diff options
Diffstat (limited to 'mm/vmscan.c')
| -rw-r--r-- | mm/vmscan.c | 61 |
1 files changed, 48 insertions, 13 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 4a43c289b23a..999ef0b9399a 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -669,6 +669,25 @@ 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 */ @@ -697,6 +716,7 @@ 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(); @@ -725,6 +745,24 @@ static unsigned long shrink_page_list(struct list_head *page_list, (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. * @@ -819,9 +857,10 @@ 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; - } - mapping = page_mapping(page); + /* Adding to swap updated mapping */ + mapping = page_mapping(page); + } /* * The page is mapped into the page tables of one or more @@ -841,11 +880,6 @@ 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 @@ -876,7 +910,6 @@ 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; @@ -1318,7 +1351,7 @@ 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); @@ -1361,7 +1394,7 @@ 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); @@ -1416,11 +1449,13 @@ 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), |
