linux.git/mm/migrate.c, branch v5.12.5

mm/migrate.c: fix potential indeterminate pte entry in migrate_vma_insert_page()

2021-05-19T08:56:30+00:00

[ Upstream commit 34f5e9b9d1990d286199084efa752530ee3d8297 ]

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: df6ad69838fc ("mm/device-public-memory: device memory cache coherent with CPU")
Signed-off-by: Miaohe Lin 
Reviewed-by: David Hildenbrand 
Cc: Alistair Popple 
Cc: Jerome Glisse 
Cc: Rafael Aquini 
Cc: Yang Shi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

mm: memcg: add swapcache stat for memcg v2

2021-02-24T21:38:29+00:00

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 
Acked-by: Michal Hocko 
Reviewed-by: Roman Gushchin 
Cc: Johannes Weiner 
Cc: Muchun Song 
Cc: Yang Shi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/filemap: pass a sleep state to put_and_wait_on_page_locked

2021-02-24T21:38:28+00:00

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) 
Reviewed-by: Kent Overstreet 
Reviewed-by: Christoph Hellwig 
Cc: Miaohe Lin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: migrate: do not migrate HugeTLB page whose refcount is one

2021-02-05T19:03:47+00:00

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 
Reviewed-by: Mike Kravetz 
Acked-by: Yang Shi 
Acked-by: Michal Hocko 
Reviewed-by: David Hildenbrand 
Reviewed-by: Oscar Salvador 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: fix numa stats for thp migration

2021-01-24T17:20:52+00:00

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: e71769ae52609 ("mm: enable thp migration for shmem thp")
Signed-off-by: Shakeel Butt 
Acked-by: Yang Shi 
Reviewed-by: Roman Gushchin 
Cc: Johannes Weiner 
Cc: Michal Hocko 
Cc: Muchun Song 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: memcg: fix memcg file_dirty numa stat

2021-01-24T17:20:52+00:00

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 5f9a4f4a7096 ("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: 5f9a4f4a7096 ("mm: memcontrol: add the missing numa_stat interface for cgroup v2")
Signed-off-by: Shakeel Butt 
Reviewed-by: Muchun Song 
Acked-by: Yang Shi 
Reviewed-by: Roman Gushchin 
Cc: Johannes Weiner 
Cc: Michal Hocko 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: fix some spelling mistakes in comments

2020-12-16T06:46:19+00:00

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 
Reviewed-by: Mike Rapoport 
Reviewed-by: Souptick Joarder 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: migrate: remove unused parameter in migrate_vma_insert_page()

2020-12-15T20:13:46+00:00

"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 
Reviewed-by: David Hildenbrand 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: migrate: return -ENOSYS if THP migration is unsupported

2020-12-15T20:13:45+00:00

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 
Cc: Jan Kara 
Cc: Matthew Wilcox 
Cc: Mel Gorman 
Cc: Michal Hocko 
Cc: Song Liu 
Cc: Zi Yan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: migrate: clean up migrate_prep{_local}

2020-12-15T20:13:45+00:00

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 
Reviewed-by: Zi Yan 
Cc: Jan Kara 
Cc: Matthew Wilcox 
Cc: Mel Gorman 
Cc: Michal Hocko 
Cc: Song Liu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds