Re: 2.6.14 kswapd eating too much CPU

From: Andrew Morton
Date: Wed Nov 23 2005 - 15:37:18 EST

Jan Kasprzak <kas@xxxxxxxxxx> wrote:
> Andrew Morton wrote:
> : Jan Kasprzak <kas@xxxxxxxxxx> wrote:
> : >
> : > I am at 2.6.15-rc2 now, the problem is still there.
> : > Currently according to top(1), kswapd1 eats >98% CPU for 50 minutes now
> : > and counting.
> :
> : When it's doing this, could you do sysrq-p a few times? The output of that
> : should tell us where the CPU is executing.
> Hmm, it does not show anything but the header. Should I enable
> something special in the kernel?

Try `dmesg -n 7' first.

> # dmesg -c >/dev/null; echo -n p >/proc/sysrq-trigger ; sleep 5; dmesg
> SysRq : Show Regs
> #

You won't get anything useful from sysrq-p via /proc/sysrq-trigger - it'll
just show the backtrace of the process `echo'. It has to be via the

If there's no keyboard, do `echo t > /proc/sysrq-trigger' to get an
all-task backtrace, then locate the trace for kswapd in the resulting


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