> > @@ -2628,16 +2628,16 @@ 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 > n))
> > ;
> >
> > /*
> > * 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);
> > + m = zone_page_state(zone, NR_SLAB_RECLAIMABLE);
> > + if (m < n)
> > + sc.nr_reclaimed += n - m;
>
> And it's not a completly trivial objection. Your patch made the above
> code snippet quite a lot harder to read (and hence harder to maintain).
Initially, I proposed following patch to Christoph. but he prefer n and m.
To be honest, I don't think this naming is big matter. so you prefer following
I'll submit it.
=====================================================================
>From 397199d69860061eaa5e1aaadac45c46c76b0522 Mon Sep 17 00:00:00 2001
From: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Date: Wed, 30 Jun 2010 13:35:16 +0900
Subject: [PATCH] vmscan: don't subtraction of unsined
'slab_reclaimable' and 'nr_pages' are unsigned. so, subtraction is
unsafe.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
---
mm/vmscan.c | 15 ++++++++-------
1 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 9c7e57c..79ff877 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2588,7 +2588,7 @@ 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;
disable_swap_token();
cond_resched();
@@ -2615,8 +2615,8 @@ 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
@@ -2628,16 +2628,17 @@ 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;
--
1.6.5.2
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