From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f71.google.com (mail-ed1-f71.google.com [209.85.208.71]) by kanga.kvack.org (Postfix) with ESMTP id 85BA18E00AE for ; Fri, 4 Jan 2019 03:58:03 -0500 (EST) Received: by mail-ed1-f71.google.com with SMTP id l45so34903739edb.1 for ; Fri, 04 Jan 2019 00:58:03 -0800 (PST) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id h53si1184579edh.287.2019.01.04.00.58.02 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 04 Jan 2019 00:58:02 -0800 (PST) Date: Fri, 4 Jan 2019 09:58:01 +0100 From: Michal Hocko Subject: Re: [PATCH v6 1/2] memory_hotplug: Free pages as higher order Message-ID: <20190104085801.GH31793@dhcp22.suse.cz> References: <1541484194-1493-1-git-send-email-arunks@codeaurora.org> <20181106140638.GN27423@dhcp22.suse.cz> <542cd3516b54d88d1bffede02c6045b8@codeaurora.org> <20181106200823.GT27423@dhcp22.suse.cz> <5e55c6e64a2bfd6eed855ea17a34788b@codeaurora.org> <40a4d5154fbd0006fbe55eb68703bb65@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <40a4d5154fbd0006fbe55eb68703bb65@codeaurora.org> Sender: owner-linux-mm@kvack.org List-ID: To: Arun KS Cc: arunks.linux@gmail.com, akpm@linux-foundation.org, vbabka@suse.cz, osalvador@suse.de, linux-kernel@vger.kernel.org, linux-mm@kvack.org, getarunks@gmail.com On Fri 04-01-19 10:35:58, Arun KS wrote: > On 2018-11-07 11:51, Arun KS wrote: > > On 2018-11-07 01:38, Michal Hocko wrote: > > > On Tue 06-11-18 21:01:29, Arun KS wrote: > > > > On 2018-11-06 19:36, Michal Hocko wrote: > > > > > On Tue 06-11-18 11:33:13, Arun KS wrote: > > > > > > When free pages are done with higher order, time spend on > > > > > > coalescing pages by buddy allocator can be reduced. With > > > > > > section size of 256MB, hot add latency of a single section > > > > > > shows improvement from 50-60 ms to less than 1 ms, hence > > > > > > improving the hot add latency by 60%. Modify external > > > > > > providers of online callback to align with the change. > > > > > > > > > > > > This patch modifies totalram_pages, zone->managed_pages and > > > > > > totalhigh_pages outside managed_page_count_lock. A follow up > > > > > > series will be send to convert these variable to atomic to > > > > > > avoid readers potentially seeing a store tear. > > > > > > > > > > Is there any reason to rush this through rather than wait for counters > > > > > conversion first? > > > > > > > > Sure Michal. > > > > > > > > Conversion patch, https://patchwork.kernel.org/cover/10657217/ > > > > is currently > > > > incremental to this patch. > > > > > > The ordering should be other way around. Because as things stand with > > > this patch first it is possible to introduce a subtle race prone > > > updates. As I've said I am skeptical the race would matter, really, > > > but > > > there is no real reason to risk for that. Especially when you have the > > > other (first) half ready. > > > > Makes sense. I have rebased the preparatory patch on top of -rc1. > > https://patchwork.kernel.org/patch/10670787/ > > Hello Michal, > > Please review version 7 sent, > https://lore.kernel.org/patchwork/patch/1028908/ I believe I have give my Acked-by to this version already, and v7 indeed has it. Are there any relevant changes since v6 for me to do the review again. If yes you should have dropped the Acked-by. -- Michal Hocko SUSE Labs