From patchwork Fri Dec 13 13:02:08 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: SeongJae Park X-Patchwork-Id: 11290573 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5E3A018B6 for ; Fri, 13 Dec 2019 20:36:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1117224720 for ; Fri, 13 Dec 2019 20:36:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="N6i0hqkB" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727197AbfLMNCd (ORCPT ); Fri, 13 Dec 2019 08:02:33 -0500 Received: from mail-pf1-f195.google.com ([209.85.210.195]:34279 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726345AbfLMNCd (ORCPT ); Fri, 13 Dec 2019 08:02:33 -0500 Received: by mail-pf1-f195.google.com with SMTP id l127so1457673pfl.1; Fri, 13 Dec 2019 05:02:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=ZPc8DBX2ZfbjwaEgLInVI3S8HFj/56kByg4DfIObTMc=; b=N6i0hqkBEVIM+jlUwMzon0U9mzngTnFvijSsH1izi82SQgmncvfMlOQRxxSCyeRErs WL56byCPvCe56fFydeRT2Ia4b/SzfWT2nd2PyfZ8vUpQ8onIG/VXPCnOIRrdUdSwtG63 ch7UzZhNMp0ZTyzc0uONuiAZkgDnVOJF3coeex5qeyFLx1wEhvsqQt9hZY585vTPGgXK FiakZ3BYj4Xz43/FfNyprjLZut5G0uv1r90pWwxn2PrmhrU878wZcyYE3R/Nk3Xz4Ckk 1VCU4LgCDj5ZlW7cKLFKT67YYsfp7cu4VgRy3/23ZycJBD8ly5bH5maHZuQspiTHJMfS OCBg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=ZPc8DBX2ZfbjwaEgLInVI3S8HFj/56kByg4DfIObTMc=; b=YXDdXkeaJnF/9SfzeE40XbvoWrnVzZl0+eJeTn8r2G953JKO8agILLYRkOpIHq6mh7 +dYOAhe8uJE4biO7saUP8O651DwkLafeWs3UgsLL50gX5Ie9VGLUI7mAYMbvbrLUs2Tz StKGHARneNDsEJXGAOSyY09zzHQ6P5CxWJEcR6yZoB6BbxSntvlOHbw90A1vdbPiro1L Q5fA9BVHV0GZFl2jUYtCJQPgzlGdRqNVAJBLY7xF+AIyWKK5Vgsr74S2mSzr6W7RAUBo Kp06a1Zh8gOaRWPZQ5V1TbxqpYjR/hf6j0WhGxc4uEHY/zO+1fxim6OjAUlnzDEKY749 oIlg== X-Gm-Message-State: APjAAAX5vBeXRidGGcVRuMX+KpFw+9EbadPRVWtRjMIfmeY7/Kwkyydf F/9fcu+UPd2FhD4EXeyKoCo= X-Google-Smtp-Source: APXvYqwwGYLLtINm/TP+G8Tba8uazrIqTPMf1a8m0SsSyI2D6fxD3WkOSpHXI4F9WCaxEyvwPl52lg== X-Received: by 2002:aa7:9808:: with SMTP id e8mr16113067pfl.32.1576242152522; Fri, 13 Dec 2019 05:02:32 -0800 (PST) Received: from localhost.localdomain ([12.176.148.120]) by smtp.gmail.com with ESMTPSA id k3sm10872278pgc.3.2019.12.13.05.02.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Dec 2019 05:02:31 -0800 (PST) From: SeongJae Park X-Google-Original-From: SeongJae Park To: jgross@suse.com, axboe@kernel.dk, konrad.wilk@oracle.com, roger.pau@citrix.com Cc: SeongJae Park , pdurrant@amazon.com, sjpark@amazon.com, sj38.park@gmail.com, xen-devel@lists.xenproject.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v8 0/3] xenbus/backend: Add a memory pressure handler callback Date: Fri, 13 Dec 2019 13:02:08 +0000 Message-Id: <20191213130211.24011-1-sjpark@amazon.de> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Granting pages consumes backend system memory. In systems configured with insufficient spare memory for those pages, it can cause a memory pressure situation. However, finding the optimal amount of the spare memory is challenging for large systems having dynamic resource utilization patterns. Also, such a static configuration might lack flexibility. To mitigate such problems, this patchset adds a memory reclaim callback to 'xenbus_driver' (patch 1) and use it to mitigate the problem in 'xen-blkback' (patch 2). The third patch is a trivial cleanup of variable names. Base Version ------------ This patch is based on v5.4. A complete tree is also available at my public git repo: https://github.com/sjp38/linux/tree/blkback_squeezing_v8 Patch History ------------- Changes from v7 (https://lore.kernel.org/xen-devel/20191211181016.14366-1-sjpark@amazon.de/) - Update sysfs-driver-xen-blkback for new parameter (suggested by Roger Pau Monné) - Use per-xen_blkif buffer_squeeze_end instead of global variable (suggested by Roger Pau Monné) Changes from v6 (https://lore.kernel.org/linux-block/20191211042428.5961-1-sjpark@amazon.de/) - Remove more unnecessary prefixes (suggested by Roger Pau Monné) - Constify a variable (suggested by Roger Pau Monné) - Rename 'reclaim' into 'reclaim_memory' (suggested by Roger Pau Monné) - More wordsmith of the commit message (suggested by Roger Pau Monné) Changes from v5 (https://lore.kernel.org/linux-block/20191210080628.5264-1-sjpark@amazon.de/) - Wordsmith the commit messages (suggested by Roger Pau Monné) - Change the reclaim callback return type (suggested by Roger Pau Monné) - Change the type of the blkback squeeze duration variable (suggested by Roger Pau Monné) - Add a patch for removal of unnecessary static variable name prefixes (suggested by Roger Pau Monné) - Fix checkpatch.pl warnings Changes from v4 (https://lore.kernel.org/xen-devel/20191209194305.20828-1-sjpark@amazon.com/) - Remove domain id parameter from the callback (suggested by Juergen Gross) - Rename xen-blkback module parameter (suggested by Stefan Nuernburger) Changes from v3 (https://lore.kernel.org/xen-devel/20191209085839.21215-1-sjpark@amazon.com/) - Add general callback in xen_driver and use it (suggested by Juergen Gross) Changes from v2 (https://lore.kernel.org/linux-block/af195033-23d5-38ed-b73b-f6e2e3b34541@amazon.com) - Rename the module parameter and variables for brevity (aggressive shrinking -> squeezing) Changes from v1 (https://lore.kernel.org/xen-devel/20191204113419.2298-1-sjpark@amazon.com/) - Adjust the description to not use the term, `arbitrarily` (suggested by Paul Durrant) - Specify time unit of the duration in the parameter description, (suggested by Maximilian Heyne) - Change default aggressive shrinking duration from 1ms to 10ms - Merge two patches into one single patch SeongJae Park (3): xenbus/backend: Add memory pressure handler callback xen/blkback: Squeeze page pools if a memory pressure is detected xen/blkback: Remove unnecessary static variable name prefixes .../ABI/testing/sysfs-driver-xen-blkback | 9 +++ drivers/block/xen-blkback/blkback.c | 57 ++++++++++++------- drivers/block/xen-blkback/common.h | 2 + drivers/block/xen-blkback/xenbus.c | 11 +++- drivers/xen/xenbus/xenbus_probe_backend.c | 32 +++++++++++ include/xen/xenbus.h | 1 + 6 files changed, 90 insertions(+), 22 deletions(-)