From nobody Mon Sep 8 09:46:49 2025 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 45EE9EB64DA for ; Thu, 20 Jul 2023 07:08:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231359AbjGTHIj (ORCPT ); Thu, 20 Jul 2023 03:08:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42928 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229942AbjGTHIb (ORCPT ); Thu, 20 Jul 2023 03:08:31 -0400 Received: from mail-pg1-x54a.google.com (mail-pg1-x54a.google.com [IPv6:2607:f8b0:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A8A12681 for ; Thu, 20 Jul 2023 00:08:30 -0700 (PDT) Received: by mail-pg1-x54a.google.com with SMTP id 41be03b00d2f7-563396c1299so385072a12.2 for ; Thu, 20 Jul 2023 00:08:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1689836910; x=1692428910; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=P4XNYMJYgxf4Y2ysW943aMZDD9DgQegnQSW9aAxie4w=; b=PyMiTiRslPlYxeAzNGyf+s2RMn2Y5D+io4F49/M2XRwJrS8TwV/LhLqLj0BM+kLdbs SJdh95igG91J+W+YW3QhUBoovRNlfDdy0rtENHO9Q0tdlMq6Mi6nZDp8wPmseQG3GEz7 yTNtdLVRNpjOoL79dp3VDPbMRHNV99200JwxoCivq9oH22XjolvYivx1g2ceZNC2Pn7s Da/CFyreh5mYpyR/lWRRdvMG1hkWdPWRhELE3hNZjAEKxkN7vhsHgeLNCSqpeMvOeAHq lRZ2ErdDGOl8n4urJ5Mk+4WBu+P+b25Mk8sxetPQU+cK2DCaPQPxX5kv/nJSdD/CPPwf W7UA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689836910; x=1692428910; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=P4XNYMJYgxf4Y2ysW943aMZDD9DgQegnQSW9aAxie4w=; b=D+x9Ttgf66GMzNraB1oKm0s+5HHbQiMS3S5v1q/h68SHLqhKP76fPiVOij5ia9+47k GaFHOMH3ePsFs1IURfOdTYpkYR7o36HUeB79w1pk8OU85coUGOy/nYuQknzhP/LxIJ82 u3vSSU/Z0E2SyTv7GtuOIZ351YdACFL3y4iEU43Hw/7Gd25HN/OEm5dx7MNtQCJ4KtN3 TI/ae9DnzcaND4HDATLTVIT/VPpjv1QeAVXm7V88OUFWIrhhgEJK8WozXucND4lxGYCQ nEy6nK0WVBRICPbAYJBvkz2VH6OdLvYPjwJOW9Sw/MUoRpKdlfDDe9FG+ZihJsI8mXgs SfLA== X-Gm-Message-State: ABy/qLYkgWSyZSUlW5W+VRyV9L2M3N3W8Hm9bjYyqT2LavrdslHbHjBj S42cv8T9kykYPwsUsENlkbT84b0Vku846GD9 X-Google-Smtp-Source: APBJJlEGR67b7I5wM02HN8lsWXpPeepUUbVvmNMwkaq7frNphjV2zKpBSorV/PgnNk3Mo7NS/0jW1PWGUeUjmfjP X-Received: from yosry.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2327]) (user=yosryahmed job=sendgmr) by 2002:a63:3e8f:0:b0:563:3b08:f869 with SMTP id l137-20020a633e8f000000b005633b08f869mr22818pga.2.1689836909753; Thu, 20 Jul 2023 00:08:29 -0700 (PDT) Date: Thu, 20 Jul 2023 07:08:18 +0000 In-Reply-To: <20230720070825.992023-1-yosryahmed@google.com> Mime-Version: 1.0 References: <20230720070825.992023-1-yosryahmed@google.com> X-Mailer: git-send-email 2.41.0.255.g8b1d071c50-goog Message-ID: <20230720070825.992023-2-yosryahmed@google.com> Subject: [RFC PATCH 1/8] memcg: refactor updating memcg->moving_account From: Yosry Ahmed To: Andrew Morton , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt Cc: Muchun Song , "Matthew Wilcox (Oracle)" , Tejun Heo , Zefan Li , Yu Zhao , Luis Chamberlain , Kees Cook , Iurii Zaikin , "T.J. Mercier" , Greg Thelen , linux-kernel@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, Yosry Ahmed Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" memcg->moving_account is used to signal that a memcg move is taking place, so that folio_memcg_lock() would start acquiring the per-memcg move lock instead of just initiating an rcu read section. Refactor incrementing and decrementing memcg->moving_account, together with rcu synchornization and the elaborate comment into helpers, to allow for reuse by incoming patches. Signed-off-by: Yosry Ahmed --- mm/memcontrol.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e8ca4bdcb03c..ffdb848f4003 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6305,16 +6305,26 @@ static const struct mm_walk_ops charge_walk_ops =3D= { .pmd_entry =3D mem_cgroup_move_charge_pte_range, }; =20 -static void mem_cgroup_move_charge(void) +static void mem_cgroup_start_move_charge(struct mem_cgroup *memcg) { - lru_add_drain_all(); /* * Signal folio_memcg_lock() to take the memcg's move_lock * while we're moving its pages to another memcg. Then wait * for already started RCU-only updates to finish. */ - atomic_inc(&mc.from->moving_account); + atomic_inc(&memcg->moving_account); synchronize_rcu(); +} + +static void mem_cgroup_end_move_charge(struct mem_cgroup *memcg) +{ + atomic_dec(&memcg->moving_account); +} + +static void mem_cgroup_move_charge(void) +{ + lru_add_drain_all(); + mem_cgroup_start_move_charge(mc.from); retry: if (unlikely(!mmap_read_trylock(mc.mm))) { /* @@ -6334,7 +6344,7 @@ static void mem_cgroup_move_charge(void) */ walk_page_range(mc.mm, 0, ULONG_MAX, &charge_walk_ops, NULL); mmap_read_unlock(mc.mm); - atomic_dec(&mc.from->moving_account); + mem_cgroup_end_move_charge(mc.from); } =20 static void mem_cgroup_move_task(void) --=20 2.41.0.255.g8b1d071c50-goog