From patchwork Wed Jun 20 11:44:12 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mel Gorman X-Patchwork-Id: 166029 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id E84FAB6FB4 for ; Wed, 20 Jun 2012 21:45:31 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932180Ab2FTLou (ORCPT ); Wed, 20 Jun 2012 07:44:50 -0400 Received: from cantor2.suse.de ([195.135.220.15]:40269 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932129Ab2FTLod (ORCPT ); Wed, 20 Jun 2012 07:44:33 -0400 Received: from relay2.suse.de (unknown [195.135.220.254]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx2.suse.de (Postfix) with ESMTP id 22E70A4665; Wed, 20 Jun 2012 13:44:33 +0200 (CEST) From: Mel Gorman To: Andrew Morton Cc: Linux-MM , Linux-Netdev , LKML , David Miller , Neil Brown , Peter Zijlstra , Mike Christie , Eric B Munson , Sebastian Andrzej Siewior , Mel Gorman Subject: [PATCH 17/17] mm: Account for the number of times direct reclaimers get throttled Date: Wed, 20 Jun 2012 12:44:12 +0100 Message-Id: <1340192652-31658-18-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 1.7.9.2 In-Reply-To: <1340192652-31658-1-git-send-email-mgorman@suse.de> References: <1340192652-31658-1-git-send-email-mgorman@suse.de> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@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 | 3 +++ mm/vmstat.c | 1 + 3 files changed, 5 insertions(+) diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h index 06f8e38..57f7b10 100644 --- a/include/linux/vm_event_item.h +++ b/include/linux/vm_event_item.h @@ -30,6 +30,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, FOR_ALL_ZONES(PGSTEAL_DIRECT), 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 bf8625c..bcc65c5 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2166,6 +2166,9 @@ 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 1bbbbd9..df7a674 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",