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From: Karl Kiniger <karl.kiniger@med.ge.com>
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 11:15:55 +0200	[thread overview]
Message-ID: <20131025091555.GA30895@kipc2.localdomain> (raw)
In-Reply-To: <CA+55aFxhJUrqdvw1To=9KLdxhYAOVwZLLeJT5yMRY5BT1weuHA@mail.gmail.com>

On Fri 131025, 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.
> 
> The modern way of expressing the dirty limits are to give the actual
> absolute byte amounts, but we default to the legacy ratio mode..
> 
>                 Linus

Is it currently possible to somehow set above values per block device?

I want default behaviour for almost everything but  DVD drives in DVD+RW
packet writing mode may easily take several minutes in case of a sync.

Karl



  reply	other threads:[~2013-10-25  9:15 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 [this message]
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       ` Disabling in-memory write cache for x86-64 in Linux II David Lang
2013-10-25  9:18     ` 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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