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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1D80C77B62 for ; Thu, 30 Mar 2023 07:43:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229572AbjC3HnV (ORCPT ); Thu, 30 Mar 2023 03:43:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43450 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229563AbjC3HnQ (ORCPT ); Thu, 30 Mar 2023 03:43:16 -0400 Received: from mail-ed1-x52f.google.com (mail-ed1-x52f.google.com [IPv6:2a00:1450:4864:20::52f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5EF7A5FF7 for ; Thu, 30 Mar 2023 00:43:14 -0700 (PDT) Received: by mail-ed1-x52f.google.com with SMTP id y4so73024015edo.2 for ; Thu, 30 Mar 2023 00:43:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1680162192; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=+Qxb+z0M56kXGKsGqUzmde7aSXJSNER5bkDSqRNFsW8=; b=UJBukVFEt5dB7HsMZhm8rpG6GkSrR6oamn4AyWhd8ZQPOX1GhBV/ZV16dR83JU1y/X N30JaFrz+2vGq5ca63TxcCERgT6qek7mqtmN81N5//AscM6N8cflImnSD/ZahG+4q0Xn 9qp/XyM4ZMQRj7L0H7/4AehjvjsguULR7WeiMPvo+WNkpMojlq5AXSO5o21krpYdZ7B3 PB9AZFZMuLkAAEJQVYvz3QY9bGxfNFE34InRWkd4v45XrEk3Mww05p5yDkBJhramLr+a T7lX9urUThW1psrr/JFE2xLVVKoi0OfuM7xGQ2KkdeGHTHhVMnrIjKr3CZ5s/MVVlIAH QpSA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680162192; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=+Qxb+z0M56kXGKsGqUzmde7aSXJSNER5bkDSqRNFsW8=; b=HNDQT8AkcdvZY2kumYVdyCuPXP94+EfcweDJxNbR9Sf56gNmtTZHLR6WxeJJpDqx7/ cdZOfhvYjfMIE93ddZ3tnDmzHOrhOpBXqY9S5S1AjJJb0ze1v/YkiBLUH541wRzkPqFk SrvE5IY9wL4UNf288NTBAn2m3MkpIkWjkGOyK6GZVEcg/2UmaNni9lGtvMeVVLQfQHeH IcS7ox21Al0zTerGDzIcu+JSC0sfa0BRjA9vGqpA66Z01AZMUQ3Zc6UN8G2Z8ztKcWJ9 uRTFGfSBNVv/uwzINfyrekwzV10r5RzeoT4pfT/L/WlfaNDP7VqYxqVeZB7kutiD8XTE OH1g== X-Gm-Message-State: AAQBX9eea4ssj4qs3tyh4/J9H1ZA6eG0afVWZ05D44Xv2ii8PkuvciLW ktw5yIUvXd7lQe1UN7PFmWZl6nZAFuo7JTKbZqm3eQ== X-Google-Smtp-Source: AKy350adp4S5XsudZey37elUZ5q0L0p7Iwz+j7h/yciRdtLAgVA0EL7LYgLVZr1SbfHf+UbmlaKLQyfCX54NppPfH9M= X-Received: by 2002:a17:907:7b8a:b0:931:6e39:3d0b with SMTP id ne10-20020a1709077b8a00b009316e393d0bmr11518130ejc.15.1680162192486; Thu, 30 Mar 2023 00:43:12 -0700 (PDT) MIME-Version: 1.0 References: <20230328221644.803272-1-yosryahmed@google.com> <20230328221644.803272-8-yosryahmed@google.com> In-Reply-To: From: Yosry Ahmed Date: Thu, 30 Mar 2023 00:42:36 -0700 Message-ID: Subject: Re: [PATCH v2 7/9] workingset: memcg: sleep when flushing stats in workingset_refault() To: Michal Hocko Cc: Tejun Heo , Josef Bacik , Jens Axboe , Zefan Li , Johannes Weiner , Roman Gushchin , Shakeel Butt , Muchun Song , Andrew Morton , =?UTF-8?Q?Michal_Koutn=C3=BD?= , Vasily Averin , cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, bpf@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Thu, Mar 30, 2023 at 12:39=E2=80=AFAM Michal Hocko wro= te: > > On Tue 28-03-23 22:16:42, Yosry Ahmed wrote: > > In workingset_refault(), we call > > mem_cgroup_flush_stats_atomic_ratelimited() to flush stats within an > > RCU read section and with sleeping disallowed. Move the call above > > the RCU read section and allow sleeping to avoid unnecessarily > > performing a lot of work without sleeping. > > Could you say few words why the flushing is done before counters are > updated rather than after (the RCU section)? It's not about the counters that are updated, it's about the counters that we read. Stats readers do a flush first to read accurate stats. We flush before a read, not after an update. > -- > Michal Hocko > SUSE Labs