Re: [PATCH 10/15] mm: Use pagevec_lookup_range_tag() in __filemap_fdatawait_range()

[Jan Kara <jack@suse.cz>]

On Thu 28-09-17 08:19:02, Dave Chinner wrote:
> On Wed, Sep 27, 2017 at 06:03:29PM +0200, Jan Kara wrote:
> > Use pagevec_lookup_range_tag() in __filemap_fdatawait_range() as it is
> > interested only in pages from given range. Remove unnecessary code
> > resulting from this.
> > 
> > Signed-off-by: Jan Kara <jack@suse.cz>
> > ---
> >  mm/filemap.c | 9 ++-------
> >  1 file changed, 2 insertions(+), 7 deletions(-)
> > 
> > diff --git a/mm/filemap.c b/mm/filemap.c
> > index fe20329c83cd..479fc54b7cd1 100644
> > --- a/mm/filemap.c
> > +++ b/mm/filemap.c
> > @@ -421,18 +421,13 @@ static void __filemap_fdatawait_range(struct address_space *mapping,
> >  
> >  	pagevec_init(&pvec, 0);
> >  	while ((index <= end) &&
> > -			(nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
> > -			PAGECACHE_TAG_WRITEBACK,
> > -			min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1)) != 0) {
> > +			(nr_pages = pagevec_lookup_range_tag(&pvec, mapping,
> > +			&index, end, PAGECACHE_TAG_WRITEBACK, PAGEVEC_SIZE))) {
> 
> While touching this, can we clean this up by moving the lookup
> outside the while condition? i.e:
> 
> 	while (index <= end) {
> 		unsigned i;
> 
> 		nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index,
> 				end, PAGECACHE_TAG_WRITEBACK, PAGEVEC_SIZE);
> 		if (!nr_pages)
> 			break;

Yeah, that makes sense. I'll update it.

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

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