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Commit 49f223a9 authored by Marek Szyprowski's avatar Marek Szyprowski
Browse files

mm: trigger page reclaim in alloc_contig_range() to stabilise watermarks 



alloc_contig_range() performs memory allocation so it also should keep
track on keeping the correct level of memory watermarks. This commit adds
a call to *_slowpath style reclaim to grab enough pages to make sure that
the final collection of contiguous pages from freelists will not starve
the system.

Signed-off-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: default avatarKyungmin Park <kyungmin.park@samsung.com>
CC: Michal Nazarewicz <mina86@mina86.com>
Tested-by: default avatarRob Clark <rob.clark@linaro.org>
Tested-by: default avatarOhad Ben-Cohen <ohad@wizery.com>
Tested-by: default avatarBenjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: default avatarRobert Nelson <robertcnelson@gmail.com>
Tested-by: default avatarBarry Song <Baohua.Song@csr.com>
parent bba90710

include/linux/mmzone.h

+9 −0
Original line number Diff line number Diff line
@@ -63,8 +63,10 @@ enum { 


#ifdef CONFIG_CMA

#  define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)

#  define cma_wmark_pages(zone)	zone->min_cma_pages

#else

#  define is_migrate_cma(migratetype) false

#  define cma_wmark_pages(zone) 0

#endif



#define for_each_migratetype_order(order, type) \
@@ -370,6 +372,13 @@ struct zone { 
#ifdef CONFIG_MEMORY_HOTPLUG

	/* see spanned/present_pages for more description */

	seqlock_t		span_seqlock;

#endif

#ifdef CONFIG_CMA

	/*

	 * CMA needs to increase watermark levels during the allocation

	 * process to make sure that the system is not starved.

	 */

	unsigned long		min_cma_pages;

#endif

	struct free_area	free_area[MAX_ORDER];

mm/page_alloc.c

+60 −0
Original line number Diff line number Diff line
@@ -5079,6 +5079,11 @@ static void __setup_per_zone_wmarks(void) 


		zone->watermark[WMARK_LOW]  = min_wmark_pages(zone) + (tmp >> 2);

		zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + (tmp >> 1);



		zone->watermark[WMARK_MIN] += cma_wmark_pages(zone);

		zone->watermark[WMARK_LOW] += cma_wmark_pages(zone);

		zone->watermark[WMARK_HIGH] += cma_wmark_pages(zone);



		setup_zone_migrate_reserve(zone);

		spin_unlock_irqrestore(&zone->lock, flags);

	}
@@ -5684,6 +5689,54 @@ static int __alloc_contig_migrate_range(unsigned long start, unsigned long end) 
	return ret > 0 ? 0 : ret;

}



/*

 * Update zone's cma pages counter used for watermark level calculation.

 */

static inline void __update_cma_watermarks(struct zone *zone, int count)

{

	unsigned long flags;

	spin_lock_irqsave(&zone->lock, flags);

	zone->min_cma_pages += count;

	spin_unlock_irqrestore(&zone->lock, flags);

	setup_per_zone_wmarks();

}



/*

 * Trigger memory pressure bump to reclaim some pages in order to be able to

 * allocate 'count' pages in single page units. Does similar work as

 *__alloc_pages_slowpath() function.

 */

static int __reclaim_pages(struct zone *zone, gfp_t gfp_mask, int count)

{

	enum zone_type high_zoneidx = gfp_zone(gfp_mask);

	struct zonelist *zonelist = node_zonelist(0, gfp_mask);

	int did_some_progress = 0;

	int order = 1;



	/*

	 * Increase level of watermarks to force kswapd do his job

	 * to stabilise at new watermark level.

	 */

	__update_cma_watermarks(zone, count);



	/* Obey watermarks as if the page was being allocated */

	while (!zone_watermark_ok(zone, 0, low_wmark_pages(zone), 0, 0)) {

		wake_all_kswapd(order, zonelist, high_zoneidx, zone_idx(zone));



		did_some_progress = __perform_reclaim(gfp_mask, order, zonelist,

						      NULL);

		if (!did_some_progress) {

			/* Exhausted what can be done so it's blamo time */

			out_of_memory(zonelist, gfp_mask, order, NULL, false);

		}

	}



	/* Restore original watermark levels. */

	__update_cma_watermarks(zone, -count);



	return count;

}



/**

 * alloc_contig_range() -- tries to allocate given range of pages

 * @start:	start PFN to allocate
@@ -5782,6 +5835,13 @@ int alloc_contig_range(unsigned long start, unsigned long end, 
		goto done;

	}



	/*

	 * Reclaim enough pages to make sure that contiguous allocation

	 * will not starve the system.

	 */

	__reclaim_pages(zone, GFP_HIGHUSER_MOVABLE, end-start);



	/* Grab isolated pages from freelists. */

	outer_end = isolate_freepages_range(outer_start, end);

	if (!outer_end) {

		ret = -EBUSY;