From 7cc30fcfd2a894589d832a192cac3dc5cd302bb8 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Thu, 28 Jul 2016 15:46:59 -0700 Subject: mm: vmstat: account per-zone stalls and pages skipped during reclaim 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. [mgorman@techsingularity.net: s/pgstall/allocstall/] Link: http://lkml.kernel.org/r/1468404004-5085-3-git-send-email-mgorman@techsingularity.netLink: http://lkml.kernel.org/r/1467970510-21195-33-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman Acked-by: Vlastimil Babka Cc: Hillf Danton Acked-by: Johannes Weiner Cc: Joonsoo Kim Cc: Michal Hocko Cc: Minchan Kim Cc: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmstat.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'mm/vmstat.c') diff --git a/mm/vmstat.c b/mm/vmstat.c index ab7f78995c89..5caaf3f7b8ab 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -983,6 +983,8 @@ const char * const vmstat_text[] = { "pswpout", TEXTS_FOR_ZONES("pgalloc") + TEXTS_FOR_ZONES("allocstall") + TEXTS_FOR_ZONES("pgskip") "pgfree", "pgactivate", @@ -1008,7 +1010,6 @@ const char * const vmstat_text[] = { "kswapd_low_wmark_hit_quickly", "kswapd_high_wmark_hit_quickly", "pageoutrun", - "allocstall", "pgrotated", -- cgit v1.2.3