From: Andrew Morton <akpm@osdl.org>
To: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, piggin@cyberone.com.au
Subject: Re: blk_congestion_wait racy?
Date: Thu, 11 Mar 2004 15:25:52 -0800 [thread overview]
Message-ID: <20040311152552.20a9bb06.akpm@osdl.org> (raw)
In-Reply-To: <OFF79FE9F7.73A1504E-ONC1256E54.006825BF-C1256E54.0068C4F9@de.ibm.com>
Martin Schwidefsky <schwidefsky@de.ibm.com> wrote:
>
> > An ouch-per-second sounds reasonable. It could simply be that the CPUs
> > were off running other tasks - those timeout are less than scheduling
> > quanta.
>
> I don't understand why an ouch-per-second is reasonable. The mempig is
> the only process that runs on the machine and the blk_congestion_wait
> uses HZ/10 as timeout value. I'd expect about 100 ouches for the 10
> seconds the test runs.
blk_congestion_wait() is supposed to be terminated by someone releasing a
disk write request. If no write requests are freed in 100 milliseconds
then either Something Is Up or that process simply was not scheduled for
some time after the wakeup was delivered.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"aart@kvack.org"> aart@kvack.org </a>
next prev parent reply other threads:[~2004-03-11 23:25 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-11 19:04 Martin Schwidefsky
2004-03-11 23:25 ` Andrew Morton [this message]
2004-03-12 2:31 ` Nick Piggin
-- strict thread matches above, loose matches on Subject: below --
2004-03-11 18:24 Martin Schwidefsky
2004-03-11 18:55 ` Andrew Morton
2004-03-09 17:54 Martin Schwidefsky
2004-03-10 5:23 ` Nick Piggin
2004-03-10 5:35 ` Andrew Morton
2004-03-10 5:47 ` Nick Piggin
2004-03-08 13:38 Martin Schwidefsky
2004-03-08 23:50 ` Nick Piggin
2004-03-08 9:59 Martin Schwidefsky
2004-03-08 12:24 ` Andrew Morton
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20040311152552.20a9bb06.akpm@osdl.org \
--to=akpm@osdl.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=piggin@cyberone.com.au \
--cc=schwidefsky@de.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox