Re: [PATCH 2/2] mm: Abort reclaim/compaction if compaction can proceed

[Rik van Riel]

On 10/07/2011 04:24 PM, Mel Gorman wrote:
> On Fri, Oct 07, 2011 at 04:07:06PM -0400, Rik van Riel wrote:
> > On 10/07/2011 11:17 AM, Mel Gorman wrote:
> > > If compaction can proceed, shrink_zones() stops doing any work but
> > > the callers still shrink_slab(), raises the priority and potentially
> > > sleeps.  This patch aborts direct reclaim/compaction entirely if
> > > compaction can proceed.
> > >
> > > Signed-off-by: Mel Gorman<mgorman@xxxxxxx>
> >
> > This patch makes sense to me, but I have not tested it like
> > the first one.
>
> Do if you can.

I'll probably build a kernel with your patch in it on
Sunday - I'll be walking across a mountain tomorrow :)

> It's marginal and could be confirmation bias on my part. Basically,
> there is noise when this path is being exercised but there were fewer
> slabs scanned.  However, I don't know what the variances are and
> whether the reduction was within the noise or not but it makes sense
> that it would scan less.  If I profiled carefully, I might be able
> to show that a few additional cycles are spent raising the priority
> but it would be marginal.

This seems clear enough.

> While patch 1 is very clear, patch 2 depends on reviewers deciding it
> "makes sense".
>
> > Having said that, I'm pretty sure the patch is ok :)
>
> Care to ack?

Sure.

Acked-by: Rik van Riel <riel@xxxxxxxxxx>


--
All rights reversed
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/