From patchwork Thu Jan 7 18:42:15 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 358557 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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 00924C4332E for ; Thu, 7 Jan 2021 18:45:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BFB12235F7 for ; Thu, 7 Jan 2021 18:45:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728674AbhAGSpP (ORCPT ); Thu, 7 Jan 2021 13:45:15 -0500 Received: from cloudserver094114.home.pl ([79.96.170.134]:53232 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729259AbhAGSpO (ORCPT ); Thu, 7 Jan 2021 13:45:14 -0500 Received: from 89-64-81-64.dynamic.chello.pl (89.64.81.64) (HELO kreacher.localnet) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83.537) id c4c52b1d753055a3; Thu, 7 Jan 2021 19:44:32 +0100 From: "Rafael J. Wysocki" To: Linux PM Cc: LKML , Srinivas Pandruvada , Chen Yu Subject: [PATCH v1 1/3] cpufreq: intel_pstate: Always read hwp_cap_cached with READ_ONCE() Date: Thu, 07 Jan 2021 19:42:15 +0100 Message-ID: <1993550.StjdRojnlU@kreacher> In-Reply-To: <5701645.lOV4Wx5bFT@kreacher> References: <5701645.lOV4Wx5bFT@kreacher> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: Rafael J. Wysocki Because intel_pstate_get_hwp_max() which updates hwp_cap_cached may run in parallel with the readers of it, annotate all of the read accesses to it with READ_ONCE(). Signed-off-by: Rafael J. Wysocki Tested-by: Chen Yu --- drivers/cpufreq/intel_pstate.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) Index: linux-pm/drivers/cpufreq/intel_pstate.c =================================================================== --- linux-pm.orig/drivers/cpufreq/intel_pstate.c +++ linux-pm/drivers/cpufreq/intel_pstate.c @@ -914,7 +914,7 @@ static void intel_pstate_hwp_offline(str } value &= ~GENMASK_ULL(31, 0); - min_perf = HWP_LOWEST_PERF(cpu->hwp_cap_cached); + min_perf = HWP_LOWEST_PERF(READ_ONCE(cpu->hwp_cap_cached)); /* Set hwp_max = hwp_min */ value |= HWP_MAX_PERF(min_perf); @@ -1750,6 +1750,7 @@ static int hwp_boost_hold_time_ns = 3 * static inline void intel_pstate_hwp_boost_up(struct cpudata *cpu) { u64 hwp_req = READ_ONCE(cpu->hwp_req_cached); + u64 hwp_cap = READ_ONCE(cpu->hwp_cap_cached); u32 max_limit = (hwp_req & 0xff00) >> 8; u32 min_limit = (hwp_req & 0xff); u32 boost_level1; @@ -1776,14 +1777,14 @@ static inline void intel_pstate_hwp_boos cpu->hwp_boost_min = min_limit; /* level at half way mark between min and guranteed */ - boost_level1 = (HWP_GUARANTEED_PERF(cpu->hwp_cap_cached) + min_limit) >> 1; + boost_level1 = (HWP_GUARANTEED_PERF(hwp_cap) + min_limit) >> 1; if (cpu->hwp_boost_min < boost_level1) cpu->hwp_boost_min = boost_level1; - else if (cpu->hwp_boost_min < HWP_GUARANTEED_PERF(cpu->hwp_cap_cached)) - cpu->hwp_boost_min = HWP_GUARANTEED_PERF(cpu->hwp_cap_cached); - else if (cpu->hwp_boost_min == HWP_GUARANTEED_PERF(cpu->hwp_cap_cached) && - max_limit != HWP_GUARANTEED_PERF(cpu->hwp_cap_cached)) + else if (cpu->hwp_boost_min < HWP_GUARANTEED_PERF(hwp_cap)) + cpu->hwp_boost_min = HWP_GUARANTEED_PERF(hwp_cap); + else if (cpu->hwp_boost_min == HWP_GUARANTEED_PERF(hwp_cap) && + max_limit != HWP_GUARANTEED_PERF(hwp_cap)) cpu->hwp_boost_min = max_limit; else return;