From 68243e76ee343d63c6cf76978588a885951e2818 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Tue, 31 Jul 2012 16:44:39 -0700 Subject: mm: account for the number of times direct reclaimers get throttled Under significant pressure when writing back to network-backed storage, direct reclaimers may get throttled. This is expected to be a short-lived event and the processes get woken up again but processes do get stalled. This patch counts how many times such stalling occurs. It's up to the administrator whether to reduce these stalls by increasing min_free_kbytes. Signed-off-by: Mel Gorman Cc: David Miller Cc: Neil Brown Cc: Peter Zijlstra Cc: Mike Christie Cc: Eric B Munson Cc: Eric Dumazet Cc: Sebastian Andrzej Siewior Cc: Mel Gorman Cc: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmscan.c | 3 +++ mm/vmstat.c | 1 + 2 files changed, 4 insertions(+) (limited to 'mm') diff --git a/mm/vmscan.c b/mm/vmscan.c index 021a44a7bd2..88804017e7d 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2167,6 +2167,9 @@ static void throttle_direct_reclaim(gfp_t gfp_mask, struct zonelist *zonelist, if (pfmemalloc_watermark_ok(pgdat)) return; + /* Account for the throttling */ + count_vm_event(PGSCAN_DIRECT_THROTTLE); + /* * If the caller cannot enter the filesystem, it's possible that it * is due to the caller holding an FS lock or performing a journal diff --git a/mm/vmstat.c b/mm/vmstat.c index 1bbbbd9776a..df7a6748231 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -745,6 +745,7 @@ const char * const vmstat_text[] = { TEXTS_FOR_ZONES("pgsteal_direct") TEXTS_FOR_ZONES("pgscan_kswapd") TEXTS_FOR_ZONES("pgscan_direct") + "pgscan_direct_throttle", #ifdef CONFIG_NUMA "zone_reclaim_failed", -- cgit v1.2.3