted in `twisted code'. Moving the code around
and avoiding then would then lead to an additional local-irq-save
section within memcg_check_events(). While looking better, it adds a
local-irq-save section to code flow which is usually within an
local-irq-off block on non-PREEMPT_RT configurations.
The threshold event handler is a deprecated memcg v1 feature. Instead
of trying to get it to work under PREEMPT_RT just disable it. There
should be no users on PREEMPT_RT. From that perspective it makes even
less sense to get it to work under PREEMPT_RT while having zero users.
Make memory.soft_limit_in_bytes and cgroup.event_control return
-EOPNOTSUPP on PREEMPT_RT. Make an empty memcg_check_events() and
memcg_write_event_control() which return only -EOPNOTSUPP on PREEMPT_RT.
Document that the two knobs are disabled on PREEMPT_RT.
Link: https://lkml.kernel.org/r/20220226204144.1008339-3-bigeasy@linutronix.de
Suggested-by: Michal Hocko <mhocko@kernel.org>
Suggested-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: kernel test robot <oliver.sang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm/memcg: Address PREEMPT_RT problems instead of disabling it", v5.
This series aims to address the memcg related problem on PREEMPT_RT.
I tested them on CONFIG_PREEMPT and CONFIG_PREEMPT_RT with the
tools/testing/selftests/cgroup/* tests and I haven't observed any
regressions (other than the lockdep report that is already there).
This patch (of 6):
The optimisation is based on a micro benchmark where local_irq_save() is
more expensive than a preempt_disable(). There is no evidence that it
is visible in a real-world workload and there are CPUs where the
opposite is true (local_irq_save() is cheaper than preempt_disable()).
Based on micro benchmarks, the optimisation makes sense on PREEMPT_NONE
where preempt_disable() is optimized away. There is no improvement with
PREEMPT_DYNAMIC since the preemption counter is always available.
The optimization makes also the PREEMPT_RT integration more complicated
since most of the assumption are not true on PREEMPT_RT.
Revert the optimisation since it complicates the PREEMPT_RT integration
and the improvement is hardly visible.
[bigeasy@linutronix.de: patch body around Michal's diff]
Link: https://lkml.kernel.org/r/20220226204144.1008339-1-bigeasy@linutronix.de
Link: https://lore.kernel.org/all/YgOGkXXCrD%2F1k+p4@dhcp22.suse.cz
Link: https://lkml.kernel.org/r/YdX+INO9gQje6d0S@linutronix.de
Link: https://lkml.kernel.org/r/20220226204144.1008339-2-bigeasy@linutronix.de
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Waiman Long <longman@redhat.com>
Cc: kernel test robot <oliver.sang@intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__setup() handlers should return 1 if the command line option is handled
and 0 if not (or maybe never return 0; it just pollutes init's
environment).
The only reason that this particular __setup handler does not pollute
init's environment is that the setup string contains a '.', as in
"cgroup.memory". This causes init/main.c::unknown_boottoption() to
consider it to be an "Unused module parameter" and ignore it. (This is
for parsing of loadable module parameters any time after kernel init.)
Otherwise the string "cgroup.memory=whatever" would be added to init's
environment strings.
Instead of relying on this '.' quirk, just return 1 to indicate that the
boot option has been handled.
Note that there is no warning message if someone enters:
cgroup.memory=anything_invalid
Link: https://lkml.kernel.org/r/20220222005811.10672-1-rdunlap@infradead.org
Fixes: f7e1cb6ec5 ("mm: memcontrol: account socket memory in unified hierarchy memory controller")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: Igor Zhbanov <i.zhbanov@omprussia.ru>
Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The high limit is used to throttle the workload without invoking the
oom-killer. Recently we tried to use the high limit to right size our
internal workloads. More specifically dynamically adjusting the limits
of the workload without letting the workload get oom-killed. However
due to the limitation of the implementation of high limit enforcement,
we observed the mechanism fails for some real workloads.
The high limit is enforced on return-to-userspace i.e. the kernel let
the usage goes over the limit and when the execution returns to
userspace, the high reclaim is triggered and the process can get
throttled as well. However this mechanism fails for workloads which do
large allocations in a single kernel entry e.g. applications that
mlock() a large chunk of memory in a single syscall. Such applications
bypass the high limit and can trigger the oom-killer.
To make high limit enforcement more robust, this patch makes the limit
enforcement synchronous only if the accumulated overcharge becomes
larger than MEMCG_CHARGE_BATCH. So, most of the allocations would still
be throttled on the return-to-userspace path but only the extreme
allocations which accumulates large amount of overcharge without
returning to the userspace will be throttled synchronously. The value
MEMCG_CHARGE_BATCH is a bit arbitrary but most of other places in the
memcg codebase uses this constant therefore for now uses the same one.
Link: https://lkml.kernel.org/r/20220211064917.2028469-5-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Chris Down <chris@chrisdown.name>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently the kernel force charges the allocations which have __GFP_HIGH
flag without triggering the memory reclaim. __GFP_HIGH indicates that
the caller is high priority and since commit 869712fd3d ("mm:
memcontrol: fix network errors from failing __GFP_ATOMIC charges") the
kernel lets such allocations do force charging. Please note that
__GFP_ATOMIC has been replaced by __GFP_HIGH.
__GFP_HIGH does not tell if the caller can block or can trigger reclaim.
There are separate checks to determine that. So, there is no need to
skip reclaiming for __GFP_HIGH allocations. So, handle __GFP_HIGH
together with __GFP_NOFAIL which also does force charging.
Please note that this is a noop change as there are no __GFP_HIGH
allocators in the kernel which also have __GFP_ACCOUNT (or SLAB_ACCOUNT)
and does not allow reclaim for now.
Link: https://lkml.kernel.org/r/20220211064917.2028469-3-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Chris Down <chris@chrisdown.name>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "memcg: robust enforcement of memory.high", v2.
Due to the semantics of memory.high enforcement i.e. throttle the
workload without oom-kill, we are trying to use it for right sizing the
workloads in our production environment. However we observed the
mechanism fails for some specific applications which does big chunck of
allocations in a single syscall. The reason behind this failure is due
to the limitation of the memory.high enforcement's current
implementation.
This patch series solves this issue by enforcing the memory.high
synchronously if the current process has accumulated a large amount of
high overcharge.
This patch (of 4):
The function mem_cgroup_oom returns enum which has four possible values
but the caller does not care about such values and only cares if the
return value is OOM_SUCCESS or not. So, remove the enum altogether and
make mem_cgroup_oom returns a simple bool.
Link: https://lkml.kernel.org/r/20220211064917.2028469-1-shakeelb@google.com
Link: https://lkml.kernel.org/r/20220211064917.2028469-2-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Chris Down <chris@chrisdown.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kzalloc_node() would set data to 0, so it's not necessary to set it
again.
Link: https://lkml.kernel.org/r/20220201004643.8391-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently memcg stats show several types of kernel memory: kernel stack,
page tables, sock, vmalloc, and slab. However, there are other
allocations with __GFP_ACCOUNT (or supersets such as GFP_KERNEL_ACCOUNT)
that are not accounted in any of those stats, a few examples are:
- various kvm allocations (e.g. allocated pages to create vcpus)
- io_uring
- tmp_page in pipes during pipe_write()
- bpf ringbuffers
- unix sockets
Keeping track of the total kernel memory is essential for the ease of
migration from cgroup v1 to v2 as there are large discrepancies between
v1's kmem.usage_in_bytes and the sum of the available kernel memory
stats in v2. Adding separate memcg stats for all __GFP_ACCOUNT kernel
allocations is an impractical maintenance burden as there a lot of those
all over the kernel code, with more use cases likely to show up in the
future.
Therefore, add a "kernel" memcg stat that is analogous to kmem page
counter, with added benefits such as using rstat infrastructure which
aggregates stats more efficiently. Additionally, this provides a
lighter alternative in case the legacy kmem is deprecated in the future
[yosryahmed@google.com: v2]
Link: https://lkml.kernel.org/r/20220203193856.972500-1-yosryahmed@google.com
Link: https://lkml.kernel.org/r/20220201200823.3283171-1-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace the deprecated in_interrupt() with !in_task() because
in_interrupt() returns true for BH disabled even if the call happens in
the task context. in_task() is the right interface to differentiate
task context from NMI, hard IRQ and softirq contexts.
Link: https://lkml.kernel.org/r/20220127162636.3461256-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vasily Averin <vvs@virtuozzo.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This removes an assumption that THPs are the only kind of compound
pages and removes a couple of hidden calls to compound_head. It
also documents that you can't pass a tail page to mem_cgroup_swapout().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Move set_notify_resume and tracehook_notify_resume into resume_user_mode.h.
While doing that rename tracehook_notify_resume to resume_user_mode_work.
Update all of the places that included tracehook.h for these functions to
include resume_user_mode.h instead.
Update all of the callers of tracehook_notify_resume to call
resume_user_mode_work.
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20220309162454.123006-12-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
ZONE_DEVICE struct pages have an extra reference count that complicates
the code for put_page() and several places in the kernel that need to
check the reference count to see that a page is not being used (gup,
compaction, migration, etc.). Clean up the code so the reference count
doesn't need to be treated specially for ZONE_DEVICE pages.
Note that this excludes the special idle page wakeup for fsdax pages,
which still happens at refcount 1. This is a separate issue and will
be sorted out later. Given that only fsdax pages require the
notifiacation when the refcount hits 1 now, the PAGEMAP_OPS Kconfig
symbol can go away and be replaced with a FS_DAX check for this hook
in the put_page fastpath.
Based on an earlier patch from Ralph Campbell <rcampbell@nvidia.com>.
Link: https://lkml.kernel.org/r/20220210072828.2930359-8-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Tested-by: "Sierra Guiza, Alejandro (Alex)" <alex.sierra@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Cc: Christian Knig <christian.koenig@amd.com>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Move the check for the actual pgmap types that need the free at refcount
one behavior into the out of line helper, and thus avoid the need to
pull memremap.h into mm.h.
Link: https://lkml.kernel.org/r/20220210072828.2930359-7-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Tested-by: "Sierra Guiza, Alejandro (Alex)" <alex.sierra@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Previous patches have been preparatory: now implement page->mlock_count.
The ordering of the "Unevictable LRU" is of no significance, and there is
no point holding unevictable pages on a list: place page->mlock_count to
overlay page->lru.prev (since page->lru.next is overlaid by compound_head,
which needs to be even so as not to satisfy PageTail - though 2 could be
added instead of 1 for each mlock, if that's ever an improvement).
But it's only safe to rely on or modify page->mlock_count while lruvec
lock is held and page is on unevictable "LRU" - we can save lots of edits
by continuing to pretend that there's an imaginary LRU here (there is an
unevictable count which still needs to be maintained, but not a list).
The mlock_count technique suffers from an unreliability much like with
page_mlock(): while someone else has the page off LRU, not much can
be done. As before, err on the safe side (behave as if mlock_count 0),
and let try_to_unlock_one() move the page to unevictable if reclaim finds
out later on - a few misplaced pages don't matter, what we want to avoid
is imbalancing reclaim by flooding evictable lists with unevictable pages.
I am not a fan of "if (!isolate_lru_page(page)) putback_lru_page(page);":
if we have taken lruvec lock to get the page off its present list, then
we save everyone trouble (and however many extra atomic ops) by putting
it on its destination list immediately.
