From mboxrd@z Thu Jan 1 00:00:00 1970 From: KOSAKI Motohiro Subject: Re: [PATCH 1/4] vmscan: delegate pageout io to flusher thread if current is kswapd Date: Thu, 15 Apr 2010 17:18:56 +0900 (JST) Message-ID: <20100415171750.D195.A69D9226@jp.fujitsu.com> References: <20100415130212.D16E.A69D9226@jp.fujitsu.com> <20100415131106.D174.A69D9226@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Cc: kosaki.motohiro@jp.fujitsu.com, Dave Chinner , Mel Gorman , Chris Mason , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org To: KOSAKI Motohiro Return-path: In-Reply-To: <20100415131106.D174.A69D9226@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org > Now, vmscan pageout() is one of IO throuput degression source. > Some IO workload makes very much order-0 allocation and reclaim > and pageout's 4K IOs are making annoying lots seeks. >=20 > At least, kswapd can avoid such pageout() because kswapd don't > need to consider OOM-Killer situation. that's no risk. I've found one bug in this patch myself. flusher thread don't pageout anon pages. then, we need PageAnon() check ;) >=20 > Signed-off-by: KOSAKI Motohiro > --- > mm/vmscan.c | 7 +++++++ > 1 files changed, 7 insertions(+), 0 deletions(-) >=20 > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 3ff3311..d392a50 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -614,6 +614,13 @@ static enum page_references page_check_references(= struct page *page, > if (referenced_page) > return PAGEREF_RECLAIM_CLEAN; > =20 > + /* > + * Delegate pageout IO to flusher thread. They can make more > + * effective IO pattern. > + */ > + if (current_is_kswapd()) > + return PAGEREF_RECLAIM_CLEAN; > + > return PAGEREF_RECLAIM; > } > =20 > --=20 > 1.6.5.2 >=20 >=20 >=20 -- 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