From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id 3D1806B007B for ; Wed, 1 Sep 2010 05:30:42 -0400 (EDT) Date: Wed, 1 Sep 2010 11:30:13 +0200 From: Johannes Weiner Subject: Re: [PATCH] vmscan,tmpfs: treat used once pages on tmpfs as used once Message-ID: <20100901093013.GB4677@cmpxchg.org> References: <20100901103653.974C.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100901103653.974C.A69D9226@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Hugh Dickins , Rik van Riel , LKML , linux-mm , Andrew Morton List-ID: On Wed, Sep 01, 2010 at 10:37:49AM +0900, KOSAKI Motohiro wrote: > When a page has PG_referenced, shrink_page_list() discard it only > if it is no dirty. This rule works completely fine if the backend > filesystem is regular one. PG_dirty is good signal that it was used > recently because flusher thread clean pages periodically. In addition, > page writeback is costly rather than simple page discard. > > However, When a page is on tmpfs, this heuristic don't works because > flusher thread don't writeback tmpfs pages. then, tmpfs pages always > rotate lru twice at least and it makes unnecessary lru churn. Merely > tmpfs streaming io shouldn't cause large anonymous page swap-out. > > This patch remove this unncessary reclaim bonus of tmpfs pages. > > Cc: Hugh Dickins > Cc: Johannes Weiner > Cc: Rik van Riel > Signed-off-by: KOSAKI Motohiro Reviewed-by: Johannes Weiner > --- > mm/vmscan.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 1919d8a..aba3402 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -617,7 +617,7 @@ static enum page_references page_check_references(struct page *page, > } > > /* Reclaim if clean, defer dirty pages to writeback */ > - if (referenced_page) > + if (referenced_page && !PageSwapBacked(page)) > return PAGEREF_RECLAIM_CLEAN; > > return PAGEREF_RECLAIM; > -- > 1.6.5.2 > > > > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org