linux/mm
Alistair Popple ffa65753c4 mm/migrate.c: rework migration_entry_wait() to not take a pageref
This fixes the FIXME in migrate_vma_check_page().

Before migrating a page migration code will take a reference and check
there are no unexpected page references, failing the migration if there
are.  When a thread faults on a migration entry it will take a temporary
reference to the page to wait for the page to become unlocked signifying
the migration entry has been removed.

This reference is dropped just prior to waiting on the page lock,
however the extra reference can cause migration failures so it is
desirable to avoid taking it.

As migration code already has a reference to the migrating page an extra
reference to wait on PG_locked is unnecessary so long as the reference
can't be dropped whilst setting up the wait.

When faulting on a migration entry the ptl is taken to check the
migration entry.  Removing a migration entry also requires the ptl, and
migration code won't drop its page reference until after the migration
entry has been removed.  Therefore retaining the ptl of a migration
entry is sufficient to ensure the page has a reference.  Reworking
migration_entry_wait() to hold the ptl until the wait setup is complete
means the extra page reference is no longer needed.

[apopple@nvidia.com: v5]
  Link: https://lkml.kernel.org/r/20211213033848.1973946-1-apopple@nvidia.com

Link: https://lkml.kernel.org/r/20211118020754.954425-1-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-22 08:33:34 +02:00
..
damon mm/damon: hide kernel pointer from tracepoint event 2022-01-15 16:30:33 +02:00
kasan Merge branch 'akpm' (patches from Andrew) 2022-01-15 20:37:06 +02:00
kfence slab changes for 5.17 2022-01-10 11:58:12 -08:00
backing-dev.c mm: bdi: initialize bdi_min_ratio when bdi is unregistered 2021-12-10 17:10:56 -08:00
balloon_compaction.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
bootmem_info.c bootmem: Use page->index instead of page->freelist 2022-01-06 12:27:03 +01:00
cleancache.c
cma_debug.c
cma_sysfs.c
cma.c memblock: rename memblock_free to memblock_phys_free 2021-11-06 13:30:41 -07:00
cma.h
compaction.c mm: compaction: fix the migration stats in trace_mm_compaction_migratepages() 2022-01-15 16:30:30 +02:00
debug_page_ref.c
debug_vm_pgtable.c mm: ptep_clear() page table helper 2022-01-15 16:30:28 +02:00
debug.c mm,fs: split dump_mapping() out from dump_page() 2022-01-15 16:30:26 +02:00
dmapool.c mm/dmapool.c: revert "make dma pool to use kmalloc_node" 2022-01-15 16:30:28 +02:00
early_ioremap.c mm/early_ioremap.c: remove redundant early_ioremap_shutdown() 2021-09-08 11:50:24 -07:00
fadvise.c
failslab.c
filemap.c mm/migrate.c: rework migration_entry_wait() to not take a pageref 2022-01-22 08:33:34 +02:00
folio-compat.c filemap: Add filemap_release_folio() 2022-01-04 13:15:34 -05:00
frontswap.c mm/frontswap.c: use non-atomic '__set_bit()' when possible 2022-01-15 16:30:26 +02:00
gup_test.c selftests/vm: gup_test: test faulting in kernel, and verify pinnable pages 2021-05-05 11:27:26 -07:00
gup_test.h selftests/vm: gup_test: fix test flag 2021-05-05 11:27:26 -07:00
gup.c mm/gup.c: stricter check on THP migration entry during follow_pmd_mask 2022-01-15 16:30:26 +02:00
highmem.c Fixes for 5.16 folios: 2021-11-25 10:13:56 -08:00
hmm.c mm/hmm.c: allow VM_MIXEDMAP to work with hmm_range_fault 2022-01-15 16:30:31 +02:00
huge_memory.c Merge branch 'akpm' (patches from Andrew) 2022-01-15 20:37:06 +02:00
hugetlb_cgroup.c hugetlb: add hugetlb.*.numa_stat file 2022-01-15 16:30:29 +02:00
hugetlb_vmemmap.c mm: hugetlb: introduce CONFIG_HUGETLB_PAGE_FREE_VMEMMAP_DEFAULT_ON 2021-06-30 20:47:26 -07:00
hugetlb_vmemmap.h mm: hugetlb: introduce nr_free_vmemmap_pages in the struct hstate 2021-06-30 20:47:25 -07:00