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Alexander reported a circular lock dependency revealed by the mmap1 ltp
test:
LOCKDEP_CIRCULAR (suite: ltp, case: mtest06 (mmap1))
WARNING: possible circular locking dependency detected
5.17.0-20220113.rc0.git0.f2211f194038.300.fc35.s390x+debug #1 Not tainted
------------------------------------------------------
mmap1/202299 is trying to acquire lock:
00000001892c0188 (css_set_lock){..-.}-{2:2}, at: obj_cgroup_release+0x4a/0xe0
but task is already holding lock:
00000000ca3b3818 (&sighand->siglock){-.-.}-{2:2}, at: force_sig_info_to_task+0x38/0x180
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&sighand->siglock){-.-.}-{2:2}:
__lock_acquire+0x604/0xbd8
lock_acquire.part.0+0xe2/0x238
lock_acquire+0xb0/0x200
_raw_spin_lock_irqsave+0x6a/0xd8
__lock_task_sighand+0x90/0x190
cgroup_freeze_task+0x2e/0x90
cgroup_migrate_execute+0x11c/0x608
cgroup_update_dfl_csses+0x246/0x270
cgroup_subtree_control_write+0x238/0x518
kernfs_fop_write_iter+0x13e/0x1e0
new_sync_write+0x100/0x190
vfs_write+0x22c/0x2d8
ksys_write+0x6c/0xf8
__do_syscall+0x1da/0x208
system_call+0x82/0xb0
-> #0 (css_set_lock){..-.}-{2:2}:
check_prev_add+0xe0/0xed8
validate_chain+0x736/0xb20
__lock_acquire+0x604/0xbd8
lock_acquire.part.0+0xe2/0x238
lock_acquire+0xb0/0x200
_raw_spin_lock_irqsave+0x6a/0xd8
obj_cgroup_release+0x4a/0xe0
percpu_ref_put_many.constprop.0+0x150/0x168
drain_obj_stock+0x94/0xe8
refill_obj_stock+0x94/0x278
obj_cgroup_charge+0x164/0x1d8
kmem_cache_alloc+0xac/0x528
__sigqueue_alloc+0x150/0x308
__send_signal+0x260/0x550
send_signal+0x7e/0x348
force_sig_info_to_task+0x104/0x180
force_sig_fault+0x48/0x58
__do_pgm_check+0x120/0x1f0
pgm_check_handler+0x11e/0x180
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&sighand->siglock);
lock(css_set_lock);
lock(&sighand->siglock);
lock(css_set_lock);
*** DEADLOCK ***
2 locks held by mmap1/202299:
#0: 00000000ca3b3818 (&sighand->siglock){-.-.}-{2:2}, at: force_sig_info_to_task+0x38/0x180
#1: 00000001892ad560 (rcu_read_lock){....}-{1:2}, at: percpu_ref_put_many.constprop.0+0x0/0x168
stack backtrace:
CPU: 15 PID: 202299 Comm: mmap1 Not tainted 5.17.0-20220113.rc0.git0.f2211f194038.300.fc35.s390x+debug #1
Hardware name: IBM 3906 M04 704 (LPAR)
Call Trace:
dump_stack_lvl+0x76/0x98
check_noncircular+0x136/0x158
check_prev_add+0xe0/0xed8
validate_chain+0x736/0xb20
__lock_acquire+0x604/0xbd8
lock_acquire.part.0+0xe2/0x238
lock_acquire+0xb0/0x200
_raw_spin_lock_irqsave+0x6a/0xd8
obj_cgroup_release+0x4a/0xe0
percpu_ref_put_many.constprop.0+0x150/0x168
drain_obj_stock+0x94/0xe8
refill_obj_stock+0x94/0x278
obj_cgroup_charge+0x164/0x1d8
kmem_cache_alloc+0xac/0x528
__sigqueue_alloc+0x150/0x308
__send_signal+0x260/0x550
send_signal+0x7e/0x348
force_sig_info_to_task+0x104/0x180
force_sig_fault+0x48/0x58
__do_pgm_check+0x120/0x1f0
pgm_check_handler+0x11e/0x180
INFO: lockdep is turned off.
In this example a slab allocation from __send_signal() caused a
refilling and draining of a percpu objcg stock, resulted in a releasing
of another non-related objcg. Objcg release path requires taking the
css_set_lock, which is used to synchronize objcg lists.
This can create a circular dependency with the sighandler lock, which is
taken with the locked css_set_lock by the freezer code (to freeze a
task).
In general it seems that using css_set_lock to synchronize objcg lists
makes any slab allocations and deallocation with the locked css_set_lock
and any intervened locks risky.
To fix the problem and make the code more robust let's stop using
css_set_lock to synchronize objcg lists and use a new dedicated spinlock
instead.
Link: https://lkml.kernel.org/r/Yfm1IHmoGdyUR81T@carbon.dhcp.thefacebook.com
Fixes: bf4f059954 ("mm: memcg/slab: obj_cgroup API")
Signed-off-by: Roman Gushchin <guro@fb.com>
Reported-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Tested-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
Tested-by: Jeremy Linton <jeremy.linton@arm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge misc updates from Andrew Morton:
"146 patches.
Subsystems affected by this patch series: kthread, ia64, scripts,
ntfs, squashfs, ocfs2, vfs, and mm (slab-generic, slab, kmemleak,
dax, kasan, debug, pagecache, gup, shmem, frontswap, memremap,
memcg, selftests, pagemap, dma, vmalloc, memory-failure, hugetlb,
userfaultfd, vmscan, mempolicy, oom-kill, hugetlbfs, migration, thp,
ksm, page-poison, percpu, rmap, zswap, zram, cleanups, hmm, and
damon)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (146 commits)
mm/damon: hide kernel pointer from tracepoint event
mm/damon/vaddr: hide kernel pointer from damon_va_three_regions() failure log
mm/damon/vaddr: use pr_debug() for damon_va_three_regions() failure logging
mm/damon/dbgfs: remove an unnecessary variable
mm/damon: move the implementation of damon_insert_region to damon.h
mm/damon: add access checking for hugetlb pages
Docs/admin-guide/mm/damon/usage: update for schemes statistics
mm/damon/dbgfs: support all DAMOS stats
Docs/admin-guide/mm/damon/reclaim: document statistics parameters
mm/damon/reclaim: provide reclamation statistics
mm/damon/schemes: account how many times quota limit has exceeded
mm/damon/schemes: account scheme actions that successfully applied
mm/damon: remove a mistakenly added comment for a future feature
Docs/admin-guide/mm/damon/usage: update for kdamond_pid and (mk|rm)_contexts
Docs/admin-guide/mm/damon/usage: mention tracepoint at the beginning
Docs/admin-guide/mm/damon/usage: remove redundant information
Docs/admin-guide/mm/damon/usage: update for scheme quotas and watermarks
mm/damon: convert macro functions to static inline functions
mm/damon: modify damon_rand() macro to static inline function
mm/damon: move damon_rand() definition into damon.h
...
The kvmalloc* allocation functions can fallback to vmalloc allocations
and more often on long running machines. In addition the kernel does
have __GFP_ACCOUNT kvmalloc* calls. So, often on long running machines,
the memory.stat does not tell the complete picture which type of memory
is charged to the memcg. So add a per-memcg vmalloc stat.
[shakeelb@google.com: page_memcg() within rcu lock, per Muchun]
Link: https://lkml.kernel.org/r/20211222052457.1960701-1-shakeelb@google.com
[akpm@linux-foundation.org: remove cast, per Muchun]
[shakeelb@google.com: remove area->page[0] checks and move to page by page accounting per Michal]
Link: https://lkml.kernel.org/r/20220104222341.3972772-1-shakeelb@google.com
Link: https://lkml.kernel.org/r/20211221215336.1922823-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: 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>
Make use of the struct_size() helper instead of an open-coded version,
in order to avoid any potential type mistakes or integer overflows that,
in the worst scenario, could lead to heap overflows.
Link: https://github.com/KSPP/linux/issues/160
Link: https://lkml.kernel.org/r/20211216022024.127375-1-wangweiyang2@huawei.com
Signed-off-by: Wang Weiyang <wangweiyang2@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 11192d9c12 ("memcg: flush stats only if updated") added
tracking of memcg stats updates which is used by the readers to flush
only if the updates are over a certain threshold. However each
individual update can correspond to a large value change for a given
stat. For example adding or removing a hugepage to an LRU changes the
stat by thp_nr_pages (512 on x86_64).
Treating the update related to THP as one can keep the stat off, in
theory, by (thp_nr_pages * nr_cpus * CHARGE_BATCH) before flush.
To handle such scenarios, this patch adds consideration of the stat
update value as well instead of just the update event. In addition let
the asyn flusher unconditionally flush the stats to put time limit on
the stats skew and hopefully a lot less readers would need to flush.
Link: https://lkml.kernel.org/r/20211118065350.697046-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Michal Koutný" <mkoutny@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Our container agent wants to know when a container exits if it was OOM
killed or not to report to the user. We use memory.oom.group = 1 to
ensure that OOM kills within the container's cgroup kill everything.
Existing memory.events are insufficient for knowing if this triggered:
1) Our current approach reads memory.events oom_kill and reports the
container was killed if the value is non-zero. This is erroneous in
some cases where containers create their children cgroups with
memory.oom.group=1 as such OOM kills will get counted against the
container cgroup's oom_kill counter despite not actually OOM killing
the entire container.
2) Reading memory.events.local will fail to identify OOM kills in leaf
cgroups (that don't set memory.oom.group) within the container
cgroup.
This patch adds a new oom_group_kill event when memory.oom.group
triggers to allow userspace to cleanly identify when an entire cgroup is
oom killed.
[schatzberg.dan@gmail.com: changes from Johannes and Chris]
Link: https://lkml.kernel.org/r/20211213162511.2492267-1-schatzberg.dan@gmail.com
Link: https://lkml.kernel.org/r/20211203162426.3375036-1-schatzberg.dan@gmail.com
Signed-off-by: Dan Schatzberg <schatzberg.dan@gmail.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Chris Down <chris@chrisdown.name>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 494c1dfe85 ("mm: memcg/slab: create a new set of kmalloc-cg-<n>
caches") makes cgroup_memory_nokmem global, however, it is unnecessary
because there is already a function mem_cgroup_kmem_disabled() which
exports it.
Just make it static and replace it with mem_cgroup_kmem_disabled() in
mm/slab_common.c.
Link: https://lkml.kernel.org/r/20211109065418.21693-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Chris Down <chris@chrisdown.name>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is no external users of slab_start/next/stop(), so make them
static. And the memory.kmem.slabinfo is deprecated, which outputs
nothing now, so move memcg_slab_show() into mm/memcontrol.c and rename
it to mem_cgroup_slab_show to be consistent with other function names.
Link: https://lkml.kernel.org/r/20211109133359.32881-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
page->memcg_data is used with MEMCG_DATA_OBJCGS flag only for slab pages
so convert all the related infrastructure to struct slab. Also use
struct folio instead of struct page when resolving object pointers.
This is not just mechanistic changing of types and names. Now in
mem_cgroup_from_obj() we use folio_test_slab() to decide if we interpret
the folio as a real slab instead of a large kmalloc, instead of relying
on MEMCG_DATA_OBJCGS bit that used to be checked in page_objcgs_check().
Similarly in memcg_slab_free_hook() where we can encounter
kmalloc_large() pages (here the folio slab flag check is implied by
virt_to_slab()). As a result, page_objcgs_check() can be dropped instead
of converted.
To avoid include cycles, move the inline definition of slab_objcgs()
from memcontrol.h to mm/slab.h.
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <cgroups@vger.kernel.org>
All the calls to mod_objcg_mlstate(), get_obj_stock() and
put_obj_stock() are done by functions defined within the same "#ifdef
CONFIG_MEMCG_KMEM" compilation block. When CONFIG_MEMCG_KMEM isn't
defined, the following compilation warnings will be issued [1] and [2].
mm/memcontrol.c:785:20: warning: unused function 'mod_objcg_mlstate'
mm/memcontrol.c:2113:33: warning: unused function 'get_obj_stock'
Fix these warning by moving those functions to under the same
CONFIG_MEMCG_KMEM compilation block. There is no functional change.
[1] https://lore.kernel.org/lkml/202111272014.WOYNLUV6-lkp@intel.com/
[2] https://lore.kernel.org/lkml/202111280551.LXsWYt1T-lkp@intel.com/
Link: https://lkml.kernel.org/r/20211129161140.306488-1-longman@redhat.com
Fixes: 559271146e ("mm/memcg: optimize user context object stock access")
Fixes: 68ac5b3c8d ("mm/memcg: cache vmstat data in percpu memcg_stock_pcp")
Signed-off-by: Waiman Long <longman@redhat.com>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These are only used in built-in core mm code.
Link: https://lkml.kernel.org/r/20210820095815.445392-3-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "unexport memcg locking helpers".
Neither the old page-based nor the new folio-based memcg locking helpers
are used in modular code at all, so drop the exports.
This patch (of 2):
folio_memcg_{,un}lock are only used in built-in core mm code.
Link: https://lkml.kernel.org/r/20210820095815.445392-1-hch@lst.de
Link: https://lkml.kernel.org/r/20210820095815.445392-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge misc updates from Andrew Morton:
"257 patches.
