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From: Mel Gorman <mgorman@suse.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Linux-MM <linux-mm@kvack.org>,
	Linux-Netdev <netdev@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	David Miller <davem@davemloft.net>, Neil Brown <neilb@suse.de>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Mel Gorman <mgorman@suse.de>
Subject: [PATCH 15/15] mm: Account for the number of times direct reclaimers get throttled
Date: Mon,  6 Feb 2012 22:56:18 +0000	[thread overview]
Message-ID: <1328568978-17553-16-git-send-email-mgorman@suse.de> (raw)
In-Reply-To: <1328568978-17553-1-git-send-email-mgorman@suse.de>

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 <mgorman@suse.de>
---
 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 87ae4314..7a43551 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2464,6 +2464,7 @@ 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));
 }
diff --git a/mm/vmstat.c b/mm/vmstat.c
index f600557..0fff13d 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -741,6 +741,7 @@ 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


  parent reply	other threads:[~2012-02-06 22:56 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-06 22:56 [PATCH 00/15] Swap-over-NBD without deadlocking V8 Mel Gorman
2012-02-06 22:56 ` [PATCH 01/15] mm: Serialize access to min_free_kbytes Mel Gorman
2012-02-08 18:47   ` Rik van Riel
2012-02-06 22:56 ` [PATCH 02/15] mm: sl[au]b: Add knowledge of PFMEMALLOC reserve pages Mel Gorman
2012-02-07 16:27   ` Christoph Lameter
2012-02-08 14:45     ` Mel Gorman
2012-02-08 15:14       ` Christoph Lameter
2012-02-08 16:34         ` Mel Gorman
2012-02-08 19:49           ` Christoph Lameter
2012-02-08 21:23             ` Mel Gorman
2012-02-08 22:13               ` Christoph Lameter
2012-02-09 12:50                 ` Mel Gorman
2012-02-09 19:53                   ` Christoph Lameter
2012-02-10 10:26                     ` Mel Gorman
2012-02-10 21:01                       ` Christoph Lameter
2012-02-10 22:07                         ` Christoph Lameter
2012-02-13 10:12                           ` Mel Gorman
2012-02-13 11:10                         ` Mel Gorman
2012-02-06 22:56 ` [PATCH 03/15] mm: Introduce __GFP_MEMALLOC to allow access to emergency reserves Mel Gorman
2012-02-06 22:56 ` [PATCH 04/15] mm: allow PF_MEMALLOC from softirq context Mel Gorman
2012-02-06 22:56 ` [PATCH 05/15] mm: Ignore mempolicies when using ALLOC_NO_WATERMARK Mel Gorman
2012-02-06 22:56 ` [PATCH 06/15] net: Introduce sk_allocation() to allow addition of GFP flags depending on the individual socket Mel Gorman
2012-02-06 22:56 ` [PATCH 07/15] netvm: Allow the use of __GFP_MEMALLOC by specific sockets Mel Gorman
2012-02-06 22:56 ` [PATCH 08/15] netvm: Allow skb allocation to use PFMEMALLOC reserves Mel Gorman
2012-02-06 22:56 ` [PATCH 09/15] netvm: Propagate page->pfmemalloc to skb Mel Gorman
2012-02-06 22:56 ` [PATCH 10/15] netvm: Propagate page->pfmemalloc from netdev_alloc_page " Mel Gorman
2012-02-07 23:38   ` Alexander Duyck
2012-02-08 15:23     ` Mel Gorman
2012-02-06 22:56 ` [PATCH 11/15] netvm: Set PF_MEMALLOC as appropriate during SKB processing Mel Gorman
2012-02-06 22:56 ` [PATCH 12/15] mm: Micro-optimise slab to avoid a function call Mel Gorman
2012-02-06 22:56 ` [PATCH 13/15] nbd: Set SOCK_MEMALLOC for access to PFMEMALLOC reserves Mel Gorman
2012-02-06 22:56 ` [PATCH 14/15] mm: Throttle direct reclaimers if PF_MEMALLOC reserves are low and swap is backed by network storage Mel Gorman
2012-02-06 22:56 ` Mel Gorman [this message]
2012-02-07 12:45 ` [PATCH 00/15] Swap-over-NBD without deadlocking V8 Hillf Danton
2012-02-07 13:27   ` Mel Gorman
2012-02-08 12:51     ` Hillf Danton
2012-02-08 15:26       ` Mel Gorman

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