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page allocator: always wake kswapd when restarting an allocation attempt after direct reclaim failed

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If a direct reclaim makes no forward progress, it considers whether it
should go OOM or not.  Whether OOM is triggered or not, it may retry the
allocation afterwards.  In times past, this would always wake kswapd as
well but currently, kswapd is not woken up after direct reclaim fails.
For order-0 allocations, this makes little difference but if there is a
heavy mix of higher-order allocations that direct reclaim is failing for,
it might mean that kswapd is not rewoken for higher orders as much as it
did previously.

This patch wakes up kswapd when an allocation is being retried after a
direct reclaim failure.  It would be expected that kswapd is already
awake, but this has the effect of telling kswapd to reclaim at the higher
order as well.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mel Gorman 2009-11-11 14:26:14 -08:00 committed by Linus Torvalds
parent b0c9065324
commit cc4a685146
1 changed files with 1 additions and 1 deletions
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2
mm/page_alloc.c
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@ -1817,9 +1817,9 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
if (NUMA_BUILD && (gfp_mask & GFP_THISNODE) == GFP_THISNODE) if (NUMA_BUILD && (gfp_mask & GFP_THISNODE) == GFP_THISNODE)
goto nopage; goto nopage;
restart:
wake_all_kswapd(order, zonelist, high_zoneidx); wake_all_kswapd(order, zonelist, high_zoneidx);
restart:
/* /*
* OK, we're below the kswapd watermark and have kicked background * OK, we're below the kswapd watermark and have kicked background
* reclaim. Now things get more complex, so set up alloc_flags according * reclaim. Now things get more complex, so set up alloc_flags according