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 3D5DBC433EF for ; Fri, 17 Dec 2021 18:04:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235303AbhLQSEm (ORCPT ); Fri, 17 Dec 2021 13:04:42 -0500 Received: from mail-oi1-f173.google.com ([209.85.167.173]:44931 "EHLO mail-oi1-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232748AbhLQSEl (ORCPT ); Fri, 17 Dec 2021 13:04:41 -0500 Received: by mail-oi1-f173.google.com with SMTP id be32so4747313oib.11; Fri, 17 Dec 2021 10:04:41 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=AH97IwBNJIJm9oc3jMyoL+svzU4PCiOwNagYFbvofyA=; b=2Et8OwygE1L10RBck00k7sVUQaWiFSYSRYFVhd3b2x/tp2yV+WlFQgKpLYIgaX0v+2 i85c035HAWmK7EeTCgeQ+AqNPBWpOiXiyuEffZEfXm35htnHbe1hqTm1ARKtYMXMZ8LS qtcDMqKU16EIUAW3nnyBkeg6xrpUURbriuT0f1mF+LplX8GMfz1uE8Sy0UHBDTC6MZ6h fTUJfvphaiWftPLlDOVgLiQrfy3eL/ENPzTMl0sAkZL8u6edMBsezmQpKZs+Rl268bhr gDhIAifNw9Fvs53yUF2EIAIgs2i/eMLYOkn6nRGBLLUhUHD4hTdocsKqZPRpqVd726w1 VxeA== X-Gm-Message-State: AOAM530G1p1lDh9/z+9gSvXZGlVHQhFQFPHwlig0NtXymJqvCn6D/tuT febMlys02jzcCLZ+IU6VrViorXGr9/8qcKkpp0gX4OtF X-Google-Smtp-Source: ABdhPJwRHo+5sgFP4kB/Ch4fx9oQJANf8NwGSAyEUculPGz+k7dGdG/jGUuGpxoQUvCwgT1+eQSVEJdX9fu9fhUPSHg= X-Received: by 2002:a05:6808:1454:: with SMTP id x20mr3061880oiv.166.1639764281033; Fri, 17 Dec 2021 10:04:41 -0800 (PST) MIME-Version: 1.0 References: <20211206122952.74139-1-kirill.shutemov@linux.intel.com> <20211206122952.74139-3-kirill.shutemov@linux.intel.com> <20211209133217.omm3mzchsfippwjc@black.fi.intel.com> In-Reply-To: <20211209133217.omm3mzchsfippwjc@black.fi.intel.com> From: "Rafael J. Wysocki" Date: Fri, 17 Dec 2021 19:04:30 +0100 Message-ID: Subject: Re: [PATCH 2/4] ACPI: PM: Remove redundant cache flushing To: "Kirill A. Shutemov" Cc: "Rafael J. Wysocki" , Andi Kleen , Borislav Petkov , Dan Williams , Dave Hansen , "H. Peter Anvin" , Kuppuswamy Sathyanarayanan , ACPI Devel Maling List , Linux Kernel Mailing List , Ingo Molnar , "Rafael J. Wysocki" , Kuppuswamy Sathyanarayanan , Thomas Gleixner , Tony Luck , "the arch/x86 maintainers" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Thu, Dec 9, 2021 at 2:32 PM Kirill A. Shutemov wrote: > > On Tue, Dec 07, 2021 at 05:35:38PM +0100, Rafael J. Wysocki wrote: > > I don't think this is needed for S2, because the function doesn't do > > anything low-level in that case and simply returns (IOW, S2 isn't > > really supported). > > Updated patch is below. Does it look good? It does, and so applied as 5.17 material with some minor edits in the changelog. Thanks! > From 5eb4ec7d8dd463ba186b779dcef2a802d999c59c Mon Sep 17 00:00:00 2001 > From: "Kirill A. Shutemov" > Date: Thu, 9 Dec 2021 16:08:02 +0300 > Subject: [PATCH 1/2] ACPI: PM: Remove redundant cache flushing > > ACPICA code takes care about cache flushing on S1/S2/S3 in > acpi_hw_extended_sleep() and acpi_hw_legacy_sleep(). > > acpi_suspend_enter() calls into ACPICA code via acpi_enter_sleep_state() > for S1 or x86_acpi_suspend_lowlevel() for S3. > > acpi_sleep_prepare() call tree: > __acpi_pm_prepare() > acpi_pm_prepare() > acpi_suspend_ops::prepare_late() > acpi_hibernation_ops::pre_snapshot() > acpi_hibernation_ops::prepare() > acpi_suspend_begin_old() > acpi_suspend_begin_old::begin() > acpi_hibernation_begin_old() > acpi_hibernation_ops_old::acpi_hibernation_begin_old() > acpi_power_off_prepare() > pm_power_off_prepare() > > Hibernation (S4) and Power Off (S5) don't require cache flushing. So, > the only interesting callsites are acpi_suspend_ops::prepare_late() and > acpi_suspend_begin_old::begin(). Both of them have cache flush on > ->enter() operation in acpi_suspend_enter(). > > Remove redundant ACPI_FLUSH_CPU_CACHE() in acpi_sleep_prepare() and > acpi_suspend_enter(). > > Signed-off-by: Kirill A. Shutemov > --- > drivers/acpi/sleep.c | 3 --- > 1 file changed, 3 deletions(-) > > diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c > index eaa47753b758..5ca6c223ba3d 100644 > --- a/drivers/acpi/sleep.c > +++ b/drivers/acpi/sleep.c > @@ -73,7 +73,6 @@ static int acpi_sleep_prepare(u32 acpi_state) > acpi_set_waking_vector(acpi_wakeup_address); > > } > - ACPI_FLUSH_CPU_CACHE(); > #endif > pr_info("Preparing to enter system sleep state S%d\n", acpi_state); > acpi_enable_wakeup_devices(acpi_state); > @@ -566,8 +565,6 @@ static int acpi_suspend_enter(suspend_state_t pm_state) > u32 acpi_state = acpi_target_sleep_state; > int error; > > - ACPI_FLUSH_CPU_CACHE(); > - > trace_suspend_resume(TPS("acpi_suspend"), acpi_state, true); > switch (acpi_state) { > case ACPI_STATE_S1: > -- > Kirill A. Shutemov