From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95063C0044C for ; Wed, 7 Nov 2018 06:21:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 56BAD20827 for ; Wed, 7 Nov 2018 06:21:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="Mo0zyB3S"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="Mo0zyB3S" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 56BAD20827 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730315AbeKGPuH (ORCPT ); Wed, 7 Nov 2018 10:50:07 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:34858 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728231AbeKGPuH (ORCPT ); Wed, 7 Nov 2018 10:50:07 -0500 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id E382060A9B; Wed, 7 Nov 2018 06:21:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1541571672; bh=hpuARF5Ld5ls4wve5IbIhIkQPc219aUgwsVT4sSlYMg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Mo0zyB3SyKC2RBs+A7NCmWI+8/KK+F+K3FM8hMhKgnWlTm+fDiEP+qza6asDM9BRa c44UPcwQwGtPV513bsFhqDkti284i1AmILe5fCpGHkM5kANnkqsSkrp3tJX433MYPC 1iL2ITWTnIeOX7dUL7isDUqvNjfbupyNdyeDgB48= Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id 35854601D4; Wed, 7 Nov 2018 06:21:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1541571672; bh=hpuARF5Ld5ls4wve5IbIhIkQPc219aUgwsVT4sSlYMg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Mo0zyB3SyKC2RBs+A7NCmWI+8/KK+F+K3FM8hMhKgnWlTm+fDiEP+qza6asDM9BRa c44UPcwQwGtPV513bsFhqDkti284i1AmILe5fCpGHkM5kANnkqsSkrp3tJX433MYPC 1iL2ITWTnIeOX7dUL7isDUqvNjfbupyNdyeDgB48= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Wed, 07 Nov 2018 11:51:12 +0530 From: Arun KS To: Michal Hocko 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 Subject: Re: [PATCH v6 1/2] memory_hotplug: Free pages as higher order In-Reply-To: <20181106200823.GT27423@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> Message-ID: <5e55c6e64a2bfd6eed855ea17a34788b@codeaurora.org> X-Sender: arunks@codeaurora.org User-Agent: Roundcube Webmail/1.2.5 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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/ Regards, Arun