Subsystems affected by this patch series: scripts, ocfs2, vfs, and
mm (slab-generic, slab, slub, kconfig, dax, kasan, debug, pagecache,
gup, swap, memcg, pagemap, mprotect, mremap, iomap, tracing, vmalloc,
pagealloc, memory-failure, hugetlb, userfaultfd, vmscan, tools,
memblock, oom-kill, hugetlbfs, migration, thp, readahead, nommu, ksm,
vmstat, madvise, memory-hotplug, rmap, zsmalloc, highmem, zram,
cleanups, kfence, and damon)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (257 commits)
mm/damon: remove return value from before_terminate callback
mm/damon: fix a few spelling mistakes in comments and a pr_debug message
mm/damon: simplify stop mechanism
Docs/admin-guide/mm/pagemap: wordsmith page flags descriptions
Docs/admin-guide/mm/damon/start: simplify the content
Docs/admin-guide/mm/damon/start: fix a wrong link
Docs/admin-guide/mm/damon/start: fix wrong example commands
mm/damon/dbgfs: add adaptive_targets list check before enable monitor_on
mm/damon: remove unnecessary variable initialization
Documentation/admin-guide/mm/damon: add a document for DAMON_RECLAIM
mm/damon: introduce DAMON-based Reclamation (DAMON_RECLAIM)
selftests/damon: support watermarks
mm/damon/dbgfs: support watermarks
mm/damon/schemes: activate schemes based on a watermarks mechanism
tools/selftests/damon: update for regions prioritization of schemes
mm/damon/dbgfs: support prioritization weights
mm/damon/vaddr,paddr: support pageout prioritization
mm/damon/schemes: prioritize regions within the quotas
mm/damon/selftests: support schemes quotas
mm/damon/dbgfs: support quotas of schemes
...
Memcg reclaim throttles on congestion if no reclaim progress is made.
This makes little sense, it might be due to writeback or a host of other
factors.
For !memcg reclaim, it's messy. Direct reclaim primarily is throttled
in the page allocator if it is failing to make progress. Kswapd
throttles if too many pages are under writeback and marked for immediate
reclaim.
This patch explicitly throttles if reclaim is failing to make progress.
[vbabka@suse.cz: Remove redundant code]
Link: https://lkml.kernel.org/r/20211022144651.19914-4-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: "Darrick J . Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Rik van Riel <riel@surriel.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Memory cgroup charging allows killed or exiting tasks to exceed the hard
limit. It is assumed that the amount of the memory charged by those
tasks is bound and most of the memory will get released while the task
is exiting. This is resembling a heuristic for the global OOM situation
when tasks get access to memory reserves. There is no global memory
shortage at the memcg level so the memcg heuristic is more relieved.
The above assumption is overly optimistic though. E.g. vmalloc can
scale to really large requests and the heuristic would allow that. We
used to have an early break in the vmalloc allocator for killed tasks
but this has been reverted by commit b8c8a338f7 ("Revert "vmalloc:
back off when the current task is killed""). There are likely other
similar code paths which do not check for fatal signals in an
allocation&charge loop. Also there are some kernel objects charged to a
memcg which are not bound to a process life time.
It has been observed that it is not really hard to trigger these
bypasses and cause global OOM situation.
One potential way to address these runaways would be to limit the amount
of excess (similar to the global OOM with limited oom reserves). This
is certainly possible but it is not really clear how much of an excess
is desirable and still protects from global OOMs as that would have to
consider the overall memcg configuration.
This patch is addressing the problem by removing the heuristic
altogether. Bypass is only allowed for requests which either cannot
fail or where the failure is not desirable while excess should be still
limited (e.g. atomic requests). Implementation wise a killed or dying
task fails to charge if it has passed the OOM killer stage. That should
give all forms of reclaim chance to restore the limit before the failure
(ENOMEM) and tell the caller to back off.
In addition, this patch renames should_force_charge() helper to
task_is_dying() because now its use is not associated witch forced
charging.
This patch depends on pagefault_out_of_memory() to not trigger
out_of_memory(), because then a memcg failure can unwind to VM_FAULT_OOM
and cause a global OOM killer.
Link: https://lkml.kernel.org/r/8f5cebbb-06da-4902-91f0-6566fc4b4203@virtuozzo.com
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now the kmem states is only used to indicate whether the kmem is
offline. However, we can set ->kmemcg_id to -1 to indicate whether the
kmem is offline. Finally, we can remove the kmem states to simplify the
code.
Link: https://lkml.kernel.org/r/20211025125259.56624-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since slab objects and kmem pages are charged to object cgroup instead
of memory cgroup, memcg_reparent_objcgs() will reparent this cgroup and
all its descendants to its parent cgroup. This already makes further
list_lru_add()'s add elements to the parent's list. So it is
unnecessary to change kmemcg_id of an offline cgroup to its parent's id.
It just wastes CPU cycles. Just remove the redundant code.
Link: https://lkml.kernel.org/r/20211025125102.56533-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The deprecation process of kmem.limit_in_bytes started with the commit
0158115f70 ("memcg, kmem: deprecate kmem.limit_in_bytes") which also
explains in detail the motivation behind the deprecation. To summarize,
it is the unexpected behavior on hitting the kmem limit. This patch
moves the deprecation process to the next stage by disallowing to set
the kmem limit. In future we might just remove the kmem.limit_in_bytes
file completely.
[akpm@linux-foundation.org: s/ENOTSUPP/EOPNOTSUPP/]
[arnd@arndb.de: mark cancel_charge() inline]
Link: https://lkml.kernel.org/r/20211022070542.679839-1-arnd@kernel.org
Link: https://lkml.kernel.org/r/20211019153408.2916808-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Vasily Averin <vvs@virtuozzo.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>
Since commit d648bcc7fe ("mm: kmem: make memcg_kmem_enabled()
irreversible"), the only thing memcg_free_kmem() does is to call
memcg_offline_kmem() when the memcg is still online which can happen
when online_css() fails due to -ENOMEM.
However, the name memcg_free_kmem() is confusing and it is more clear
and straight forward to call memcg_offline_kmem() directly from
mem_cgroup_css_free().
Link: https://lkml.kernel.org/r/20211005202450.11775-1-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Suggested-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Aaron Tomlin <atomlin@redhat.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The memcg stats can be flushed in multiple context and potentially in
parallel too. For example multiple parallel user space readers for
memcg stats will contend on the rstat locks with each other. There is
no need for that. We just need one flusher and everyone else can
benefit.
In addition after aa48e47e39 ("memcg: infrastructure to flush memcg
stats") the kernel periodically flush the memcg stats from the root, so,
the other flushers will potentially have much less work to do.
Link: https://lkml.kernel.org/r/20211001190040.48086-2-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Michal Koutný" <mkoutny@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
At the moment, the kernel flushes the memcg stats on every refault and
also on every reclaim iteration. Although rstat maintains per-cpu
update tree but on the flush the kernel still has to go through all the
cpu rstat update tree to check if there is anything to flush. This
patch adds the tracking on the stats update side to make flush side more
clever by skipping the flush if there is no update.
The stats update codepath is very sensitive performance wise for many
workloads and benchmarks. So, we can not follow what the commit
aa48e47e39 ("memcg: infrastructure to flush memcg stats") did which
was triggering async flush through queue_work() and caused a lot
performance regression reports. That got reverted by the commit
1f828223b7 ("memcg: flush lruvec stats in the refault").
In this patch we kept the stats update codepath very minimal and let the
stats reader side to flush the stats only when the updates are over a
specific threshold. For now the threshold is (nr_cpus * CHARGE_BATCH).
To evaluate the impact of this patch, an 8 GiB tmpfs file is created on
a system with swap-on-zram and the file was pushed to swap through
memory.force_empty interface. On reading the whole file, the memcg stat
flush in the refault code path is triggered. With this patch, we
observed 63% reduction in the read time of 8 GiB file.
Link: https://lkml.kernel.org/r/20211001190040.48086-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Reviewed-by: "Michal Koutný" <mkoutny@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It is unused after the rework of commit f5df8635c5 ("mm: use
find_get_incore_page in memcontrol").
Link: https://lkml.kernel.org/r/20210916193014.80129-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These are the folio equivalents of lock_page_lruvec() and similar
functions. Also convert lruvec_memcg_debug() to take a folio.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
This replaces mem_cgroup_page_lruvec(). All callers converted.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
This saves dozens of bytes of text by eliminating a lot of calls to
compound_head().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
These are the folio equivalents of lock_page_memcg() and
unlock_page_memcg().
lock_page_memcg() and unlock_page_memcg() have too many callers to be
easily replaced in a single patch, so reimplement them as wrappers for
now to be cleaned up later when enough callers have been converted to
use folios.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
The page was only being used for the memcg and to gather trace
information, so this is a simple conversion. The only caller of
mem_cgroup_track_foreign_dirty() will be converted to folios in a later
patch, so doing this now makes that patch simpler.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Convert all callers of mem_cgroup_migrate() to call page_folio() first.
They all look like they're using head pages already, but this proves it.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Convert all the callers to call page_folio(). Most of them were already
using a head page, but a few of them I can't prove were, so this may
actually fix a bug.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Use a folio rather than a page to ensure that we're only operating on
base or head pages, and not tail pages.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Convert all callers of mem_cgroup_charge() to call page_folio() on the
page they're currently passing in. Many of them will be converted to
use folios themselves soon.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
The memcg_data is only set on the head page, so enforce that by
typing it as a folio.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
memcg information is only stored in the head page, so the memcg
subsystem needs to assure that all accesses are to the head page.
The first step is converting page_memcg() to folio_memcg().
The callers of page_memcg() and PageMemcgKmem() are not yet ready to be
converted to use folios, so retain them as wrappers around folio_memcg()
and folio_memcg_kmem(). They will be converted in a later patch set.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
memcg_check_events only uses the page's nid, so call page_to_nid in the
callers to make the interface easier to understand.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Opencode this one-line function in its three callers.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
By using the node id in mem_cgroup_update_tree(), we can delete
soft_limit_tree_from_page() and mem_cgroup_page_nodeinfo(). Saves 42
bytes of kernel text on my config.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
The last use of 'page' was removed by commit 468c398233 ("mm:
memcontrol: switch to native NR_ANON_THPS counter"), so we can now remove
the parameter from the function.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Prior to the commit 7e1c0d6f58 ("memcg: switch lruvec stats to rstat")
and the commit aa48e47e39 ("memcg: infrastructure to flush memcg
stats"), each lruvec memcg stats can be off by (nr_cgroups * nr_cpus *
32) at worst and for unbounded amount of time. The commit aa48e47e39
moved the lruvec stats to rstat infrastructure and the commit
7e1c0d6f58 bounded the error for all the lruvec stats to (nr_cpus *
32) at worst for at most 2 seconds. More specifically it decoupled the
number of stats and the number of cgroups from the error rate.
However this reduction in error comes with the cost of triggering the
slowpath of stats update more frequently. Previously in the slowpath
the kernel adds the stats up the memcg tree. After aa48e47e39, the
kernel triggers the asyn lruvec stats flush through queue_work(). This
causes regression reports from 0day kernel bot [1] as well as from
phoronix test suite [2].
We tried two options to fix the regression:
1) Increase the threshold to trigger the slowpath in lruvec stats
update codepath from 32 to 512.
2) Remove the slowpath from lruvec stats update codepath and instead
flush the stats in the page refault codepath. The assumption is that
the kernel timely flush the stats, so, the update tree would be
small in the refault codepath to not cause the preformance impact.
Following are the results of will-it-scale/page_fault[1|2|3] benchmark
on four settings i.e. (1) 5.15-rc1 as baseline (2) 5.15-rc1 with
aa48e47e39 and 7e1c0d6f58 reverted (3) 5.15-rc1 with option-1
(4) 5.15-rc1 with option-2.
test (1) (2) (3) (4)
pg_f1 368563 406277 (10.23%) 399693 (8.44%) 416398 (12.97%)
pg_f2 338399 372133 (9.96%) 369180 (9.09%) 381024 (12.59%)
pg_f3 500853 575399 (14.88%) 570388 (13.88%) 576083 (15.02%)
From the above result, it seems like the option-2 not only solves the
regression but also improves the performance for at least these
benchmarks.
Feng Tang (intel) ran the aim7 benchmark with these two options and
confirms that option-1 reduces the regression but option-2 removes the
regression.
Michael Larabel (phoronix) ran multiple benchmarks with these options
and reported the results at [3] and it shows for most benchmarks
option-2 removes the regression introduced by the commit aa48e47e39
("memcg: infrastructure to flush memcg stats").
Based on the experiment results, this patch proposed the option-2 as the
solution to resolve the regression.
