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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 99275C3A5A1 for ; Wed, 28 Aug 2019 13:15:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6ABB12070B for ; Wed, 28 Aug 2019 13:15:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566998105; bh=L+I8dLseUtNd85ooOmhvIDWkFtsUxJU9ZMvZK+A2JIg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=NADnYbNUMmKU1C7WzKAwOalv2qzf8d8wWapGYK/jWO7H/euakHJmOrFYH8bVTBGvE gAU0g6nt10oX8J6bSBADhrkaEthgHE+EPWX41NeyaCMk1y3KK7SIVY5faiUP1yt+2G XJnQxc+3VIeaFZn6YyrZTR+gThjJUcby5+aWkqWg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726447AbfH1NPE (ORCPT ); Wed, 28 Aug 2019 09:15:04 -0400 Received: from mx2.suse.de ([195.135.220.15]:53752 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726394AbfH1NPE (ORCPT ); Wed, 28 Aug 2019 09:15:04 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 9C991AFA4; Wed, 28 Aug 2019 13:15:02 +0000 (UTC) Date: Wed, 28 Aug 2019 15:15:01 +0200 From: Michal Hocko To: Bharath Vedartham Cc: Khalid Aziz , akpm@linux-foundation.org, vbabka@suse.cz, mgorman@techsingularity.net, dan.j.williams@intel.com, osalvador@suse.de, richard.weiyang@gmail.com, hannes@cmpxchg.org, arunks@codeaurora.org, rppt@linux.vnet.ibm.com, jgg@ziepe.ca, amir73il@gmail.com, alexander.h.duyck@linux.intel.com, linux-mm@kvack.org, linux-kernel-mentees@lists.linuxfoundation.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 0/2] Add predictive memory reclamation and compaction Message-ID: <20190828131501.GK28313@dhcp22.suse.cz> References: <20190813140553.GK17933@dhcp22.suse.cz> <3cb0af00-f091-2f3e-d6cc-73a5171e6eda@oracle.com> <20190814085831.GS17933@dhcp22.suse.cz> <20190815170215.GQ9477@dhcp22.suse.cz> <2668ad2e-ee52-8c88-22c0-1952243af5a1@oracle.com> <20190821140632.GI3111@dhcp22.suse.cz> <20190826204420.GA16800@bharath12345-Inspiron-5559> <20190827061606.GN7538@dhcp22.suse.cz> <20190828130922.GA10127@bharath12345-Inspiron-5559> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190828130922.GA10127@bharath12345-Inspiron-5559> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 28-08-19 18:39:22, Bharath Vedartham wrote: [...] > > Therefore I would like to shift the discussion towards existing APIs and > > whether they are suitable for such an advance auto-tuning. I haven't > > heard any arguments about missing pieces. > I understand your concern here. Just confirming, by APIs you are > referring to sysctls, sysfs files and stuff like that right? Yup > > > If memory exhaustion > > > occurs, we reclaim some more memory. kswapd stops reclaim when > > > hwmark is reached. hwmark is usually set to a fairly low percentage of > > > total memory, in my system for zone Normal hwmark is 13% of total pages. > > > So there is scope for reclaiming more pages to make sure system does not > > > suffer from a lack of pages. > > > > Yes and we have ways to control those watermarks that your monitoring > > tool can use to alter the reclaim behavior. > Just to confirm here, I am aware of one way which is to alter > min_kfree_bytes values. What other ways are there to alter watermarks > from user space? /proc/sys/vm/watermark_*factor -- Michal Hocko SUSE Labs