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=-12.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 A0B21C433E0 for ; Mon, 3 Aug 2020 13:29:44 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 61C17206DA for ; Mon, 3 Aug 2020 13:29:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="a5aYPfft" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 61C17206DA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id CD7D08D00F9; Mon, 3 Aug 2020 09:29:44 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C886B8D0081; Mon, 3 Aug 2020 09:29:44 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B9F1E8D00F9; Mon, 3 Aug 2020 09:29:44 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0171.hostedemail.com [216.40.44.171]) by kanga.kvack.org (Postfix) with ESMTP id A55908D0081 for ; Mon, 3 Aug 2020 09:29:44 -0400 (EDT) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 45C228248047 for ; Mon, 3 Aug 2020 13:29:44 +0000 (UTC) X-FDA: 77109339888.29.juice95_4515c6026f9e Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin29.hostedemail.com (Postfix) with ESMTP id 0B83618086E4E for ; Mon, 3 Aug 2020 13:29:37 +0000 (UTC) X-HE-Tag: juice95_4515c6026f9e X-Filterd-Recvd-Size: 5685 Received: from mail29.static.mailgun.info (mail29.static.mailgun.info [104.130.122.29]) by imf40.hostedemail.com (Postfix) with ESMTP for ; Mon, 3 Aug 2020 13:29:34 +0000 (UTC) DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1596461376; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=5lz/yjuFSbfi7AP16DemqYxIyN/7sfSVueFdw1yEZKU=; b=a5aYPfftpndfpgLgzxOKna59T+o+IWlFjSz7MHR1h4l0CI0/gp10qMOgGmn0247jKdu3SL+x OiPqu74ogs2/Mwk0YSnGguV/IWQ4LJDZtmRRFgqV15zCU7iY+bq9ESw7JgnlN30aTrcH3mtH ecu26+biHdOGl1zPZy+th1pcycA= X-Mailgun-Sending-Ip: 104.130.122.29 X-Mailgun-Sid: WyIwY2Q3OCIsICJsaW51eC1tbUBrdmFjay5vcmciLCAiYmU5ZTRhIl0= Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n12.prod.us-west-2.postgun.com with SMTP id 5f281110b59946e9e32e8aab (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Mon, 03 Aug 2020 13:28:48 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 72171C433CB; Mon, 3 Aug 2020 13:28:47 +0000 (UTC) Received: from [192.168.1.103] (unknown [183.83.143.239]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: charante) by smtp.codeaurora.org (Postfix) with ESMTPSA id 1E264C433C9; Mon, 3 Aug 2020 13:28:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 1E264C433C9 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=charante@codeaurora.org Subject: Re: [PATCH] mm, memory_hotplug: update pcp lists everytime onlining a memory block To: David Hildenbrand , akpm@linux-foundation.org, linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, vinmenon@codeaurora.org References: <1596372896-15336-1-git-send-email-charante@codeaurora.org> From: Charan Teja Kalla Message-ID: Date: Mon, 3 Aug 2020 18:58:42 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 0B83618086E4E X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Thanks David for the comments. On 8/3/2020 1:35 PM, David Hildenbrand wrote: > On 02.08.20 14:54, Charan Teja Reddy wrote: >> When onlining a first memory block in a zone, pcp lists are not updated >> thus pcp struct will have the default setting of ->high = 0,->batch = 1. >> This means till the second memory block in a zone(if it have) is onlined >> the pcp lists of this zone will not contain any pages because pcp's >> ->count is always greater than ->high thus free_pcppages_bulk() is >> called to free batch size(=1) pages every time system wants to add a >> page to the pcp list through free_unref_page(). To put this in a word, >> system is not using benefits offered by the pcp lists when there is a >> single onlineable memory block in a zone. Correct this by always >> updating the pcp lists when memory block is onlined. > > I guess such setups are rare ... but I can imagine it being the case > with virtio-mem in the future ... not 100% if this performance > optimization is really relevant in practice ... how did you identify this? Even the Snapdragon hardware that I had tested on contain multiple onlineable memory blocks. But we have the use case in which we online single memory block and once it is filled then online the next block. In the step where single block is onlined, we observed the below pageset params. pagesets cpu: 0 count: 0 high: 0 batch: 1 Once the second block is onlined then only seeing some sane values as below. cpu: 0 count: 32 high: 378 batch: 63 In the above case, till the second block is onlined, no page is held in the pcp list. So, updating the pcp params every time when onlining the memory block is required, as an example in the usecase that I had mentioned. > >> >> Signed-off-by: Charan Teja Reddy >> --- >> mm/memory_hotplug.c | 3 +-- >> 1 file changed, 1 insertion(+), 2 deletions(-) >> >> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c >> index dcdf327..7f62d69 100644 >> --- a/mm/memory_hotplug.c >> +++ b/mm/memory_hotplug.c >> @@ -854,8 +854,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, >> node_states_set_node(nid, &arg); >> if (need_zonelists_rebuild) >> build_all_zonelists(NULL); >> - else >> - zone_pcp_update(zone); >> + zone_pcp_update(zone); >> >> init_per_zone_wmark_min(); >> >> > > Does, in general, look sane to me. > > Reviewed-by: David Hildenbrand Thanks for the ACK. > -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project