Link: https://lore.kernel.org/all/20210726022421.GB21872@xsang-OptiPlex-9020 [1]
Link: https://www.phoronix.com/scan.php?page=article&item=linux515-compile-regress [2]
Link: https://openbenchmarking.org/result/2109226-DEBU-LINUX5104 [3]
Fixes: aa48e47e39 ("memcg: infrastructure to flush memcg stats")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Tested-by: Michael Larabel <Michael@phoronix.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Hillf Danton <hdanton@sina.com>,
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge misc updates from Andrew Morton:
"173 patches.
Subsystems affected by this series: ia64, ocfs2, block, and mm (debug,
pagecache, gup, swap, shmem, memcg, selftests, pagemap, mremap,
bootmem, sparsemem, vmalloc, kasan, pagealloc, memory-failure,
hugetlb, userfaultfd, vmscan, compaction, mempolicy, memblock,
oom-kill, migration, ksm, percpu, vmstat, and madvise)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (173 commits)
mm/madvise: add MADV_WILLNEED to process_madvise()
mm/vmstat: remove unneeded return value
mm/vmstat: simplify the array size calculation
mm/vmstat: correct some wrong comments
mm/percpu,c: remove obsolete comments of pcpu_chunk_populated()
selftests: vm: add COW time test for KSM pages
selftests: vm: add KSM merging time test
mm: KSM: fix data type
selftests: vm: add KSM merging across nodes test
selftests: vm: add KSM zero page merging test
selftests: vm: add KSM unmerge test
selftests: vm: add KSM merge test
mm/migrate: correct kernel-doc notation
mm: wire up syscall process_mrelease
mm: introduce process_mrelease system call
memblock: make memblock_find_in_range method private
mm/mempolicy.c: use in_task() in mempolicy_slab_node()
mm/mempolicy: unify the create() func for bind/interleave/prefer-many policies
mm/mempolicy: advertise new MPOL_PREFERRED_MANY
mm/hugetlb: add support for mempolicy MPOL_PREFERRED_MANY
...
We can get memcg directly form vmpr instead of vmpr->memcg->css->memcg, so
add a new func helper vmpressure_to_memcg(). And no code will use
vmpressure_to_css(), so delete it.
Link: https://lkml.kernel.org/r/20210630112146.455103-1-suhui@zeku.com
Signed-off-by: Hui Su <suhui@zeku.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Chris Down <chris@chrisdown.name>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The memcg->event_list_lock is usually taken in the normal context but when
the userspace closes the corresponding eventfd, eventfd_release through
memcg_event_wake takes memcg->event_list_lock with interrupts disabled.
This is not an issue on its own but it creates a nested dependency from
eventfd_ctx->wqh.lock to memcg->event_list_lock.
Independently, for unrelated eventfd, eventfd_signal() can be called in
the irq context, thus making eventfd_ctx->wqh.lock an irq lock. For
example, FPGA DFL driver, VHOST VPDA driver and couple of VFIO drivers.
This will force memcg->event_list_lock to be an irqsafe lock as well.
One way to break the nested dependency between eventfd_ctx->wqh.lock and
memcg->event_list_lock is to add an indirection. However the simplest
solution would be to make memcg->event_list_lock irqsafe. This is cgroup
v1 feature, is in maintenance and may get deprecated in near future. So,
no need to add more code.
BTW this has been discussed previously [1] but there weren't irq users of
eventfd_signal() at the time.
[1] https://www.spinics.net/lists/cgroups/msg06248.html
Link: https://lkml.kernel.org/r/20210830172953.207257-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Thomas and Vlastimil have noticed that the comment in drain_local_stock
doesn't quite make sense. It talks about a synchronization with the
memory hotplug but there is no actual memory hotplug involvement here. I
meant to talk about cpu hotplug here. Fix that up and hopefuly make the
comment more helpful by referencing the cpu hotplug callback as well.
Link: https://lkml.kernel.org/r/YRDwOhVglJmY7ES5@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add 'else' to save some atomic ops in obj_stock_flush_required() when
flush is already true. No functional change intended here.
Link: https://lkml.kernel.org/r/20210807082835.61281-3-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit c843966c55 ("mm: allow swappiness that prefers reclaiming
anon over the file workingset") has expended the swappiness value to make
swap to be preferred in some systems. We should also change the memcg
swappiness restriction to allow memcg swap-preferred.
Link: https://lkml.kernel.org/r/d77469b90c45c49953ccbc51e54a1d465bc18f70.1627626255.git.baolin.wang@linux.alibaba.com
Fixes: c843966c55 ("mm: allow swappiness that prefers reclaiming anon over the file workingset")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
At the moment memcg stats are read in four contexts:
1. memcg stat user interfaces
2. dirty throttling
3. page fault
4. memory reclaim
Currently the kernel flushes the stats for first two cases. Flushing the
stats for remaining two casese may have performance impact. Always
flushing the memcg stats on the page fault code path may negatively
impacts the performance of the applications. In addition flushing in the
memory reclaim code path, though treated as slowpath, can become the
source of contention for the global lock taken for stat flushing because
when system or memcg is under memory pressure, many tasks may enter the
reclaim path.
This patch uses following mechanisms to solve these challenges:
1. Periodically flush the stats from root memcg every 2 seconds. This
will time limit the out of sync stats.
2. Asynchronously flush the stats after fixed number of stat updates.
In the worst case the stat can be out of sync by O(nr_cpus * BATCH) for
2 seconds.
3. For avoiding thundering herd to flush the stats particularly from
the memory reclaim context, introduce memcg local spinlock and let only
one flusher active at a time. This could have been done through
cgroup_rstat_lock lock but that lock is used by other subsystem and for
userspace reading memcg stats. So, it is better to keep flushers
introduced by this patch decoupled from cgroup_rstat_lock. However we
would have to use irqsafe version of rstat flush but that is fine as
this code path will be flushing for whole tree and do the work for
everyone. No one will be waiting for that worker.
[shakeelb@google.com: fix sleep-in-wrong context bug]
Link: https://lkml.kernel.org/r/20210716212137.1391164-2-shakeelb@google.com
Link: https://lkml.kernel.org/r/20210714013948.270662-2-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The commit 2d146aa3aa ("mm: memcontrol: switch to rstat") switched memcg
stats to rstat infrastructure but skipped the conversion of the lruvec
stats as such stats are read in the performance critical code paths and
flushing stats may have impacted the performances of the applications.
This patch converts the lruvec stats to rstat and later patches add
mechanisms to keep the performance impact to minimum.
The rstat conversion comes with the price i.e. memory cost. Effectively
this patch reverts the savings done by the commit f3344adf38 ("mm:
memcontrol: optimize per-lruvec stats counter memory usage"). However
this cost is justified due to negative impact of the inaccurate lruvec
stats on many heuristics. One such case is reported in [1].
The memory reclaim code is filled with plethora of heuristics and many of
those heuristics reads the lruvec stats. So, inaccurate stats can make
such heuristics ineffective. [1] reports the impact of inaccurate lruvec
stats on the "cache trim mode" heuristic. Inaccurate lruvec stats can
impact the deactivation and aging anon heuristics as well.
[1] https://lore.kernel.org/linux-mm/20210311004449.1170308-1-ying.huang@intel.com/
Link: https://lkml.kernel.org/r/20210716212137.1391164-1-shakeelb@google.com
Link: https://lkml.kernel.org/r/20210714013948.270662-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Inline mem_cgroup_try_charge_swap, mem_cgroup_uncharge_swap and
cgroup_throttle_swaprate functions to perform mem_cgroup_disabled static
key check inline before calling the main body of the function. This
minimizes the memcg overhead in the pagefault and exit_mmap paths when
memcgs are disabled using cgroup_disable=memory command-line option. This
change results in ~1% overhead reduction when running PFT test [1]
comparing {CONFIG_MEMCG=n} against {CONFIG_MEMCG=y, cgroup_disable=memory}
configuration on an 8-core ARM64 Android device.
[1] https://lkml.org/lkml/2006/8/29/294 also used in mmtests suite
Link: https://lkml.kernel.org/r/20210713010934.299876-3-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Inline mem_cgroup_{charge/uncharge} and mem_cgroup_uncharge_list functions
functions to perform mem_cgroup_disabled static key check inline before
calling the main body of the function. This minimizes the memcg overhead
in the pagefault and exit_mmap paths when memcgs are disabled using
cgroup_disable=memory command-line option.
This change results in ~0.4% overhead reduction when running PFT test [1]
comparing {CONFIG_MEMCG=n} against {CONFIG_MEMCG=y, cgroup_disable=memory}
configuration on an 8-core ARM64 Android device.
[1] https://lkml.org/lkml/2006/8/29/294 also used in mmtests suite
Link: https://lkml.kernel.org/r/20210713010934.299876-2-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add mem_cgroup_disabled check in vmpressure, mem_cgroup_uncharge_swap and
cgroup_throttle_swaprate functions. This minimizes the memcg overhead in
the pagefault and exit_mmap paths when memcgs are disabled using
cgroup_disable=memory command-line option.
This change results in ~2.1% overhead reduction when running PFT test [1]
comparing {CONFIG_MEMCG=n, CONFIG_MEMCG_SWAP=n} against {CONFIG_MEMCG=y,
CONFIG_MEMCG_SWAP=y, cgroup_disable=memory} configuration on an 8-core
ARM64 Android device.
[1] https://lkml.org/lkml/2006/8/29/294 also used in mmtests suite
Link: https://lkml.kernel.org/r/20210713010934.299876-1-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently cgroup_writeback_by_id calls mem_cgroup_wb_stats() to get dirty
pages for a memcg. However mem_cgroup_wb_stats() does a lot more than
just get the number of dirty pages. Just directly get the number of dirty
pages instead of calling mem_cgroup_wb_stats(). Also
cgroup_writeback_by_id() is only called for best-effort dirty flushing, so
remove the unused 'nr' parameter and no need to explicitly flush memcg
stats.
Link: https://lkml.kernel.org/r/20210722182627.2267368-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add gfp_t mask as an input parameter to mem_cgroup_charge_skmem(),
to give more control to the networking stack and enable it to change
memcg charging behavior. In the future, the networking stack may decide
to avoid oom-kills when fallbacks are more appropriate.
One behavior change in mem_cgroup_charge_skmem() by this patch is to
avoid force charging by default and let the caller decide when and if
force charging is needed through the presence or absence of
__GFP_NOFAIL.
Signed-off-by: Wei Wang <weiwan@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When mod_objcg_state() is called with a pgdat that is different from
that in the obj_stock, the old lruvec data cached in obj_stock are
flushed out. Unfortunately, they were flushed to the new pgdat and so
the data go to the wrong node. This will screw up the slab data
reported in /sys/devices/system/node/node*/meminfo.
Fix that by flushing the data to the cached pgdat instead.
Link: https://lkml.kernel.org/r/20210802143834.30578-1-longman@redhat.com
Fixes: 68ac5b3c8d ("mm/memcg: cache vmstat data in percpu memcg_stock_pcp")
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Chris Down <chris@chrisdown.name>
Cc: Yafang Shao <laoar.shao@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Masayoshi Mizuma <msys.mizuma@gmail.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dan Carpenter reports:
The patch 2d146aa3aa84: "mm: memcontrol: switch to rstat" from Apr
29, 2021, leads to the following static checker warning:
kernel/cgroup/rstat.c:200 cgroup_rstat_flush()
warn: sleeping in atomic context
mm/memcontrol.c
3572 static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
3573 {
3574 unsigned long val;
3575
3576 if (mem_cgroup_is_root(memcg)) {
3577 cgroup_rstat_flush(memcg->css.cgroup);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This is from static analysis and potentially a false positive. The
problem is that mem_cgroup_usage() is called from __mem_cgroup_threshold()
which holds an rcu_read_lock(). And the cgroup_rstat_flush() function
can sleep.
3578 val = memcg_page_state(memcg, NR_FILE_PAGES) +
3579 memcg_page_state(memcg, NR_ANON_MAPPED);
3580 if (swap)
3581 val += memcg_page_state(memcg, MEMCG_SWAP);
3582 } else {
3583 if (!swap)
3584 val = page_counter_read(&memcg->memory);
3585 else
3586 val = page_counter_read(&memcg->memsw);
3587 }
3588 return val;
3589 }
__mem_cgroup_threshold() indeed holds the rcu lock. In addition, the
thresholding code is invoked during stat changes, and those contexts
have irqs disabled as well. If the lock breaking occurs inside the
flush function, it will result in a sleep from an atomic context.
Use the irqsafe flushing variant in mem_cgroup_usage() to fix this.
