diff options
| author | Suren Baghdasaryan <surenb@google.com> | 2023-08-04 17:27:19 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-08-21 22:07:20 +0200 |
| commit | 49b0638502da097c15d46cd4e871dbaa022caf7c (patch) | |
| tree | a36bae8bb4dd533dbe491ae25c3e506cd4dfb679 /mm/vmscan.c | |
| parent | smaps: use vm_normal_page_pmd() instead of follow_trans_huge_pmd() (diff) | |
| download | linux-49b0638502da097c15d46cd4e871dbaa022caf7c.tar.xz linux-49b0638502da097c15d46cd4e871dbaa022caf7c.zip | |
mm: enable page walking API to lock vmas during the walk
walk_page_range() and friends often operate under write-locked mmap_lock.
With introduction of vma locks, the vmas have to be locked as well during
such walks to prevent concurrent page faults in these areas. Add an
additional member to mm_walk_ops to indicate locking requirements for the
walk.
The change ensures that page walks which prevent concurrent page faults
by write-locking mmap_lock, operate correctly after introduction of
per-vma locks. With per-vma locks page faults can be handled under vma
lock without taking mmap_lock at all, so write locking mmap_lock would
not stop them. The change ensures vmas are properly locked during such
walks.
A sample issue this solves is do_mbind() performing queue_pages_range()
to queue pages for migration. Without this change a concurrent page
can be faulted into the area and be left out of migration.
Link: https://lkml.kernel.org/r/20230804152724.3090321-2-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Suggested-by: Jann Horn <jannh@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michel Lespinasse <michel@lespinasse.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/vmscan.c')
| -rw-r--r-- | mm/vmscan.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 1080209a568b..3555927df9b5 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4284,6 +4284,7 @@ static void walk_mm(struct lruvec *lruvec, struct mm_struct *mm, struct lru_gen_ static const struct mm_walk_ops mm_walk_ops = { .test_walk = should_skip_vma, .p4d_entry = walk_pud_range, + .walk_lock = PGWALK_RDLOCK, }; int err; |