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From: Trond Myklebust <trond.myklebust@fys.uio.no>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrew Morton <akpm@osdl.org>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] nfs: fix congestion control
Date: Wed, 17 Jan 2007 08:50:14 -0500	[thread overview]
Message-ID: <1169041814.6102.3.camel@lade.trondhjem.org> (raw)
In-Reply-To: <1169023798.22935.96.camel@twins>

On Wed, 2007-01-17 at 09:49 +0100, Peter Zijlstra wrote: 
> > They are certainly _not_ dirty pages. They are pages that have been
> > written to the server but are not yet guaranteed to have hit the disk
> > (they were only written to the server's page cache). We don't care if
> > they are paged in or swapped out on the local client.
> > 
> > \All the COMMIT does, is to ask the server to write the data from its
> > page cache onto disk. Once that has been done, we can release the pages.
> > If the commit fails, then we iterate through the whole writepage()
> > process again. The commit itself does, however, not even look at the
> > page data.
> 
> Thou art correct from an NFS point of view, however for the VM they are
> (still) just dirty pages and we need shed them.
> 
> You talk of swapping them out, they are filecache pages not swapcache
> pages. The writepage() process needs to complete and that entails
> committing them.

My point is that we can and should collect as many of the little buggers
as we can and treat them with ONE commit call. We don't look at the
data, we don't lock the pages, we don't care what the VM is doing with
them. Throttling is not only unnecessary, it is actually a bad idea
since it slows up the rate at which we can free up the pages.

Trond


  reply	other threads:[~2007-01-17 13:50 UTC|newest]

