Re: [PATCH] vmscan: evict use-once pages first (v2)

Andrew Morton
2009-05-01T00:51:04Z

On Thu, 30 Apr 2009 00:20:58 -0700
Elladan <elladan@eskimo.com> wrote:

> > Elladan, does this smaller patch still work as expected?
>
> Rik, since the third patch doesn't work on 2.6.28 (without disabling a lot of
> code), I went ahead and tested this patch.
>
> The system does seem relatively responsive with this patch for the most part,
> with occasional lag. I don't see much evidence at least over the course of a
> few minutes that it pages out applications significantly. It seems about
> equivalent to the first patch.
>
> Given Andrew Morton's request that I track the Mapped: field in /proc/meminfo,
> I went ahead and did that with this patch built into a kernel. Compared to the
> standard Ubuntu kernel, this patch keeps significantly more Mapped memory
> around, and it shrinks at a slower rate after the test runs for a while.
> Eventually, it seems to reach a steady state.
>
> For example, with your patch, Mapped will often go for 30 seconds without
> changing significantly. Without your patch, it continuously lost about
> 500-1000K every 5 seconds, and then jumped up again significantly when I
> touched Firefox or other applications. I do see some of that behavior with
> your patch too, but it's much less significant.

Were you able to tell whether altering /proc/sys/vm/swappiness appropriately
regulated the rate at which the mapped page count decreased?

Thanks.