From: torvalds@transmeta.com (Linus Torvalds)
To: linux-kernel@vger.kernel.org
Subject: Re: DVD blockdevice buffers
Date: 19 May 2001 19:36:07 -0700 [thread overview]
Message-ID: <9e7ain$lis$1@penguin.transmeta.com> (raw)
In-Reply-To: <20010518210226.A7147@moserv.hasi> <20010518212531.A6763@suse.de>
In article <20010518212531.A6763@suse.de>, Jens Axboe <axboe@suse.de> wrote:
>>
>> As a result the system performance goes down. I'm still able to use
>> my applications, but es every single piece of unused memory is swapped
>> out, and swapping in costs a certain amount of time.
>
>That's why streaming media applications like a dvd player should use raw
>I/O -- to bypass system cache. See /dev/raw*
I disagree..
The fact is that the block device fs infrastructure is just sadly
broken. By using the buffer cache, it makes memory management very hard,
and just upgrading to the page cache would (a) speed stuff up and (b)
make it much easier for the kernel to do the right thing wrt the MM use.
Right now we don't try to aggressively drop streaming pages, but it's
possible. Using raw devices is a silly work-around that should not be
needed, and this load shows a real problem in current Linux (one soon to
be fixed, I think - Andrea already has some experimental patches for the
page-cache thing).
Linus
next prev parent reply other threads:[~2001-05-20 2:36 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-05-18 19:02 DVD blockdevice buffers Eduard Hasenleithner
2001-05-18 19:25 ` Jens Axboe
2001-05-18 19:59 ` Eduard Hasenleithner
2001-05-20 2:36 ` Linus Torvalds [this message]
2001-05-23 17:34 ` Stephen C. Tweedie
2001-05-23 18:12 ` Linus Torvalds
2001-05-23 19:57 ` Stephen C. Tweedie
2001-05-23 20:01 ` Linus Torvalds
2001-05-23 20:40 ` Jeff Garzik
2001-05-23 22:32 ` Andrea Arcangeli
2001-05-25 20:12 ` blkdev-pagecache-2 [was Re: DVD blockdevice buffers] Andrea Arcangeli
2001-05-25 20:15 ` Andrea Arcangeli
2001-05-23 22:09 ` DVD blockdevice buffers Andrea Arcangeli
2001-05-23 22:13 ` Alexander Viro
2001-05-23 22:24 ` Andrea Arcangeli
2001-05-24 11:36 ` Stephen C. Tweedie
2001-05-25 15:09 ` Eric W. Biederman
2001-05-25 15:45 ` Stephen C. Tweedie
2001-05-25 17:16 ` Linus Torvalds
2001-05-25 17:40 ` Alexander Viro
2001-05-25 18:05 ` Linus Torvalds
2001-05-25 18:24 ` Alexander Viro
2001-05-25 19:02 ` Stephen C. Tweedie
2001-05-27 6:38 ` Pavel Machek
2001-05-25 21:07 ` Eric W. Biederman
2001-05-25 21:18 ` Linus Torvalds
2001-05-25 22:31 ` Eric W. Biederman
-- strict thread matches above, loose matches on Subject: below --
2001-05-19 18:16 Adam Schrotenboer
2001-05-19 22:56 ` Jens Axboe
2001-05-20 1:55 ` Adam Schrotenboer
2001-05-21 15:44 ` Adam Schrotenboer
2001-05-21 15:47 ` Jens Axboe
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