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: Marek Szyprowski m.szyprowski@samsung.com Signed-off-by: Kyungmin Park kyungmin.park@samsung.com CC: Michal Nazarewicz mina86@mina86.com Tested-by: Rob Clark rob.clark@linaro.org Tested-by: Ohad Ben-Cohen ohad@wizery.com Tested-by: Benjamin Gaignard benjamin.gaignard@linaro.org Tested-by: Robert Nelson robertcnelson@gmail.com --- include/linux/mmzone.h | 9 +++++++ mm/page_alloc.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 71 insertions(+), 0 deletions(-)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 4781f30..77db8c0 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -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) \ @@ -371,6 +373,13 @@ struct zone { /* 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];
#ifndef CONFIG_SPARSEMEM diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 7a0d286..39cd74f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5092,6 +5092,11 @@ static void __setup_per_zone_wmarks(void) low + (min >> 2); zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + low + (min >> 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); } @@ -5695,6 +5700,56 @@ 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; + unsigned long watermark; + + /* + * 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 */ + watermark = low_wmark_pages(zone) + count; + while (!zone_watermark_ok(zone, 0, watermark, 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); + } + } + + /* 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 @@ -5793,6 +5848,13 @@ 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;