From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id 1ECA06B0044 for ; Mon, 14 Dec 2009 18:09:00 -0500 (EST) Received: by ywh3 with SMTP id 3so3683109ywh.22 for ; Mon, 14 Dec 2009 15:08:59 -0800 (PST) Date: Tue, 15 Dec 2009 08:03:28 +0900 From: Minchan Kim Subject: Re: [PATCH 4/8] Use prepare_to_wait_exclusive() instead prepare_to_wait() Message-Id: <20091215080328.b4af59ad.minchan.kim@barrios-desktop> In-Reply-To: <20091214212936.BBBA.A69D9226@jp.fujitsu.com> References: <20091211164651.036f5340@annuminas.surriel.com> <20091214210823.BBAE.A69D9226@jp.fujitsu.com> <20091214212936.BBBA.A69D9226@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Rik van Riel , lwoodman@redhat.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, minchan.kim@gmail.com List-ID: On Mon, 14 Dec 2009 21:30:19 +0900 (JST) KOSAKI Motohiro wrote: > if we don't use exclusive queue, wake_up() function wake _all_ waited > task. This is simply cpu wasting. > > Signed-off-by: KOSAKI Motohiro > --- > mm/vmscan.c | 4 ++-- > 1 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index e0cb834..3562a2d 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -1618,7 +1618,7 @@ static int shrink_zone_begin(struct zone *zone, struct scan_control *sc) > * we would just make things slower. > */ > for (;;) { > - prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); > + prepare_to_wait_exclusive(wq, &wait, TASK_UNINTERRUPTIBLE); > > if (atomic_read(&zone->concurrent_reclaimers) <= > max_zone_concurrent_reclaimers) > @@ -1632,7 +1632,7 @@ static int shrink_zone_begin(struct zone *zone, struct scan_control *sc) > */ > if (zone_watermark_ok(zone, sc->order, low_wmark_pages(zone), > 0, 0)) { > - wake_up(wq); > + wake_up_all(wq); I think it's typo. The description in changelog says we want "wake_up". Otherwise, looks good to me. Reviewed-by: Minchan Kim -- Kind regards, Minchan Kim -- 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