forked from Minki/linux
mm: kswapd: use the order that kswapd was reclaiming at for sleeping_prematurely()
Before kswapd goes to sleep, it uses sleeping_prematurely() to check if there was a race pushing a zone below its watermark. If the race happened, it stays awake. However, balance_pgdat() can decide to reclaim at order-0 if it decides that high-order reclaim is not working as expected. This information is not passed back to sleeping_prematurely(). The impact is that kswapd remains awake reclaiming pages long after it should have gone to sleep. This patch passes the adjusted order to sleeping_prematurely and uses the same logic as balance_pgdat to decide if it's ok to go to sleep. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Eric B Munson <emunson@mgebm.net> Cc: Simon Kirby <sim@hostway.ca> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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0abdee2bd4
16
mm/vmscan.c
16
mm/vmscan.c
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@ -2227,7 +2227,7 @@ static bool pgdat_balanced(pg_data_t *pgdat, unsigned long balanced_pages,
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}
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}
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/* is kswapd sleeping prematurely? */
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/* is kswapd sleeping prematurely? */
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static int sleeping_prematurely(pg_data_t *pgdat, int order, long remaining)
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static bool sleeping_prematurely(pg_data_t *pgdat, int order, long remaining)
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{
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{
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int i;
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int i;
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unsigned long balanced = 0;
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unsigned long balanced = 0;
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@ -2237,7 +2237,7 @@ static int sleeping_prematurely(pg_data_t *pgdat, int order, long remaining)
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if (remaining)
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if (remaining)
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return 1;
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return 1;
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/* If after HZ/10, a zone is below the high mark, it's premature */
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/* Check the watermark levels */
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for (i = 0; i < pgdat->nr_zones; i++) {
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for (i = 0; i < pgdat->nr_zones; i++) {
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struct zone *zone = pgdat->node_zones + i;
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struct zone *zone = pgdat->node_zones + i;
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@ -2269,7 +2269,7 @@ static int sleeping_prematurely(pg_data_t *pgdat, int order, long remaining)
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* For kswapd, balance_pgdat() will work across all this node's zones until
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* For kswapd, balance_pgdat() will work across all this node's zones until
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* they are all at high_wmark_pages(zone).
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* they are all at high_wmark_pages(zone).
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*
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*
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* Returns the number of pages which were actually freed.
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* Returns the final order kswapd was reclaiming at
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*
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*
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* There is special handling here for zones which are full of pinned pages.
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* There is special handling here for zones which are full of pinned pages.
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* This can happen if the pages are all mlocked, or if they are all used by
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* This can happen if the pages are all mlocked, or if they are all used by
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@ -2532,7 +2532,13 @@ out:
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}
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}
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}
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}
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return sc.nr_reclaimed;
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/*
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* Return the order we were reclaiming at so sleeping_prematurely()
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* makes a decision on the order we were last reclaiming at. However,
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* if another caller entered the allocator slow path while kswapd
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* was awake, order will remain at the higher level
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*/
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return order;
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}
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}
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static void kswapd_try_to_sleep(pg_data_t *pgdat, int order)
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static void kswapd_try_to_sleep(pg_data_t *pgdat, int order)
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@ -2659,7 +2665,7 @@ static int kswapd(void *p)
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*/
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*/
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if (!ret) {
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if (!ret) {
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trace_mm_vmscan_kswapd_wake(pgdat->node_id, order);
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trace_mm_vmscan_kswapd_wake(pgdat->node_id, order);
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balance_pgdat(pgdat, order, classzone_idx);
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order = balance_pgdat(pgdat, order, classzone_idx);
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}
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}
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}
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}
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return 0;
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return 0;
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