Re: 2.6.21-mm1: many processes end up in D state

["Jiri Slaby" <jirislaby@gmail.com>]

On 4/30/07, Andrew Morton <akpm@linux-foundation.org> wrote:
> On Mon, 30 Apr 2007 17:39:19 +0200
> Jiri Slaby <jirislaby@gmail.com> wrote:
>
> > Hi,
> >
> > I have a problem with higher disk loads (e.g. running git-log or yum update).
> > Many processes end up in D state and system is unusable -- I'm not able to run
> > anything but smooth mouse moving when this happens.
> >
> > If I wait for a 20-30sec it becomes usable. This happens in 2.6.21-rc7-mm2 and
> > also in 2007-04-28-05-06 broken-out snapshot. I think 2.6.21-rc6-mm1 worked
> > fine, but I'm uncertain. If it is important, let me know to re-test.
> >
>
> It is important, but I doubt if retesting 2.6.21-rc6-mm1 will clarify
> things a lot.
>
> Could you try switching to a different IO scheduler please?  Anticipatory
> would suit.

As I wrote below the sysrq-t, switch to noop didn't help, but it seems
that it's harder to reproduce with that:

<cite it's_bad_to_write_anything_below_logs="true">
Note that yum works on lvm on raid0 and git too, but on the another md volume.
Both ext3s. Drivers are sata_promise and ata_piix (sata disk); CFQ scheduler.
Using noop is no change (but seems to be harder to reproduce with it). I figured
out that it probably happens when 2+ processes are on both "processors" (HT on
P4) and are IO wait (multiload-applet shows red above the half).

Swap usage is 0 all the time.
</cite>

> Please keep a close eye on mainline, too.  Wait for it to appear there :(

Ok, I'll try to play with that...

thanks,
--
http://www.fi.muni.cz/~xslaby/            Jiri Slaby
faculty of informatics, masaryk university, brno, cz
e-mail: jirislaby gmail com, gpg pubkey fingerprint:
B674 9967 0407 CE62 ACC8  22A0 32CC 55C3 39D4 7A7E
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