From: Mel Gorman Date: Wed, 11 Nov 2009 22:26:14 +0000 (-0800) Subject: page allocator: always wake kswapd when restarting an allocation attempt after direct... X-Git-Tag: v2.6.31.7~83 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ffb83b9e7d0e935ccc665ed09f2f7273828c9cfb;p=thirdparty%2Fkernel%2Fstable.git page allocator: always wake kswapd when restarting an allocation attempt after direct reclaim failed commit cc4a6851466039a8a688c843962a05689059ff3b upstream. 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 Reviewed-by: Christoph Lameter Reviewed-by: Pekka Enberg Reviewed-by: KOSAKI Motohiro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- diff --git a/mm/page_alloc.c b/mm/page_alloc.c index b28d09ad30611..957b551f0b417 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1763,6 +1763,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, if (NUMA_BUILD && (gfp_mask & GFP_THISNODE) == GFP_THISNODE) goto nopage; +restart: wake_all_kswapd(order, zonelist, high_zoneidx); /* @@ -1772,7 +1773,6 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, */ alloc_flags = gfp_to_alloc_flags(gfp_mask); -restart: /* This is the last chance, in general, before the goto nopage. */ page = get_page_from_freelist(gfp_mask, nodemask, order, zonelist, high_zoneidx, alloc_flags & ~ALLOC_NO_WATERMARKS,