Commit Graph

478 Commits

Author SHA1 Message Date
Ingo Molnar f0953a1bba mm: fix typos in comments
Fix ~94 single-word typos in locking code comments, plus a few
very obvious grammar mistakes.

Link: https://lkml.kernel.org/r/20210322212624.GA1963421@gmail.com
Link: https://lore.kernel.org/r/20210322205203.GB1959563@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-07 00:26:35 -07:00
Liam Mark 7bc1aec5e2 mm: cma: add trace events for CMA alloc perf testing
Add cma and migrate trace events to enable CMA allocation performance to
be measured via ftrace.

[georgi.djakov@linaro.org: add the CMA instance name to the cma_alloc_start trace event]
  Link: https://lkml.kernel.org/r/20210326155414.25006-1-georgi.djakov@linaro.org

Link: https://lkml.kernel.org/r/20210324160740.15901-1-georgi.djakov@linaro.org
Signed-off-by: Liam Mark <lmark@codeaurora.org>
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-05 11:27:24 -07:00
Miaohe Lin 7ee820ee72 Revert "mm: migrate: skip shared exec THP for NUMA balancing"
This reverts commit c77c5cbafe.

Since commit c77c5cbafe ("mm: migrate: skip shared exec THP for NUMA
balancing"), the NUMA balancing would skip shared exec transhuge page.
But this enhancement is not suitable for transhuge page.  Because it's
required that page_mapcount() must be 1 due to no migration pte dance is
done here.  On the other hand, the shared exec transhuge page will leave
the migrate_misplaced_page() with pte entry untouched and page locked.
Thus pagefault for NUMA will be triggered again and deadlock occurs when
we start waiting for the page lock held by ourselves.

Yang Shi said:

 "Thanks for catching this. By relooking the code I think the other
  important reason for removing this is
  migrate_misplaced_transhuge_page() actually can't see shared exec
  file THP at all since page_lock_anon_vma_read() is called before
  and if page is not anonymous page it will just restore the PMD
  without migrating anything.
  The pages for private mapped file vma may be anonymous pages due to
  COW but they can't be THP so it won't trigger THP numa fault at all. I
  think this is why no bug was reported. I overlooked this in the first
  place."

Link: https://lkml.kernel.org/r/20210325131524.48181-6-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-05 11:27:24 -07:00
Miaohe Lin 843e1be108 mm/migrate.c: use helper migrate_vma_collect_skip() in migrate_vma_collect_hole()
It's more recommended to use helper function migrate_vma_collect_skip() to
skip the unexpected case and it also helps remove some duplicated codes.
Move migrate_vma_collect_skip() above migrate_vma_collect_hole() to avoid
compiler warning.

Link: https://lkml.kernel.org/r/20210325131524.48181-5-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Rafael Aquini <aquini@redhat.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>
2021-05-05 11:27:24 -07:00
Miaohe Lin 34f5e9b9d1 mm/migrate.c: fix potential indeterminate pte entry in migrate_vma_insert_page()
If the zone device page does not belong to un-addressable device memory,
the variable entry will be uninitialized and lead to indeterminate pte
entry ultimately.  Fix this unexpected case and warn about it.

Link: https://lkml.kernel.org/r/20210325131524.48181-4-linmiaohe@huawei.com
Fixes: df6ad69838 ("mm/device-public-memory: device memory cache coherent with CPU")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Rafael Aquini <aquini@redhat.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>
2021-05-05 11:27:24 -07:00
Miaohe Lin a04840c684 mm/migrate.c: remove unnecessary rc != MIGRATEPAGE_SUCCESS check in 'else' case
It's guaranteed that in the 'else' case of the rc == MIGRATEPAGE_SUCCESS
check, rc does not equal to MIGRATEPAGE_SUCCESS.  Remove this unnecessary
check.

Link: https://lkml.kernel.org/r/20210325131524.48181-3-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-05 11:27:24 -07:00
Miaohe Lin 606a6f71a2 mm/migrate.c: make putback_movable_page() static
Patch series "Cleanup and fixup for mm/migrate.c", v3.

This series contains cleanups to remove unnecessary VM_BUG_ON_PAGE and rc
!= MIGRATEPAGE_SUCCESS check.  Also use helper function to remove some
duplicated codes.  What's more, this fixes potential deadlock in NUMA
balancing shared exec THP case and so on.  More details can be found in
the respective changelogs.

This patch (of 5):

The putback_movable_page() is just called by putback_movable_pages() and
we know the page is locked and both PageMovable() and PageIsolated() is
checked right before calling putback_movable_page().  So we make it static
and remove all the 3 VM_BUG_ON_PAGE().

Link: https://lkml.kernel.org/r/20210325131524.48181-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20210325131524.48181-2-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-05 11:27:24 -07:00
Minchan Kim 361a2a229f mm: replace migrate_[prep|finish] with lru_cache_[disable|enable]
Currently, migrate_[prep|finish] is merely a wrapper of
lru_cache_[disable|enable].  There is not much to gain from having
additional abstraction.

Use lru_cache_[disable|enable] instead of migrate_[prep|finish], which
would be more descriptive.

note: migrate_prep_local in compaction.c changed into lru_add_drain to
avoid CPU schedule cost with involving many other CPUs to keep old
behavior.

