From: NeilBrown <neilb@suse.de>
To: Mel Gorman <mgorman@suse.de>
Cc: Linux-MM <linux-mm@kvack.org>,
Linux-Netdev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH 12/12] mm: Throttle direct reclaimers if PF_MEMALLOC reserves are low and swap is backed by network storage
Date: Mon, 18 Apr 2011 22:32:51 +1000 [thread overview]
Message-ID: <20110418223251.7ab148bb@notabene.brown> (raw)
In-Reply-To: <1302777698-28237-13-git-send-email-mgorman@suse.de>
On Thu, 14 Apr 2011 11:41:38 +0100 Mel Gorman <mgorman@suse.de> wrote:
> If swap is backed by network storage such as NBD, there is a risk that a
> large number of reclaimers can hang the system by consuming all
> PF_MEMALLOC reserves. To avoid these hangs, the administrator must tune
> min_free_kbytes in advance. This patch will throttle direct reclaimers
> if half the PF_MEMALLOC reserves are in use as the system is at risk of
> hanging. A message will be displayed so the administrator knows that
> min_free_kbytes should be tuned to a higher value to avoid the
> throttling in the future.
>
(I knew there was something else).
I understand that there are suggestions that direct reclaim should always be
serialised as this reduces lock contention and improve data patterns (or
something like that).
Would that make this patch redundant? Or does this provide some extra
guarantee that the other proposal would not?
Thanks again,
NeilBrown
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2011-04-18 12:33 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-14 10:41 [PATCH 00/12] Swap-over-NBD without deadlocking v1 Mel Gorman
2011-04-14 10:41 ` [PATCH 01/12] mm: Serialize access to min_free_kbytes Mel Gorman
2011-04-14 10:41 ` [PATCH 02/12] mm: sl[au]b: Add knowledge of PFMEMALLOC reserve pages Mel Gorman
2011-04-14 10:41 ` [PATCH 03/12] mm: Introduce __GFP_MEMALLOC to allow access to emergency reserves Mel Gorman
2011-04-14 10:41 ` [PATCH 04/12] mm: allow PF_MEMALLOC from softirq context Mel Gorman
2011-04-14 10:41 ` [PATCH 05/12] mm: Ignore mempolicies when using ALLOC_NO_WATERMARK Mel Gorman
2011-04-14 10:41 ` [PATCH 06/12] net: Introduce sk_allocation() to allow addition of GFP flags depending on the individual socket Mel Gorman
2011-04-14 10:41 ` [PATCH 07/12] netvm: Allow the use of __GFP_MEMALLOC by specific sockets Mel Gorman
2011-04-14 10:41 ` [PATCH 08/12] netvm: Allow skb allocation to use PFMEMALLOC reserves Mel Gorman
2011-04-14 21:33 ` David Miller
2011-04-15 10:44 ` Mel Gorman
2011-04-14 10:41 ` [PATCH 09/12] netvm: Set PF_MEMALLOC as appropriate during SKB processing Mel Gorman
2011-04-14 10:41 ` [PATCH 10/12] mm: Micro-optimise slab to avoid a function call Mel Gorman
2011-04-14 10:41 ` [PATCH 11/12] nbd: Set SOCK_MEMALLOC for access to PFMEMALLOC reserves Mel Gorman
2011-04-14 10:41 ` [PATCH 12/12] mm: Throttle direct reclaimers if PF_MEMALLOC reserves are low and swap is backed by network storage Mel Gorman
2011-04-18 12:30 ` NeilBrown
2011-04-18 14:04 ` Mel Gorman
2011-04-18 12:32 ` NeilBrown [this message]
2011-04-18 14:08 ` Mel Gorman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20110418223251.7ab148bb@notabene.brown \
--to=neilb@suse.de \
--cc=a.p.zijlstra@chello.nl \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@suse.de \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).