From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f174.google.com (mail-ob0-f174.google.com [209.85.214.174]) by kanga.kvack.org (Postfix) with ESMTP id 83BE46B0088 for ; Tue, 10 Dec 2013 03:49:57 -0500 (EST) Received: by mail-ob0-f174.google.com with SMTP id wn1so4967437obc.19 for ; Tue, 10 Dec 2013 00:49:57 -0800 (PST) Received: from e28smtp02.in.ibm.com (e28smtp02.in.ibm.com. [122.248.162.2]) by mx.google.com with ESMTPS id co8si9769538oec.112.2013.12.10.00.49.51 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 10 Dec 2013 00:49:56 -0800 (PST) Received: from /spool/local by e28smtp02.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 10 Dec 2013 14:19:41 +0530 Received: from d28relay05.in.ibm.com (d28relay05.in.ibm.com [9.184.220.62]) by d28dlp02.in.ibm.com (Postfix) with ESMTP id E6000394005A for ; Tue, 10 Dec 2013 14:19:38 +0530 (IST) Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay05.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id rBA8nZUb6291814 for ; Tue, 10 Dec 2013 14:19:36 +0530 Received: from d28av05.in.ibm.com (localhost [127.0.0.1]) by d28av05.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id rBA8nbdr028817 for ; Tue, 10 Dec 2013 14:19:38 +0530 Date: Tue, 10 Dec 2013 16:49:35 +0800 From: Wanpeng Li Subject: Re: [PATCH v3 09/12] sched/numa: fix task scan rate adjustment Message-ID: <52a6d5b4.48b13c0a.0edd.6b08SMTPIN_ADDED_BROKEN@mx.google.com> Reply-To: Wanpeng Li References: <1386483293-15354-1-git-send-email-liwanp@linux.vnet.ibm.com> <1386483293-15354-9-git-send-email-liwanp@linux.vnet.ibm.com> <1386657875-icl2pjx6-mutt-n-horiguchi@ah.jp.nec.com> <20131210082758.GC11295@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131210082758.GC11295@suse.de> Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Naoya Horiguchi , Andrew Morton , Ingo Molnar , Rik van Riel , Peter Zijlstra , linux-kernel@vger.kernel.org, linux-mm@kvack.org On Tue, Dec 10, 2013 at 08:27:59AM +0000, Mel Gorman wrote: >On Tue, Dec 10, 2013 at 01:44:35AM -0500, Naoya Horiguchi wrote: >> Hi Wanpeng, >> >> On Sun, Dec 08, 2013 at 02:14:50PM +0800, Wanpeng Li wrote: >> > commit 04bb2f947 (sched/numa: Adjust scan rate in task_numa_placement) calculate >> > period_slot which should be used as base value of scan rate increase if remote >> > access dominate. However, current codes forget to use it, this patch fix it. >> > >> > Signed-off-by: Wanpeng Li >> > --- >> > kernel/sched/fair.c | 2 +- >> > 1 files changed, 1 insertions(+), 1 deletions(-) >> > >> > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> > index 7073c76..b077f1b3 100644 >> > --- a/kernel/sched/fair.c >> > +++ b/kernel/sched/fair.c >> > @@ -1358,7 +1358,7 @@ static void update_task_scan_period(struct task_struct *p, >> > */ >> > period_slot = DIV_ROUND_UP(diff, NUMA_PERIOD_SLOTS); >> > ratio = DIV_ROUND_UP(private * NUMA_PERIOD_SLOTS, (private + shared)); >> > - diff = (diff * ratio) / NUMA_PERIOD_SLOTS; >> > + diff = (period_slot * ratio) / NUMA_PERIOD_SLOTS; >> > } >> > >> > p->numa_scan_period = clamp(p->numa_scan_period + diff, >> >> It seems to me that the original code is correct, because the mathematical >> meaning of this hunk is clear: >> >> diff = (diff calculated by local-remote ratio) * (private-shared ratio) >> > >Thanks Naoya. > >The original code is as intended and was meant to scale the difference >between the NUMA_PERIOD_THRESHOLD and local/remote ratio when adjusting >the scan period. The period_slot recalculation can be dropped. > Thanks Mel's pointing out. ;-) Regards, Wanpeng Li >-- >Mel Gorman >SUSE Labs -- 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