diff options
Diffstat (limited to 'mm/vmscan.c')
| -rw-r--r-- | mm/vmscan.c | 126 |
1 files changed, 75 insertions, 51 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 403f59edd53e..1ecc648b6191 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -116,6 +116,16 @@ struct scan_control { /* Number of pages freed so far during a call to shrink_zones() */ unsigned long nr_reclaimed; + + struct { + unsigned int dirty; + unsigned int unqueued_dirty; + unsigned int congested; + unsigned int writeback; + unsigned int immediate; + unsigned int file_taken; + unsigned int taken; + } nr; }; #ifdef ARCH_HAS_PREFETCH @@ -1755,23 +1765,6 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, free_unref_page_list(&page_list); /* - * If reclaim is isolating dirty pages under writeback, it implies - * that the long-lived page allocation rate is exceeding the page - * laundering rate. Either the global limits are not being effective - * at throttling processes due to the page distribution throughout - * zones or there is heavy usage of a slow backing device. The - * only option is to throttle from reclaim context which is not ideal - * as there is no guarantee the dirtying process is throttled in the - * same way balance_dirty_pages() manages. - * - * Once a node is flagged PGDAT_WRITEBACK, kswapd will count the number - * of pages under pages flagged for immediate reclaim and stall if any - * are encountered in the nr_immediate check below. - */ - if (stat.nr_writeback && stat.nr_writeback == nr_taken) - set_bit(PGDAT_WRITEBACK, &pgdat->flags); - - /* * If dirty pages are scanned that are not queued for IO, it * implies that flushers are not doing their job. This can * happen when memory pressure pushes dirty pages to the end of @@ -1785,40 +1778,14 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, if (stat.nr_unqueued_dirty == nr_taken) wakeup_flusher_threads(WB_REASON_VMSCAN); - /* - * Legacy memcg will stall in page writeback so avoid forcibly - * stalling here. - */ - if (sane_reclaim(sc)) { - /* - * Tag a node as congested if all the dirty pages scanned were - * backed by a congested BDI and wait_iff_congested will stall. - */ - if (stat.nr_dirty && stat.nr_dirty == stat.nr_congested) - set_bit(PGDAT_CONGESTED, &pgdat->flags); - - /* Allow kswapd to start writing pages during reclaim. */ - if (stat.nr_unqueued_dirty == nr_taken) - set_bit(PGDAT_DIRTY, &pgdat->flags); - - /* - * If kswapd scans pages marked marked for immediate - * reclaim and under writeback (nr_immediate), it implies - * that pages are cycling through the LRU faster than - * they are written so also forcibly stall. - */ - if (stat.nr_immediate) - congestion_wait(BLK_RW_ASYNC, HZ/10); - } - - /* - * Stall direct reclaim for IO completions if underlying BDIs and node - * is congested. Allow kswapd to continue until it starts encountering - * unqueued dirty pages or cycling through the LRU too quickly. - */ - if (!sc->hibernation_mode && !current_is_kswapd() && - current_may_throttle()) - wait_iff_congested(pgdat, BLK_RW_ASYNC, HZ/10); + sc->nr.dirty += stat.nr_dirty; + sc->nr.congested += stat.nr_congested; + sc->nr.unqueued_dirty += stat.nr_unqueued_dirty; + sc->nr.writeback += stat.nr_writeback; + sc->nr.immediate += stat.nr_immediate; + sc->nr.taken += nr_taken; + if (file) + sc->nr.file_taken += nr_taken; trace_mm_vmscan_lru_shrink_inactive(pgdat->node_id, nr_scanned, nr_reclaimed, @@ -2522,6 +2489,8 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc) unsigned long node_lru_pages = 0; struct mem_cgroup *memcg; + memset(&sc->nr, 0, sizeof(sc->nr)); + nr_reclaimed = sc->nr_reclaimed; nr_scanned = sc->nr_scanned; @@ -2587,6 +2556,61 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc) if (sc->nr_reclaimed - nr_reclaimed) reclaimable = true; + /* + * If reclaim is isolating dirty pages under writeback, it + * implies that the long-lived page allocation rate is exceeding + * the page laundering rate. Either the global limits are not + * being effective at throttling processes due to the page + * distribution throughout zones or there is heavy usage of a + * slow backing device. The only option is to throttle from + * reclaim context which is not ideal as there is no guarantee + * the dirtying process is throttled in the same way + * balance_dirty_pages() manages. + * + * Once a node is flagged PGDAT_WRITEBACK, kswapd will count the + * number of pages under pages flagged for immediate reclaim and + * stall if any are encountered in the nr_immediate check below. + */ + if (sc->nr.writeback && sc->nr.writeback == sc->nr.taken) + set_bit(PGDAT_WRITEBACK, &pgdat->flags); + + /* + * Legacy memcg will stall in page writeback so avoid forcibly + * stalling here. + */ + if (sane_reclaim(sc)) { + /* + * Tag a node as congested if all the dirty pages + * scanned were backed by a congested BDI and + * wait_iff_congested will stall. + */ + if (sc->nr.dirty && sc->nr.dirty == sc->nr.congested) + set_bit(PGDAT_CONGESTED, &pgdat->flags); + + /* Allow kswapd to start writing pages during reclaim.*/ + if (sc->nr.unqueued_dirty == sc->nr.file_taken) + set_bit(PGDAT_DIRTY, &pgdat->flags); + + /* + * If kswapd scans pages marked marked for immediate + * reclaim and under writeback (nr_immediate), it + * implies that pages are cycling through the LRU + * faster than they are written so also forcibly stall. + */ + if (sc->nr.immediate) + congestion_wait(BLK_RW_ASYNC, HZ/10); + } + + /* + * Stall direct reclaim for IO completions if underlying BDIs + * and node is congested. Allow kswapd to continue until it + * starts encountering unqueued dirty pages or cycling through + * the LRU too quickly. + */ + if (!sc->hibernation_mode && !current_is_kswapd() && + current_may_throttle()) + wait_iff_congested(pgdat, BLK_RW_ASYNC, HZ/10); + } while (should_continue_reclaim(pgdat, sc->nr_reclaimed - nr_reclaimed, sc->nr_scanned - nr_scanned, sc)); |