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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 40EFFCA9EAF for ; Thu, 24 Oct 2019 16:16:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 15C7120659 for ; Thu, 24 Oct 2019 16:16:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="BHGKBeKv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2439752AbfJXQQq (ORCPT ); Thu, 24 Oct 2019 12:16:46 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:53847 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2436642AbfJXQQq (ORCPT ); Thu, 24 Oct 2019 12:16:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1571933805; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WrXRA91ehMR0EzuxH1to9rpY9XdaZv5EaEIpkHE/k+E=; b=BHGKBeKvEFcueCgTCabNqJHKHhYnM/wFHerReqCnDnDpCfEABJXsSCP/6VwIBGL/VBRv5J Z8hL4aPSBNwljgvrTr38+2F44ySOTwJexghUFPR/AmKgVStcGAmoN/uQrVzg9NT2NRxot3 wMxrhRRfFWmQoOt7u5qxJq+4QFzc76w= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-71-XIdfVkwhOSmqJ6Ejx3r1Tw-1; Thu, 24 Oct 2019 12:16:41 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5B520800D5A; Thu, 24 Oct 2019 16:16:39 +0000 (UTC) Received: from llong.remote.csb (ovpn-125-205.rdu2.redhat.com [10.10.125.205]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9CE85452B; Thu, 24 Oct 2019 16:16:34 +0000 (UTC) Subject: Re: [RFC PATCH 0/2] mm/vmstat: Reduce zone lock hold time when reading /proc/pagetypeinfo To: Michal Hocko , Andrew Morton , Mel Gorman Cc: Johannes Weiner , Roman Gushchin , Vlastimil Babka , Konstantin Khlebnikov , Jann Horn , Song Liu , Greg Kroah-Hartman , Rafael Aquini , linux-mm@kvack.org, LKML References: <20191023095607.GE3016@techsingularity.net> <20191023102737.32274-1-mhocko@kernel.org> <20191024082042.GS17610@dhcp22.suse.cz> From: Waiman Long Organization: Red Hat Message-ID: <55c08581-a9c8-27cc-9710-b2bfe1934c8e@redhat.com> Date: Thu, 24 Oct 2019 12:16:34 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20191024082042.GS17610@dhcp22.suse.cz> Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-MC-Unique: XIdfVkwhOSmqJ6Ejx3r1Tw-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/24/19 4:20 AM, Michal Hocko wrote: > On Wed 23-10-19 12:27:35, Michal Hocko wrote: > [...] >> I went with a bound to the pages iteratred over in the free_list. See >> patch 2. > I will fold http://lkml.kernel.org/r/20191023180121.GN17610@dhcp22.suse.c= z > to patch 2 unless there are any objections. If there are no further > comments I will send the two patches without an RFC tomorrow. > > Thanks for all the feedback. I am fine with your change. My concern is to make sure that there is a reasonable bound to the worst case scenario. With that change, the upper bound is iterating 100,000 list entries. I think Andrew suggested lowering it to 1024. That I think may be too low, but I don't mind if it is lowered somewhat from the current value. Cheers, Longman