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>
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parent
7ee9225547
commit
1574804899
15
mm/vmscan.c
15
mm/vmscan.c
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@ -2600,7 +2600,7 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
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.swappiness = vm_swappiness,
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.swappiness = vm_swappiness,
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.order = order,
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.order = order,
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};
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};
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unsigned long slab_reclaimable;
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unsigned long nr_slab_pages0, nr_slab_pages1;
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cond_resched();
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cond_resched();
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/*
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/*
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@ -2625,8 +2625,8 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
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} while (priority >= 0 && sc.nr_reclaimed < nr_pages);
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} while (priority >= 0 && sc.nr_reclaimed < nr_pages);
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}
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}
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slab_reclaimable = zone_page_state(zone, NR_SLAB_RECLAIMABLE);
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nr_slab_pages0 = zone_page_state(zone, NR_SLAB_RECLAIMABLE);
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if (slab_reclaimable > zone->min_slab_pages) {
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if (nr_slab_pages0 > zone->min_slab_pages) {
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/*
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/*
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* shrink_slab() does not currently allow us to determine how
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* shrink_slab() does not currently allow us to determine how
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* many pages were freed in this zone. So we take the current
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* many pages were freed in this zone. So we take the current
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@ -2638,16 +2638,17 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
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* take a long time.
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* take a long time.
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*/
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*/
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while (shrink_slab(sc.nr_scanned, gfp_mask, order) &&
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while (shrink_slab(sc.nr_scanned, gfp_mask, order) &&
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zone_page_state(zone, NR_SLAB_RECLAIMABLE) >
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(zone_page_state(zone, NR_SLAB_RECLAIMABLE) + nr_pages >
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slab_reclaimable - nr_pages)
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nr_slab_pages0))
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;
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;
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/*
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/*
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* Update nr_reclaimed by the number of slab pages we
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* Update nr_reclaimed by the number of slab pages we
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* reclaimed from this zone.
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* reclaimed from this zone.
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*/
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*/
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sc.nr_reclaimed += slab_reclaimable -
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nr_slab_pages1 = zone_page_state(zone, NR_SLAB_RECLAIMABLE);
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zone_page_state(zone, NR_SLAB_RECLAIMABLE);
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if (nr_slab_pages1 < nr_slab_pages0)
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sc.nr_reclaimed += nr_slab_pages0 - nr_slab_pages1;
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}
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}
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p->reclaim_state = NULL;
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p->reclaim_state = NULL;
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