From patchwork Tue Feb 28 08:50:00 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yosry Ahmed X-Patchwork-Id: 13154530 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33441C64EC7 for ; Tue, 28 Feb 2023 08:50:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230450AbjB1IuQ (ORCPT ); Tue, 28 Feb 2023 03:50:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33100 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229786AbjB1IuO (ORCPT ); Tue, 28 Feb 2023 03:50:14 -0500 Received: from mail-pf1-x449.google.com (mail-pf1-x449.google.com [IPv6:2607:f8b0:4864:20::449]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E35C9900B for ; Tue, 28 Feb 2023 00:50:06 -0800 (PST) Received: by mail-pf1-x449.google.com with SMTP id a25-20020a056a001d1900b005e82b3dc9f4so4773193pfx.1 for ; Tue, 28 Feb 2023 00:50:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1677574206; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=xdSAVrwCtkhEWC8GgYYqKMfIX8yBwrpfZDbmqtRyDyA=; b=SOVV++5ZdqitZ36JKIv2fFMUIZWr2mRvM+1SYrMDqxcU64YKMcyXiXS7/JBzrMzVGR a6lwTwArMZ5cvyX8urVSHUrUuVQOSfF42XGvNomA8Tvnp0LV06/wsJWl0LMz4W76Db5h y3jUa5jifEAMLoWLF0Zr9sO3rNX27weBBlTgPK6tlMagy9lhu6URapPi6JL/AiWDq+/O xpiOl8e/9NHV1lIOw2MgMwgF5M6/In9pOSbo61IAhJJdv/IGVjLeA7M8iH+2ekiFYHMp H9Jqpmo7RoeMES/COvqdvDIkncurMcMLwWiPU0V57IM51nNJ+lMIpEBY3rU7HFrTSgtB lU7w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1677574206; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=xdSAVrwCtkhEWC8GgYYqKMfIX8yBwrpfZDbmqtRyDyA=; b=xMDT0Hc96jeOyBBU7BXEILd0SPUnraWUKaLugf9Sf2EszlKJPsRBwIpCXOHYUcag71 iVe56vhVrDXy4YvyBW8iVWw0L8LP4HUJn3K8uJMtpPr2sjrL2Citt2cQb0CG2loCU3Cr O21wg1v3ufAGlScOJrah8OWMIFyu4A4BCrEnmMZQfGB6R0Oop8uXQuKSnf+j1AWIa0R1 g/IuFfiFZ0oUixZCRVe8uNM5ftJEJVMuViN2eo16ppm4bGnGYt3e8bUHMchxZtZEfCTu sNKGxVin7OFg6WVcNPXayNxGVEv//ZdpnGAJQzUA/z6101AJTmr2Bfc2Mdbb2ZmXOmyy Sb+Q== X-Gm-Message-State: AO0yUKW62kTyWmHO1iTXiobe/5ixD2xJj2ChwbPcKFndKvig5WFvCoay U+k1/1b7nBxEwDOpAmK5POQkVpbixjwbl/a0 X-Google-Smtp-Source: AK7set9xyaSEGINDP0JdrxfWpmvgvG2OFkld3cb1qL57vscSNy7S0nejYo/cjvFVY+VnsY2ooCNyScP6qk2951NZ X-Received: from yosry.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2327]) (user=yosryahmed job=sendgmr) by 2002:a17:902:6bc5:b0:19c:fc1b:e600 with SMTP id m5-20020a1709026bc500b0019cfc1be600mr684030plt.5.1677574206196; Tue, 28 Feb 2023 00:50:06 -0800 (PST) Date: Tue, 28 Feb 2023 08:50:00 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.39.2.722.g9855ee24e9-goog Message-ID: <20230228085002.2592473-1-yosryahmed@google.com> Subject: [PATCH v1 0/2] Ignore non-LRU-based reclaim in memcg reclaim From: Yosry Ahmed To: Alexander Viro , "Darrick J. Wong" , Christoph Lameter , David Rientjes , Joonsoo Kim , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, "Matthew Wilcox (Oracle)" , Miaohe Lin , David Hildenbrand , Johannes Weiner , Peter Xu , NeilBrown , Shakeel Butt , Michal Hocko Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, Yosry Ahmed Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Reclaimed pages through other means than LRU-based reclaim are tracked through reclaim_state in struct scan_control, which is stashed in current task_struct. These pages are added to the number of reclaimed pages through LRUs. For memcg reclaim, these pages generally cannot be linked to the memcg under reclaim and can cause an overestimated count of reclaimed pages. This short series tries to address that. Patch 1 is just refactoring updating reclaim_state into a helper function, and renames reclaimed_slab to just reclaimed, with a comment describing its true purpose. Patch 2 ignores pages reclaimed outside of LRU reclaim in memcg reclaim. The pages are uncharged anyway, so even if we end up under-reporting reclaimed pages we will still succeed in making progress during charging. Do not let the diff stat trick you, patch 2 is a one-line change. All the rest is moving a couple of functions around and a huge comment :) RFC -> v1: - Exported report_freed_pages in case XFS is built as a module (Matthew Wilcox). - Renamed reclaimed_slab to reclaim in previously missed MGLRU code. - Refactored using reclaim_state to update sc->nr_reclaimed into a helper and added an XL comment explaining why we ignore reclaim_state->reclaimed in memcg reclaim (Johannes Weiner). Yosry Ahmed (2): mm: vmscan: refactor updating reclaimed pages in reclaim_state mm: vmscan: ignore non-LRU-based reclaim in memcg reclaim fs/inode.c | 3 +- fs/xfs/xfs_buf.c | 3 +- include/linux/swap.h | 5 ++- mm/slab.c | 3 +- mm/slob.c | 6 ++-- mm/slub.c | 5 ++- mm/vmscan.c | 79 +++++++++++++++++++++++++++++++++++--------- 7 files changed, 74 insertions(+), 30 deletions(-)