From: Mel Gorman <mel@csn.ul.ie>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org,
Chris Mason <chris.mason@oracle.com>,
Dave Chinner <david@fromorbit.com>,
Andi Kleen <andi@firstfloor.org>,
Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH 09/10] vmscan: Setup pagevec as late as possible in shrink_page_list()
Date: Fri, 16 Apr 2010 15:34:29 +0100 [thread overview]
Message-ID: <20100416143429.GG19264@csn.ul.ie> (raw)
In-Reply-To: <20100416115248.27A7.A69D9226@jp.fujitsu.com>
On Fri, Apr 16, 2010 at 04:54:03PM +0900, KOSAKI Motohiro wrote:
> > shrink_page_list() sets up a pagevec to release pages as according as they
> > are free. It uses significant amounts of stack on the pagevec. This
> > patch adds pages to be freed via pagevec to a linked list which is then
> > freed en-masse at the end. This avoids using stack in the main path that
> > potentially calls writepage().
> >
> > Signed-off-by: Mel Gorman <mel@csn.ul.ie>
> > ---
> > mm/vmscan.c | 34 ++++++++++++++++++++++++++--------
> > 1 files changed, 26 insertions(+), 8 deletions(-)
> >
> > diff --git a/mm/vmscan.c b/mm/vmscan.c
> > index 9bc1ede..2c22c83 100644
> > --- a/mm/vmscan.c
> > +++ b/mm/vmscan.c
> > @@ -619,6 +619,22 @@ static enum page_references page_check_references(struct page *page,
> > return PAGEREF_RECLAIM;
> > }
> >
> > +static void free_page_list(struct list_head *free_list)
> > +{
> > + struct pagevec freed_pvec;
> > + struct page *page, *tmp;
> > +
> > + pagevec_init(&freed_pvec, 1);
> > +
> > + list_for_each_entry_safe(page, tmp, free_list, lru) {
> > + list_del(&page->lru);
> > + if (!pagevec_add(&freed_pvec, page)) {
> > + __pagevec_free(&freed_pvec);
> > + pagevec_reinit(&freed_pvec);
> > + }
> > + }
>
> Need this two line at this? because we need consider number of
> list element are not 14xN.
>
> if (pagevec_count(&freed_pvec))
> __pagevec_free(&freed_pvec);
>
Whoops, yes indeed. Otherwise this potentially leaks and as
SWAP_CLUSTER_MAX is 32, it's often not going to be 14xN
>
> > +}
> > +
> > /*
> > * shrink_page_list() returns the number of reclaimed pages
> > */
> > @@ -627,13 +643,12 @@ static unsigned long shrink_page_list(struct list_head *page_list,
> > enum pageout_io sync_writeback)
> > {
> > LIST_HEAD(ret_pages);
> > - struct pagevec freed_pvec;
> > + LIST_HEAD(free_list);
> > int pgactivate = 0;
> > unsigned long nr_reclaimed = 0;
> >
> > cond_resched();
> >
> > - pagevec_init(&freed_pvec, 1);
> > while (!list_empty(page_list)) {
> > enum page_references references;
> > struct address_space *mapping;
> > @@ -808,10 +823,12 @@ static unsigned long shrink_page_list(struct list_head *page_list,
> > __clear_page_locked(page);
> > free_it:
> > nr_reclaimed++;
> > - if (!pagevec_add(&freed_pvec, page)) {
> > - __pagevec_free(&freed_pvec);
> > - pagevec_reinit(&freed_pvec);
> > - }
> > +
> > + /*
> > + * Is there need to periodically free_page_list? It would
> > + * appear not as the counts should be low
> > + */
> > + list_add(&page->lru, &free_list);
> > continue;
> >
> > cull_mlocked:
> > @@ -834,9 +851,10 @@ keep:
> > list_add(&page->lru, &ret_pages);
> > VM_BUG_ON(PageLRU(page) || PageUnevictable(page));
> > }
> > +
> > + free_page_list(&free_list);
> > +
> > list_splice(&ret_pages, page_list);
> > - if (pagevec_count(&freed_pvec))
> > - __pagevec_free(&freed_pvec);
> > count_vm_events(PGACTIVATE, pgactivate);
> > return nr_reclaimed;
> > }
> > --
> > 1.6.5
> >
>
>
>
--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab
next prev parent reply other threads:[~2010-04-16 14:34 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-15 17:21 [RFC PATCH 00/10] Reduce stack usage used by page reclaim V1 Mel Gorman
2010-04-15 17:21 ` [PATCH 01/10] vmscan: kill prev_priority completely Mel Gorman
2010-04-16 22:37 ` Johannes Weiner
2010-04-15 17:21 ` [PATCH 02/10] vmscan: move priority variable into scan_control Mel Gorman
2010-04-16 22:48 ` Johannes Weiner
2010-05-26 10:23 ` Mel Gorman
2010-05-28 2:39 ` KOSAKI Motohiro
2010-04-15 17:21 ` [PATCH 03/10] vmscan: simplify shrink_inactive_list() Mel Gorman
2010-04-16 22:54 ` Johannes Weiner
2010-04-15 17:21 ` [PATCH 04/10] vmscan: Remove useless loop at end of do_try_to_free_pages Mel Gorman
2010-04-16 2:48 ` KOSAKI Motohiro
2010-04-16 22:56 ` Johannes Weiner
2010-04-15 17:21 ` [PATCH 05/10] vmscan: Remove unnecessary temporary vars in do_try_to_free_pages Mel Gorman
2010-04-16 2:47 ` KOSAKI Motohiro
2010-04-15 17:21 ` [PATCH 06/10] vmscan: Split shrink_zone to reduce stack usage Mel Gorman
2010-04-16 4:23 ` Dave Chinner
2010-04-16 14:27 ` Mel Gorman
2010-04-16 6:26 ` KOSAKI Motohiro
2010-04-16 23:14 ` Johannes Weiner
2010-04-15 17:21 ` [PATCH 07/10] vmscan: Remove unnecessary temporary variables in shrink_zone() Mel Gorman
2010-04-16 2:51 ` KOSAKI Motohiro
2010-04-16 23:03 ` Johannes Weiner
2010-05-26 11:21 ` Mel Gorman
2010-05-28 2:51 ` KOSAKI Motohiro
2010-04-15 17:21 ` [PATCH 08/10] vmscan: Setup pagevec as late as possible in shrink_inactive_list() Mel Gorman
2010-04-16 4:27 ` Dave Chinner
2010-04-16 6:30 ` KOSAKI Motohiro
2010-04-16 14:31 ` Mel Gorman
2010-04-16 23:28 ` Johannes Weiner
2010-04-15 17:21 ` [PATCH 09/10] vmscan: Setup pagevec as late as possible in shrink_page_list() Mel Gorman
2010-04-16 7:54 ` KOSAKI Motohiro
2010-04-16 14:34 ` Mel Gorman [this message]
2010-04-15 17:21 ` [PATCH 10/10] vmscan: Update isolated page counters outside of main path in shrink_inactive_list() Mel Gorman
2010-04-16 11:19 ` KOSAKI Motohiro
2010-04-16 14:35 ` Mel Gorman
2010-04-16 23:34 ` Johannes Weiner
2010-04-16 14:50 ` [RFC PATCH 00/10] Reduce stack usage used by page reclaim V1 Mel Gorman
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