mm, thp: copying user pages must schedule on collapse
authorDavid Rientjes <rientjes@google.com>
Fri, 12 May 2017 22:47:03 +0000 (15:47 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 12 May 2017 22:57:16 +0000 (15:57 -0700)
commit338a16ba154959b049458d4f507d60f694550b68
tree1c70e3bc5d6a1692874e9f569d944aeac684522a
parent876f29460cbd4086b43475890c1bf2488fa11d40
mm, thp: copying user pages must schedule on collapse

We have encountered need_resched warnings in __collapse_huge_page_copy()
while doing {clear,copy}_user_highpage() over HPAGE_PMD_NR source pages.

mm->mmap_sem is held for write, but the iteration is well bounded.

Reschedule as needed.

Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1705101426380.109808@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/khugepaged.c