Link: https://lkml.kernel.org/r/20210319175127.886124-2-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Chris Goldsworthy <cgoldswo@codeaurora.org>
Cc: John Dias <joaodias@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oliver Sang <oliver.sang@intel.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-05 11:27:24 -07:00
Minchan Kim d479960e44 mm: disable LRU pagevec during the migration temporarily
LRU pagevec holds refcount of pages until the pagevec are drained.  It
could prevent migration since the refcount of the page is greater than
the expection in migration logic.  To mitigate the issue, callers of
migrate_pages drains LRU pagevec via migrate_prep or lru_add_drain_all
before migrate_pages call.

However, it's not enough because pages coming into pagevec after the
draining call still could stay at the pagevec so it could keep
preventing page migration.  Since some callers of migrate_pages have
retrial logic with LRU draining, the page would migrate at next trail
but it is still fragile in that it doesn't close the fundamental race
between upcoming LRU pages into pagvec and migration so the migration
failure could cause contiguous memory allocation failure in the end.

To close the race, this patch disables lru caches(i.e, pagevec) during
ongoing migration until migrate is done.

Since it's really hard to reproduce, I measured how many times
migrate_pages retried with force mode(it is about a fallback to a sync
migration) with below debug code.

int migrate_pages(struct list_head *from, new_page_t get_new_page,
			..
			..

  if (rc && reason == MR_CONTIG_RANGE && pass > 2) {
         printk(KERN_ERR, "pfn 0x%lx reason %d", page_to_pfn(page), rc);
         dump_page(page, "fail to migrate");
  }

The test was repeating android apps launching with cma allocation in
background every five seconds.  Total cma allocation count was about 500
during the testing.  With this patch, the dump_page count was reduced
from 400 to 30.

The new interface is also useful for memory hotplug which currently
drains lru pcp caches after each migration failure.  This is rather
suboptimal as it has to disrupt others running during the operation.
With the new interface the operation happens only once.  This is also in
line with pcp allocator cache which are disabled for the offlining as
well.

Link: https://lkml.kernel.org/r/20210319175127.886124-1-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Chris Goldsworthy <cgoldswo@codeaurora.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: John Dias <joaodias@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Oliver Sang <oliver.sang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-05 11:27:24 -07:00
Matthew Wilcox (Oracle) 84172f4bb7 mm/page_alloc: combine __alloc_pages and __alloc_pages_nodemask
There are only two callers of __alloc_pages() so prune the thicket of
alloc_page variants by combining the two functions together.  Current
callers of __alloc_pages() simply add an extra 'NULL' parameter and
current callers of __alloc_pages_nodemask() call __alloc_pages() instead.

Link: https://lkml.kernel.org/r/20210225150642.2582252-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30 11:20:42 -07:00
Shakeel Butt b603894248 mm: memcg: add swapcache stat for memcg v2
This patch adds swapcache stat for the cgroup v2.  The swapcache
represents the memory that is accounted against both the memory and the
swap limit of the cgroup.  The main motivation behind exposing the
swapcache stat is for enabling users to gracefully migrate from cgroup
v1's memsw counter to cgroup v2's memory and swap counters.

Cgroup v1's memsw limit allows users to limit the memory+swap usage of a
workload but without control on the exact proportion of memory and swap.
Cgroup v2 provides separate limits for memory and swap which enables more
control on the exact usage of memory and swap individually for the
workload.

With some little subtleties, the v1's memsw limit can be switched with the
sum of the v2's memory and swap limits.  However the alternative for memsw
usage is not yet available in cgroup v2.  Exposing per-cgroup swapcache
stat enables that alternative.  Adding the memory usage and swap usage and
subtracting the swapcache will approximate the memsw usage.  This will
help in the transparent migration of the workloads depending on memsw
usage and limit to v2' memory and swap counters.

The reasons these applications are still interested in this approximate
memsw usage are: (1) these applications are not really interested in two
separate memory and swap usage metrics.  A single usage metric is more
simple to use and reason about for them.

(2) The memsw usage metric hides the underlying system's swap setup from
the applications.  Applications with multiple instances running in a
datacenter with heterogeneous systems (some have swap and some don't) will
keep seeing a consistent view of their usage.

[akpm@linux-foundation.org: fix CONFIG_SWAP=n build]

Link: https://lkml.kernel.org/r/20210108155813.2914586-3-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Muchun Song <songmuchun@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>
2021-02-24 13:38:29 -08:00
Matthew Wilcox (Oracle) 4805462598 mm/filemap: pass a sleep state to put_and_wait_on_page_locked
This is prep work for the next patch, but I think at least one of the
current callers would prefer a killable sleep to an uninterruptible one.

Link: https://lkml.kernel.org/r/20210122160140.223228-6-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-24 13:38:28 -08:00
Muchun Song 71a64f618b mm: migrate: do not migrate HugeTLB page whose refcount is one
All pages isolated for the migration have an elevated reference count and
therefore seeing a reference count equal to 1 means that the last user of
the page has dropped the reference and the page has became unused and
there doesn't make much sense to migrate it anymore.

This has been done for regular pages and this patch does the same for
hugetlb pages.  Although the likelihood of the race is rather small for
hugetlb pages it makes sense the two code paths in sync.

Link: https://lkml.kernel.org/r/20210115124942.46403-2-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Yang Shi <shy828301@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-05 11:03:47 -08:00
Shakeel Butt 5c447d274f mm: fix numa stats for thp migration
Currently the kernel is not correctly updating the numa stats for
NR_FILE_PAGES and NR_SHMEM on THP migration.  Fix that.

