From: David Lang <david@lang.hm>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Artem S. Tashkinov" <t.artem@lycos.com>,
Wu Fengguang <fengguang.wu@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Disabling in-memory write cache for x86-64 in Linux II
Date: Fri, 25 Oct 2013 04:28:27 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.02.1310250426510.22538@nftneq.ynat.uz> (raw)
In-Reply-To: <CA+55aFxhJUrqdvw1To=9KLdxhYAOVwZLLeJT5yMRY5BT1weuHA@mail.gmail.com>
On Fri, 25 Oct 2013, Linus Torvalds wrote:
> On Fri, Oct 25, 2013 at 9:30 AM, Artem S. Tashkinov <t.artem@lycos.com> wrote:
>>
>> My feeling is that vm.dirty_ratio/vm.dirty_background_ratio should _not_ be
>> percentage based, 'cause for PCs/servers with a lot of memory (say 64GB or
>> more) this value becomes unrealistic (13GB) and I've already had some
>> unpleasant effects due to it.
>
> Right. The percentage notion really goes back to the days when we
> typically had 8-64 *megabytes* of memory So if you had a 8MB machine
> you wouldn't want to have more than one megabyte of dirty data, but if
> you were "Mr Moneybags" and could afford 64MB, you might want to have
> up to 8MB dirty!!
>
> Things have changed.
>
> So I would suggest we change the defaults. Or pwehaps make the rule be
> that "the ratio numbers are 'ratio of memory up to 1GB'", to make the
> semantics similar across 32-bit HIGHMEM machines and 64-bit machines.
If you go this direction, allow ratios larger than 100%, some people may be
willing to have huge amounts of dirty data on large memory machines (if the load
is extremely bursty, they don't have other needs for I/O, or they have a very
fast storage system, as a few examples)
David Lang
next prev parent reply other threads:[~2013-10-25 11:28 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-25 7:25 Disabling in-memory write cache for x86-64 in Linux II Artem S. Tashkinov
2013-10-25 8:18 ` Linus Torvalds
2013-10-25 8:30 ` Artem S. Tashkinov
2013-10-25 8:43 ` Linus Torvalds
2013-10-25 9:15 ` Karl Kiniger
2013-10-29 20:30 ` Jan Kara
2013-10-29 20:43 ` Andrew Morton
2013-10-29 21:30 ` Jan Kara
2013-10-29 21:36 ` Linus Torvalds
2013-10-31 14:26 ` Karl Kiniger
2013-11-01 14:25 ` Maxim Patlasov
2013-11-01 14:31 ` [PATCH] mm: add strictlimit knob Maxim Patlasov
2013-11-04 22:01 ` Andrew Morton
2013-11-06 14:30 ` Maxim Patlasov
2013-11-06 15:05 ` [PATCH] mm: add strictlimit knob -v2 Maxim Patlasov
2013-11-07 12:26 ` Henrique de Moraes Holschuh
2013-11-22 23:45 ` Andrew Morton
2013-10-25 11:28 ` David Lang [this message]
2013-10-25 9:18 ` Disabling in-memory write cache for x86-64 in Linux II Theodore Ts'o
2013-10-25 9:29 ` Andrew Morton
2013-10-25 9:32 ` Linus Torvalds
2013-10-26 11:32 ` Pavel Machek
2013-10-26 20:03 ` Linus Torvalds
2013-10-29 20:57 ` Jan Kara
2013-10-29 21:33 ` Linus Torvalds
2013-10-29 22:13 ` Jan Kara
2013-10-29 22:42 ` Linus Torvalds
2013-11-01 17:22 ` Fengguang Wu
2013-11-04 12:19 ` Pavel Machek
2013-11-04 12:26 ` Pavel Machek
2013-10-30 12:01 ` Mel Gorman
2013-11-19 17:17 ` Rob Landley
2013-11-20 20:52 ` One Thousand Gnomes
2013-10-25 22:37 ` Fengguang Wu
2013-10-25 23:05 ` Fengguang Wu
2013-10-25 23:37 ` Theodore Ts'o
2013-10-29 20:40 ` Jan Kara
2013-10-30 10:07 ` Artem S. Tashkinov
2013-10-30 15:12 ` Jan Kara
2013-11-05 0:50 ` Andreas Dilger
2013-11-05 4:12 ` Dave Chinner
2013-11-07 13:48 ` Jan Kara
2013-11-11 3:22 ` Dave Chinner
2013-11-11 19:31 ` Jan Kara
2013-10-25 10:49 ` NeilBrown
2013-10-25 11:26 ` David Lang
2013-10-25 18:26 ` Artem S. Tashkinov
2013-10-25 19:40 ` Diego Calleja
2013-10-25 23:32 ` Fengguang Wu
2013-11-15 15:48 ` Diego Calleja
2013-10-25 20:43 ` NeilBrown
2013-10-25 21:03 ` Artem S. Tashkinov
2013-10-25 22:11 ` NeilBrown
[not found] ` <CAF7GXvpJVLYDS5NfH-NVuN9bOJjAS5c1MQqSTjoiVBHJt6bWcw@mail.gmail.com>
2013-11-05 1:47 ` David Lang
2013-11-05 2:08 ` NeilBrown
2013-10-29 20:49 ` Jan Kara
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