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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 8DEEBC433DB for ; Tue, 2 Feb 2021 12:17:17 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B5D6A64DAF for ; Tue, 2 Feb 2021 12:17:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B5D6A64DAF 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 1E4176B0071; Tue, 2 Feb 2021 07:17:15 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1926F6B0072; Tue, 2 Feb 2021 07:17:15 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 05BE76B0073; Tue, 2 Feb 2021 07:17:15 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0048.hostedemail.com [216.40.44.48]) by kanga.kvack.org (Postfix) with ESMTP id E38C26B0071 for ; Tue, 2 Feb 2021 07:17:14 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id AA1D91EE6 for ; Tue, 2 Feb 2021 12:17:14 +0000 (UTC) X-FDA: 77773227588.29.drug95_3e02eac275ca Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin29.hostedemail.com (Postfix) with ESMTP id 8B9B2180868DA for ; Tue, 2 Feb 2021 12:17:14 +0000 (UTC) X-HE-Tag: drug95_3e02eac275ca X-Filterd-Recvd-Size: 4066 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Tue, 2 Feb 2021 12:17:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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=k2RaVcotdcFu8XtC0FHhOwZVl2mL0n0CI/DzN9Tnq0k=; b=Mlq/Kbsh9al83KXXilK1z+etHY Y8n56IRFwIVfPokruVKN9TPIMY+alFEyb5SDyf2oq+QFJX1LYSKwSvAE2/Nuc0bBlJHVhvr2Mu6iL CzDdpFw6bUhbC4FIdH2Vmo/2wdUWTSfo14IT/T8jCQVFVUwotOw1dYQat1LoBFb3GXaOpr75PASZa fSS5JO5CtZcfTX0s5TD5B6hcRcUe+DWp7GconOLA+4YNrBzZYbeVPvX3aDg0/bdAm70WKKjcy5mu/ kdmYkykXP/KM/jqOjdhGPp+29FyM6S5jVVqJlb7jMj6JMK2wAFs3QdUFlsnHPJ37ZoGcYgH3l/poc ljrJKQmQ==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1l6ucG-00FAbn-Al; Tue, 02 Feb 2021 12:17:10 +0000 Date: Tue, 2 Feb 2021 12:17:08 +0000 From: Matthew Wilcox To: Yu Zhao Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, page-reclaim@google.com Subject: Re: Augmented Page Reclaim Message-ID: <20210202121708.GT308988@casper.infradead.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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: It's hard to know which 'note' refers to which reference. Here's my attempt to figure that out. On Tue, Feb 02, 2021 at 01:57:15AM -0700, Yu Zhao wrote: > Versatility > =========== > Userspace can trigger aging and eviction independently via the > ``debugfs`` interface [note]_ for working set estimation, proactive 1. `Long-term SLOs for reclaimed cloud computing resources `_ > reclaim, far memory tiering, NUMA-aware job scheduling, etc. The > metrics from the interface are easily interpretable, which allows > intuitive provisioning and discoveries like the Borg example above. > For a warehouse-scale computer, the interface is intended to be a > building block of a closed-loop control system, with a machine > learning algorithm being the controller. > > Simplicity > ========== > The workflow [note]_ is well defined and each step in it has a clear 2. `Profiling a warehouse-scale computer `_ > meaning. There are no magic numbers or heuristics involved but a few > basic data structures that have negligible memory footprint. This > simplicity has served us well as the scale and the diversity of our > workloads constantly grow. [...] > FAQ > === > What is the motivation for this work? > ------------------------------------- > In our case, DRAM is a major factor in total cost of ownership, and > improving memory overcommit brings a high return on investment. > Moreover, Google-Wide Profiling has been observing the high CPU > overhead [note]_ from page reclaim. 3. `Evaluation of NUMA-Aware Scheduling in Warehouse-Scale Clusters `_ > Why not try to improve the existing code? > ----------------------------------------- > We have tried but concluded the two limiting factors [note]_ in the 4. `Software-defined far memory in warehouse-scale computers `_ > existing code are fundamental, and therefore changes made atop them > will not result in substantial gains on any of the aspects above. > > What particular workloads does it help? > --------------------------------------- > This work optimizes page reclaim for workloads that are not IO bound, > because we find they are the norm on servers and clients in the cloud > era. It would most likely help any workloads that share the common > characteristics [note]_ we observed. 5. `Borg: the Next Generation `_