Re: [patch] mm: pagecache insertion fewer atomics

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

On Tue, 19 Aug 2008 14:41:50 +0900 KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote:

> Hi Nick,
> 
> > Setting and clearing the page locked when inserting it into swapcache /
> > pagecache when it has no other references can use non-atomic page flags
> > operations because no other CPU may be operating on it at this time.
> > 
> > This saves one atomic operation when inserting a page into pagecache.
> > 
> > Signed-off-by: Nick Piggin <npiggin@suse.de>
> > ---
> >  include/linux/pagemap.h |   37 +++++++++++++++++++++++++++++++++----
> >  mm/swap_state.c         |    4 ++--
> >  2 files changed, 35 insertions(+), 6 deletions(-)
> > 
> > Index: linux-2.6/mm/swap_state.c
> > ===================================================================
> > --- linux-2.6.orig/mm/swap_state.c
> > +++ linux-2.6/mm/swap_state.c
> > @@ -302,7 +302,7 @@ struct page *read_swap_cache_async(swp_e
> >  		 * re-using the just freed swap entry for an existing page.
> >  		 * May fail (-ENOMEM) if radix-tree node allocation failed.
> >  		 */
> > -		set_page_locked(new_page);
> > +		__set_page_locked(new_page);
> >  		err = add_to_swap_cache(new_page, entry, gfp_mask & GFP_KERNEL);
> >  		if (likely(!err)) {
> >  			/*
> 
> What version do you working on?

Who knows...  I had to fix a few rejects.

> 2.6.27-rc1-mm1 is not contain set_page_locked().
> mmotm?

Current mmotm has these patches integrated.

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