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| author | KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> | 2010-08-09 17:19:50 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-08-09 20:45:02 -0700 |
| commit | 15748048991e801a2d18ce5da4e0d528852bc106 (patch) | |
| tree | e31dcdf36bbcfdd1c78546637d59faa963597bac /mm | |
| parent | 7ee92255470daa0edb93866aec6e27534cd9a177 (diff) | |
| download | linux-15748048991e801a2d18ce5da4e0d528852bc106.tar.gz | |
vmscan: avoid subtraction of unsigned types
'slab_reclaimable' and 'nr_pages' are unsigned. Subtraction is unsafe because negative results would be misinterpreted. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/vmscan.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 1c3d960de9d2..1b4e4a597caa 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2600,7 +2600,7 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) .swappiness = vm_swappiness, .order = order, }; - unsigned long slab_reclaimable; + unsigned long nr_slab_pages0, nr_slab_pages1; cond_resched(); /* @@ -2625,8 +2625,8 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) } while (priority >= 0 && sc.nr_reclaimed < nr_pages); } - slab_reclaimable = zone_page_state(zone, NR_SLAB_RECLAIMABLE); - if (slab_reclaimable > zone->min_slab_pages) { + nr_slab_pages0 = zone_page_state(zone, NR_SLAB_RECLAIMABLE); + if (nr_slab_pages0 > zone->min_slab_pages) { /* * shrink_slab() does not currently allow us to determine how * many pages were freed in this zone. So we take the current @@ -2638,16 +2638,17 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) * take a long time. */ while (shrink_slab(sc.nr_scanned, gfp_mask, order) && - zone_page_state(zone, NR_SLAB_RECLAIMABLE) > - slab_reclaimable - nr_pages) + (zone_page_state(zone, NR_SLAB_RECLAIMABLE) + nr_pages > + nr_slab_pages0)) ; /* * Update nr_reclaimed by the number of slab pages we * reclaimed from this zone. */ - sc.nr_reclaimed += slab_reclaimable - - zone_page_state(zone, NR_SLAB_RECLAIMABLE); + nr_slab_pages1 = zone_page_state(zone, NR_SLAB_RECLAIMABLE); + if (nr_slab_pages1 < nr_slab_pages0) + sc.nr_reclaimed += nr_slab_pages0 - nr_slab_pages1; } p->reclaim_state = NULL; |