mm: vmscan: move direct reclaim wait_iff_congested into shrink_list
shrink_inactive_list makes decisions on whether to stall based on the number of dirty pages encountered. The wait_iff_congested() call in shrink_page_list does no such thing and it's arbitrary. This patch moves the decision on whether to set ZONE_CONGESTED and the wait_iff_congested call into shrink_page_list. This keeps all the decisions on whether to stall or not in the one place. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Rik van Riel <riel@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Cc: Zlatko Calusic <zcalusic@bitsync.net> Cc: dormando <dormando@rydia.net> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
f7ab8db791
commit
8e95028280
62
mm/vmscan.c
62
mm/vmscan.c
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@ -695,7 +695,9 @@ static unsigned long shrink_page_list(struct list_head *page_list,
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struct zone *zone,
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struct scan_control *sc,
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enum ttu_flags ttu_flags,
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unsigned long *ret_nr_dirty,
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unsigned long *ret_nr_unqueued_dirty,
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unsigned long *ret_nr_congested,
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unsigned long *ret_nr_writeback,
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unsigned long *ret_nr_immediate,
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bool force_reclaim)
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@ -1017,20 +1019,13 @@ keep:
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VM_BUG_ON(PageLRU(page) || PageUnevictable(page));
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}
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/*
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* Tag a zone as congested if all the dirty pages encountered were
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* backed by a congested BDI. In this case, reclaimers should just
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* back off and wait for congestion to clear because further reclaim
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* will encounter the same problem
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*/
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if (nr_dirty && nr_dirty == nr_congested && global_reclaim(sc))
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zone_set_flag(zone, ZONE_CONGESTED);
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free_hot_cold_page_list(&free_pages, 1);
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list_splice(&ret_pages, page_list);
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count_vm_events(PGACTIVATE, pgactivate);
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mem_cgroup_uncharge_end();
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*ret_nr_dirty += nr_dirty;
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*ret_nr_congested += nr_congested;
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*ret_nr_unqueued_dirty += nr_unqueued_dirty;
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*ret_nr_writeback += nr_writeback;
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*ret_nr_immediate += nr_immediate;
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@ -1045,7 +1040,7 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone,
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.priority = DEF_PRIORITY,
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.may_unmap = 1,
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};
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unsigned long ret, dummy1, dummy2, dummy3;
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unsigned long ret, dummy1, dummy2, dummy3, dummy4, dummy5;
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struct page *page, *next;
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LIST_HEAD(clean_pages);
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@ -1057,8 +1052,8 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone,
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}
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ret = shrink_page_list(&clean_pages, zone, &sc,
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TTU_UNMAP|TTU_IGNORE_ACCESS,
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&dummy1, &dummy2, &dummy3, true);
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TTU_UNMAP|TTU_IGNORE_ACCESS,
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&dummy1, &dummy2, &dummy3, &dummy4, &dummy5, true);
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list_splice(&clean_pages, page_list);
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__mod_zone_page_state(zone, NR_ISOLATED_FILE, -ret);
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return ret;
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@ -1352,6 +1347,8 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
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unsigned long nr_scanned;
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unsigned long nr_reclaimed = 0;
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unsigned long nr_taken;
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unsigned long nr_dirty = 0;
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unsigned long nr_congested = 0;
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unsigned long nr_unqueued_dirty = 0;
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unsigned long nr_writeback = 0;
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unsigned long nr_immediate = 0;
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@ -1396,8 +1393,9 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
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return 0;
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nr_reclaimed = shrink_page_list(&page_list, zone, sc, TTU_UNMAP,
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&nr_unqueued_dirty, &nr_writeback, &nr_immediate,
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false);
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&nr_dirty, &nr_unqueued_dirty, &nr_congested,
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&nr_writeback, &nr_immediate,
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false);
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spin_lock_irq(&zone->lru_lock);
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@ -1431,7 +1429,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
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* same way balance_dirty_pages() manages.
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*
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* This scales the number of dirty pages that must be under writeback
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* before throttling depending on priority. It is a simple backoff
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* before a zone gets flagged ZONE_WRITEBACK. It is a simple backoff
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* function that has the most effect in the range DEF_PRIORITY to
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* DEF_PRIORITY-2 which is the priority reclaim is considered to be
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* in trouble and reclaim is considered to be in trouble.
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@ -1442,18 +1440,27 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
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* ...
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* DEF_PRIORITY-6 For SWAP_CLUSTER_MAX isolated pages, throttle if any
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* isolated page is PageWriteback
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*
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* Once a zone is flagged ZONE_WRITEBACK, kswapd will count the number
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* of pages under pages flagged for immediate reclaim and stall if any
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* are encountered in the nr_immediate check below.
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*/
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if (nr_writeback && nr_writeback >=
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(nr_taken >> (DEF_PRIORITY - sc->priority))) {
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(nr_taken >> (DEF_PRIORITY - sc->priority)))
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zone_set_flag(zone, ZONE_WRITEBACK);
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wait_iff_congested(zone, BLK_RW_ASYNC, HZ/10);
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}
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/*
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* memcg will stall in page writeback so only consider forcibly
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* stalling for global reclaim
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*/
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if (global_reclaim(sc)) {
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/*
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* Tag a zone as congested if all the dirty pages scanned were
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* backed by a congested BDI and wait_iff_congested will stall.
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*/
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if (nr_dirty && nr_dirty == nr_congested)
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zone_set_flag(zone, ZONE_CONGESTED);
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/*
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* If dirty pages are scanned that are not queued for IO, it
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* implies that flushers are not keeping up. In this case, flag
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@ -1474,6 +1481,14 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
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congestion_wait(BLK_RW_ASYNC, HZ/10);
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}
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/*
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* Stall direct reclaim for IO completions if underlying BDIs or zone
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* is congested. Allow kswapd to continue until it starts encountering
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* unqueued dirty pages or cycling through the LRU too quickly.
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*/
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if (!sc->hibernation_mode && !current_is_kswapd())
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wait_iff_congested(zone, BLK_RW_ASYNC, HZ/10);
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trace_mm_vmscan_lru_shrink_inactive(zone->zone_pgdat->node_id,
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zone_idx(zone),
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nr_scanned, nr_reclaimed,
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@ -2374,17 +2389,6 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
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WB_REASON_TRY_TO_FREE_PAGES);
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sc->may_writepage = 1;
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}
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/* Take a nap, wait for some writeback to complete */
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if (!sc->hibernation_mode && sc->nr_scanned &&
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sc->priority < DEF_PRIORITY - 2) {
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struct zone *preferred_zone;
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first_zones_zonelist(zonelist, gfp_zone(sc->gfp_mask),
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&cpuset_current_mems_allowed,
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&preferred_zone);
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wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/10);
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}
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} while (--sc->priority >= 0);
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out:
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