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Commit e2c55dc8 authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
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Drain per-cpu lists when high-order allocations fail 



Per-cpu pages can accidentally cause fragmentation because they are free, but
pinned pages in an otherwise contiguous block.  When this patch is applied,
the per-cpu caches are drained after the direct-reclaim is entered if the
requested order is greater than 0.  It simply reuses the code used by suspend
and hotplug.

Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b92a6edd

mm/page_alloc.c

+27 −1
Original line number Diff line number Diff line
@@ -876,7 +876,9 @@ void mark_free_pages(struct zone *zone) 
	}

	spin_unlock_irqrestore(&zone->lock, flags);

}

#endif /* CONFIG_PM */



#if defined(CONFIG_HIBERNATION) || defined(CONFIG_PAGE_GROUP_BY_MOBILITY)

/*

 * Spill all of this CPU's per-cpu pages back into the buddy allocator.

 */
@@ -888,7 +890,28 @@ void drain_local_pages(void) 
	__drain_pages(smp_processor_id());

	local_irq_restore(flags);	

}

#endif /* CONFIG_HIBERNATION */



void smp_drain_local_pages(void *arg)

{

	drain_local_pages();

}



/*

 * Spill all the per-cpu pages from all CPUs back into the buddy allocator

 */

void drain_all_local_pages(void)

{

	unsigned long flags;



	local_irq_save(flags);

	__drain_pages(smp_processor_id());

	local_irq_restore(flags);



	smp_call_function(smp_drain_local_pages, NULL, 0, 1);

}

#else

void drain_all_local_pages(void) {}

#endif /* CONFIG_HIBERNATION || CONFIG_PAGE_GROUP_BY_MOBILITY */



/*

 * Free a 0-order page
@@ -1480,6 +1503,9 @@ nofail_alloc: 


	cond_resched();



	if (order != 0)

		drain_all_local_pages();



	if (likely(did_some_progress)) {

		page = get_page_from_freelist(gfp_mask, order,

						zonelist, alloc_flags);