Link: https://lkml.kernel.org/r/20210726150019.251820-1-hannes@cmpxchg.org
Fixes: 2d146aa3aa ("mm: memcontrol: switch to rstat")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Chris Down <chris@chrisdown.name>
Reviewed-by: Rik van Riel <riel@surriel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
An netadmin inside container can use 'ip a a' and 'ip r a'
to assign a large number of ipv4/ipv6 addresses and routing entries
and force kernel to allocate megabytes of unaccounted memory
for long-lived per-netdevice related kernel objects:
'struct in_ifaddr', 'struct inet6_ifaddr', 'struct fib6_node',
'struct rt6_info', 'struct fib_rules' and ip_fib caches.
These objects can be manually removed, though usually they lives
in memory till destroy of its net namespace.
It makes sense to account for them to restrict the host's memory
consumption from inside the memcg-limited container.
One of such objects is the 'struct fib6_node' mostly allocated in
net/ipv6/route.c::__ip6_ins_rt() inside the lock_bh()/unlock_bh() section:
write_lock_bh(&table->tb6_lock);
err = fib6_add(&table->tb6_root, rt, info, mxc);
write_unlock_bh(&table->tb6_lock);
In this case it is not enough to simply add SLAB_ACCOUNT to corresponding
kmem cache. The proper memory cgroup still cannot be found due to the
incorrect 'in_interrupt()' check used in memcg_kmem_bypass().
Obsoleted in_interrupt() does not describe real execution context properly.
>From include/linux/preempt.h:
The following macros are deprecated and should not be used in new code:
in_interrupt() - We're in NMI,IRQ,SoftIRQ context or have BH disabled
To verify the current execution context new macro should be used instead:
in_task() - We're in task context
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Merge more updates from Andrew Morton:
"190 patches.
Subsystems affected by this patch series: mm (hugetlb, userfaultfd,
vmscan, kconfig, proc, z3fold, zbud, ras, mempolicy, memblock,
migration, thp, nommu, kconfig, madvise, memory-hotplug, zswap,
zsmalloc, zram, cleanups, kfence, and hmm), procfs, sysctl, misc,
core-kernel, lib, lz4, checkpatch, init, kprobes, nilfs2, hfs,
signals, exec, kcov, selftests, compress/decompress, and ipc"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (190 commits)
ipc/util.c: use binary search for max_idx
ipc/sem.c: use READ_ONCE()/WRITE_ONCE() for use_global_lock
ipc: use kmalloc for msg_queue and shmid_kernel
ipc sem: use kvmalloc for sem_undo allocation
lib/decompressors: remove set but not used variabled 'level'
selftests/vm/pkeys: exercise x86 XSAVE init state
selftests/vm/pkeys: refill shadow register after implicit kernel write
selftests/vm/pkeys: handle negative sys_pkey_alloc() return code
selftests/vm/pkeys: fix alloc_random_pkey() to make it really, really random
kcov: add __no_sanitize_coverage to fix noinstr for all architectures
exec: remove checks in __register_bimfmt()
x86: signal: don't do sas_ss_reset() until we are certain that sigframe won't be abandoned
hfsplus: report create_date to kstat.btime
hfsplus: remove unnecessary oom message
nilfs2: remove redundant continue statement in a while-loop
kprobes: remove duplicated strong free_insn_page in x86 and s390
init: print out unknown kernel parameters
checkpatch: do not complain about positive return values starting with EPOLL
checkpatch: improve the indented label test
checkpatch: scripts/spdxcheck.py now requires python3
...
Pull percpu updates from Dennis Zhou:
- percpu chunk depopulation - depopulate backing pages for chunks with
empty pages when we exceed a global threshold without those pages.
This lets us reclaim a portion of memory that would previously be
lost until the full chunk would be freed (possibly never).
- memcg accounting cleanup - previously separate chunks were managed
for normal allocations and __GFP_ACCOUNT allocations. These are now
consolidated which cleans up the code quite a bit.
- a few misc clean ups for clang warnings
* 'for-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu:
percpu: optimize locking in pcpu_balance_workfn()
percpu: initialize best_upa variable
percpu: rework memcg accounting
mm, memcg: introduce mem_cgroup_kmem_disabled()
mm, memcg: mark cgroup_memory_nosocket, nokmem and noswap as __ro_after_init
percpu: make symbol 'pcpu_free_slot' static
percpu: implement partial chunk depopulation
percpu: use pcpu_free_slot instead of pcpu_nr_slots - 1
percpu: factor out pcpu_check_block_hint()
percpu: split __pcpu_balance_workfn()
percpu: fix a comment about the chunks ordering
Patch series "Add support for SVM atomics in Nouveau", v11.
Introduction
============
Some devices have features such as atomic PTE bits that can be used to
implement atomic access to system memory. To support atomic operations to
a shared virtual memory page such a device needs access to that page which
is exclusive of the CPU. This series introduces a mechanism to
temporarily unmap pages granting exclusive access to a device.
These changes are required to support OpenCL atomic operations in Nouveau
to shared virtual memory (SVM) regions allocated with the
CL_MEM_SVM_ATOMICS clSVMAlloc flag. A more complete description of the
OpenCL SVM feature is available at
https://www.khronos.org/registry/OpenCL/specs/3.0-unified/html/
OpenCL_API.html#_shared_virtual_memory .
Implementation
==============
Exclusive device access is implemented by adding a new swap entry type
(SWAP_DEVICE_EXCLUSIVE) which is similar to a migration entry. The main
difference is that on fault the original entry is immediately restored by
the fault handler instead of waiting.
Restoring the entry triggers calls to MMU notifers which allows a device
driver to revoke the atomic access permission from the GPU prior to the
CPU finalising the entry.
Patches
=======
Patches 1 & 2 refactor existing migration and device private entry
functions.
Patches 3 & 4 rework try_to_unmap_one() by splitting out unrelated
functionality into separate functions - try_to_migrate_one() and
try_to_munlock_one().
Patch 5 renames some existing code but does not introduce functionality.
Patch 6 is a small clean-up to swap entry handling in copy_pte_range().
Patch 7 contains the bulk of the implementation for device exclusive
memory.
Patch 8 contains some additions to the HMM selftests to ensure everything
works as expected.
Patch 9 is a cleanup for the Nouveau SVM implementation.
Patch 10 contains the implementation of atomic access for the Nouveau
driver.
Testing
=======
This has been tested with upstream Mesa 21.1.0 and a simple OpenCL program
which checks that GPU atomic accesses to system memory are atomic.
Without this series the test fails as there is no way of write-protecting
the page mapping which results in the device clobbering CPU writes. For
reference the test is available at
https://ozlabs.org/~apopple/opencl_svm_atomics/
Further testing has been performed by adding support for testing exclusive
access to the hmm-tests kselftests.
This patch (of 10):
Remove multiple similar inline functions for dealing with different types
of special swap entries.
Both migration and device private swap entries use the swap offset to
store a pfn. Instead of multiple inline functions to obtain a struct page
for each swap entry type use a common function pfn_swap_entry_to_page().
Also open-code the various entry_to_pfn() functions as this results is
shorter code that is easier to understand.
Link: https://lkml.kernel.org/r/20210616105937.23201-1-apopple@nvidia.com
Link: https://lkml.kernel.org/r/20210616105937.23201-2-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
make W=1 generates the following warning for mem_cgroup_calculate_protection
mm/memcontrol.c:6468: warning: expecting prototype for mem_cgroup_protected(). Prototype was for mem_cgroup_calculate_protection() instead
Commit 45c7f7e1ef ("mm, memcg: decouple e{low,min} state mutations from
protection checks") changed the function definition but not the associated
kerneldoc comment.
Link: https://lkml.kernel.org/r/20210520084809.8576-7-mgorman@techsingularity.net
Fixes: 45c7f7e1ef ("mm, memcg: decouple e{low,min} state mutations from protection checks")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Acked-by: Chris Down <chris@chrisdown.name>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: David Hildenbrand <david@redhat.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>
The current code only associates with the existing blkcg when aio is used
to access the backing file. This patch covers all types of i/o to the
backing file and also associates the memcg so if the backing file is on
tmpfs, memory is charged appropriately.
This patch also exports cgroup_get_e_css and int_active_memcg so it can be
used by the loop module.
Link: https://lkml.kernel.org/r/20210610173944.1203706-4-schatzberg.dan@gmail.com
Signed-off-by: Dan Schatzberg <schatzberg.dan@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: Chris Down <chris@chrisdown.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
set_active_memcg() worked for kernel allocations but was silently ignored
for user pages.
This patch establishes a precedence order for who gets charged:
1. If there is a memcg associated with the page already, that memcg is
charged. This happens during swapin.
2. If an explicit mm is passed, mm->memcg is charged. This happens
during page faults, which can be triggered in remote VMs (eg gup).
3. Otherwise consult the current process context. If there is an
active_memcg, use that. Otherwise, current->mm->memcg.
Previously, if a NULL mm was passed to mem_cgroup_charge (case 3) it would
always charge the root cgroup. Now it looks up the active_memcg first
(falling back to charging the root cgroup if not set).
Link: https://lkml.kernel.org/r/20210610173944.1203706-3-schatzberg.dan@gmail.com
Signed-off-by: Dan Schatzberg <schatzberg.dan@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Chris Down <chris@chrisdown.name>
Acked-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The css_set_lock is used to guard the list of inherited objcgs. So there
is no need to uncharge kernel memory under css_set_lock. Just move it out
of the lock.
Link: https://lkml.kernel.org/r/20210417043538.9793-8-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The obj_cgroup_release() and memcg_reparent_objcgs() are serialized by the
css_set_lock. We do not need to care about objcg->memcg being released in
the process of obj_cgroup_release(). So there is no need to pin memcg
before releasing objcg. Remove those pinning logic to simplfy the code.
There are only two places that modifies the objcg->memcg. One is the
initialization to objcg->memcg in the memcg_online_kmem(), another is
objcgs reparenting in the memcg_reparent_objcgs(). It is also impossible
for the two to run in parallel. So xchg() is unnecessary and it is enough
to use WRITE_ONCE().
Link: https://lkml.kernel.org/r/20210417043538.9793-7-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
All the callers of mem_cgroup_page_lruvec() just pass page_pgdat(page) as
the 2nd parameter to it (except isolate_migratepages_block()). But for
isolate_migratepages_block(), the page_pgdat(page) is also equal to the
local variable of @pgdat. So mem_cgroup_page_lruvec() do not need the
pgdat parameter. Just remove it to simplify the code.
Link: https://lkml.kernel.org/r/20210417043538.9793-4-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When mm is NULL, we do not need to hold rcu lock and call css_tryget for
the root memcg. And we also do not need to check !mm in every loop of
while. So bail out early when !mm.
Link: https://lkml.kernel.org/r/20210417043538.9793-3-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "memcontrol code cleanup and simplification", v3.
This patch (of 8):
The pages aren't accounted at the root level, so do not charge the page to
the root memcg in page replacement. Although we do not display the value
(mem_cgroup_usage) so there shouldn't be any actual problem, but there is
a WARN_ON_ONCE in the page_counter_cancel(). Who knows if it will
trigger? So it is better to fix it.
Link: https://lkml.kernel.org/r/20210417043538.9793-1-songmuchun@bytedance.com
Link: https://lkml.kernel.org/r/20210417043538.9793-2-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The below scenario can cause the page counters of the root_mem_cgroup to
be out of balance.
CPU0: CPU1:
objcg = get_obj_cgroup_from_current()
obj_cgroup_charge_pages(objcg)
memcg_reparent_objcgs()
// reparent to root_mem_cgroup
WRITE_ONCE(iter->memcg, parent)
// memcg == root_mem_cgroup
memcg = get_mem_cgroup_from_objcg(objcg)
// do not charge to the root_mem_cgroup
try_charge(memcg)
obj_cgroup_uncharge_pages(objcg)
memcg = get_mem_cgroup_from_objcg(objcg)
// uncharge from the root_mem_cgroup
refill_stock(memcg)
drain_stock(memcg)
page_counter_uncharge(&memcg->memory)
get_obj_cgroup_from_current() never returns a root_mem_cgroup's objcg, so
we never explicitly charge the root_mem_cgroup. And it's not going to
change. It's all about a race when we got an obj_cgroup pointing at some
non-root memcg, but before we were able to charge it, the cgroup was gone,
objcg was reparented to the root and so we're skipping the charging. Then
we store the objcg pointer and later use to uncharge the root_mem_cgroup.
This can cause the page counter to be less than the actual value.
Although we do not display the value (mem_cgroup_usage) so there shouldn't
be any actual problem, but there is a WARN_ON_ONCE in the
page_counter_cancel(). Who knows if it will trigger? So it is better to
fix it.
