From: "Artem S. Tashkinov" <t.artem@lycos.com>
To: jack@suse.cz
Cc: tytso@mit.edu, fengguang.wu@intel.com,
torvalds@linux-foundation.org, akpm@linux-foundation.org,
linux-kernel@vger.kernel.org, diegocg@gmail.com, david@lang.hm,
neilb@suse.de
Subject: Re: Disabling in-memory write cache for x86-64 in Linux II
Date: Wed, 30 Oct 2013 10:07:08 +0000 (UTC) [thread overview]
Message-ID: <1532891663.73423.1383127628582.JavaMail.mail@webmail14> (raw)
In-Reply-To: 20131029204052.GF9568@quack.suse.cz
Oct 30, 2013 02:41:01 AM, Jack wrote:
On Fri 25-10-13 19:37:53, Ted Tso wrote:
>> Sure, although I wonder if it would be worth it calcuate some kind of
>> rolling average of the write bandwidth while we are doing writeback,
>> so if it turns out we got unlucky with the contents of the first 100MB
>> of dirty data (it could be either highly random or highly sequential)
>> the we'll eventually correct to the right level.
> We already do average measured throughput over a longer time window and
>have kind of rolling average algorithm doing some averaging.
>
>> This means that VM would have to keep dirty page counters for each BDI
>> --- which I thought we weren't doing right now, which is why we have a
>> global vm.dirty_ratio/vm.dirty_background_ratio threshold. (Or do I
>> have cause and effect reversed? :-)
> And we do currently keep the number of dirty & under writeback pages per
>BDI. We have global limits because mm wants to limit the total number of dirty
>pages (as those are harder to free). It doesn't care as much to which device
>these pages belong (although it probably should care a bit more because
>there are huge differences between how quickly can different devices get rid
>of dirty pages).
This might sound like an absolutely stupid question which makes no sense at
all, so I want to apologize for it in advance, but since the Linux kernel lacks
revoke(), does that mean that dirty buffers will always occupy the kernel memory
if I for instance remove my USB stick before the kernel has had the time to flush
these buffers?
next prev parent reply other threads:[~2013-10-30 10:07 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 ` 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 [this message]
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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