Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966644Ab2EQO4s (ORCPT ); Thu, 17 May 2012 10:56:48 -0400 Received: from cantor2.suse.de ([195.135.220.15]:33470 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762025Ab2EQOuv (ORCPT ); Thu, 17 May 2012 10:50:51 -0400 From: Mel Gorman To: Andrew Morton Cc: Linux-MM , Linux-Netdev , LKML , David Miller , Neil Brown , Peter Zijlstra , Mike Christie , Eric B Munson , Mel Gorman Subject: [PATCH 17/17] mm: Account for the number of times direct reclaimers get throttled Date: Thu, 17 May 2012 15:50:31 +0100 Message-Id: <1337266231-8031-18-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 1.7.9.2 In-Reply-To: <1337266231-8031-1-git-send-email-mgorman@suse.de> References: <1337266231-8031-1-git-send-email-mgorman@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2088 Lines: 60 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 97c766f..141ab5c 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2486,6 +2486,9 @@ 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 7db1b9b..7861cbe 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -742,6 +742,7 @@ 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", -- 1.7.9.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/