thp: allow a hwpoisoned head page to be put back to LRU
authorDean Nelson <dnelson@redhat.com>
Wed, 21 Mar 2012 23:34:05 +0000 (16:34 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 22 Mar 2012 00:54:58 +0000 (17:54 -0700)
commit385de35722c9a22917e7bc5e63cd83a8cffa5ecd
tree41ae2e23e096d189cdf614cf1eaf0c8f9ddeeb3b
parent6d9d88d07e132259c35f9493b15429e19198489c
thp: allow a hwpoisoned head page to be put back to LRU

Andrea Arcangeli pointed out to me that a check in __memory_failure()
which was intended to prevent THP tail pages from being checked for the
absence of the PG_lru flag (something that is always the case), was also
preventing THP head pages from being checked.

A THP head page could actually benefit from the call to shake_page() by
ending up being put back to a LRU, provided it had been waiting in a
pagevec array.

Andrea suggested that the "!PageTransCompound(p)" in the if-statement
should be replaced by a "!PageTransTail(p)", thus allowing THP head pages
to be checked and possibly shaken.

Signed-off-by: Dean Nelson <dnelson@redhat.com>
Cc: Jin Dongming <jin.dongming@np.css.fujitsu.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/page-flags.h
mm/memory-failure.c