Merge "mm: vmscan: have kswapd writeback pages based on dirty pages encountered, not priority" (faf56be4) · Commits · e / devices / android_kernel_sony_msm8994

include/linux/mmzone.h

+9 −0

Original line number	Diff line number	Diff line
		@@ -523,6 +523,10 @@ typedef enum {
		ZONE_CONGESTED, /* zone has many dirty pages backed by
		* a congested BDI
		*/
		ZONE_TAIL_LRU_DIRTY, /* reclaim scanning has recently found
		* many dirty file pages at the tail
		* of the LRU.
		*/
		} zone_flags_t;

		static inline void zone_set_flag(struct zone *zone, zone_flags_t flag)
		@@ -545,6 +549,11 @@ static inline int zone_is_reclaim_congested(const struct zone *zone)
		return test_bit(ZONE_CONGESTED, &zone->flags);
		}

		static inline int zone_is_reclaim_dirty(const struct zone *zone)
		{
		return test_bit(ZONE_TAIL_LRU_DIRTY, &zone->flags);
		}

		static inline int zone_is_reclaim_locked(const struct zone *zone)
		{
		return test_bit(ZONE_RECLAIM_LOCKED, &zone->flags);

mm/vmscan.c

+25 −6

Original line number	Diff line number	Diff line
		@@ -764,13 +764,14 @@ static unsigned long shrink_page_list(struct list_head *page_list,
		struct zone *zone,
		struct scan_control *sc,
		enum ttu_flags ttu_flags,
		unsigned long *ret_nr_dirty,
		unsigned long *ret_nr_unqueued_dirty,
		unsigned long *ret_nr_writeback,
		bool force_reclaim)
		{
		LIST_HEAD(ret_pages);
		LIST_HEAD(free_pages);
		int pgactivate = 0;
		unsigned long nr_unqueued_dirty = 0;
		unsigned long nr_dirty = 0;
		unsigned long nr_congested = 0;
		unsigned long nr_reclaimed = 0;
		@@ -896,14 +897,17 @@ static unsigned long shrink_page_list(struct list_head *page_list,
		if (PageDirty(page)) {
		nr_dirty++;

		if (!PageWriteback(page))
		nr_unqueued_dirty++;

		/*
		* Only kswapd can writeback filesystem pages to
		* avoid risk of stack overflow but do not writeback
		* unless under significant pressure.
		* avoid risk of stack overflow but only writeback
		* if many dirty pages have been encountered.
		*/
		if (page_is_file_cache(page) &&
		(!current_is_kswapd() \|\|
		sc->priority >= DEF_PRIORITY - 2)) {
		!zone_is_reclaim_dirty(zone))) {
		/*
		* Immediately reclaim when written back.
		* Similar in principal to deactivate_page()
		@@ -1048,7 +1052,7 @@ keep:
		list_splice(&ret_pages, page_list);
		count_vm_events(PGACTIVATE, pgactivate);
		mem_cgroup_uncharge_end();
		*ret_nr_dirty += nr_dirty;
		*ret_nr_unqueued_dirty += nr_unqueued_dirty;
		*ret_nr_writeback += nr_writeback;
		return nr_reclaimed;
		}
		@@ -1462,6 +1466,15 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
		(nr_taken >> (DEF_PRIORITY - sc->priority)))
		wait_iff_congested(zone, BLK_RW_ASYNC, HZ/10);

		/*
		* Similarly, if many dirty pages are encountered that are not
		* currently being written then flag that kswapd should start
		* writing back pages.
		*/
		if (global_reclaim(sc) && nr_dirty &&
		nr_dirty >= (nr_taken >> (DEF_PRIORITY - sc->priority)))
		zone_set_flag(zone, ZONE_TAIL_LRU_DIRTY);

		trace_mm_vmscan_lru_shrink_inactive(zone->zone_pgdat->node_id,
		zone_idx(zone),
		nr_scanned, nr_reclaimed,
		@@ -2882,8 +2895,12 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
		end_zone = i;
		break;
		} else {
		/* If balanced, clear the congested flag */
		/*
		* If balanced, clear the dirty and congested
		* flags
		*/
		zone_clear_flag(zone, ZONE_CONGESTED);
		zone_clear_flag(zone, ZONE_TAIL_LRU_DIRTY);
		}
		}

		@@ -3001,8 +3018,10 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
		* possible there are dirty pages backed by
		* congested BDIs but as pressure is relieved,
		* speculatively avoid congestion waits
		* or writing pages from kswapd context.
		*/
		zone_clear_flag(zone, ZONE_CONGESTED);
		zone_clear_flag(zone, ZONE_TAIL_LRU_DIRTY);
		}

		/*