Re: I/O lockup

Marcelo Tosatti (marcelo@conectiva.com.br)
Mon, 12 Nov 2001 16:18:12 -0200 (BRST)


On Mon, 12 Nov 2001, Gord R. Lamb wrote:

> Hi everyone,
>
> I've been having a problem for a while now with a strange lockup induced
> under heavy SCSI I/O (particularly when I write directly to block devices
> with dd of=/dev/sd?, but also when writing to a filesystem on that
> device). I'm writing around 50-100mb/sec over FC (qlogic 2200) under
> Linux 2.4 (tried 2.4.3 through 2.4.10).
>
> It seems that some vm or I/O related spinlock is being taken and held, but
> not released (?). There is no oops or BUG() or anything (no messages at
> all in fact).. all I/O just stops. I can still invoke sysrq, type
> characters at the console, etc. In fact, usually top continues to run and
> display kswapd as the dominant process.

If kswapd is eating the CPU, its probably a VM problem.

Please try the newest 2.4.xx which has VM updates and if the problem
happens again, tell us.

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