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Commit bc0155b4 authored by Sudarshan Rajagopalan's avatar Sudarshan Rajagopalan
Browse files

ion: defer pool refill on low zone watermarks 



Make pool_refill_ok more aggressive to make sure there is
no unwanted repetitive refilling and reclaiming of buddy
pages on the pool. Also defer the pool refilling within a
certain window if the zone watermarks are not ok.

Change-Id: Ib13411cdd75bec49cdd073c00da26168d93af841
Signed-off-by: default avatarSudarshan Rajagopalan <sudaraja@codeaurora.org>
parent c5f80a76

drivers/staging/android/ion/ion.h

+4 −0
Original line number Diff line number Diff line
@@ -66,6 +66,9 @@ 
#define ION_POOL_LOW_MARK 0UL

#endif



/* if low watermark of zones have reached, defer the refill in this window */

#define ION_POOL_REFILL_DEFER_WINDOW_MS	10



/**

 * struct ion_platform_heap - defines a heap in the given platform

 * @type:	type of the heap from ion_heap_type enum
@@ -435,6 +438,7 @@ struct ion_page_pool { 
	bool cached;

	struct list_head high_items;

	struct list_head low_items;

	ktime_t last_low_watermark_ktime;

	/* Protect the pool */

	struct mutex mutex;

	gfp_t gfp_mask;

drivers/staging/android/ion/ion_page_pool.c

+18 −2
Original line number Diff line number Diff line
@@ -19,14 +19,30 @@ static bool pool_refill_ok(struct ion_page_pool *pool) 
	struct zoneref *z;

	struct zone *zone;

	int mark;

	int classzone_idx = (int)gfp_zone(pool->gfp_mask);

	enum zone_type classzone_idx = gfp_zone(pool->gfp_mask);

	s64 delta;



	/* check if we are within the refill defer window */

	delta = ktime_ms_delta(ktime_get(), pool->last_low_watermark_ktime);

	if (delta < ION_POOL_REFILL_DEFER_WINDOW_MS)

		return false;



	zonelist = node_zonelist(numa_node_id(), pool->gfp_mask);

	/*

	 * make sure that if we allocate a pool->order page from buddy,

	 * we don't put the zone watermarks go below the high threshold.

	 * This makes sure there's no unwanted repetitive refilling and

	 * reclaiming of buddy pages on the pool.

	 */

	for_each_zone_zonelist(zone, z, zonelist, classzone_idx) {

		mark = high_wmark_pages(zone);

		if (!zone_watermark_ok_safe(zone, 0, mark, classzone_idx))

		mark += 1 << pool->order;

		if (!zone_watermark_ok_safe(zone, pool->order, mark,

					    classzone_idx)) {

			pool->last_low_watermark_ktime = ktime_get();

			return false;

		}

	}



	return true;

}