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authorMel Gorman <mgorman@suse.de>2014-01-02 12:58:49 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-02 14:40:30 -0800
commitd0319bd52e373c661f9bc0c04dec85d6f87ac517 (patch)
tree6b437b89634575b73e090ff3efe296014320b486
parent695c60830764945cf61a2cc623eb1392d137223e (diff)
mm: remove bogus warning in copy_huge_pmd()
Sasha Levin reported the following warning being triggered WARNING: CPU: 28 PID: 35287 at mm/huge_memory.c:887 copy_huge_pmd+0x145/ 0x3a0() Call Trace: copy_huge_pmd+0x145/0x3a0 copy_page_range+0x3f2/0x560 dup_mmap+0x2c9/0x3d0 dup_mm+0xad/0x150 copy_process+0xa68/0x12e0 do_fork+0x96/0x270 SyS_clone+0x16/0x20 stub_clone+0x69/0x90 This warning was introduced by "mm: numa: Avoid unnecessary disruption of NUMA hinting during migration" for paranoia reasons but the warning is bogus. I was thinking of parallel races between NUMA hinting faults and forks but this warning would also be triggered by a parallel reclaim splitting a THP during a fork. Remote the bogus warning. Signed-off-by: Mel Gorman <mgorman@suse.de> Reported-by: Sasha Levin <sasha.levin@oracle.com> Cc: Alex Thorlton <athorlton@sgi.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/huge_memory.c3
1 files changed, 0 insertions, 3 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 7de1bf85f683..9c0b17295ba0 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -883,9 +883,6 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
goto out_unlock;
}
- /* mmap_sem prevents this happening but warn if that changes */
- WARN_ON(pmd_trans_migrating(pmd));
-
if (unlikely(pmd_trans_splitting(pmd))) {
/* split huge page running from under us */
spin_unlock(src_ptl);