Link: https://lkml.kernel.org/r/20210425075410.19255-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are currently two problems in the way the objcg pointer array
(memcg_data) in the page structure is being allocated and freed.
On its allocation, it is possible that the allocated objcg pointer
array comes from the same slab that requires memory accounting. If this
happens, the slab will never become empty again as there is at least
one object left (the obj_cgroup array) in the slab.
When it is freed, the objcg pointer array object may be the last one
in its slab and hence causes kfree() to be called again. With the
right workload, the slab cache may be set up in a way that allows the
recursive kfree() calling loop to nest deep enough to cause a kernel
stack overflow and panic the system.
One way to solve this problem is to split the kmalloc-<n> caches
(KMALLOC_NORMAL) into two separate sets - a new set of kmalloc-<n>
(KMALLOC_NORMAL) caches for unaccounted objects only and a new set of
kmalloc-cg-<n> (KMALLOC_CGROUP) caches for accounted objects only. All
the other caches can still allow a mix of accounted and unaccounted
objects.
With this change, all the objcg pointer array objects will come from
KMALLOC_NORMAL caches which won't have their objcg pointer arrays. So
both the recursive kfree() problem and non-freeable slab problem are
gone.
Since both the KMALLOC_NORMAL and KMALLOC_CGROUP caches no longer have
mixed accounted and unaccounted objects, this will slightly reduce the
number of objcg pointer arrays that need to be allocated and save a bit
of memory. On the other hand, creating a new set of kmalloc caches does
have the effect of reducing cache utilization. So it is properly a wash.
The new KMALLOC_CGROUP is added between KMALLOC_NORMAL and
KMALLOC_RECLAIM so that the first for loop in create_kmalloc_caches()
will include the newly added caches without change.
[vbabka@suse.cz: don't create kmalloc-cg caches with cgroup.memory=nokmem]
Link: https://lkml.kernel.org/r/20210512145107.6208-1-longman@redhat.com
[akpm@linux-foundation.org: un-fat-finger v5 delta creation]
[longman@redhat.com: disable cache merging for KMALLOC_NORMAL caches]
Link: https://lkml.kernel.org/r/20210505200610.13943-4-longman@redhat.com
Link: https://lkml.kernel.org/r/20210512145107.6208-1-longman@redhat.com
Link: https://lkml.kernel.org/r/20210505200610.13943-3-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
[longman@redhat.com: fix for CONFIG_ZONE_DMA=n]
Suggested-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm: memcg/slab: Fix objcg pointer array handling problem", v4.
Since the merging of the new slab memory controller in v5.9, the page
structure stores a pointer to objcg pointer array for slab pages. When
the slab has no used objects, it can be freed in free_slab() which will
call kfree() to free the objcg pointer array in
memcg_alloc_page_obj_cgroups(). If it happens that the objcg pointer
array is the last used object in its slab, that slab may then be freed
which may caused kfree() to be called again.
With the right workload, the slab cache may be set up in a way that allows
the recursive kfree() calling loop to nest deep enough to cause a kernel
stack overflow and panic the system. In fact, we have a reproducer that
can cause kernel stack overflow on a s390 system involving kmalloc-rcl-256
and kmalloc-rcl-128 slabs with the following kfree() loop recursively
called 74 times:
[ 285.520739] [<000000000ec432fc>] kfree+0x4bc/0x560 [ 285.520740]
[<000000000ec43466>] __free_slab+0xc6/0x228 [ 285.520741]
[<000000000ec41fc2>] __slab_free+0x3c2/0x3e0 [ 285.520742]
[<000000000ec432fc>] kfree+0x4bc/0x560 : While investigating this issue, I
also found an issue on the allocation side. If the objcg pointer array
happen to come from the same slab or a circular dependency linkage is
formed with multiple slabs, those affected slabs can never be freed again.
This patch series addresses these two issues by introducing a new set of
kmalloc-cg-<n> caches split from kmalloc-<n> caches. The new set will
only contain non-reclaimable and non-dma objects that are accounted in
memory cgroups whereas the old set are now for unaccounted objects only.
By making this split, all the objcg pointer arrays will come from the
kmalloc-<n> caches, but those caches will never hold any objcg pointer
array. As a result, deeply nested kfree() call and the unfreeable slab
problems are now gone.
This patch (of 4):
Since the merging of the new slab memory controller in v5.9, the page
structure may store a pointer to obj_cgroup pointer array for slab pages.
Currently, only the __GFP_ACCOUNT bit is masked off. However, the array
is not readily reclaimable and doesn't need to come from the DMA buffer.
So those GFP bits should be masked off as well.
Do the flag bit clearing at memcg_alloc_page_obj_cgroups() to make sure
that it is consistently applied no matter where it is called.
Link: https://lkml.kernel.org/r/20210505200610.13943-1-longman@redhat.com
Link: https://lkml.kernel.org/r/20210505200610.13943-2-longman@redhat.com
Fixes: 286e04b8ed ("mm: memcg/slab: allocate obj_cgroups for non-root slab pages")
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Most kmem_cache_alloc() calls are from user context. With instrumentation
enabled, the measured amount of kmem_cache_alloc() calls from non-task
context was about 0.01% of the total.
The irq disable/enable sequence used in this case to access content from
object stock is slow. To optimize for user context access, there are now
two sets of object stocks (in the new obj_stock structure) for task
context and interrupt context access respectively.
The task context object stock can be accessed after disabling preemption
which is cheap in non-preempt kernel. The interrupt context object stock
can only be accessed after disabling interrupt. User context code can
access interrupt object stock, but not vice versa.
The downside of this change is that there are more data stored in local
object stocks and not reflected in the charge counter and the vmstat
arrays. However, this is a small price to pay for better performance.
[longman@redhat.com: fix potential uninitialized variable warning]
Link: https://lkml.kernel.org/r/20210526193602.8742-1-longman@redhat.com
[akpm@linux-foundation.org: coding style fixes]
Link: https://lkml.kernel.org/r/20210506150007.16288-5-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Roman Gushchin <guro@fb.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Chris Down <chris@chrisdown.name>
Cc: Yafang Shao <laoar.shao@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Masayoshi Mizuma <msys.mizuma@gmail.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are two issues with the current refill_obj_stock() code. First of
all, when nr_bytes reaches over PAGE_SIZE, it calls drain_obj_stock() to
atomically flush out remaining bytes to obj_cgroup, clear cached_objcg and
do a obj_cgroup_put(). It is likely that the same obj_cgroup will be used
again which leads to another call to drain_obj_stock() and
obj_cgroup_get() as well as atomically retrieve the available byte from
obj_cgroup. That is costly. Instead, we should just uncharge the excess
pages, reduce the stock bytes and be done with it. The drain_obj_stock()
function should only be called when obj_cgroup changes.
Secondly, when charging an object of size not less than a page in
obj_cgroup_charge(), it is possible that the remaining bytes to be
refilled to the stock will overflow a page and cause refill_obj_stock() to
uncharge 1 page. To avoid the additional uncharge in this case, a new
allow_uncharge flag is added to refill_obj_stock() which will be set to
false when called from obj_cgroup_charge() so that an uncharge_pages()
call won't be issued right after a charge_pages() call unless the objcg
changes.
A multithreaded kmalloc+kfree microbenchmark on a 2-socket 48-core
96-thread x86-64 system with 96 testing threads were run. Before this
patch, the total number of kilo kmalloc+kfree operations done for a 4k
large object by all the testing threads per second were 4,304 kops/s
(cgroup v1) and 8,478 kops/s (cgroup v2). After applying this patch, the
number were 4,731 (cgroup v1) and 418,142 (cgroup v2) respectively. This
represents a performance improvement of 1.10X (cgroup v1) and 49.3X
(cgroup v2).
Link: https://lkml.kernel.org/r/20210506150007.16288-4-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Chris Down <chris@chrisdown.name>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Masayoshi Mizuma <msys.mizuma@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Before the new slab memory controller with per object byte charging,
charging and vmstat data update happen only when new slab pages are
allocated or freed. Now they are done with every kmem_cache_alloc() and
kmem_cache_free(). This causes additional overhead for workloads that
generate a lot of alloc and free calls.
The memcg_stock_pcp is used to cache byte charge for a specific obj_cgroup
to reduce that overhead. To further reducing it, this patch makes the
vmstat data cached in the memcg_stock_pcp structure as well until it
accumulates a page size worth of update or when other cached data change.
Caching the vmstat data in the per-cpu stock eliminates two writes to
non-hot cachelines for memcg specific as well as memcg-lruvecs specific
vmstat data by a write to a hot local stock cacheline.
On a 2-socket Cascade Lake server with instrumentation enabled and this
patch applied, it was found that about 20% (634400 out of 3243830) of the
time when mod_objcg_state() is called leads to an actual call to
__mod_objcg_state() after initial boot. When doing parallel kernel build,
the figure was about 17% (24329265 out of 142512465). So caching the
vmstat data reduces the number of calls to __mod_objcg_state() by more
than 80%.
Link: https://lkml.kernel.org/r/20210506150007.16288-3-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Chris Down <chris@chrisdown.name>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Masayoshi Mizuma <msys.mizuma@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm/memcg: Reduce kmemcache memory accounting overhead", v6.
With the recent introduction of the new slab memory controller, we
eliminate the need for having separate kmemcaches for each memory cgroup
and reduce overall kernel memory usage. However, we also add additional
memory accounting overhead to each call of kmem_cache_alloc() and
kmem_cache_free().
For workloads that require a lot of kmemcache allocations and
de-allocations, they may experience performance regression as illustrated
in [1] and [2].
A simple kernel module that performs repeated loop of 100,000,000
kmem_cache_alloc() and kmem_cache_free() of either a small 32-byte object
or a big 4k object at module init time with a batch size of 4 (4 kmalloc's
followed by 4 kfree's) is used for benchmarking. The benchmarking tool
was run on a kernel based on linux-next-20210419. The test was run on a
CascadeLake server with turbo-boosting disable to reduce run-to-run
variation.
The small object test exercises mainly the object stock charging and
vmstat update code paths. The large object test also exercises the
refill_obj_stock() and __memcg_kmem_charge()/__memcg_kmem_uncharge() code
paths.
With memory accounting disabled, the run time was 3.130s with both small
object big object tests.
With memory accounting enabled, both cgroup v1 and v2 showed similar
results in the small object test. The performance results of the large
object test, however, differed between cgroup v1 and v2.
The execution times with the application of various patches in the
patchset were:
Applied patches Run time Accounting overhead %age 1 %age 2
--------------- -------- ------------------- ------ ------
Small 32-byte object:
None 11.634s 8.504s 100.0% 271.7%
1-2 9.425s 6.295s 74.0% 201.1%
1-3 9.708s 6.578s 77.4% 210.2%
1-4 8.062s 4.932s 58.0% 157.6%
Large 4k object (v2):
None 22.107s 18.977s 100.0% 606.3%
1-2 20.960s 17.830s 94.0% 569.6%
1-3 14.238s 11.108s 58.5% 354.9%
1-4 11.329s 8.199s 43.2% 261.9%
Large 4k object (v1):
None 36.807s 33.677s 100.0% 1075.9%
1-2 36.648s 33.518s 99.5% 1070.9%
1-3 22.345s 19.215s 57.1% 613.9%
1-4 18.662s 15.532s 46.1% 496.2%
N.B. %age 1 = overhead/unpatched overhead
%age 2 = overhead/accounting disabled time
Patch 2 (vmstat data stock caching) helps in both the small object test
and the large v2 object test. It doesn't help much in v1 big object test.
Patch 3 (refill_obj_stock improvement) does help the small object test
but offer significant performance improvement for the large object test
(both v1 and v2).
Patch 4 (eliminating irq disable/enable) helps in all test cases.
To test for the extreme case, a multi-threaded kmalloc/kfree
microbenchmark was run on the 2-socket 48-core 96-thread system with
96 testing threads in the same memcg doing kmalloc+kfree of a 4k object
with accounting enabled for 10s. The total number of kmalloc+kfree done
in kilo operations per second (kops/s) were as follows:
Applied patches v1 kops/s v1 change v2 kops/s v2 change
--------------- --------- --------- --------- ---------
None 3,520 1.00X 6,242 1.00X
1-2 4,304 1.22X 8,478 1.36X
1-3 4,731 1.34X 418,142 66.99X
1-4 4,587 1.30X 438,838 70.30X
With memory accounting disabled, the kmalloc/kfree rate was 1,481,291
kop/s. This test shows how significant the memory accouting overhead
can be in some extreme situations.
