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From: Andrew Morton <akpm@osdl.org>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Christoph Lameter <clameter@sgi.com>,
	aubreylee@gmail.com, svaidy@linux.vnet.ibm.com,
	nickpiggin@yahoo.com.au, rgetz@blackfin.uclinux.org,
	Michael.Hennerich@analog.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC] Limit the size of the pagecache
Date: Fri, 26 Jan 2007 02:29:55 -0800	[thread overview]
Message-ID: <20070126022955.f9b6b11f.akpm@osdl.org> (raw)
In-Reply-To: <20070124141510.7775829c.kamezawa.hiroyu@jp.fujitsu.com>

On Wed, 24 Jan 2007 14:15:10 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:

> - One for stability
>   When a customer constructs their detabase(Oracle), the system often goes to oom.
>   This is because that the system cannot allocate DMA_ZOME memory for 32bit device.
>   (USB or e100)
>   Not allowing to use almost all pages as page cache (for temporal use) will be some help.
>   (Note: construction DB on ext3....so all writes are serialized and the system couldn't
>    free page cache.)

I'm surprised that any reasonable driver has a dependency on ZONE_DMA.  Are
you sure?  Send full oom-killer output, please.


> - One for tuing.
>   Sometimes our cutomer requests us to limit size of page-cache.
>   
>   Many cutomers's memory usage reaches 99.x%. (this is very common situation.)
>   If almost all memories are used by page-cache, and we can think we can free it.
>   But the customer cannot estimate what amount of page-cache can be freed (without 
>   perfromance regression).
>   
>   When a cutomer wants to add a new application, he tunes the system.
>   But memory usage is always 99%.
>   page-cache limitation is useful when the customer tunes his system and find
>   sets of data and page-cache. 
>   (Of course, we can use some other complicated resource management system for this.)
>   This will allow the users to decide that they need extra memory or not.
> 
>   And...some customers want to keep memory Free as much as possible.
>   99% memory usage makes insecure them ;)

Tell them to do "echo 3 > /proc/sys/vm/drop_caches", then wait three minutes?

  parent reply	other threads:[~2007-01-26 10:36 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-24  0:49 Christoph Lameter
2007-01-24  2:53 ` KAMEZAWA Hiroyuki
2007-01-24  3:01   ` Christoph Lameter
2007-01-24  5:47   ` Aubrey Li
2007-01-24  3:00 ` Nick Piggin
2007-01-24  3:14   ` Christoph Lameter
2007-01-24  3:51     ` Aubrey Li
2007-01-24  4:03       ` Nick Piggin
2007-01-26 10:27         ` Andrew Morton
2007-01-24  3:13 ` KAMEZAWA Hiroyuki
2007-01-24  4:30   ` Christoph Lameter
2007-01-24  5:15     ` KAMEZAWA Hiroyuki
2007-01-25  0:32       ` KAMEZAWA Hiroyuki
2007-01-25  2:41         ` Christoph Lameter
2007-01-25  3:12           ` KAMEZAWA Hiroyuki
2007-01-25  4:28             ` Rik van Riel
2007-01-25  5:19               ` KAMEZAWA Hiroyuki
2007-01-25  5:40                 ` Rik van Riel
2007-01-25  6:00                   ` KAMEZAWA Hiroyuki
2007-01-26 10:29       ` Andrew Morton [this message]
2007-01-26 18:01         ` KAMEZAWA Hiroyuki
2007-01-24  7:04 ` Vaidyanathan Srinivasan
2007-01-24  7:55 ` Peter Zijlstra
2007-01-24 12:50   ` Nick Piggin
2007-01-24 12:58     ` Peter Zijlstra
2007-01-24 14:58     ` Christoph Lameter
2007-01-24 20:06       ` Erik Andersen
2007-01-25  2:40         ` Christoph Lameter
2007-01-25  8:07           ` Vaidyanathan Srinivasan
2007-01-24 14:22   ` Aubrey Li
2007-01-24 14:56     ` Peter Zijlstra
2007-01-25  2:27       ` Aubrey Li
2007-01-24 12:33 ` Vaidyanathan Srinivasan
2007-01-24 14:56   ` Christoph Lameter
2007-01-25  4:17     ` Vaidyanathan Srinivasan
2007-01-25  4:45       ` Rik van Riel
2007-01-25  5:49         ` Vaidyanathan Srinivasan
2007-01-25 16:07           ` Rik van Riel
2007-01-25 17:57             ` Balbir Singh
2007-01-25  6:35       ` Aubrey Li
2007-01-25  6:47         ` Christoph Lameter
2007-01-25  7:49         ` Vaidyanathan Srinivasan
2007-01-25  4:18 ` Rik van Riel
2007-01-25  6:42 Al Boldi
2007-01-25  8:24 ` Vaidyanathan Srinivasan
2007-01-25 10:29   ` Peter Zijlstra
2007-01-25 11:23     ` Vaidyanathan Srinivasan
2007-01-25 11:57     ` Al Boldi
2007-01-25 11:57   ` Al Boldi
2007-01-25 18:37     ` Vaidyanathan Srinivasan
     [not found] <7GEEK-4lH-39@gated-at.bofh.it>
     [not found] ` <7GLdb-5Uz-13@gated-at.bofh.it>
     [not found]   ` <7GRix-7fU-1@gated-at.bofh.it>
     [not found]     ` <7GRLZ-7Uy-29@gated-at.bofh.it>
2007-01-25 14:51       ` Bodo Eggert

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