From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758440Ab1JFMmt (ORCPT ); Thu, 6 Oct 2011 08:42:49 -0400 Received: from cantor2.suse.de ([195.135.220.15]:54609 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758365Ab1JFMmJ (ORCPT ); Thu, 6 Oct 2011 08:42:09 -0400 From: Mel Gorman To: Andrew Morton Cc: Linux-MM , Linux-Netdev , LKML , David Miller , Neil Brown , Peter Zijlstra , Mel Gorman Subject: [PATCH 14/14] mm: Account for the number of times direct reclaimers get throttled Date: Thu, 6 Oct 2011 13:41:50 +0100 Message-Id: <1317904910-14095-15-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 1.7.3.4 In-Reply-To: <1317904910-14095-1-git-send-email-mgorman@suse.de> References: <1317904910-14095-1-git-send-email-mgorman@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- include/linux/vm_event_item.h | 1 + mm/vmscan.c | 1 + mm/vmstat.c | 1 + 3 files changed, 3 insertions(+), 0 deletions(-) diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h index 03b90cdc..652e5f3 100644 --- a/include/linux/vm_event_item.h +++ b/include/linux/vm_event_item.h @@ -29,6 +29,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, FOR_ALL_ZONES(PGSTEAL), FOR_ALL_ZONES(PGSCAN_KSWAPD), FOR_ALL_ZONES(PGSCAN_DIRECT), + PGSCAN_DIRECT_THROTTLE, #ifdef CONFIG_NUMA PGSCAN_ZONE_RECLAIM_FAILED, #endif diff --git a/mm/vmscan.c b/mm/vmscan.c index ca5ca02..6cb1aee 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2258,6 +2258,7 @@ static void throttle_direct_reclaim(gfp_t gfp_mask, struct zonelist *zonelist, return; /* Throttle */ + count_vm_event(PGSCAN_DIRECT_THROTTLE); wait_event_killable(zone->zone_pgdat->pfmemalloc_wait, pfmemalloc_watermark_ok(zone->zone_pgdat, high_zoneidx)); } diff --git a/mm/vmstat.c b/mm/vmstat.c index d52b13d..96070b4 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -740,6 +740,7 @@ const char * const vmstat_text[] = { TEXTS_FOR_ZONES("pgsteal") TEXTS_FOR_ZONES("pgscan_kswapd") TEXTS_FOR_ZONES("pgscan_direct") + "pgscan_direct_throttle", #ifdef CONFIG_NUMA "zone_reclaim_failed", -- 1.7.3.4