hugetlb.c mm: change page type prior to adding page table entry 2022-01-15 16:30:28 +02:00
hwpoison-inject.c mm: hwpoison: don't drop slab caches for offlining non-LRU page 2021-09-03 09:58:15 -07:00
init-mm.c mm: add setup_initial_init_mm() helper 2021-07-08 11:48:21 -07:00
internal.h Merge branch 'akpm' (patches from Andrew) 2022-01-15 20:37:06 +02:00
interval_tree.c
io-mapping.c
ioremap.c mm: move ioremap_page_range to vmalloc.c 2021-09-08 11:50:24 -07:00
Kconfig Merge branch 'akpm' (patches from Andrew) 2022-01-20 10:41:01 +02:00
Kconfig.debug mm: page table check 2022-01-15 16:30:28 +02:00
khugepaged.c Merge branch 'akpm' (patches from Andrew) 2022-01-15 20:37:06 +02:00
kmemleak.c kmemleak: fix kmemleak false positive report with HW tag-based kasan enable 2022-01-15 16:30:25 +02:00
ksm.c mm: ksm: fix use-after-free kasan report in ksm_might_need_to_copy 2022-01-15 16:30:31 +02:00
list_lru.c mm: list_lru: only add memcg-aware lrus to the global lru list 2021-11-06 13:30:35 -07:00
maccess.c ARM: 9115/1: mm/maccess: fix unaligned copy_{from,to}_kernel_nofault 2021-08-20 11:39:25 +01:00
madvise.c mm: move anon_vma declarations to linux/mm_inline.h 2022-01-15 16:30:27 +02:00
Makefile Merge branch 'akpm' (patches from Andrew) 2022-01-15 20:37:06 +02:00
mapping_dirty_helpers.c mm: move tlb_flush_pending inline helpers to mm_inline.h 2022-01-15 16:30:27 +02:00
memblock.c arm64 fixes for -rc1 2021-11-10 11:29:30 -08:00
memcontrol.c Merge branch 'akpm' (patches from Andrew) 2022-01-15 20:37:06 +02:00
memfd.c mm,hugetlb: remove mlock ulimit for SHM_HUGETLB 2021-11-09 10:02:48 -08:00
memory_hotplug.c treewide: Add missing includes masked by cgroup -> bpf dependency 2021-12-03 10:58:13 -08:00
memory-failure.c Merge branch 'akpm' (patches from Andrew) 2022-01-15 20:37:06 +02:00
memory.c Merge branch 'akpm' (patches from Andrew) 2022-01-20 10:41:01 +02:00
mempolicy.c mm/mempolicy: fix all kernel-doc warnings 2022-01-15 16:30:30 +02:00
mempool.c mm: remove spurious blkdev.h includes 2021-10-18 06:17:01 -06:00
memremap.c Merge branch 'akpm' (patches from Andrew) 2022-01-15 20:37:06 +02:00
memtest.c
migrate.c mm/migrate.c: rework migration_entry_wait() to not take a pageref 2022-01-22 08:33:34 +02:00
mincore.c
mlock.c mm: add a field to store names for private anonymous memory 2022-01-15 16:30:27 +02:00
mm_init.c
mmap_lock.c mm: mmap_lock: fix disabling preemption directly 2021-07-23 17:43:28 -07:00
mmap.c Merge branch 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2022-01-17 05:49:30 +02:00
mmu_gather.c mm: move tlb_flush_pending inline helpers to mm_inline.h 2022-01-15 16:30:27 +02:00
mmu_notifier.c
mmzone.c
mprotect.c mm: add a field to store names for private anonymous memory 2022-01-15 16:30:27 +02:00
mremap.c mm, hugepages: add mremap() support for hugepage backed vma 2021-11-06 13:30:39 -07:00
msync.c
nommu.c Merge branch 'akpm' (patches from Andrew) 2021-11-06 14:08:17 -07:00
oom_kill.c Merge branch 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2022-01-17 05:49:30 +02:00
page_alloc.c Merge branch 'akpm' (patches from Andrew) 2022-01-20 10:41:01 +02:00
page_counter.c mm/page_counter: remove an incorrect call to propagate_protected_usage() 2022-01-15 16:30:27 +02:00
page_ext.c mm: make some vars and functions static or __init 2022-01-15 16:30:31 +02:00
page_idle.c mm/idle_page_tracking: make PG_idle reusable 2021-09-08 11:50:24 -07:00
page_io.c delayacct: support swapin delay accounting for swapping without blkio 2022-01-20 08:52:55 +02:00
page_isolation.c mm/page_isolation: unset migratetype directly for non Buddy page 2022-01-15 16:30:30 +02:00
page_owner.c mm: make some vars and functions static or __init 2022-01-15 16:30:31 +02:00
page_poison.c
page_reporting.c mm/page_reporting: allow driver to specify reporting order 2021-06-29 10:53:47 -07:00