For NR_FILE_DIRTY and NR_ZONE_WRITE_PENDING, although at the moment
there is no need to handle THP migration as kernel still does not have
write support for file THP but to be more future proof, this patch adds
the THP support for those stats as well.

Link: https://lkml.kernel.org/r/20210108155813.2914586-2-shakeelb@google.com
Fixes: e71769ae52 ("mm: enable thp migration for shmem thp")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-24 09:20:52 -08:00
Shakeel Butt 8a8792f600 mm: memcg: fix memcg file_dirty numa stat
The kernel updates the per-node NR_FILE_DIRTY stats on page migration
but not the memcg numa stats.

That was not an issue until recently the commit 5f9a4f4a70 ("mm:
memcontrol: add the missing numa_stat interface for cgroup v2") exposed
numa stats for the memcg.

So fix the file_dirty per-memcg numa stat.

Link: https://lkml.kernel.org/r/20210108155813.2914586-1-shakeelb@google.com
Fixes: 5f9a4f4a70 ("mm: memcontrol: add the missing numa_stat interface for cgroup v2")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-24 09:20:52 -08:00
Haitao Shi 8958b24911 mm: fix some spelling mistakes in comments
Fix some spelling mistakes in comments:
	udpate ==> update
	succesful ==> successful
	exmaple ==> example
	unneccessary ==> unnecessary
	stoping ==> stopping
	uknown ==> unknown

Link: https://lkml.kernel.org/r/20201127011747.86005-1-shihaitao1@huawei.com
Signed-off-by: Haitao Shi <shihaitao1@huawei.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15 22:46:19 -08:00
Stephen Zhang d85c6db4cc mm: migrate: remove unused parameter in migrate_vma_insert_page()
"dst" parameter to migrate_vma_insert_page() is not used anymore.

Link: https://lkml.kernel.org/r/CANubcdUwCAMuUyamG2dkWP=cqSR9MAS=tHLDc95kQkqU-rEnAg@mail.gmail.com
Signed-off-by: Stephen Zhang <starzhangzsd@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15 12:13:46 -08:00
Yang Shi d532e2e57e mm: migrate: return -ENOSYS if THP migration is unsupported
In the current implementation unmap_and_move() would return -ENOMEM if THP
migration is unsupported, then the THP will be split.  If split is failed
just exit without trying to migrate other pages.  It doesn't make too much
sense since there may be enough free memory to migrate other pages and
there may be a lot base pages on the list.

Return -ENOSYS to make consistent with hugetlb.  And if THP split is
failed just skip and try other pages on the list.

Just skip the whole list and exit when free memory is really low.

Link: https://lkml.kernel.org/r/20201113205359.556831-6-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15 12:13:45 -08:00
Yang Shi 236c32eb10 mm: migrate: clean up migrate_prep{_local}
The migrate_prep{_local} never fails, so it is pointless to have return
value and check the return value.

Link: https://lkml.kernel.org/r/20201113205359.556831-5-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15 12:13:45 -08:00
Yang Shi c77c5cbafe mm: migrate: skip shared exec THP for NUMA balancing
The NUMA balancing skip shared exec base page.  Since
CONFIG_READ_ONLY_THP_FOR_FS was introduced, there are probably shared exec
THP, so skip such THPs for NUMA balancing as well.

And Willy's regular filesystem THP support patches could create shared
exec THP wven without that config.

In addition, the page_is_file_lru() is used to tell if the page is file
cache or not, but it filters out shmem page.  It sounds like a typical
usecase by putting executables in shmem to achieve performance gain via
using shmem-THP, so it sounds worth skipping migration for such case too.

Link: https://lkml.kernel.org/r/20201113205359.556831-4-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15 12:13:45 -08:00
Yang Shi dd4ae78a21 mm: migrate: simplify the logic for handling permanent failure
When unmap_and_move{_huge_page}() returns !-EAGAIN and
!MIGRATEPAGE_SUCCESS, the page would be put back to LRU or proper list if
it is non-LRU movable page.  But, the callers always call
putback_movable_pages() to put the failed pages back later on, so it seems
not very efficient to put every single page back immediately, and the code
looks convoluted.

Put the failed page on a separate list, then splice the list to migrate
list when all pages are tried.  It is the caller's responsibility to call
putback_movable_pages() to handle failures.  This also makes the code
simpler and more readable.

After the change the rules are:
    * Success: non hugetlb page will be freed, hugetlb page will be put
               back
    * -EAGAIN: stay on the from list
    * -ENOMEM: stay on the from list
    * Other errno: put on ret_pages list then splice to from list

The from list would be empty iff all pages are migrated successfully, it
was not so before.  This has no impact to current existing callsites.

Link: https://lkml.kernel.org/r/20201113205359.556831-3-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15 12:13:45 -08:00
Yang Shi d12b8951ad mm: truncate_complete_page() does not exist any more
Patch series "mm: misc migrate cleanup and improvement", v3.

This patch (of 5):

The commit 9f4e41f471 ("mm: refactor truncate_complete_page()")
refactored truncate_complete_page(), and it is not existed anymore,
correct the comment in vmscan and migrate to avoid confusion.

