From patchwork Thu Jul 26 15:56:56 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eduardo Valentin X-Patchwork-Id: 10546099 X-Patchwork-Delegate: rjw@sisk.pl Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2C87F112E for ; Thu, 26 Jul 2018 15:57:12 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1A2DB2B757 for ; Thu, 26 Jul 2018 15:57:12 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0DC092B77D; Thu, 26 Jul 2018 15:57:12 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 52D0E2B757 for ; Thu, 26 Jul 2018 15:57:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732009AbeGZROd (ORCPT ); Thu, 26 Jul 2018 13:14:33 -0400 Received: from smtp-fw-6001.amazon.com ([52.95.48.154]:60598 "EHLO smtp-fw-6001.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730413AbeGZROd (ORCPT ); Thu, 26 Jul 2018 13:14:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1532620625; x=1564156625; h=from:to:cc:subject:date:message-id:mime-version; bh=z4BIzbPHdEU6SvDRqMmX28XcZhsZwFBJKx17wqXUjt0=; b=NJBZzzI6ZKsPYFYSN7yTWyid4ahaQ/TH65291BO0C7DyH4MIlDnBq7Vt xX7eHPnEMraU4LQER4YXEjA8rXqRfdl4wWCviFb7N4rI6NsRc/TEOWLti QkeuBQcHwOCidBvEawU0vFcBLtHaa3jhQn0qnz+MA7NFNVJHVx9Mkdjzo 0=; X-IronPort-AV: E=Sophos;i="5.51,405,1526342400"; d="scan'208";a="349406153" Received: from iad6-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-2c-579b7f5b.us-west-2.amazon.com) ([10.124.125.6]) by smtp-border-fw-out-6001.iad6.amazon.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 26 Jul 2018 15:57:02 +0000 Received: from EX13MTAUWB001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan2.pdx.amazon.com [10.236.137.194]) by email-inbound-relay-2c-579b7f5b.us-west-2.amazon.com (8.14.7/8.14.7) with ESMTP id w6QFuxVa066597 (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=FAIL); Thu, 26 Jul 2018 15:57:00 GMT Received: from EX13D05UWB001.ant.amazon.com (10.43.161.181) by EX13MTAUWB001.ant.amazon.com (10.43.161.249) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Thu, 26 Jul 2018 15:56:59 +0000 Received: from EX13MTAUWB001.ant.amazon.com (10.43.161.207) by EX13D05UWB001.ant.amazon.com (10.43.161.181) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Thu, 26 Jul 2018 15:56:59 +0000 Received: from localhost (10.88.47.215) by mail-relay.amazon.com (10.43.161.249) with Microsoft SMTP Server id 15.0.1367.3 via Frontend Transport; Thu, 26 Jul 2018 15:56:58 +0000 From: Eduardo Valentin To: Peter Zijlstra , "Rafael J . Wysocki" CC: Eduardo Valentin , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Dou Liyang , Len Brown , "Rafael J. Wysocki" , "mike.travis@hpe.com" , Rajvi Jingar , Pavel Tatashin , Philippe Ombredanne , Kate Stewart , Greg Kroah-Hartman , , , Subject: [PATCH RESEND 1/1] x86: tsc: avoid system instability in hibernation Date: Thu, 26 Jul 2018 08:56:56 -0700 Message-ID: <20180726155656.14873-1-eduval@amazon.com> X-Mailer: git-send-email 2.18.0 MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP System instability are seen during resume from hibernation when system is under heavy CPU load. This is due to the lack of update of sched clock data, and the scheduler would then think that heavy CPU hog tasks need more time in CPU, causing the system to freeze during the unfreezing of tasks. For example, threaded irqs, and kernel processes servicing network interface may be delayed for several tens of seconds, causing the system to be unreachable. Situation like this can be reported by using lockup detectors such as workqueue lockup detectors: [root@ip-172-31-67-114 ec2-user]# echo disk > /sys/power/state Message from syslogd@ip-172-31-67-114 