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 678EDC433F5 for ; Thu, 31 Mar 2022 06:40:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231316AbiCaGlv (ORCPT ); Thu, 31 Mar 2022 02:41:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59766 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230375AbiCaGlr (ORCPT ); Thu, 31 Mar 2022 02:41:47 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7AEF3656F for ; Wed, 30 Mar 2022 23:40:00 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id x9-20020a5b0809000000b00631d9edfb96so17185699ybp.22 for ; Wed, 30 Mar 2022 23:40:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc:content-transfer-encoding; bh=2EO1zCBkMeInrvtUm5zFLSJgdsvUYdhYvGrInIQEHn8=; b=BuraXhTICGesUuAWshpPBGws+qpwfbbToioiwotOHb/5C7i4EF/ANXjMpswRm2Amcy NzVB9MrpgHzoXUX4+6yujhXOdX4S1tUk9vWlZGm39O2Mikz+KUApMWDYtFXEqkYh7Luw zyh+TARfdaiF3PszRIMmm/mzUHOeGUT/0fWReMG5Fyj9dn/LjNoGbC1OWvFCT2tk06ge aQfZPXeGJ4grNqItzGlUsH0WFjVwzTPu2I1HyXPDW/RnZlPBtSUJ3984lac5I3jwsNvD srATOlGPmkvXo3TEQ3WQ4pHZ55OCSFX93ec/0vMwhOd5xmRlCWLOoolX/XTXpiNH9uyq AqIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc:content-transfer-encoding; bh=2EO1zCBkMeInrvtUm5zFLSJgdsvUYdhYvGrInIQEHn8=; b=HUrrRQ0HKuqq+puaOMjJIp9YdnOFfECLcXk6bnP2MITyzHN6jm3fB6F/6p+269jLzv WPcMw6ar9zeR1cBr8kBj99QhyRBa36xHBWsWnaTXP5itv3kw+KMOfsZ+Co3FbWMZeRQV wXXr6kmIpv+Fthr6cPDWZ2u5/qRwlUJPdQzqz3YfTiw1wiw4Lbp+XIZ5i2d/9nv3tk9c nnPR2suxtv1sV4f+XjaSuhh96VWDjcha//dOMJyxXD17h+15xIat9xoVn89DgLDUwEdm bjEA0BfryisXulO7qxC5DZ6bVVpaUS3+kjrUcOa6mjKUw3auB0usy9WaIqNsqaM0eU2S 0w/w== X-Gm-Message-State: AOAM531qzDZSnfrOguyxVaBmCAIVsj3XgDFGSrZmS1B496WktNZT2/Os kNa2wZxjVg1LgONOIy3QjClo3P1PbcS6vw== X-Google-Smtp-Source: ABdhPJyt7GDJgAVqiqYMHwpK4PthMSnXQEN6sLNCWOjUDvSjiidXMxyP21GtktoorZ34FUmloIhvrzRQBKD8QA== X-Received: from shakeelb.c.googlers.com ([fda3:e722:ac3:cc00:20:ed76:c0a8:28b]) (user=shakeelb job=sendgmr) by 2002:a25:b889:0:b0:633:c93e:3e18 with SMTP id w9-20020a25b889000000b00633c93e3e18mr3141444ybj.263.1648708799467; Wed, 30 Mar 2022 23:39:59 -0700 (PDT) Date: Thu, 31 Mar 2022 06:39:56 +0000 In-Reply-To: <89B53D3A-FCC5-4107-8D49-81D5B9AE5172@linux.dev> Message-Id: <20220331063956.5uqnab64cqnmcwyr@google.com> Mime-Version: 1.0 References: <20220330191440.1cc1b2de2b849d1ba93d2ba7@linux-foundation.org> <89B53D3A-FCC5-4107-8D49-81D5B9AE5172@linux.dev> Subject: Re: [PATCH v2] mm/list_lru: Fix possible race in memcg_reparent_list_lru_node() From: Shakeel Butt To: Roman Gushchin Cc: Andrew Morton , Waiman Long , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Muchun Song Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 30, 2022 at 07:48:45PM -0700, Roman Gushchin wrote: >=20 >=20 [...] >=20 >=20 > But honestly, I=E2=80=99d drop the original optimization together with th= e fix, if only there is no _real world_ data on the problem and the improve= ment. It seems like it has started as a nice simple improvement, but the ra= ce makes it complex and probably not worth the added complexity and fragili= ty. I agree with dropping the original optimization as it is not really fixing an observed issue which may justify adding some complexity. thanks, Shakeel