From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id BEB4E6B0038 for ; Mon, 20 Feb 2017 23:10:40 -0500 (EST) Received: by mail-pg0-f71.google.com with SMTP id 1so120397459pgz.5 for ; Mon, 20 Feb 2017 20:10:40 -0800 (PST) Received: from out0-156.mail.aliyun.com (out0-156.mail.aliyun.com. [140.205.0.156]) by mx.google.com with ESMTP id q4si4227142plb.147.2017.02.20.20.10.39 for ; Mon, 20 Feb 2017 20:10:39 -0800 (PST) Reply-To: "Hillf Danton" From: "Hillf Danton" References: <20170215092247.15989-1-mgorman@techsingularity.net> <20170215092247.15989-4-mgorman@techsingularity.net> <001501d2881d$242aa790$6c7ff6b0$@alibaba-inc.com> <20170216081039.ukbxl2b4khnwwbic@techsingularity.net> <001f01d2882d$9dd14850$d973d8f0$@alibaba-inc.com> In-Reply-To: Subject: Re: [PATCH 3/3] mm, vmscan: Prevent kswapd sleeping prematurely due to mismatched classzone_idx Date: Tue, 21 Feb 2017 12:10:34 +0800 Message-ID: <012701d28bf8$7380d920$5a828b60$@alibaba-inc.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Language: zh-cn Sender: owner-linux-mm@kvack.org List-ID: To: 'Vlastimil Babka' , 'Mel Gorman' Cc: 'Andrew Morton' , 'Shantanu Goel' , 'Chris Mason' , 'Johannes Weiner' , 'LKML' , 'Linux-MM' On February 21, 2017 12:34 AM Vlastimil Babka wrote: > On 02/16/2017 09:21 AM, Hillf Danton wrote: > > Right, but the order-3 request can also come up while kswapd is active and > > gives up order-5. > > "Giving up on order-5" means it will set sc.order to 0, go to sleep (assuming > order-0 watermarks are OK) and wakeup kcompactd for order-5. There's no way how > kswapd could help an order-3 allocation at that point - it's up to kcompactd. > cpu0 cpu1 give up order-5 fall back to order-0 wake up kswapd for order-3 wake up kswapd for order-5 fall in sleep wake up kswapd for order-3 what order would we try? It is order-5 in the patch. Given the fresh new world without hike ban after napping, one tenth second or 3 minutes, we feel free IMHO to select any order and go another round of reclaiming pages. thanks Hillf -- 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