at May 7 18:23:21 ... kernel:BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 57s! Message from syslogd@ip-172-31-67-114 at May 7 18:23:21 ... kernel:BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 57s! Message from syslogd@ip-172-31-67-114 at May 7 18:23:21 ... kernel:BUG: workqueue lockup - pool cpus=3 node=0 flags=0x1 nice=0 stuck for 57s! Message from syslogd@ip-172-31-67-114 at May 7 18:29:06 ... kernel:BUG: workqueue lockup - pool cpus=3 node=0 flags=0x1 nice=0 stuck for 403s! The fix for this situation is to mark the sched clock as unstable as early as possible in the resume path, leaving it unstable for the duration of the resume process. This will force the scheduler to attempt to align the sched clock across CPUs using the delta with time of day, updating sched clock data. In a post hibernation event, we can then mark the sched clock as stable again, avoiding unnecessary syncs with time of day on systems in which TSC is reliable. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Peter Zijlstra Cc: Dou Liyang Cc: Len Brown Cc: "Rafael J. Wysocki" Cc: Eduardo Valentin Cc: "mike.travis@hpe.com" Cc: Rajvi Jingar Cc: Pavel Tatashin Cc: Philippe Ombredanne Cc: Kate Stewart Cc: Greg Kroah-Hartman Cc: x86@kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-pm@vger.kernel.org Signed-off-by: Eduardo Valentin --- Hey, No changes from first attempt, no pressure on resending. The RESEND tag is just because I missed linux-pm in the first attempt. BR, arch/x86/kernel/tsc.c | 29 +++++++++++++++++++++++++++++ include/linux/sched/clock.h | 5 +++++ kernel/sched/clock.c | 4 ++-- 3 files changed, 36 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 8ea117f8142e..f197c9742fef 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include @@ -1377,3 +1378,31 @@ unsigned long calibrate_delay_is_known(void) return 0; } #endif + +static int tsc_pm_notifier(struct notifier_block *notifier, + unsigned long pm_event, void *unused) +{ + switch (pm_event) { + case PM_HIBERNATION_PREPARE: + clear_sched_clock_stable(); + break; + case PM_POST_HIBERNATION: + /* Set back to the default */ + if (!check_tsc_unstable()) + set_sched_clock_stable(); + break; + } + + return 0; +}; + +static struct notifier_block tsc_pm_notifier_block = { + .notifier_call = tsc_pm_notifier, +}; + +static int tsc_setup_pm_notifier(void) +{ + return register_pm_notifier(&tsc_pm_notifier_block); +} + +subsys_initcall(tsc_setup_pm_notifier); diff --git a/include/linux/sched/clock.h b/include/linux/sched/clock.h index 867d588314e0..902654ac5f7e 100644 --- a/include/linux/sched/clock.h +++ b/include/linux/sched/clock.h @@ -32,6 +32,10 @@ static inline void clear_sched_clock_stable(void) { } +static inline void set_sched_clock_stable(void) +{ +} + static inline void sched_clock_idle_sleep_event(void) { } @@ -51,6 +55,7 @@ static inline u64 local_clock(void) } #else extern int sched_clock_stable(void); +extern void set_sched_clock_stable(void); extern void clear_sched_clock_stable(void); /* diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c index e086babe6c61..8453440e236c 100644 --- a/kernel/sched/clock.c +++ b/kernel/sched/clock.c @@ -131,7 +131,7 @@ static void __scd_stamp(struct sched_clock_data *scd) scd->tick_raw = sched_clock(); } -static void __set_sched_clock_stable(void) +void set_sched_clock_stable(void) { struct sched_clock_data *scd; @@ -228,7 +228,7 @@ static int __init sched_clock_init_late(void) smp_mb(); /* matches {set,clear}_sched_clock_stable() */ if (__sched_clock_stable_early) - __set_sched_clock_stable(); + set_sched_clock_stable(); return 0; }