The patch titled
Subject: mm-thp-fix-madv_dontneed-vs-migrate_misplaced_transhuge_page-race-condition-fix
has been added to the -mm tree. Its filename is
mm-thp-fix-madv_dontneed-vs-migrate_misplaced_transhuge_page-race-condition-fix.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-thp-fix-madv_dontneed-vs-migrate_misplaced_transhuge_page-race-condition-fix.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-thp-fix-madv_dontneed-vs-migrate_misplaced_transhuge_page-race-condition-fix.patch
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------------------------------------------------------
From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Subject: mm-thp-fix-madv_dontneed-vs-migrate_misplaced_transhuge_page-race-condition-fix
reflow comment to 80 cols, fix grammar and typo (beacuse)
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/migrate.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
--- a/mm/migrate.c~mm-thp-fix-madv_dontneed-vs-migrate_misplaced_transhuge_page-race-condition-fix
+++ a/mm/migrate.c
@@ -2041,16 +2041,15 @@ int migrate_misplaced_transhuge_page(str
flush_cache_range(vma, mmun_start, mmun_end);
page_add_anon_rmap(new_page, vma, mmun_start, true);
/*
- * At this point the pmd is numa/protnone (i.e. non present)
- * and the TLB has already been flushed globally. So no TLB
- * can be currently caching this non present pmd mapping.
- * There's no need of clearing the pmd before doing
- * set_pmd_at(), nor to flush the TLB after
- * set_pmd_at(). Clearing the pmd here would introduce a race
- * condition against MADV_DONTNEED, beacuse MADV_DONTNEED only
- * holds the mmap_sem for reading. If the pmd is set to NULL
- * at any given time, MADV_DONTNEED won't wait on the pmd lock
- * and it'll skip clearing this pmd.
+ * At this point the pmd is numa/protnone (i.e. non present) and the TLB
+ * has already been flushed globally. So no TLB can be currently
+ * caching this non present pmd mapping. There's no need to clear the
+ * pmd before doing set_pmd_at(), nor to flush the TLB after
+ * set_pmd_at(). Clearing the pmd here would introduce a race
+ * condition against MADV_DONTNEED, because MADV_DONTNEED only holds the
+ * mmap_sem for reading. If the pmd is set to NULL at any given time,
+ * MADV_DONTNEED won't wait on the pmd lock and it'll skip clearing this
+ * pmd.
*/
set_pmd_at(mm, mmun_start, pmd, entry);
update_mmu_cache_pmd(vma, address, &entry);
_
Patches currently in -mm which might be from akpm@xxxxxxxxxxxxxxxxxxxx are
arm-arch-arm-include-asm-pageh-needs-personalityh.patch
fix-clusters-leak-in-ocfs2_defrag_extent-fix.patch
mm.patch
mmpage_alloc-pf_wq_worker-threads-must-sleep-at-should_reclaim_retry-fix.patch
sched-loadavg-consolidate-load_int-load_frac-calc_load-fix.patch
mm-workingset-add-vmstat-counter-for-shadow-nodes-fix.patch
mm-workingset-add-vmstat-counter-for-shadow-nodes-fix-fix.patch
mm-mremap-downgrade-mmap_sem-to-read-when-shrinking-fix.patch
mm-brk-downgrade-mmap_sem-to-read-when-shrinking-fix.patch
memory_hotplug-free-pages-as-higher-order-fix.patch
mm-calculate-deferred-pages-after-skipping-mirrored-memory-fix.patch
mm-gup_benchmark-time-put_page-fix.patch
tools-gup_benchmark-allow-user-specified-file-fix.patch
mm-thp-fix-madv_dontneed-vs-migrate_misplaced_transhuge_page-race-condition-fix.patch
list_lru-prefetch-neighboring-list-entries-before-acquiring-lock-fix.patch
lib-bitmapc-fix-remaining-space-computation-in-bitmap_print_to_pagebuf-fix.patch
lib-bitmapc-fix-remaining-space-computation-in-bitmap_print_to_pagebuf-fix-fix.patch
ipc-allow-boot-time-extension-of-ipcmni-from-32k-to-8m-checkpatch-fixes.patch
linux-next-rejects.patch
memblock-stop-using-implicit-alignement-to-smp_cache_bytes-checkpatch-fixes.patch
kernel-forkc-export-kernel_thread-to-modules.patch
slab-leaks3-default-y.patch
