[PATCH] vmscan: fix zone_reclaim

- PF_SWAPWRITE needs to be set for RECLAIM_SWAP to be able to write
  out pages to swap. Currently RECLAIM_SWAP may not do that.

- remove setting nr_reclaimed pages after slab reclaim since the slab shrinking
  code does not use that and the nr_reclaimed pages is just right for the
  intended follow up action.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 1838c15..b0af759 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1908,7 +1908,12 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
                sc.swap_cluster_max = SWAP_CLUSTER_MAX;
 
        cond_resched();
-       p->flags |= PF_MEMALLOC;
+       /*
+        * We need to be able to allocate from the reserves for RECLAIM_SWAP
+        * and we also need to be able to write out pages for RECLAIM_WRITE
+        * and RECLAIM_SWAP.
+        */
+       p->flags |= PF_MEMALLOC | PF_SWAPWRITE;
        reclaim_state.reclaimed_slab = 0;
        p->reclaim_state = &reclaim_state;
 
@@ -1932,11 +1937,10 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
                 * a long time.
                 */
                shrink_slab(sc.nr_scanned, gfp_mask, order);
-               sc.nr_reclaimed = 1;    /* Avoid getting the off node timeout */
        }
 
        p->reclaim_state = NULL;
-       current->flags &= ~PF_MEMALLOC;
+       current->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE);
 
        if (sc.nr_reclaimed == 0)
                zone->last_unsuccessful_zone_reclaim = jiffies;