linux-kernel - Re: [PATCH 3/4] mm: move lazy free pages to inactive list

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Date:	Tue, 31 Mar 2015 13:45:25 +0900
From:	Minchan Kim <minchan@...nel.org>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	Michal Hocko <mhocko@...e.cz>,
	Johannes Weiner <hannes@...xchg.org>,
	Mel Gorman <mgorman@...e.de>, Rik van Riel <riel@...hat.com>,
	Shaohua Li <shli@...nel.org>, Yalin.Wang@...ymobile.com
Subject: Re: [PATCH 3/4] mm: move lazy free pages to inactive list

Hello Andrew,

On Mon, Mar 30, 2015 at 02:20:10PM -0700, Andrew Morton wrote:
> On Mon, 30 Mar 2015 14:35:02 +0900 Minchan Kim <minchan@...nel.org> wrote:
> 
> > --- a/mm/swap.c
> > +++ b/mm/swap.c
> > @@ -866,6 +866,13 @@ void deactivate_file_page(struct page *page)
> >  	}
> >  }
> >  
> > +/**
> > + * deactivate_page - deactivate a page
> > + * @page: page to deactivate
> > + *
> > + * This function moves @page to inactive list if @page was on active list and
> > + * was not unevictable page to accelerate to reclaim @page.
> > + */
> >  void deactivate_page(struct page *page)
> >  {
> >  	if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) {
> 
> Thanks.
> 
> deactivate_page() doesn't look at or alter PageReferenced().  Should it?

Absolutely true. Thanks.
Here it goes.

>From 2b2c92eb73a1cceac615b9abd4c0f5f0c3395ff5 Mon Sep 17 00:00:00 2001
From: Minchan Kim <minchan@...nel.org>
Date: Tue, 31 Mar 2015 13:38:46 +0900
Subject: [PATCH] mm: lru_deactivate_fn should clear PG_referenced

deactivate_page aims for accelerate for reclaiming through
moving pages from active list to inactive list so we should
clear PG_referenced for the goal.

Suggested-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Minchan Kim <minchan@...nel.org>
---
 mm/swap.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/swap.c b/mm/swap.c
index b65fc8c..6b420022 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -800,6 +800,7 @@ static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec,
 
 		del_page_from_lru_list(page, lruvec, lru + LRU_ACTIVE);
 		ClearPageActive(page);
+		ClearPageReferenced(page);
 		add_page_to_lru_list(page, lruvec, lru);
 
 		__count_vm_event(PGDEACTIVATE);
-- 
1.9.3



-- 
Kind regards,
Minchan Kim
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