3c187b4a12
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> (cherry picked from commit 2ebc368f59eedcef0de7c832fe1d62935cd3a7ff https: //git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable) [surenb: changed locking in break_ksm since it's done differently, skipped the change in the missing __ksm_del_vma(), skipped the change in the missing walk_page_range_vma(), removed unused local variables] Bug: 293665307 Change-Id: Iede9eaa950ea59a268a2e74a8d3022162f0bbd80 Signed-off-by: Suren Baghdasaryan <surenb@google.com> |
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| .. | ||
| core-test.h | ||
| core.c | ||
| dbgfs-test.h | ||
| dbgfs.c | ||
| Kconfig | ||
| lru_sort.c | ||
| Makefile | ||
| modules-common.h | ||
| ops-common.c | ||
| ops-common.h | ||
| paddr.c | ||
| reclaim.c | ||
| sysfs.c | ||
| vaddr-test.h | ||
| vaddr.c | ||