Nick Piggin wrote:

> > With kernel 2.6.10-rc3 and 256 M RAM, when I start a task taht eats a ot
> > of RAM (for example, viewing a big TIFF file; also tested with a
> > synthetic "eater"), in the resulting swapping process kswapd tahes quite
> > a bit of CPU time. The computer becomes extremely unresponsive, the clock
> > (in icewm) stops for periods of time up to a minute). And the task
> > startup itself is somewhaat slow.
> >
> > I have checked both 2.6.8.1 and 2.6.9 for comparison, and they fare a lot
> > better. The CPU hogging is not there, the computer is much more
> > responsive, and the task starts faster.
> I'm not quite sure what the problem would be. Please check that you are
> using the same config for each kernel, and both kernels have detected the
> same amount of memory.

Seems so.

> Then, can you start by posting /proc/vmstat before and after running the
> synthetic "eater" for some amount of time, with both 2.6.9 and 2.6.10-rc3;

I have rerun the tests to record the data, and this time 2.6.9 behaved 
differently. There was no CPU hog for kswapd, but at some poing the computer 
went un-interactive, and after about 20 seconds the task was killed.

2.6.8.1 hummed along nicely and remained interactive (somewhat jerky as one 
would expect under heavy swapping, but at least the clock always ran)

2.6.10-rc3 started with some kswapd CPU hogging, and then became more and more 
unresponsive. It took me some minutes to become able to simply get the vmstat 
data!

The requested files (cat's of /proc/meminfo and /proc/slabinfo before the run, 
and /proc/vmstat before and during the run ["after" for 2.6.9 which killed 
the process]) are attached, as well as the eater code. I told the eater to 
eat 300 MB.

BTW, somebody told me in a private email to try the oomkiller patch, but I 
could not extract it from the Web archive, so I don't have the latest version 
of that :( I'd apreciate if anyone emailed that to me, or gave me a link. or 
a pointer to instructions on getting it right from obe of the Web archives.

-- 
Yours, Mikhail Ramendik