Re: Very aggressive memory reclaim

Dave Chinner
2011-03-29T01:54:21Z

On Mon, Mar 28, 2011 at 04:58:50PM -0700, Andi Kleen wrote:
> Dave Chinner <david@fromorbit.com> writes:
> >
> > First it would be useful to determine why the VM is reclaiming so
> > much memory. If it is somewhat predictable when the excessive
> > reclaim is going to happen, it might be worth capturing an event
>
> Often it's to get pages of a higher order. Just tracing alloc_pages
> should tell you that.

Yes, the kmem/mm_page_alloc tracepoint gives us that. But in case
that is not the cause, grabbing all the trace points I suggested is
more likely to indicate where the problem is. I'd prefer to get more
data than needed the first time around than have to do multiple
round trips because a single trace point doesn't tell us the cause...

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com