From: "Theodore Ts'o" <tytso@mit.edu>
To: "Artem S. Tashkinov" <t.artem@lycos.com>
Cc: torvalds@linux-foundation.org, fengguang.wu@intel.com,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: Disabling in-memory write cache for x86-64 in Linux II
Date: Fri, 25 Oct 2013 05:18:42 -0400 [thread overview]
Message-ID: <20131025091842.GA28681@thunk.org> (raw)
In-Reply-To: <1814253454.3449.1382689853825.JavaMail.mail@webmail07>
On Fri, Oct 25, 2013 at 08:30:53AM +0000, Artem S. Tashkinov 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.
What I think would make sense is to dynamically measure the speed of
writeback, so that we can set these limits as a function of the device
speed. It's already the case that the writeback limits don't make
sense on a slow USB 2.0 storage stick; I suspect that for really huge
RAID arrays or very fast flash devices, it doesn't make much sense
either.
The problem is that if you have a system that has *both* a USB stick
_and_ a fast flash/RAID storage array both needing writeback, this
doesn't work well --- but what we have right now doesn't work all that
well anyway.
- Ted
next prev parent reply other threads:[~2013-10-25 9:18 UTC|newest]
Thread overview: 83+ 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 7:25 ` Artem S. Tashkinov
2013-10-25 8:18 ` Linus Torvalds
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
2013-11-01 14:31 ` Maxim Patlasov
2013-11-04 22:01 ` Andrew Morton
2013-11-04 22:01 ` Andrew Morton
2013-11-06 14:30 ` Maxim Patlasov
2013-11-06 14:30 ` Maxim Patlasov
2013-11-06 15:05 ` [PATCH] mm: add strictlimit knob -v2 Maxim Patlasov
2013-11-06 15:05 ` Maxim Patlasov
2013-11-07 12:26 ` Henrique de Moraes Holschuh
2013-11-07 12:26 ` Henrique de Moraes Holschuh
2013-11-22 23:45 ` Andrew Morton
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 [this message]
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 0:50 ` Andreas Dilger
2013-11-05 4:12 ` Dave Chinner
2013-11-05 4:12 ` Dave Chinner
2013-11-05 4:12 ` Dave Chinner
2013-11-07 13:48 ` Jan Kara
2013-11-07 13:48 ` Jan Kara
2013-11-07 13:48 ` Jan Kara
2013-11-11 3:22 ` Dave Chinner
2013-11-11 3:22 ` Dave Chinner
2013-11-11 3:22 ` Dave Chinner
2013-11-11 19:31 ` Jan Kara
2013-11-11 19:31 ` Jan Kara
2013-11-05 6:32 ` Figo.zhang
2013-10-25 10:49 ` NeilBrown
2013-10-25 11:26 ` David Lang
2013-10-25 11:26 ` David Lang
2013-10-25 18:26 ` Artem S. Tashkinov
2013-10-25 18:26 ` Artem S. Tashkinov
2013-10-25 19:40 ` Diego Calleja
2013-10-25 19:40 ` Diego Calleja
2013-10-25 23:32 ` Fengguang Wu
2013-10-25 23:32 ` Fengguang Wu
2013-10-25 23:32 ` Fengguang Wu
2013-11-15 15:48 ` Diego Calleja
2013-11-15 15:48 ` Diego Calleja
2013-10-25 20:43 ` NeilBrown
2013-10-25 21:03 ` Artem S. Tashkinov
2013-10-25 21:03 ` Artem S. Tashkinov
2013-10-25 22:11 ` NeilBrown
2013-11-05 1:40 ` Figo.zhang
2013-11-05 1:47 ` David Lang
2013-11-05 1:47 ` David Lang
2013-11-05 2:08 ` NeilBrown
2013-10-29 20:49 ` Jan Kara
2013-10-29 20:49 ` Jan Kara
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