Link: https://lkml.kernel.org/r/20201113205359.556831-1-shy828301@gmail.com
Link: https://lkml.kernel.org/r/20201113205359.556831-2-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15 12:13:45 -08:00
Ralph Campbell 5e5dda81a0 mm/migrate.c: optimize migrate_vma_pages() mmu notifier
When migrating a zero page or pte_none() anonymous page to device private
memory, migrate_vma_setup() will initialize the src[] array with a NULL
PFN.  This lets the device driver allocate device private memory and clear
it instead of DMAing a page of zeros over the device bus.

Since the source page didn't exist at the time, no struct page was locked
nor a migration PTE inserted into the CPU page tables.  The actual PTE
insertion happens in migrate_vma_pages() when it tries to insert the
device private struct page PTE into the CPU page tables.
migrate_vma_pages() has to call the mmu notifiers again since another
device could fault on the same page before the page table locks are
acquired.

Allow device drivers to optimize the invalidation similar to
migrate_vma_setup() by calling mmu_notifier_range_init() which sets struct
mmu_notifier_range event type to MMU_NOTIFY_MIGRATE and the
migrate_pgmap_owner field.

Link: https://lkml.kernel.org/r/20201021191335.10916-1-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15 12:13:45 -08:00
Long Li ab9dd4f8a1 mm/migrate.c: fix comment spelling
The word in the comment is misspelled, it should be "include".

Link: https://lkml.kernel.org/r/20201024114144.GA20552@lilong
Signed-off-by: Long Li <lonuxli.64@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15 12:13:45 -08:00
Shakeel Butt 013339df11 mm/rmap: always do TTU_IGNORE_ACCESS
Since commit 369ea8242c ("mm/rmap: update to new mmu_notifier semantic
v2"), the code to check the secondary MMU's page table access bit is
broken for !(TTU_IGNORE_ACCESS) because the page is unmapped from the
secondary MMU's page table before the check.  More specifically for those
secondary MMUs which unmap the memory in
mmu_notifier_invalidate_range_start() like kvm.

However memory reclaim is the only user of !(TTU_IGNORE_ACCESS) or the
absence of TTU_IGNORE_ACCESS and it explicitly performs the page table
access check before trying to unmap the page.  So, at worst the reclaim
will miss accesses in a very short window if we remove page table access
check in unmapping code.

There is an unintented consequence of !(TTU_IGNORE_ACCESS) for the memcg
reclaim.  From memcg reclaim the page_referenced() only account the
accesses from the processes which are in the same memcg of the target page
but the unmapping code is considering accesses from all the processes, so,
decreasing the effectiveness of memcg reclaim.

The simplest solution is to always assume TTU_IGNORE_ACCESS in unmapping
code.

Link: https://lkml.kernel.org/r/20201104231928.1494083-1-shakeelb@google.com
Fixes: 369ea8242c ("mm/rmap: update to new mmu_notifier semantic v2")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15 12:13:39 -08:00
Mike Kravetz 336bf30eb7 hugetlbfs: fix anon huge page migration race
Qian Cai reported the following BUG in [1]

  LTP: starting move_pages12
  BUG: unable to handle page fault for address: ffffffffffffffe0
  ...
  RIP: 0010:anon_vma_interval_tree_iter_first+0xa2/0x170 avc_start_pgoff at mm/interval_tree.c:63
  Call Trace:
    rmap_walk_anon+0x141/0xa30 rmap_walk_anon at mm/rmap.c:1864
    try_to_unmap+0x209/0x2d0 try_to_unmap at mm/rmap.c:1763
    migrate_pages+0x1005/0x1fb0
    move_pages_and_store_status.isra.47+0xd7/0x1a0
    __x64_sys_move_pages+0xa5c/0x1100
    do_syscall_64+0x5f/0x310
    entry_SYSCALL_64_after_hwframe+0x44/0xa9

Hugh Dickins diagnosed this as a migration bug caused by code introduced
to use i_mmap_rwsem for pmd sharing synchronization.  Specifically, the
routine unmap_and_move_huge_page() is always passing the TTU_RMAP_LOCKED
flag to try_to_unmap() while holding i_mmap_rwsem.  This is wrong for
anon pages as the anon_vma_lock should be held in this case.  Further
analysis suggested that i_mmap_rwsem was not required to he held at all
when calling try_to_unmap for anon pages as an anon page could never be
part of a shared pmd mapping.

Discussion also revealed that the hack in hugetlb_page_mapping_lock_write
to drop page lock and acquire i_mmap_rwsem is wrong.  There is no way to
keep mapping valid while dropping page lock.

This patch does the following:

 - Do not take i_mmap_rwsem and set TTU_RMAP_LOCKED for anon pages when
   calling try_to_unmap.

 - Remove the hacky code in hugetlb_page_mapping_lock_write. The routine
   will now simply do a 'trylock' while still holding the page lock. If
   the trylock fails, it will return NULL. This could impact the
   callers:

    - migration calling code will receive -EAGAIN and retry up to the
      hard coded limit (10).

    - memory error code will treat the page as BUSY. This will force
      killing (SIGKILL) instead of SIGBUS any mapping tasks.

   Do note that this change in behavior only happens when there is a
   race. None of the standard kernel testing suites actually hit this
   race, but it is possible.

