Re: [PATCH] mm: optimize replace_page_cache_page

[Andrew Morton <akpm@linux-foundation.org>]

On Thu, 24 Feb 2011 11:56:55 +0100
Miklos Szeredi <mszeredi@suse.cz> wrote:

> On Thu, 2011-02-24 at 08:37 +0900, Minchan Kim wrote:
> > On Thu, Feb 24, 2011 at 7:44 AM, Andrew Morton
> > <akpm@linux-foundation.org> wrote:
> > > On Sun, 20 Feb 2011 08:41:21 +0900
> > > Minchan Kim <minchan.kim@gmail.com> wrote:
> > >
> > >> Resend.
> > >
> > > Reignore.
> > >
> > >> he patch is based on mmotm-2011-02-04 +
> > >> mm-add-replace_page_cache_page-function-add-freepage-hook.patch.
> > >>
> > >> On Fri, Feb 11, 2011 at 01:33:46AM +0900, Minchan Kim wrote:
> > >> > This patch optmizes replace_page_cache_page.
> > >> >
> > >> > 1) remove radix_tree_preload
> > >> > 2) single radix_tree_lookup_slot and replace radix tree slot
> > >> > 3) page accounting optimization if both pages are in same zone.
> > >> >
> > >> > Cc: Miklos Szeredi <mszeredi@suse.cz>
> > >> > Cc: Rik van Riel <riel@redhat.com>
> > >> > Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> > >> > Cc: Mel Gorman <mel@csn.ul.ie>
> > >> > Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
> > >> > ---
> > >> >  mm/filemap.c |   61 ++++++++++++++++++++++++++++++++++++++++++++++++---------
> > >> >  1 files changed, 51 insertions(+), 10 deletions(-)
> > >> >
> > >> > Hi Miklos,
> > >> > This patch is totally not tested.
> > >> > Could you test this patch?
> > >
> > > ^^^ Because of this.
> > >
> > > Is it tested yet?
> > >
> > 
> > Miklos. Could you test this?
> > If you are busy, let me know how to test it. I will.
> > Thanks.
> 
> Grab git version of libfuse and do something like this:
> 
>  fuse/example/fusexmp_fh -obig_writes /mnt/fuse/
>  dd if=/tmp/random0 of=/mnt/fuse/tmp/random1 bs=1M
>  md5sum /tmp/radom0 /tmp/random1
> 
> This should exercise the page moving.
> 
> I'll review and test the patch when I have some time.
> 

Too late.  It took months to half-finish Miklos's patch and now I'm
sitting on other patches which depend on it, so it's going in.