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>,
Mike Christie <michaelc@cs.wisc.edu>,
Eric B Munson <emunson@mgebm.net>, Mel Gorman <mgorman@suse.de>
Subject: [PATCH 16/17] mm: Account for the number of times direct reclaimers get throttled
Date: Wed, 20 Jun 2012 10:35:19 +0100 [thread overview]
Message-ID: <1340184920-22288-17-git-send-email-mgorman@suse.de> (raw)
In-Reply-To: <1340184920-22288-1-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 | 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",
--
1.7.9.2
--
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next prev parent reply other threads:[~2012-06-20 9:35 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-20 9:35 [PATCH 00/17] Swap-over-NBD without deadlocking V12 Mel Gorman
2012-06-20 9:35 ` [PATCH 01/17] mm: sl[au]b: Add knowledge of PFMEMALLOC reserve pages Mel Gorman
2012-06-20 11:05 ` Sebastian Andrzej Siewior
2012-06-20 11:44 ` Mel Gorman
2012-06-20 9:35 ` [PATCH 02/17] mm: slub: Optimise the SLUB fast path to avoid pfmemalloc checks Mel Gorman
2012-06-20 9:35 ` [PATCH 03/17] mm: Introduce __GFP_MEMALLOC to allow access to emergency reserves Mel Gorman
2012-06-20 9:35 ` [PATCH 04/17] mm: allow PF_MEMALLOC from softirq context Mel Gorman
2012-06-20 9:35 ` [PATCH 05/17] mm: Only set page->pfmemalloc when ALLOC_NO_WATERMARKS was used Mel Gorman
2012-06-20 9:35 ` [PATCH 06/17] mm: Ignore mempolicies when using ALLOC_NO_WATERMARK Mel Gorman
2012-06-20 9:35 ` [PATCH 07/17] net: Introduce sk_gfp_atomic() to allow addition of GFP flags depending on the individual socket Mel Gorman
2012-06-20 9:35 ` [PATCH 08/17] netvm: Allow the use of __GFP_MEMALLOC by specific sockets Mel Gorman
2012-06-20 9:35 ` [PATCH 09/17] netvm: Allow skb allocation to use PFMEMALLOC reserves Mel Gorman
2012-06-20 9:35 ` [PATCH 10/17] netvm: Propagate page->pfmemalloc to skb Mel Gorman
2012-06-20 9:35 ` [PATCH 11/17] netvm: Propagate page->pfmemalloc from skb_alloc_page " Mel Gorman
2012-06-20 9:35 ` [PATCH 12/17] netvm: Set PF_MEMALLOC as appropriate during SKB processing Mel Gorman
2012-06-20 9:35 ` [PATCH 13/17] mm: Micro-optimise slab to avoid a function call Mel Gorman
2012-06-20 9:35 ` [PATCH 14/17] nbd: Set SOCK_MEMALLOC for access to PFMEMALLOC reserves Mel Gorman
2012-06-20 9:35 ` [PATCH 15/17] mm: Throttle direct reclaimers if PF_MEMALLOC reserves are low and swap is backed by network storage Mel Gorman
2012-06-20 9:35 ` Mel Gorman [this message]
2012-06-20 9:35 ` [PATCH 17/17] netvm: Prevent a stream-specific deadlock Mel Gorman
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