[1] https://lore.kernel.org/lkml/20200708012044.GC992@lca.pw/
[2] https://lore.kernel.org/linux-mm/alpine.LSU.2.11.2010071833100.2214@eggly.anvils/

Fixes: c0d0381ade ("hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization")
Reported-by: Qian Cai <cai@lca.pw>
Suggested-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201105195058.78401-1-mike.kravetz@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-14 11:26:04 -08:00
Miaohe Lin 4dc200cee1 mm/migrate: avoid possible unnecessary process right check in kernel_move_pages()
There is no need to check if this process has the right to modify the
specified process when they are same.  And we could also skip the security
hook call if a process is modifying its own pages.  Add helper function to
handle these.

Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Hongxiang Lou <louhongxiang@huawei.com>
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christopher Lameter <cl@linux.com>
Link: https://lkml.kernel.org/r/20200819083331.19012-1-linmiaohe@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:09 -07:00
Oscar Salvador 79f5f8fab4 mm,hwpoison: rework soft offline for in-use pages
This patch changes the way we set and handle in-use poisoned pages.  Until
now, poisoned pages were released to the buddy allocator, trusting that
the checks that take place at allocation time would act as a safe net and
would skip that page.

This has proved to be wrong, as we got some pfn walkers out there, like
compaction, that all they care is the page to be in a buddy freelist.

Although this might not be the only user, having poisoned pages in the
buddy allocator seems a bad idea as we should only have free pages that
are ready and meant to be used as such.

Before explaining the taken approach, let us break down the kind of pages
we can soft offline.

- Anonymous THP (after the split, they end up being 4K pages)
- Hugetlb
- Order-0 pages (that can be either migrated or invalited)

* Normal pages (order-0 and anon-THP)

  - If they are clean and unmapped page cache pages, we invalidate
    then by means of invalidate_inode_page().
  - If they are mapped/dirty, we do the isolate-and-migrate dance.

Either way, do not call put_page directly from those paths.  Instead, we
keep the page and send it to page_handle_poison to perform the right
handling.

page_handle_poison sets the HWPoison flag and does the last put_page.

Down the chain, we placed a check for HWPoison page in
free_pages_prepare, that just skips any poisoned page, so those pages
do not end up in any pcplist/freelist.

After that, we set the refcount on the page to 1 and we increment
the poisoned pages counter.

If we see that the check in free_pages_prepare creates trouble, we can
always do what we do for free pages:

  - wait until the page hits buddy's freelists
  - take it off, and flag it

The downside of the above approach is that we could race with an
allocation, so by the time we  want to take the page off the buddy, the
page has been already allocated so we cannot soft offline it.
But the user could always retry it.

* Hugetlb pages

  - We isolate-and-migrate them

After the migration has been successful, we call dissolve_free_huge_page,
and we set HWPoison on the page if we succeed.
Hugetlb has a slightly different handling though.

While for non-hugetlb pages we cared about closing the race with an
allocation, doing so for hugetlb pages requires quite some additional
and intrusive code (we would need to hook in free_huge_page and some other
places).
So I decided to not make the code overly complicated and just fail
normally if the page we allocated in the meantime.

We can always build on top of this.

As a bonus, because of the way we handle now in-use pages, we no longer
need the put-as-isolation-migratetype dance, that was guarding for poisoned
pages to end up in pcplists.

Signed-off-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Aristeu Rozanski <aris@ruivo.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Yakunin <zeil@yandex-team.ru>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20200922135650.1634-10-osalvador@suse.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-16 11:11:16 -07:00
Ralph Campbell f1f4f3ab54 mm/migrate: remove obsolete comment about device public
Device public memory never had an in tree consumer and was removed in
commit 25b2995a35 ("mm: remove MEMORY_DEVICE_PUBLIC support").  Delete
the obsolete comment.

Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20200827190735.12752-2-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-13 18:38:36 -07:00
Ralph Campbell 4257889124 mm/migrate: remove cpages-- in migrate_vma_finalize()
The variable struct migrate_vma->cpages is only used in
migrate_vma_setup().  There is no need to decrement it in
migrate_vma_finalize() since it is never checked.

Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20200827190735.12752-1-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-13 18:38:35 -07:00
Linus Torvalds 3ad11d7ac8 block-5.10-2020-10-12
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Merge tag 'block-5.10-2020-10-12' of git://git.kernel.dk/linux-block

Pull block updates from Jens Axboe:

 - Series of merge handling cleanups (Baolin, Christoph)

 - Series of blk-throttle fixes and cleanups (Baolin)

 - Series cleaning up BDI, seperating the block device from the
   backing_dev_info (Christoph)

 - Removal of bdget() as a generic API (Christoph)

 - Removal of blkdev_get() as a generic API (Christoph)

 - Cleanup of is-partition checks (Christoph)

 - Series reworking disk revalidation (Christoph)

 - Series cleaning up bio flags (Christoph)

 - bio crypt fixes (Eric)

 - IO stats inflight tweak (Gabriel)

 - blk-mq tags fixes (Hannes)

 - Buffer invalidation fixes (Jan)

 - Allow soft limits for zone append (Johannes)

 - Shared tag set improvements (John, Kashyap)

 - Allow IOPRIO_CLASS_RT for CAP_SYS_NICE (Khazhismel)

 - DM no-wait support (Mike, Konstantin)

 - Request allocation improvements (Ming)

 - Allow md/dm/bcache to use IO stat helpers (Song)

 - Series improving blk-iocost (Tejun)

 - Various cleanups (Geert, Damien, Danny, Julia, Tetsuo, Tian, Wang,
   Xianting, Yang, Yufen, yangerkun)

