Merge "mm: vmscan: stall page reclaim and writeback pages based on... (d7fbf1b8) · Commits · e / devices / android_kernel_sony_msm8994

mm/vmscan.c

+48 −13

Original line number	Diff line number	Diff line
		@@ -757,6 +757,25 @@ static enum page_references page_check_references(struct page *page,
		return PAGEREF_RECLAIM;
		}

		/* Check if a page is dirty or under writeback */
		static void page_check_dirty_writeback(struct page *page,
		bool dirty, bool writeback)
		{
		/*
		* Anonymous pages are not handled by flushers and must be written
		* from reclaim context. Do not stall reclaim based on them
		*/
		if (!page_is_file_cache(page)) {
		*dirty = false;
		*writeback = false;
		return;
		}

		/* By default assume that the page flags are accurate */
		*dirty = PageDirty(page);
		*writeback = PageWriteback(page);
		}

		/*
		* shrink_page_list() returns the number of reclaimed pages
		*/
		@@ -785,6 +804,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
		struct page *page;
		int may_enter_fs;
		enum page_references references = PAGEREF_RECLAIM_CLEAN;
		bool dirty, writeback;

		cond_resched();

		@@ -812,6 +832,24 @@ static unsigned long shrink_page_list(struct list_head *page_list,
		may_enter_fs = (sc->gfp_mask & __GFP_FS) \|\|
		(PageSwapCache(page) && (sc->gfp_mask & __GFP_IO));

		/*
		* The number of dirty pages determines if a zone is marked
		* reclaim_congested which affects wait_iff_congested. kswapd
		* will stall and start writing pages if the tail of the LRU
		* is all dirty unqueued pages.
		*/
		page_check_dirty_writeback(page, &dirty, &writeback);
		if (dirty \|\| writeback)
		nr_dirty++;

		if (dirty && !writeback)
		nr_unqueued_dirty++;

		/* Treat this page as congested if underlying BDI is */
		mapping = page_mapping(page);
		if (mapping && bdi_write_congested(mapping->backing_dev_info))
		nr_congested++;

		/*
		* If a page at the tail of the LRU is under writeback, there
		* are three cases to consider.
		@@ -907,9 +945,10 @@ static unsigned long shrink_page_list(struct list_head *page_list,
		if (!add_to_swap(page, page_list))
		goto activate_locked;
		may_enter_fs = 1;
		}

		/* Adding to swap updated mapping */
		mapping = page_mapping(page);
		}

		/*
		* The page is mapped into the page tables of one or more
		@@ -929,11 +968,6 @@ 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 only writeback
		@@ -964,7 +998,6 @@ static unsigned long shrink_page_list(struct list_head *page_list,
		/* Page is dirty, try to write it out here */
		switch (pageout(page, mapping, sc)) {
		case PAGE_KEEP:
		nr_congested++;
		goto keep_locked;
		case PAGE_ACTIVATE:
		goto activate_locked;
		@@ -1407,7 +1440,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
		unsigned long nr_scanned;
		unsigned long nr_reclaimed = 0;
		unsigned long nr_taken;
		unsigned long nr_dirty = 0;
		unsigned long nr_unqueued_dirty = 0;
		unsigned long nr_writeback = 0;
		isolate_mode_t isolate_mode = 0;
		int file = is_file_lru(lru);
		@@ -1450,7 +1483,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
		return 0;

		nr_reclaimed = shrink_page_list(&page_list, zone, sc, TTU_UNMAP,
		&nr_dirty, &nr_writeback, false);
		&nr_unqueued_dirty, &nr_writeback, false);

		spin_lock_irq(&zone->lru_lock);

		@@ -1505,11 +1538,13 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
		/*
		* Similarly, if many dirty pages are encountered that are not
		* currently being written then flag that kswapd should start
		* writing back pages.
		* writing back pages and stall to give a chance for flushers
		* to catch up.
		*/
		if (global_reclaim(sc) && nr_dirty &&
		nr_dirty >= (nr_taken >> (DEF_PRIORITY - sc->priority)))
		if (global_reclaim(sc) && nr_unqueued_dirty == nr_taken) {
		congestion_wait(BLK_RW_ASYNC, HZ/10);
		zone_set_flag(zone, ZONE_TAIL_LRU_DIRTY);
		}

		trace_mm_vmscan_lru_shrink_inactive(zone->zone_pgdat->node_id,
		zone_idx(zone),