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 X-Spam-Level: X-Spam-Status: No, score=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6EAFEC11F64 for ; Thu, 1 Jul 2021 16:09:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 39C6561222 for ; Thu, 1 Jul 2021 16:09:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232167AbhGAQMJ (ORCPT ); Thu, 1 Jul 2021 12:12:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55912 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231698AbhGAQMI (ORCPT ); Thu, 1 Jul 2021 12:12:08 -0400 Received: from mail-yb1-xb2e.google.com (mail-yb1-xb2e.google.com [IPv6:2607:f8b0:4864:20::b2e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA37CC061762 for ; Thu, 1 Jul 2021 09:09:36 -0700 (PDT) Received: by mail-yb1-xb2e.google.com with SMTP id s129so11712678ybf.3 for ; Thu, 01 Jul 2021 09:09:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=uzi1kcVee3nZI004Eqmdf8y65g93K4CPvU+WDS5oQ0o=; b=UbI4NvvhXAKF6UJlUQJnCnIZTrPzaWdjQcU6NH0GrVU6eIit+YEfiMywDOAfxqk9o9 tAUXpeb60OkDSx9bD6lOX62A/UBZAJD8ptJRlCml6KoBg4ua6O6q9JCyDDSeZAj+QAkc WrJ5xeq2NOCp7aRcUS+yoclphDIkKOJdP8slkfbniGOfPxYm2Q/Jjjtv4olDqfLSSyxZ Dg7d03u2ogyibOVT+ShLOuJkKEI+IxOjT8XjAxolKK3GwvR6JtkTLTQBfj7oACQa/1cF C9yD3GteMdLWIIqy6hn/UTSwQ4n+A0f+lkYgWr+9bF5kE11px+0WS5EtvAqbmPm5iY/O 0TgA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=uzi1kcVee3nZI004Eqmdf8y65g93K4CPvU+WDS5oQ0o=; b=eNqRqIPrU26jsyCa1FwYwefa/Isa/GHrgQ38bVGKsWeB/Mcuz+E2kfMQzjRMoQh4KJ kmXDK9fBldQB/uq7s6ZH34HRd43nSzjzL8PQ1F4EVMVTV69TgB8vOfO9PgxqYkfkVNXW zRxi/GnxFfZPeeARKIdp+joBHAcW8MJeDSt6p3e3HG8ktOoDICkxM0DFwudIcKx48KML sruyspJ+ivRc+ROi0gKfM9i7woVLu9bT1XxL5iyAr4uuAVLnd4eJ+R8zo7EwAd7a4h2u JvKpSkNUeBk3Am/M7ZoNpCmYejBOIe1Pr6WtEfhya0q0GU4f7jFOzoPeIrzed8DosAjt 2Dow== X-Gm-Message-State: AOAM532wXe8FRrlrNNuBjUUMMp2zyUtgIIUGLsTyH2DagNVdW3GFymid jPCgqlpuTomhUdzZVeoFCRhQwgVBEnDukbrxYH67kg== X-Google-Smtp-Source: ABdhPJw73TwvlM3X+UsxZTrZkl7Yi035kGpgDESa4lssYP9pUQ2usK2Q7Aza4S0poCiOx0NH2LqRyPpMJYSPU/Q/uYs= X-Received: by 2002:a25:7ec4:: with SMTP id z187mr668800ybc.136.1625155775937; Thu, 01 Jul 2021 09:09:35 -0700 (PDT) MIME-Version: 1.0 References: <20210630205151.137001-1-surenb@google.com> In-Reply-To: From: Suren Baghdasaryan Date: Thu, 1 Jul 2021 09:09:25 -0700 Message-ID: Subject: Re: [PATCH v2 1/1] psi: stop relying on timer_pending for poll_work rescheduling To: Peter Zijlstra Cc: Johannes Weiner , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Benjamin Segall , Mel Gorman , Daniel Bristot de Oliveira , matthias.bgg@gmail.com, Minchan Kim , Tim Murray , YT Chang , =?UTF-8?B?V2VuanUgWHUgKOiuuOaWh+S4vik=?= , =?UTF-8?B?Sm9uYXRoYW4gSk1DaGVuICjpmbPlrrbmmI4p?= , LKML , linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, kernel-team , SH Chen Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 1, 2021 at 1:59 AM Peter Zijlstra wrote: > > On Wed, Jun 30, 2021 at 01:51:51PM -0700, Suren Baghdasaryan wrote: > > + /* cmpxchg should be called even when !force to set poll_scheduled */ > > + if (atomic_cmpxchg(&group->poll_scheduled, 0, 1) && !force) > > return; > > Why is that a cmpxchg() ? We want to set poll_scheduled and proceed with rescheduling the timer unless it's already scheduled, so cmpxchg helps us to make that decision atomically. Or did I misunderstand your question? > > -- > To unsubscribe from this group and stop receiving emails from it, send an email to kernel-team+unsubscribe@android.com. >