mm: trigger page reclaim in alloc_contig_range() to stabilise watermarks (49f223a9) · Commits · 戴 / test

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;

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