* tag 'block-5.10-2020-10-12' of git://git.kernel.dk/linux-block: (191 commits)
  block: fix uapi blkzoned.h comments
  blk-mq: move cancel of hctx->run_work to the front of blk_exit_queue
  blk-mq: get rid of the dead flush handle code path
  block: get rid of unnecessary local variable
  block: fix comment and add lockdep assert
  blk-mq: use helper function to test hw stopped
  block: use helper function to test queue register
  block: remove redundant mq check
  block: invoke blk_mq_exit_sched no matter whether have .exit_sched
  percpu_ref: don't refer to ref->data if it isn't allocated
  block: ratelimit handle_bad_sector() message
  blk-throttle: Re-use the throtl_set_slice_end()
  blk-throttle: Open code __throtl_de/enqueue_tg()
  blk-throttle: Move service tree validation out of the throtl_rb_first()
  blk-throttle: Move the list operation after list validation
  blk-throttle: Fix IO hang for a corner case
  blk-throttle: Avoid tracking latency if low limit is invalid
  blk-throttle: Avoid getting the current time if tg->last_finish_time is 0
  blk-throttle: Remove a meaningless parameter for throtl_downgrade_state()
  block: Remove redundant 'return' statement
  ...
2020-10-13 12:12:44 -07:00
Zi Yan 6c5c7b9f33 mm/migrate: correct thp migration stats
PageTransHuge returns true for both thp and hugetlb, so thp stats was
counting both thp and hugetlb migrations.  Exclude hugetlb migration by
setting is_thp variable right.

Clean up thp handling code too when we are there.

Fixes: 1a5bae25e3 ("mm/vmstat: add events for THP migration without split")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lkml.kernel.org/r/20200917210413.1462975-1-zi.yan@sent.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-26 10:33:57 -07:00
Christoph Hellwig f56753ac2a bdi: replace BDI_CAP_NO_{WRITEBACK,ACCT_DIRTY} with a single flag
Replace the two negative flags that are always used together with a
single positive flag that indicates the writeback capability instead
of two related non-capabilities.  Also remove the pointless wrappers
to just check the flag.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-24 13:43:39 -06:00
Hugh Dickins a333e3e73b mm: migration of hugetlbfs page skip memcg
hugetlbfs pages do not participate in memcg: so although they do find most
of migrate_page_states() useful, it would be better if they did not call
into mem_cgroup_migrate() - where Qian Cai reported that LTP's
move_pages12 triggers the warning in Alex Shi's prospective commit
"mm/memcg: warning on !memcg after readahead page charged".

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxch.org>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Qian Cai <cai@lca.pw>
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008301359460.5954@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-19 13:13:38 -07:00
Ralph Campbell 3d321bf82c mm/migrate: preserve soft dirty in remove_migration_pte()
The code to remove a migration PTE and replace it with a device private
PTE was not copying the soft dirty bit from the migration entry.  This
could lead to page contents not being marked dirty when faulting the page
back from device private memory.

Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Bharata B Rao <bharata@linux.ibm.com>
Link: https://lkml.kernel.org/r/20200831212222.22409-3-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-05 12:14:30 -07:00
Ralph Campbell 6128763fc3 mm/migrate: remove unnecessary is_zone_device_page() check
Patch series "mm/migrate: preserve soft dirty in remove_migration_pte()".

I happened to notice this from code inspection after seeing Alistair
Popple's patch ("mm/rmap: Fixup copying of soft dirty and uffd ptes").

This patch (of 2):

The check for is_zone_device_page() and is_device_private_page() is
unnecessary since the latter is sufficient to determine if the page is a
device private page.  Simplify the code for easier reading.

Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Bharata B Rao <bharata@linux.ibm.com>
Link: https://lkml.kernel.org/r/20200831212222.22409-1-rcampbell@nvidia.com
Link: https://lkml.kernel.org/r/20200831212222.22409-2-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-05 12:14:30 -07:00
Alistair Popple ad7df764b7 mm/rmap: fixup copying of soft dirty and uffd ptes
During memory migration a pte is temporarily replaced with a migration
swap pte.  Some pte bits from the existing mapping such as the soft-dirty
and uffd write-protect bits are preserved by copying these to the
temporary migration swap pte.

However these bits are not stored at the same location for swap and
non-swap ptes.  Therefore testing these bits requires using the
appropriate helper function for the given pte type.

Unfortunately several code locations were found where the wrong helper
function is being used to test soft_dirty and uffd_wp bits which leads to
them getting incorrectly set or cleared during page-migration.

Fix these by using the correct tests based on pte type.

Fixes: a5430dda8a ("mm/migrate: support un-addressable ZONE_DEVICE page in migration")
Fixes: 8c3328f1f3 ("mm/migrate: migrate_vma() unmap page from vma while collecting pages")
Fixes: f45ec5ff16 ("userfaultfd: wp: support swap and page migration")
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Alistair Popple <alistair@popple.id.au>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200825064232.10023-2-alistair@popple.id.au
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-05 12:14:30 -07:00
Alistair Popple ebdf8321ee mm/migrate: fixup setting UFFD_WP flag
Commit f45ec5ff16 ("userfaultfd: wp: support swap and page migration")
introduced support for tracking the uffd wp bit during page migration.
However the non-swap PTE variant was used to set the flag for zone device
private pages which are a type of swap page.

