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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 99706C2BA19 for ; Wed, 15 Apr 2020 11:32:33 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5284020737 for ; Wed, 15 Apr 2020 11:32:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Hvd2px1g" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5284020737 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id EEF3C8E000E; Wed, 15 Apr 2020 07:32:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E9F3B8E0001; Wed, 15 Apr 2020 07:32:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D400F8E000E; Wed, 15 Apr 2020 07:32:32 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0187.hostedemail.com [216.40.44.187]) by kanga.kvack.org (Postfix) with ESMTP id B7E5D8E0001 for ; Wed, 15 Apr 2020 07:32:32 -0400 (EDT) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 5E6AF5DD3 for ; Wed, 15 Apr 2020 11:32:32 +0000 (UTC) X-FDA: 76709876544.18.corn27_333d53f261b08 X-HE-Tag: corn27_333d53f261b08 X-Filterd-Recvd-Size: 3176 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf29.hostedemail.com (Postfix) with ESMTP for ; Wed, 15 Apr 2020 11:32:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=IJiQ+eOHsfyCYt3l0kllphhznQD2NCgBQ/HSamSBJWY=; b=Hvd2px1ghMgtRjoeyAfhjQ4Pgg wF35jYsZarX+C95QKpbHD2KQpRe+JDpJIuuu7Sgw6wyCMWobQVpi8CgvB4XND6weM357HTLruYWJA yq/rBe56qZQDyyxhVR2SB0NPKPTuUDZ4FWaYVuB6DSv98kdM9tpI3tJnljUuR8JvSfZIRKKxOL7qy f+9Wy1/y8jaYpNmju0yyfO9ZBY0RtnVtWz1cqM+vi+br0lCAt3eHoUiLcYstMed0HkSFqBJ8kqeOi GagxHZAMETWaDiG7TvDzCmQOr8P77GRvHU4p4JFXmAVvjmK4+iAIolj4oGQQmQYIH9jtOuK6XwnpQ DzqviHUA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jOgHN-000539-M3; Wed, 15 Apr 2020 11:32:29 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 0CA7F30066E; Wed, 15 Apr 2020 13:32:26 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id C2365203A8983; Wed, 15 Apr 2020 13:32:26 +0200 (CEST) Date: Wed, 15 Apr 2020 13:32:26 +0200 From: Peter Zijlstra To: Mel Gorman Cc: Huang Ying , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Ingo Molnar , Mel Gorman , Rik van Riel , Daniel Jordan , Tejun Heo , Dave Hansen , Tim Chen , Aubrey Li Subject: Re: [RFC] autonuma: Support to scan page table asynchronously Message-ID: <20200415113226.GE20730@hirez.programming.kicks-ass.net> References: <20200414081951.297676-1-ying.huang@intel.com> <20200414120646.GN3818@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200414120646.GN3818@techsingularity.net> 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: On Tue, Apr 14, 2020 at 01:06:46PM +0100, Mel Gorman wrote: > While it's just an opinion, my preference would be to focus on reducing > the cost and amount of scanning done -- particularly for threads. This; I really don't believe in those back-charging things, esp. since not having cgroups or having multiple applications in a single cgroup is a valid setup. Another way to reduce latency spikes is to decrease both sysctl_numa_balancing_scan_delay and sysctl_numa_balancing_scan_size. Then you do more smaller scans. By scanning more often you reduce the contrast, by reducing the size you lower the max latency. And this is all assuming you actually want numa balancing for this process.