page_reporting.h mm/page_reporting: export reporting order as module parameter 2021-06-29 10:53:47 -07:00
page_table_check.c mm: page table check 2022-01-15 16:30:28 +02:00
page_vma_mapped.c mm: device exclusive memory access 2021-07-01 11:06:03 -07:00
page-writeback.c mm/writeback: Improve __folio_mark_dirty() comment 2022-01-02 20:28:57 -05:00
pagewalk.c mm: pagewalk: fix walk for hugepage tables 2021-06-29 10:53:49 -07:00
percpu-internal.h mm: memcg/percpu: account extra objcg space to memory cgroups 2022-01-15 16:30:31 +02:00
percpu-km.c percpu: flush tlb in pcpu_reclaim_populated() 2021-07-04 18:30:17 +00:00
percpu-stats.c percpu: rework memcg accounting 2021-06-05 20:43:15 +00:00
percpu-vm.c percpu: flush tlb in pcpu_reclaim_populated() 2021-07-04 18:30:17 +00:00
percpu.c Merge branch 'akpm' (patches from Andrew) 2022-01-20 10:41:01 +02:00
pgalloc-track.h mm: fix typos in comments 2021-05-07 00:26:35 -07:00
pgtable-generic.c mm: move tlb_flush_pending inline helpers to mm_inline.h 2022-01-15 16:30:27 +02:00
process_vm_access.c mm/process_vm_access.c: remove duplicate include 2021-05-05 11:27:27 -07:00
ptdump.c
readahead.c readahead: Convert page_cache_ra_unbounded to folios 2022-01-04 13:15:34 -05:00
rmap.c mm/rmap: fix potential batched TLB flush race 2022-01-15 16:30:31 +02:00
rodata_test.c
secretmem.c mm/secretmem: avoid letting secretmem_users drop to zero 2021-10-28 17:18:55 -07:00
shmem.c Merge branch 'akpm' (patches from Andrew) 2022-01-15 20:37:06 +02:00
shuffle.c
shuffle.h mm/shuffle: fix section mismatch warning 2021-05-22 15:09:07 -10:00
slab_common.c Merge branch 'akpm' (patches from Andrew) 2022-01-15 20:37:06 +02:00
slab.c mm/kasan: Convert to struct folio and struct slab 2022-01-06 12:26:14 +01:00
slab.h slab changes for 5.17 - part 2 2022-01-18 06:40:47 +02:00
slob.c mm/slob: Remove unnecessary page_mapcount_reset() function call 2022-01-06 12:27:28 +01:00
slub.c mm/slub: Define struct slab fields for CONFIG_SLUB_CPU_PARTIAL only when enabled 2022-01-06 12:26:53 +01:00
sparse-vmemmap.c mm: remove redundant smp_wmb() 2021-11-06 13:30:36 -07:00
sparse.c bootmem: Use page->index instead of page->freelist 2022-01-06 12:27:03 +01:00
swap_cgroup.c
swap_slots.c treewide: Add missing includes masked by cgroup -> bpf dependency 2021-12-03 10:58:13 -08:00
swap_state.c mm/workingset: Convert workingset_refault() to take a folio 2021-10-18 07:49:40 -04:00
swap.c Merge branch 'akpm' (patches from Andrew) 2022-01-15 20:37:06 +02:00
swapfile.c mm: remove the total_mapcount argument from page_trans_huge_mapcount() 2022-01-15 16:30:28 +02:00
truncate.c Merge branch 'akpm' (patches from Andrew) 2022-01-15 20:37:06 +02:00
usercopy.c mm: Convert check_heap_object() to use struct slab 2022-01-06 12:25:51 +01:00
userfaultfd.c mm: shmem: don't truncate page if memory failure happens 2022-01-15 16:30:26 +02:00
util.c mm: allow !GFP_KERNEL allocations for kvmalloc 2022-01-15 16:30:29 +02:00
vmacache.c
vmalloc.c mm/vmalloc: be more explicit about supported gfp flags. 2022-01-15 16:30:28 +02:00
vmpressure.c mm/vmpressure: fix data-race with memcg->socket_pressure 2021-11-06 13:30:40 -07:00
vmscan.c vmscan: make drop_slab_node static 2022-01-15 16:30:30 +02:00
vmstat.c mm/vmstat: add events for THP max_ptes_* exceeds 2022-01-15 16:30:29 +02:00
workingset.c Merge branch 'akpm' (patches from Andrew) 2021-11-09 10:11:53 -08:00
z3fold.c mm/z3fold: add kerneldoc fields for z3fold_pool 2021-07-01 11:06:03 -07:00
zbud.c mm/zbud: add kerneldoc fields for zbud_pool 2021-07-01 11:06:03 -07:00
zpool.c zpool: remove the list of pools_head 2022-01-15 16:30:31 +02:00
zsmalloc.c zsmalloc: Stop using slab fields in struct page 2022-01-06 12:27:03 +01:00
zswap.c mm/zswap.c: fix two bugs in zswap_writeback_entry() 2021-06-30 20:47:31 -07:00