This leads to corruption of the swap offset if the original PTE has the
uffd_wp flag set.

Fixes: f45ec5ff16 ("userfaultfd: wp: support swap and page migration")
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Link: https://lkml.kernel.org/r/20200825064232.10023-1-alistair@popple.id.au
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-05 12:14:30 -07:00
Matthew Wilcox (Oracle) 6c357848b4 mm: replace hpage_nr_pages with thp_nr_pages
The thp prefix is more frequently used than hpage and we should be
consistent between the various functions.

[akpm@linux-foundation.org: fix mm/migrate.c]

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Link: http://lkml.kernel.org/r/20200629151959.15779-6-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14 19:56:56 -07:00
Joonsoo Kim a097631160 mm/mempolicy: use a standard migration target allocation callback
There is a well-defined migration target allocation callback.  Use it.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1594622517-20681-7-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:58:02 -07:00
Joonsoo Kim 19fc7bed25 mm/migrate: introduce a standard migration target allocation function
There are some similar functions for migration target allocation.  Since
there is no fundamental difference, it's better to keep just one rather
than keeping all variants.  This patch implements base migration target
allocation function.  In the following patches, variants will be converted
to use this function.

Changes should be mechanical, but, unfortunately, there are some
differences.  First, some callers' nodemask is assgined to NULL since NULL
nodemask will be considered as all available nodes, that is,
&node_states[N_MEMORY].  Second, for hugetlb page allocation, gfp_mask is
redefined as regular hugetlb allocation gfp_mask plus __GFP_THISNODE if
user provided gfp_mask has it.  This is because future caller of this
function requires to set this node constaint.  Lastly, if provided nodeid
is NUMA_NO_NODE, nodeid is set up to the node where migration source
lives.  It helps to remove simple wrappers for setting up the nodeid.

Note that PageHighmem() call in previous function is changed to open-code
"is_highmem_idx()" since it provides more readability.

[akpm@linux-foundation.org: tweak patch title, per Vlastimil]
[akpm@linux-foundation.org: fix typo in comment]

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1594622517-20681-6-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:58:02 -07:00
Joonsoo Kim 9933a0c8a5 mm/migrate: clear __GFP_RECLAIM to make the migration callback consistent with regular THP allocations
new_page_nodemask is a migration callback and it tries to use a common gfp
flags for the target page allocation whether it is a base page or a THP.
The later only adds GFP_TRANSHUGE to the given mask.  This results in the
allocation being slightly more aggressive than necessary because the
resulting gfp mask will contain also __GFP_RECLAIM_KSWAPD.  THP
allocations usually exclude this flag to reduce over eager background
reclaim during a high THP allocation load which has been seen during large
mmaps initialization.  There is no indication that this is a problem for
migration as well but theoretically the same might happen when migrating
large mappings to a different node.  Make the migration callback
consistent with regular THP allocations.

[akpm@linux-foundation.org: fix comment typo, per Vlastimil]

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1594622517-20681-5-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:58:02 -07:00
Joonsoo Kim d92bbc2719 mm/hugetlb: unify migration callbacks
There is no difference between two migration callback functions,
alloc_huge_page_node() and alloc_huge_page_nodemask(), except
__GFP_THISNODE handling.  It's redundant to have two almost similar
functions in order to handle this flag.  So, this patch tries to remove
one by introducing a new argument, gfp_mask, to
alloc_huge_page_nodemask().

After introducing gfp_mask argument, it's caller's job to provide correct
gfp_mask.  So, every callsites for alloc_huge_page_nodemask() are changed
to provide gfp_mask.

Note that it's safe to remove a node id check in alloc_huge_page_node()
since there is no caller passing NUMA_NO_NODE as a node id.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1594622517-20681-4-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:58:02 -07:00
Joonsoo Kim b4b382238e mm/migrate: move migration helper from .h to .c
It's not performance sensitive function.  Move it to .c.  This is a
preparation step for future change.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1594622517-20681-3-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:58:02 -07:00
Randy Dunlap eaf444deed mm/migrate.c: delete duplicated word
Drop the repeated word "and".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Link: http://lkml.kernel.org/r/20200801173822.14973-8-rdunlap@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:57:58 -07:00
Anshuman Khandual 1a5bae25e3 mm/vmstat: add events for THP migration without split
Add following new vmstat events which will help in validating THP
migration without split.  Statistics reported through these new VM events
will help in performance debugging.

1. THP_MIGRATION_SUCCESS
2. THP_MIGRATION_FAILURE
3. THP_MIGRATION_SPLIT

In addition, these new events also update normal page migration statistics
appropriately via PGMIGRATE_SUCCESS and PGMIGRATE_FAILURE.  While here,
this updates current trace event 'mm_migrate_pages' to accommodate now
available THP statistics.

[akpm@linux-foundation.org: s/hpage_nr_pages/thp_nr_pages/]
[ziy@nvidia.com: v2]
  Link: http://lkml.kernel.org/r/C5E3C65C-8253-4638-9D3C-71A61858BB8B@nvidia.com
[anshuman.khandual@arm.com: s/thp_nr_pages/hpage_nr_pages/]
  Link: http://lkml.kernel.org/r/1594287583-16568-1-git-send-email-anshuman.khandual@arm.com

Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Link: http://lkml.kernel.org/r/1594080415-27924-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:57:57 -07:00
Ralph Campbell 0744f2807a mm/migrate: optimize migrate_vma_setup() for holes
Patch series "mm/migrate: optimize migrate_vma_setup() for holes".