For this multithreaded test, the improvement from patch 2 mainly
comes from the conditional atomic xchg of objcg->nr_charged_bytes in
mod_objcg_state(). By using an unconditional xchg, the operation rates
were similar to the unpatched kernel.
Patch 3 elminates the single highly contended cacheline of
objcg->nr_charged_bytes for cgroup v2 leading to a huge performance
improvement. Cgroup v1, however, still has another highly contended
cacheline in the shared page counter &memcg->kmem. So the improvement
is only modest.
Patch 4 helps in cgroup v2, but performs worse in cgroup v1 as
eliminating the irq_disable/irq_enable overhead seems to aggravate the
cacheline contention.
[1] https://lore.kernel.org/linux-mm/20210408193948.vfktg3azh2wrt56t@gabell/T/#u
[2] https://lore.kernel.org/lkml/20210114025151.GA22932@xsang-OptiPlex-9020/
This patch (of 4):
mod_objcg_state() is moved from mm/slab.h to mm/memcontrol.c so that
further optimization can be done to it in later patches without exposing
unnecessary details to other mm components.
Link: https://lkml.kernel.org/r/20210506150007.16288-1-longman@redhat.com
Link: https://lkml.kernel.org/r/20210506150007.16288-2-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Chris Down <chris@chrisdown.name>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Masayoshi Mizuma <msys.mizuma@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce a new mem_cgroup_kmem_disabled() helper, similar to
mem_cgroup_disabled(), to check whether the kernel memory accounting
is off. A user could disable it using a boot option to eliminate
some associated costs.
The helper can be used outside of memcontrol.c to dynamically disable
the kmem-related code. The returned value is stable after the kernel
initialization is finished.
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
cgroup_memory_nosocket, cgroup_memory_nokmem and cgroup_memory_noswap
are initialized during the kernel initialization and never change
their value afterwards.
cgroup_memory_nosocket, cgroup_memory_nokmem are written only from
cgroup_memory(), which is marked as __init.
cgroup_memory_noswap is written from setup_swap_account() and
mem_cgroup_swap_init(), both are marked as __init.
Mark all three variables as __ro_after_init.
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Now shrinker's nr_deferred is per memcg for memcg aware shrinkers, add
to parent's corresponding nr_deferred when memcg offline.
Link: https://lkml.kernel.org/r/20210311190845.9708-13-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The following patch is going to add nr_deferred into shrinker_map, the
change will make shrinker_map not only include map anymore, so rename it
to "memcg_shrinker_info". And this should make the patch adding
nr_deferred cleaner and readable and make review easier. Also remove the
"memcg_" prefix.
Link: https://lkml.kernel.org/r/20210311190845.9708-7-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The shrinker map management is not purely memcg specific, it is at the
intersection between memory cgroup and shrinkers. It's allocation and
assignment of a structure, and the only memcg bit is the map is being
stored in a memcg structure. So move the shrinker_maps handling code
into vmscan.c for tighter integration with shrinker code, and remove the
"memcg_" prefix. There is no functional change.
Link: https://lkml.kernel.org/r/20210311190845.9708-3-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is only one user of __memcg_kmem_charge(), so manually inline
__memcg_kmem_charge() to obj_cgroup_charge_pages(). Similarly manually
inline __memcg_kmem_uncharge() into obj_cgroup_uncharge_pages() and call
obj_cgroup_uncharge_pages() in obj_cgroup_release().
This is just code cleanup without any functionality changes.
Link: https://lkml.kernel.org/r/20210319163821.20704-7-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since Roman's series "The new cgroup slab memory controller" applied.
All slab objects are charged via the new APIs of obj_cgroup. The new
APIs introduce a struct obj_cgroup to charge slab objects. It prevents
long-living objects from pinning the original memory cgroup in the
memory. But there are still some corner objects (e.g. allocations
larger than order-1 page on SLUB) which are not charged via the new
APIs. Those objects (include the pages which are allocated from buddy
allocator directly) are charged as kmem pages which still hold a
reference to the memory cgroup.
We want to reuse the obj_cgroup APIs to charge the kmem pages. If we do
that, we should store an object cgroup pointer to page->memcg_data for
the kmem pages.
Finally, page->memcg_data will have 3 different meanings.
1) For the slab pages, page->memcg_data points to an object cgroups
vector.
2) For the kmem pages (exclude the slab pages), page->memcg_data
points to an object cgroup.
3) For the user pages (e.g. the LRU pages), page->memcg_data points
to a memory cgroup.
We do not change the behavior of page_memcg() and page_memcg_rcu(). They
are also suitable for LRU pages and kmem pages. Why?
Because memory allocations pinning memcgs for a long time - it exists at a
larger scale and is causing recurring problems in the real world: page
cache doesn't get reclaimed for a long time, or is used by the second,
third, fourth, ... instance of the same job that was restarted into a new
cgroup every time. Unreclaimable dying cgroups pile up, waste memory, and
make page reclaim very inefficient.
We can convert LRU pages and most other raw memcg pins to the objcg
direction to fix this problem, and then the page->memcg will always point
to an object cgroup pointer. At that time, LRU pages and kmem pages will
be treated the same. The implementation of page_memcg() will remove the
kmem page check.
This patch aims to charge the kmem pages by using the new APIs of
obj_cgroup. Finally, the page->memcg_data of the kmem page points to an
object cgroup. We can use the __page_objcg() to get the object cgroup
associated with a kmem page. Or we can use page_memcg() to get the memory
cgroup associated with a kmem page, but caller must ensure that the
returned memcg won't be released (e.g. acquire the rcu_read_lock or
css_set_lock).
Link: https://lkml.kernel.org/r/20210401030141.37061-1-songmuchun@bytedance.com
Link: https://lkml.kernel.org/r/20210319163821.20704-6-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
[songmuchun@bytedance.com: fix forget to obtain the ref to objcg in split_page_memcg]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Just like assignment to ug->memcg, we only need to update ug->dummy_page
if memcg changed. So move it to there. This is a very small
optimization.
Link: https://lkml.kernel.org/r/20210319163821.20704-5-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We know that the unit of slab object charging is bytes, the unit of kmem
page charging is PAGE_SIZE. If we want to reuse obj_cgroup APIs to
charge the kmem pages, we should pass PAGE_SIZE (as third parameter) to
obj_cgroup_charge(). Because the size is already PAGE_SIZE, we can skip
touch the objcg stock. And obj_cgroup_{un}charge_pages() are introduced
to charge in units of page level.
In the latter patch, we also can reuse those two helpers to charge or
uncharge a number of kernel pages to a object cgroup. This is just a
code movement without any functional changes.
Link: https://lkml.kernel.org/r/20210319163821.20704-3-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Use obj_cgroup APIs to charge kmem pages", v5.
Since Roman's series "The new cgroup slab memory controller" applied.
All slab objects are charged with the new APIs of obj_cgroup. The new
APIs introduce a struct obj_cgroup to charge slab objects. It prevents
long-living objects from pinning the original memory cgroup in the
memory. But there are still some corner objects (e.g. allocations
larger than order-1 page on SLUB) which are not charged with the new
APIs. Those objects (include the pages which are allocated from buddy
allocator directly) are charged as kmem pages which still hold a
reference to the memory cgroup.
E.g. We know that the kernel stack is charged as kmem pages because the
size of the kernel stack can be greater than 2 pages (e.g. 16KB on
x86_64 or arm64). If we create a thread (suppose the thread stack is
charged to memory cgroup A) and then move it from memory cgroup A to
memory cgroup B. Because the kernel stack of the thread hold a
reference to the memory cgroup A. The thread can pin the memory cgroup
A in the memory even if we remove the cgroup A. If we want to see this
scenario by using the following script. We can see that the system has
added 500 dying cgroups (This is not a real world issue, just a script
to show that the large kmallocs are charged as kmem pages which can pin
the memory cgroup in the memory).
#!/bin/bash
cat /proc/cgroups | grep memory
cd /sys/fs/cgroup/memory
echo 1 > memory.move_charge_at_immigrate
for i in range{1..500}
do
mkdir kmem_test
echo $$ > kmem_test/cgroup.procs
sleep 3600 &
echo $$ > cgroup.procs
echo `cat kmem_test/cgroup.procs` > cgroup.procs
rmdir kmem_test
done
cat /proc/cgroups | grep memory
This patchset aims to make those kmem pages to drop the reference to
memory cgroup by using the APIs of obj_cgroup. Finally, we can see that
the number of the dying cgroups will not increase if we run the above test
script.
This patch (of 7):
The rcu_read_lock/unlock only can guarantee that the memcg will not be
freed, but it cannot guarantee the success of css_get (which is in the
refill_stock when cached memcg changed) to memcg.
rcu_read_lock()
memcg = obj_cgroup_memcg(old)
__memcg_kmem_uncharge(memcg)
refill_stock(memcg)
if (stock->cached != memcg)
// css_get can change the ref counter from 0 back to 1.
css_get(&memcg->css)
rcu_read_unlock()
This fix is very like the commit:
eefbfa7fd6 ("mm: memcg/slab: fix use after free in obj_cgroup_charge")
Fix this by holding a reference to the memcg which is passed to the
__memcg_kmem_uncharge() before calling __memcg_kmem_uncharge().
Link: https://lkml.kernel.org/r/20210319163821.20704-1-songmuchun@bytedance.com
Link: https://lkml.kernel.org/r/20210319163821.20704-2-songmuchun@bytedance.com
Fixes: 3de7d4f25a ("mm: memcg/slab: optimize objcg stock draining")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently the kernel adds the page, allocated for swapin, to the
swapcache before charging the page. This is fine but now we want a
per-memcg swapcache stat which is essential for folks who wants to
transparently migrate from cgroup v1's memsw to cgroup v2's memory and
swap counters. In addition charging a page before exposing it to other
parts of the kernel is a step in the right direction.
To correctly maintain the per-memcg swapcache stat, this patch has
adopted to charge the page before adding it to swapcache. One challenge
in this option is the failure case of add_to_swap_cache() on which we
need to undo the mem_cgroup_charge(). Specifically undoing
mem_cgroup_uncharge_swap() is not simple.
To resolve the issue, this patch decouples the charging for swapin pages
from mem_cgroup_charge(). Two new functions are introduced,
mem_cgroup_swapin_charge_page() for just charging the swapin page and
mem_cgroup_swapin_uncharge_swap() for uncharging the swap slot once the
page has been successfully added to the swapcache.
[shakeelb@google.com: set page->private before calling swap_readpage]
Link: https://lkml.kernel.org/r/20210318015959.2986837-1-shakeelb@google.com
Link: https://lkml.kernel.org/r/20210305212639.775498-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Hugh Dickins <hughd@google.com>
Tested-by: Heiko Carstens <hca@linux.ibm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are two functions to flush the per-cpu data of an lruvec into the
rest of the cgroup tree: when the cgroup is being freed, and when a CPU
disappears during hotplug. The difference is whether all CPUs or just
one is being collected, but the rest of the flushing code is the same.
Merge them into one function and share the common code.
Link: https://lkml.kernel.org/r/20210209163304.77088-8-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace the memory controller's custom hierarchical stats code with the
generic rstat infrastructure provided by the cgroup core.
The current implementation does batched upward propagation from the
write side (i.e. as stats change). The per-cpu batches introduce an
error, which is multiplied by the number of subgroups in a tree. In
systems with many CPUs and sizable cgroup trees, the error can be large
enough to confuse users (e.g. 32 batch pages * 32 CPUs * 32 subgroups
results in an error of up to 128M per stat item). This can entirely
swallow allocation bursts inside a workload that the user is expecting
to see reflected in the statistics.
In the past, we've done read-side aggregation, where a memory.stat read
would have to walk the entire subtree and add up per-cpu counts. This
became problematic with lazily-freed cgroups: we could have large
subtrees where most cgroups were entirely idle. Hence the switch to
change-driven upward propagation. Unfortunately, it needed to trade
accuracy for speed due to the write side being so hot.
Rstat combines the best of both worlds: from the write side, it cheaply
maintains a queue of cgroups that have pending changes, so that the read
side can do selective tree aggregation. This way the reported stats
will always be precise and recent as can be, while the aggregation can
skip over potentially large numbers of idle cgroups.
The way rstat works is that it implements a tree for tracking cgroups
with pending local changes, as well as a flush function that walks the
tree upwards. The controller then drives this by 1) telling rstat when
a local cgroup stat changes (e.g. mod_memcg_state) and 2) when a flush
is required to get uptodate hierarchy stats for a given subtree (e.g.
when memory.stat is read). The controller also provides a flush
callback that is called during the rstat flush walk for each cgroup and
aggregates its local per-cpu counters and propagates them upwards.
