Re: [RFC][PATCH] mm: the page of MIGRATE_RESERVE don't insert into pcp

KAMEZAWA Hiroyuki
2008-11-07T11:03:55Z

On Fri, 7 Nov 2008 10:42:42 +0000
Mel Gorman <mel@csn.ul.ie> wrote:

> On Fri, Nov 07, 2008 at 10:42:24AM +0900, KAMEZAWA Hiroyuki wrote:
> > On Thu, 6 Nov 2008 16:46:45 +0000
> > Mel Gorman <mel@csn.ul.ie> wrote:
> > > > otherwise, the system have unnecessary memory starvation risk
> > > > because other cpu can't use this emergency pages.
> > > >
> > > >
> > > >
> > > > Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
> > > > CC: Mel Gorman <mel@csn.ul.ie>
> > > > CC: Christoph Lameter <cl@linux-foundation.org>
> > > >
> > >
> > > This patch seems functionally sound but as Christoph points out, this
> > > adds another branch to the fast path. Now, I ran some tests and those that
> > > completed didn't show any problems but adding branches in the fast path can
> > > eventually lead to hard-to-detect performance problems.
> > >
> > dividing pcp-list into MIGRATE_TYPES is bad ?
>
> I do not understand what your question is.
>
Hmm. like this.

pcp = &zone_pcp(zone, get_cpu())->pcp[migrate_type];

Thanks,
-Kame