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From: Christoph Lameter <clameter@sgi.com>
To: Nikita Danilov <nikita@clusterfs.com>
Cc: Paul Menage <menage@google.com>,
	linux-kernel@vger.kernel.org,
	Nick Piggin <nickpiggin@yahoo.com.au>,
	linux-mm@kvack.org, Andi Kleen <ak@suse.de>,
	Paul Jackson <pj@sgi.com>, Dave Chinner <dgc@sgi.com>
Subject: Re: [RFC 7/8] Exclude unreclaimable pages from dirty ration calculation
Date: Thu, 18 Jan 2007 11:56:45 -0800 (PST)	[thread overview]
Message-ID: <Pine.LNX.4.64.0701181152020.11639@schroedinger.engr.sgi.com> (raw)
In-Reply-To: <17839.38576.779132.455963@gargle.gargle.HOWL>

On Thu, 18 Jan 2007, Nikita Danilov wrote:

> I think that simpler solution of this problem is to use only potentially
> reclaimable pages (that is, active, inactive, and free pages) to
> calculate writeout threshold. This way there is no need to maintain
> counters for unreclaimable pages. Below is a patch implementing this
> idea, it got some testing.

Hmmm... the problem is that it is expensive to calculate these numbers on 
larger systems. In order to calculate active and inactive pages we 
have to first go through all the zones of the system. In a NUMA system 
there could be many zones.

> +/* Maximal number of pages that can be consumed by pageable caches. */
> +static unsigned long total_pageable_pages(void)
> +{
> +	unsigned long active;
> +	unsigned long inactive;
> +	unsigned long free;
> +
> +	get_zone_counts(&active, &inactive, &free);
> +	/* +1 to never return 0. */
> +	return active + inactive + free + 1;
> +}

An expensive function. And we need to call it whenever we calculate dirty 
limits.

Maybe could create ZVC counters that allow an inexpensive determination of 
these numbers? Then we first need to make sure that the counters are not 
assumed to be accurate at all times.



  reply	other threads:[~2007-01-18 19:57 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 [this message]
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
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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