Thread overview: 110+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-16  5:47 [RFC 0/8] Cpuset aware writeback Christoph Lameter
2007-01-16  5:47 ` [RFC 1/8] Convert higest_possible_node_id() into nr_node_ids Christoph Lameter
2007-01-16 22:05   ` Andi Kleen
2007-01-17  3:14     ` Christoph Lameter
2007-01-17  4:15       ` Andi Kleen
2007-01-17  4:23         ` Christoph Lameter
2007-01-16  5:47 ` [RFC 2/8] Add a map to inodes to track dirty pages per node Christoph Lameter
2007-01-16  5:47 ` [RFC 3/8] Add a nodemask to pdflush functions Christoph Lameter
2007-01-16  5:48 ` [RFC 4/8] Per cpuset dirty ratio handling and writeout Christoph Lameter
2007-01-16  5:48 ` [RFC 5/8] Make writeout during reclaim cpuset aware Christoph Lameter
2007-01-16 22:07   ` Andi Kleen
2007-01-17  4:20     ` Paul Jackson
2007-01-17  4:28       ` Andi Kleen
2007-01-17  4:36         ` Paul Jackson
2007-01-17  5:59           ` Andi Kleen
2007-01-17  6:19             ` Christoph Lameter
2007-01-17  4:23     ` Christoph Lameter
2007-01-16  5:48 ` [RFC 6/8] Throttle vm writeout per cpuset Christoph Lameter
2007-01-16  5:48 ` [RFC 7/8] Exclude unreclaimable pages from dirty ration calculation Christoph Lameter
2007-01-18 15:48   ` Nikita Danilov
2007-01-18 19:56     ` Christoph Lameter
2007-01-16  5:48 ` [RFC 8/8] Reduce inode memory usage for systems with a high MAX_NUMNODES Christoph Lameter
2007-01-16 19:52   ` Paul Menage
2007-01-16 20:00     ` Christoph Lameter
2007-01-16 20:06       ` Paul Menage
2007-01-16 20:51         ` Christoph Lameter
2007-01-16  7:38 ` [RFC 0/8] Cpuset aware writeback Peter Zijlstra
2007-01-16 20:10   ` Christoph Lameter
2007-01-16  9:25 ` Paul Jackson
2007-01-16 17:13   ` Christoph Lameter
2007-01-16 21:53 ` Andrew Morton
2007-01-16 22:08   ` [PATCH] nfs: fix congestion control Peter Zijlstra
2007-01-16 22:27     ` Trond Myklebust
2007-01-17  2:41       ` Peter Zijlstra
2007-01-17  6:15         ` Trond Myklebust
2007-01-17  8:49           ` Peter Zijlstra
2007-01-17 13:50             ` Trond Myklebust [this message]
2007-01-17 14:29               ` Peter Zijlstra
2007-01-17 14:45                 ` Trond Myklebust
2007-01-17 20:05     ` Christoph Lameter
2007-01-17 21:52       ` Peter Zijlstra
2007-01-17 21:54         ` Trond Myklebust
2007-01-18 13:27           ` Peter Zijlstra
2007-01-18 15:49             ` Trond Myklebust
2007-01-19  9:33               ` Peter Zijlstra
2007-01-19 13:07                 ` Peter Zijlstra
2007-01-19 16:51                   ` Trond Myklebust
2007-01-19 17:54                     ` Peter Zijlstra
2007-01-19 17:20                   ` Christoph Lameter
2007-01-19 17:57                     ` Peter Zijlstra
2007-01-19 18:02                       ` Christoph Lameter
2007-01-19 18:26                       ` Trond Myklebust
2007-01-19 18:27                         ` Christoph Lameter
2007-01-20  7:01                         ` [PATCH] nfs: fix congestion control -v3 Peter Zijlstra
2007-01-22 16:12                           ` Trond Myklebust
2007-01-25 15:32                             ` [PATCH] nfs: fix congestion control -v4 Peter Zijlstra
2007-01-26  5:02                               ` Andrew Morton
2007-01-26  8:00                                 ` Peter Zijlstra
2007-01-26  8:50                                   ` Peter Zijlstra
2007-01-26  5:09                               ` Andrew Morton
2007-01-26  5:31                                 ` Christoph Lameter
2007-01-26  6:04                                   ` Andrew Morton
2007-01-26  6:53                                     ` Christoph Lameter
2007-01-26  8:03                                     ` Peter Zijlstra
2007-01-26  8:51                                       ` Andrew Morton
2007-01-26  9:01                                         ` Peter Zijlstra
2007-02-20 12:59                                         ` Peter Zijlstra
2007-01-22 17:59                           ` [PATCH] nfs: fix congestion control -v3 Christoph Lameter
2007-01-17 23:15     ` [PATCH] nfs: fix congestion control Christoph Hellwig
2007-01-16 22:15   ` [RFC 0/8] Cpuset aware writeback Christoph Lameter
2007-01-16 23:40     ` Andrew Morton
2007-01-17  0:16       ` Christoph Lameter
2007-01-17  1:07         ` Andrew Morton
2007-01-17  1:30           ` Christoph Lameter
2007-01-17  2:34             ` Andrew Morton
2007-01-17  3:40               ` Christoph Lameter
2007-01-17  4:02                 ` Paul Jackson
2007-01-17  4:05                 ` Andrew Morton
2007-01-17  6:27                   ` Christoph Lameter
2007-01-17  7:00                     ` Andrew Morton
2007-01-17  8:01                       ` Paul Jackson
2007-01-17  9:57                         ` Andrew Morton
2007-01-17 19:43                       ` Christoph Lameter
2007-01-17 22:10                         ` Andrew Morton
2007-01-18  1:10                           ` Christoph Lameter
2007-01-18  1:25                             ` Andrew Morton
2007-01-18  5:21                               ` Christoph Lameter
2007-01-16 23:44   ` David Chinner
2007-01-16 22:01 ` Andi Kleen
2007-01-16 22:18   ` Christoph Lameter
2007-02-02  1:38 ` Ethan Solomita
2007-02-02  2:16   ` Christoph Lameter
2007-02-02  4:03     ` Andrew Morton
2007-02-02  5:29       ` Christoph Lameter
2007-02-02  6:02         ` Neil Brown
2007-02-02  6:17           ` Christoph Lameter
2007-02-02  6:41             ` Neil Brown
2007-02-02  7:12         ` Andrew Morton
2007-03-21 21:11     ` Ethan Solomita
2007-03-21 21:29       ` Christoph Lameter
2007-03-21 21:52         ` Andrew Morton
2007-03-21 21:57           ` Christoph Lameter
2007-04-19  2:07         ` Ethan Solomita
2007-04-19  2:55           ` Christoph Lameter
2007-04-19  7:52             ` Ethan Solomita
2007-04-19 16:03               ` Christoph Lameter
2007-04-21  1:37             ` Ethan Solomita
2007-04-21  1:48               ` Christoph Lameter
2007-04-21  8:15                 ` Ethan Solomita
2007-04-21 15:40                   ` Christoph Lameter

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