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author | Johannes Weiner <hannes@cmpxchg.org> | 2011-01-20 14:44:21 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-01-20 17:02:05 -0800 |
commit | 82478fb7bca28e3ca2f3c55c14e690f749dd4dbb (patch) | |
tree | 71023f480667dc3bfd255673437c76db77a05aa0 /fs/direct-io.c | |
parent | 3305de51bf612603c9a4e4dc98ceb839ef933749 (diff) | |
download | linux-82478fb7bca28e3ca2f3c55c14e690f749dd4dbb.tar.bz2 |
mm: compaction: prevent division-by-zero during user-requested compaction
Up until 3e7d344 ("mm: vmscan: reclaim order-0 and use compaction instead
of lumpy reclaim"), compaction skipped calculating the fragmentation index
of a zone when compaction was explicitely requested through the procfs
knob.
However, when compaction_suitable was introduced, it did not come with an
extra check for order == -1, set on explicit compaction requests, and
passed this order on to the fragmentation index calculation, where it
overshifts the number of requested pages, leading to a division by zero.
This patch makes sure that order == -1 is recognized as the flag it is
rather than passing it along as valid order parameter.
[akpm@linux-foundation.org: add comment, per Mel]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/direct-io.c')
0 files changed, 0 insertions, 0 deletions