From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f72.google.com (mail-lf0-f72.google.com [209.85.215.72]) by kanga.kvack.org (Postfix) with ESMTP id 6B07B828E1 for ; Fri, 1 Jul 2016 16:06:49 -0400 (EDT) Received: by mail-lf0-f72.google.com with SMTP id g18so88278036lfg.2 for ; Fri, 01 Jul 2016 13:06:49 -0700 (PDT) Received: from outbound-smtp07.blacknight.com (outbound-smtp07.blacknight.com. [46.22.139.12]) by mx.google.com with ESMTPS id j10si5020097wjl.139.2016.07.01.13.06.47 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 01 Jul 2016 13:06:48 -0700 (PDT) Received: from mail.blacknight.com (pemlinmail04.blacknight.ie [81.17.254.17]) by outbound-smtp07.blacknight.com (Postfix) with ESMTPS id A961A1C185A for ; Fri, 1 Jul 2016 21:06:47 +0100 (IST) From: Mel Gorman Subject: [PATCH 29/31] mm: vmstat: account per-zone stalls and pages skipped during reclaim Date: Fri, 1 Jul 2016 21:01:37 +0100 Message-Id: <1467403299-25786-30-git-send-email-mgorman@techsingularity.net> In-Reply-To: <1467403299-25786-1-git-send-email-mgorman@techsingularity.net> References: <1467403299-25786-1-git-send-email-mgorman@techsingularity.net> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , Linux-MM Cc: Rik van Riel , Vlastimil Babka , Johannes Weiner , LKML , Mel Gorman The vmstat allocstall was fairly useful in the general sense but node-based LRUs change that. It's important to know if a stall was for an address-limited allocation request as this will require skipping pages from other zones. This patch adds pgstall_* counters to replace allocstall. The sum of the counters will equal the old allocstall so it can be trivially recalculated. A high number of address-limited allocation requests may result in a lot of useless LRU scanning for suitable pages. As address-limited allocations require pages to be skipped, it's important to know how much useless LRU scanning took place so this patch adds pgskip* counters. This yields the following model 1. The number of address-space limited stalls can be accounted for (pgstall) 2. The amount of useless work required to reclaim the data is accounted (pgskip) 3. The total number of scans is available from pgscan_kswapd and pgscan_direct so from that the ratio of useful to useless scans can be calculated. Signed-off-by: Mel Gorman Acked-by: Vlastimil Babka --- include/linux/vm_event_item.h | 4 +++- mm/vmscan.c | 15 +++++++++++++-- mm/vmstat.c | 3 ++- 3 files changed, 18 insertions(+), 4 deletions(-) diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h index 1798ff542517..6d47f66f0e9c 100644 --- a/include/linux/vm_event_item.h +++ b/include/linux/vm_event_item.h @@ -23,6 +23,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, FOR_ALL_ZONES(PGALLOC), + FOR_ALL_ZONES(PGSTALL), + FOR_ALL_ZONES(PGSCAN_SKIP), PGFREE, PGACTIVATE, PGDEACTIVATE, PGFAULT, PGMAJFAULT, PGLAZYFREED, @@ -37,7 +39,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, #endif PGINODESTEAL, SLABS_SCANNED, KSWAPD_INODESTEAL, KSWAPD_LOW_WMARK_HIT_QUICKLY, KSWAPD_HIGH_WMARK_HIT_QUICKLY, - PAGEOUTRUN, ALLOCSTALL, PGROTATED, + PAGEOUTRUN, PGROTATED, DROP_PAGECACHE, DROP_SLAB, #ifdef CONFIG_NUMA_BALANCING NUMA_PTE_UPDATES, diff --git a/mm/vmscan.c b/mm/vmscan.c index a687cfa91166..151c30dd27e2 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1394,6 +1394,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, struct list_head *src = &lruvec->lists[lru]; unsigned long nr_taken = 0; unsigned long nr_zone_taken[MAX_NR_ZONES] = { 0 }; + unsigned long nr_skipped[MAX_NR_ZONES] = { 0, }; unsigned long scan, nr_pages; LIST_HEAD(pages_skipped); @@ -1408,6 +1409,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, if (page_zonenum(page) > sc->reclaim_idx) { list_move(&page->lru, &pages_skipped); + nr_skipped[page_zonenum(page)]++; continue; } @@ -1436,8 +1438,17 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, * scanning would soon rescan the same pages to skip and put the * system at risk of premature OOM. */ - if (!list_empty(&pages_skipped)) + if (!list_empty(&pages_skipped)) { + int zid; + list_splice(&pages_skipped, src); + for (zid = 0; zid < MAX_NR_ZONES; zid++) { + if (!nr_skipped[zid]) + continue; + + __count_zid_vm_events(PGSCAN_SKIP, zid, nr_skipped[zid]); + } + } *nr_scanned = scan; trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan, scan, nr_taken, mode, is_file_lru(lru)); @@ -2676,7 +2687,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, delayacct_freepages_start(); if (global_reclaim(sc)) - count_vm_event(ALLOCSTALL); + __count_zid_vm_events(PGSTALL, sc->reclaim_idx, 1); do { vmpressure_prio(sc->gfp_mask, sc->target_mem_cgroup, diff --git a/mm/vmstat.c b/mm/vmstat.c index 905ea9ae2d5a..b9a9844e3142 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -970,6 +970,8 @@ const char * const vmstat_text[] = { "pswpout", TEXTS_FOR_ZONES("pgalloc") + TEXTS_FOR_ZONES("pgstall") + TEXTS_FOR_ZONES("pgskip") "pgfree", "pgactivate", @@ -995,7 +997,6 @@ const char * const vmstat_text[] = { "kswapd_low_wmark_hit_quickly", "kswapd_high_wmark_hit_quickly", "pageoutrun", - "allocstall", "pgrotated", -- 2.6.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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