'slab_reclaimable' and 'nr_pages' are unsigned. so, subtraction is
unsafe.
Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
---
mm/vmscan.c | 18 ++++++++++++------
1 files changed, 12 insertions(+), 6 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index c927948..b1a90f8 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2612,6 +2612,8 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
slab_reclaimable = zone_page_state(zone, NR_SLAB_RECLAIMABLE);
if (slab_reclaimable > zone->min_slab_pages) {
unsigned long lru_pages = zone_reclaimable_pages(zone);
+ unsigned long srec_new;
+
/*
* shrink_slab() does not currently allow us to determine how
* many pages were freed in this zone. So we take the current
@@ -2622,17 +2624,21 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
* Note that shrink_slab will free memory on all zones and may
* take a long time.
*/
- while (shrink_slab(sc.nr_scanned, gfp_mask, lru_pages) &&
- zone_page_state(zone, NR_SLAB_RECLAIMABLE) >
- slab_reclaimable - nr_pages)
- ;
+ for (;;) {
+ if (!shrink_slab(sc.nr_scanned, gfp_mask, lru_pages))
+ break;
+ srec_new = zone_page_state(zone, NR_SLAB_RECLAIMABLE);
+ if (srec_new + nr_pages <= slab_reclaimable)
+ break;
+ }
/*
* 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);
+ srec_new = zone_page_state(zone, NR_SLAB_RECLAIMABLE);
+ if (srec_new < slab_reclaimable)
+ sc.nr_reclaimed += slab_reclaimable - srec_new;
}
p->reclaim_state = NULL;
--
1.6.5.2
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