This adds a second vmstats to struct mem_cgroup (MEMCG_NR_STAT +
NR_VM_EVENT_ITEMS) to track pending subtree deltas during upward
aggregation. It removes 3 words from the per-cpu data. It eliminates
memcg_exact_page_state(), since memcg_page_state() is now exact.
[akpm@linux-foundation.org: merge fix]
[hannes@cmpxchg.org: fix a sleep in atomic section problem]
Link: https://lkml.kernel.org/r/20210315234100.64307-1-hannes@cmpxchg.org
Link: https://lkml.kernel.org/r/20210209163304.77088-7-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are no users outside of the memory controller itself. The rest
of the kernel cares either about node or lruvec stats.
Link: https://lkml.kernel.org/r/20210209163304.77088-4-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
No need to encapsulate a simple struct member access.
Link: https://lkml.kernel.org/r/20210209163304.77088-3-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm: memcontrol: switch to rstat", v3.
This series converts memcg stats tracking to the streamlined rstat
infrastructure provided by the cgroup core code. rstat is already used by
the CPU controller and the IO controller. This change is motivated by
recent accuracy problems in memcg's custom stats code, as well as the
benefits of sharing common infra with other controllers.
The current memcg implementation does batched tree aggregation on the
write side: local stat changes are cached in per-cpu counters, which are
then propagated upward in batches when a threshold (32 pages) is exceeded.
This is cheap, but the error introduced by the lazy upward propagation
adds up: 32 pages times CPUs times cgroups in the subtree. We've had
complaints from service owners that the stats do not reliably track and
react to allocation behavior as expected, sometimes swallowing the results
of entire test applications.
The original memcg stat implementation used to do tree aggregation
exclusively on the read side: local stats would only ever be tracked in
per-cpu counters, and a memory.stat read would iterate the entire subtree
and sum those counters up. This didn't keep up with the times:
- Cgroup trees are much bigger now. We switched to lazily-freed
cgroups, where deleted groups would hang around until their remaining
page cache has been reclaimed. This can result in large subtrees that
are expensive to walk, while most of the groups are idle and their
statistics don't change much anymore.
- Automated monitoring increased. With the proliferation of userspace
oom killing, proactive reclaim, and higher-resolution logging of
workload trends in general, top-level stat files are polled at least
once a second in many deployments.
- The lifetime of cgroups got shorter. Where most cgroup setups in the
past would have a few large policy-oriented cgroups for everything
running on the system, newer cgroup deployments tend to create one
group per application - which gets deleted again as the processes
exit. An aggregation scheme that doesn't retain child data inside the
parents loses event history of the subtree.
Rstat addresses all three of those concerns through intelligent,
persistent read-side aggregation. As statistics change at the local
level, rstat tracks - on a per-cpu basis - only those parts of a subtree
that have changes pending and require aggregation. The actual
aggregation occurs on the colder read side - which can now skip over
(potentially large) numbers of recently idle cgroups.
===
The test_kmem cgroup selftest is currently failing due to excessive
cumulative vmstat drift from 100 subgroups:
ok 1 test_kmem_basic
memory.current = 8810496
slab + anon + file + kernel_stack = 17074568
slab = 6101384
anon = 946176
file = 0
kernel_stack = 10027008
not ok 2 test_kmem_memcg_deletion
ok 3 test_kmem_proc_kpagecgroup
ok 4 test_kmem_kernel_stacks
ok 5 test_kmem_dead_cgroups
ok 6 test_percpu_basic
As you can see, memory.stat items far exceed memory.current. The kernel
stack alone is bigger than all of charged memory. That's because the
memory of the test has been uncharged from memory.current, but the
negative vmstat deltas are still sitting in the percpu caches.
The test at this time isn't even counting percpu, pagetables etc. yet,
which would further contribute to the error. The last patch in the series
updates the test to include them - as well as reduces the vmstat
tolerances in general to only expect page_counter batching.
With all patches applied, the (now more stringent) test succeeds:
ok 1 test_kmem_basic
ok 2 test_kmem_memcg_deletion
ok 3 test_kmem_proc_kpagecgroup
ok 4 test_kmem_kernel_stacks
ok 5 test_kmem_dead_cgroups
ok 6 test_percpu_basic
===
A kernel build test confirms that overhead is comparable. Two kernels are
built simultaneously in a nested tree with several idle siblings:
root - kernelbuild - one - two - three - four - build-a (defconfig, make -j16)
`- build-b (defconfig, make -j16)
`- idle-1
`- ...
`- idle-9
During the builds, kernelbuild/memory.stat is read once a second.
A perf diff shows that the changes in cycle distribution is
minimal. Top 10 kernel symbols:
0.09% +0.08% [kernel.kallsyms] [k] __mod_memcg_lruvec_state
0.00% +0.06% [kernel.kallsyms] [k] cgroup_rstat_updated
0.08% -0.05% [kernel.kallsyms] [k] __mod_memcg_state.part.0
0.16% -0.04% [kernel.kallsyms] [k] release_pages
0.00% +0.03% [kernel.kallsyms] [k] __count_memcg_events
0.01% +0.03% [kernel.kallsyms] [k] mem_cgroup_charge_statistics.constprop.0
0.10% -0.02% [kernel.kallsyms] [k] get_mem_cgroup_from_mm
0.05% -0.02% [kernel.kallsyms] [k] mem_cgroup_update_lru_size
0.57% +0.01% [kernel.kallsyms] [k] asm_exc_page_fault
===
The on-demand aggregated stats are now fully accurate:
$ grep -e nr_inactive_file /proc/vmstat | awk '{print($1,$2*4096)}'; \
grep -e inactive_file /sys/fs/cgroup/memory.stat
vanilla: patched:
nr_inactive_file 1574105088 nr_inactive_file 1027801088
inactive_file 1577410560 inactive_file 1027801088
===
This patch (of 8):
The memcg hotunplug callback erroneously flushes counts on the local CPU,
not the counts of the CPU going away; those counts will be lost.
Flush the CPU that is actually going away.
Also simplify the code a bit by using mod_memcg_state() and
count_memcg_events() instead of open-coding the upward flush - this is
comparable to how vmstat.c handles hotunplug flushing.
Link: https://lkml.kernel.org/r/20210209163304.77088-1-hannes@cmpxchg.org
Link: https://lkml.kernel.org/r/20210209163304.77088-2-hannes@cmpxchg.org
Fixes: a983b5ebee ("mm: memcontrol: fix excessive complexity in memory.stat reporting")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Tejun Heo <tj@kernel.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>
In the era of async memcg oom-killer, the commit a0d8b00a33 ("mm: memcg:
do not declare OOM from __GFP_NOFAIL allocations") added the code to skip
memcg oom-killer for __GFP_NOFAIL allocations. The reason was that the
__GFP_NOFAIL callers will not enter aync oom synchronization path and will
keep the task marked as in memcg oom. At that time the tasks marked in
memcg oom can bypass the memcg limits and the oom synchronization would
have happened later in the later userspace triggered page fault. Thus
letting the task marked as under memcg oom bypass the memcg limit for
arbitrary time.
With the synchronous memcg oom-killer (commit 29ef680ae7 ("memcg, oom:
move out_of_memory back to the charge path")) and not letting the task
marked under memcg oom to bypass the memcg limits (commit 1f14c1ac19
("mm: memcg: do not allow task about to OOM kill to bypass the limit")),
we can again allow __GFP_NOFAIL allocations to trigger memcg oom-kill.
This will make memcg oom behavior closer to page allocator oom behavior.
Link: https://lkml.kernel.org/r/20210223204337.2785120-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
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>
Replace the implicit checking of root memcg with explicit root memcg
checking i.e. !css->parent with mem_cgroup_is_root().
Link: https://lkml.kernel.org/r/20210223205625.2792891-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: 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>
Page writeback doesn't hold a page reference, which allows truncate to
free a page the second PageWriteback is cleared. This used to require
special attention in test_clear_page_writeback(), where we had to be
careful not to rely on the unstable page->memcg binding and look up all
the necessary information before clearing the writeback flag.
Since commit 073861ed77 ("mm: fix VM_BUG_ON(PageTail) and
BUG_ON(PageWriteback)") test_clear_page_writeback() is called with an
explicit reference on the page, and this dance is no longer needed.
Use unlock_page_memcg() and dec_lruvec_page_state() directly.
This removes the last user of the lock_page_memcg() return value, change
it to void. Touch up the comments in there as well. This also removes
the last extern user of __unlock_page_memcg(), make it static. Further,
it removes the last user of dec_lruvec_state(), delete it, along with a
few other unused helpers.
Link: https://lkml.kernel.org/r/YCQbYAWg4nvBFL6h@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rename mem_cgroup_split_huge_fixup to split_page_memcg and explicitly pass
in page number argument.
In this way, the interface name is more common and can be used by
potential users. In addition, the complete info(memcg and flag) of the
memcg needs to be set to the tail pages.
Link: https://lkml.kernel.org/r/20210304074053.65527-2-zhouguanghui1@huawei.com
Signed-off-by: Zhou Guanghui <zhouguanghui1@huawei.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Tianhong Ding <dingtianhong@huawei.com>
Cc: Weilong Chen <chenweilong@huawei.com>
Cc: Rui Xiang <rui.xiang@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>
We use a global percpu int_active_memcg variable to store the remote memcg
when we are in the interrupt context. But get_active_memcg always return
the current->active_memcg or root_mem_cgroup. The remote memcg (set in
the interrupt context) is ignored. This is not what we want. So fix it.
Link: https://lkml.kernel.org/r/20210223091101.42150-1-songmuchun@bytedance.com
Fixes: 37d5985c00 ("mm: kmem: prepare remote memcg charging infra for interrupt contexts")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When pages are swapped in, the VM may retain the swap copy to avoid
repeated writes in the future. It's also retained if shared pages are
faulted back in some processes, but not in others. During that time we
have an in-memory copy of the page, as well as an on-swap copy. Cgroup1
and cgroup2 handle these overlapping lifetimes slightly differently due to
the nature of how they account memory and swap:
Cgroup1 has a unified memory+swap counter that tracks a data page
regardless whether it's in-core or swapped out. On swapin, we transfer
the charge from the swap entry to the newly allocated swapcache page, even
though the swap entry might stick around for a while. That's why we have
a mem_cgroup_uncharge_swap() call inside mem_cgroup_charge().
Cgroup2 tracks memory and swap as separate, independent resources and thus
has split memory and swap counters. On swapin, we charge the newly
allocated swapcache page as memory, while the swap slot in turn must
remain charged to the swap counter as long as its allocated too.
The cgroup2 logic was broken by commit 2d1c498072 ("mm: memcontrol: make
swap tracking an integral part of memory control"), because it
accidentally removed the do_memsw_account() check in the branch inside
mem_cgroup_uncharge() that was supposed to tell the difference between the
charge transfer in cgroup1 and the separate counters in cgroup2.
As a result, cgroup2 currently undercounts retained swap to varying
degrees: swap slots are cached up to 50% of the configured limit or total
available swap space; partially faulted back shared pages are only limited
by physical capacity. This in turn allows cgroups to significantly
overconsume their alloted swap space.
Add the do_memsw_account() check back to fix this problem.
Link: https://lkml.kernel.org/r/20210217153237.92484-1-songmuchun@bytedance.com
Fixes: 2d1c498072 ("mm: memcontrol: make swap tracking an integral part of memory control")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <stable@vger.kernel.org> [5.8+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
alloc_page_buffers() currently uses get_mem_cgroup_from_page() for
charging the buffers to the page owner, which does an rcu-protected
page->memcg lookup and acquires a reference. But buffer allocation has
the page lock held throughout, which pins the page to the memcg and
thereby the memcg - neither rcu nor holding an extra reference during the
allocation are necessary. Use a raw page_memcg() instead.
This was the last user of get_mem_cgroup_from_page(), delete it.
Link: https://lkml.kernel.org/r/20210209190126.97842-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The rule of list walk has gone since commit a9d5adeeb4
("mm/memcontrol: allow to uncharge page without using page->lru field")
So remove the strange comment and replace the loop with a
list_for_each_entry().
There is only one caller of the uncharge_list(). So just fold it into
mem_cgroup_uncharge_list() and remove it.
Link: https://lkml.kernel.org/r/20210204163055.56080-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Roman Gushchin