A simple optimization for migrate_vma_*() when the source vma is not an
anonymous vma and a new test case to exercise it.

This patch (of 2):

When migrating system memory to device private memory, if the source
address range is a valid VMA range and there is no memory or a zero page,
the source PFN array is marked as valid but with no PFN.

This lets the device driver allocate private memory and clear it, then
insert the new device private struct page into the CPU's page tables when
migrate_vma_pages() is called.  migrate_vma_pages() only inserts the new
page if the VMA is an anonymous range.

There is no point in telling the device driver to allocate device private
memory and then not migrate the page.  Instead, mark the source PFN array
entries as not migrating to avoid this overhead.

[rcampbell@nvidia.com: v2]
  Link: http://lkml.kernel.org/r/20200710194840.7602-2-rcampbell@nvidia.com

Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: "Bharata B Rao" <bharata@linux.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Link: http://lkml.kernel.org/r/20200710194840.7602-1-rcampbell@nvidia.com
Link: http://lkml.kernel.org/r/20200709165711.26584-1-rcampbell@nvidia.com
Link: http://lkml.kernel.org/r/20200709165711.26584-2-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:57:56 -07:00
Joonsoo Kim b518154e59 mm/vmscan: protect the workingset on anonymous LRU
In current implementation, newly created or swap-in anonymous page is
started on active list.  Growing active list results in rebalancing
active/inactive list so old pages on active list are demoted to inactive
list.  Hence, the page on active list isn't protected at all.

Following is an example of this situation.

Assume that 50 hot pages on active list.  Numbers denote the number of
pages on active/inactive list (active | inactive).

1. 50 hot pages on active list
50(h) | 0

2. workload: 50 newly created (used-once) pages
50(uo) | 50(h)

3. workload: another 50 newly created (used-once) pages
50(uo) | 50(uo), swap-out 50(h)

This patch tries to fix this issue.  Like as file LRU, newly created or
swap-in anonymous pages will be inserted to the inactive list.  They are
promoted to active list if enough reference happens.  This simple
modification changes the above example as following.

1. 50 hot pages on active list
50(h) | 0

2. workload: 50 newly created (used-once) pages
50(h) | 50(uo)

3. workload: another 50 newly created (used-once) pages
50(h) | 50(uo), swap-out 50(uo)

As you can see, hot pages on active list would be protected.

Note that, this implementation has a drawback that the page cannot be
promoted and will be swapped-out if re-access interval is greater than the
size of inactive list but less than the size of total(active+inactive).
To solve this potential issue, following patch will apply workingset
detection similar to the one that's already applied to file LRU.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Link: http://lkml.kernel.org/r/1595490560-15117-3-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:57:55 -07:00
Ralph Campbell c1a06df6eb mm/migrate: fix migrate_pgmap_owner w/o CONFIG_MMU_NOTIFIER
On x86_64, when CONFIG_MMU_NOTIFIER is not set/enabled, there is a
compiler error:

   mm/migrate.c: In function 'migrate_vma_collect':
   mm/migrate.c:2481:7: error: 'struct mmu_notifier_range' has no member named 'migrate_pgmap_owner'
     range.migrate_pgmap_owner = migrate->pgmap_owner;
          ^

Fixes: 998427b3ad ("mm/notifier: add migration invalidation type")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "Jason Gunthorpe" <jgg@mellanox.com>
Link: http://lkml.kernel.org/r/20200806193353.7124-1-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 11:33:21 -07:00
Linus Torvalds fffe3ae0ee hmm related patches for 5.9
This series adds reporting of the page table order from hmm_range_fault()
 and some optimization of migrate_vma():
 
 - Report the size of the page table mapping out of hmm_range_fault(). This
   makes it easier to establish a large/huge/etc mapping in the device's
   page table.
 
 - Allow devices to ignore the invalidations during migration in cases
   where the migration is not going to change pages. For instance migrating
   pages to a device does not require the device to invalidate pages
   already in the device.
 
 - Update nouveau and hmm_tests to use the above
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Merge tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma

Pull hmm updates from Jason Gunthorpe:
 "Ralph has been working on nouveau's use of hmm_range_fault() and
  migrate_vma() which resulted in this small series. It adds reporting
  of the page table order from hmm_range_fault() and some optimization
  of migrate_vma():

   - Report the size of the page table mapping out of hmm_range_fault().

     This makes it easier to establish a large/huge/etc mapping in the
     device's page table.

   - Allow devices to ignore the invalidations during migration in cases
     where the migration is not going to change pages.

     For instance migrating pages to a device does not require the
     device to invalidate pages already in the device.

   - Update nouveau and hmm_tests to use the above"

* tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
  mm/hmm/test: use the new migration invalidation
  nouveau/svm: use the new migration invalidation
  mm/notifier: add migration invalidation type
  mm/migrate: add a flags parameter to migrate_vma
  nouveau: fix storing invalid ptes
  nouveau/hmm: support mapping large sysmem pages
  nouveau: fix mapping 2MB sysmem pages
  nouveau/hmm: fault one page at a time
  mm/hmm: add tests for hmm_pfn_to_map_order()
  mm/hmm: provide the page mapping order in hmm_range_fault()
2020-08-05 13:28:50 -07:00