From patchwork Thu Jan 31 04:55:32 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: fli24 X-Patchwork-Id: 2070901 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id 5E7AB3FD1A for ; Thu, 31 Jan 2013 04:57:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756162Ab3AaE5H (ORCPT ); Wed, 30 Jan 2013 23:57:07 -0500 Received: from mga11.intel.com ([192.55.52.93]:13809 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753504Ab3AaE5H (ORCPT ); Wed, 30 Jan 2013 23:57:07 -0500 Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga102.fm.intel.com with ESMTP; 30 Jan 2013 20:57:06 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.84,574,1355126400"; d="scan'208";a="280661915" Received: from fli24-hp-compaq-8100-elite-cmt-pc.sh.intel.com (HELO [10.239.67.67]) ([10.239.67.67]) by fmsmga001.fm.intel.com with ESMTP; 30 Jan 2013 20:57:05 -0800 Subject: [PATCH V3] suspend: enable freeze timeout configuration through sys From: fli24 To: rjw@sisk.pl, akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, chuansheng.liu@intel.com, fei.li@intel.com In-Reply-To: <1359527019.26790.3.camel@fli24-HP-Compaq-8100-Elite-CMT-PC> References: <1359428300.3211.3.camel@fli24-HP-Compaq-8100-Elite-CMT-PC> <1359527019.26790.3.camel@fli24-HP-Compaq-8100-Elite-CMT-PC> Date: Thu, 31 Jan 2013 12:55:32 +0800 Message-ID: <1359608132.7918.2.camel@fli24-HP-Compaq-8100-Elite-CMT-PC> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org At present, the value of timeout for freezing is 20s, which is meaningless in case that one thread is frozen with mutex locked and another thread is trying to lock the mutex, as this time of freezing will fail unavoidably. And if there is no new wakeup event registered, the system will waste at most 20s for such meaningless trying of freezing. With this patch, the value of timeout can be configured to smaller value, so such meaningless trying of freezing will be aborted in earlier time, and later freezing can be also triggered in earlier time. And more power will be saved. In normal case on mobile phone, it costs real little time to freeze processes. On some platform, it only costs about 20ms to freeze user space processes and 10ms to freeze kernel freezable threads. Signed-off-by: Liu Chuansheng Signed-off-by: Li Fei --- Documentation/power/freezing-of-tasks.txt | 5 +++++ include/linux/freezer.h | 5 +++++ kernel/power/main.c | 27 +++++++++++++++++++++++++++ kernel/power/process.c | 4 ++-- 4 files changed, 39 insertions(+), 2 deletions(-) diff --git a/Documentation/power/freezing-of-tasks.txt b/Documentation/power/freezing-of-tasks.txt index 6ec291e..85894d8 100644 --- a/Documentation/power/freezing-of-tasks.txt +++ b/Documentation/power/freezing-of-tasks.txt @@ -223,3 +223,8 @@ since they ask the freezer to skip freezing this task, since it is anyway only after the entire suspend/hibernation sequence is complete. So, to summarize, use [un]lock_system_sleep() instead of directly using mutex_[un]lock(&pm_mutex). That would prevent freezing failures. + +V. Miscellaneous +/sys/power/pm_freeze_timeout controls how long it will cost at most to freeze +all user space processes or all freezable kernel threads, in unit of millisecond. +The default value is 20000, with range of unsigned integer. diff --git a/include/linux/freezer.h b/include/linux/freezer.h index e4238ce..5a24a33 100644 --- a/include/linux/freezer.h +++ b/include/linux/freezer.h @@ -13,6 +13,11 @@ extern bool pm_freezing; /* PM freezing in effect */ extern bool pm_nosig_freezing; /* PM nosig freezing in effect */ /* + * Timeout for stopping processes + */ +extern unsigned int sys_freeze_process_timeout_msecs; + +/* * Check if a process has been frozen */ static inline bool frozen(struct task_struct *p) diff --git a/kernel/power/main.c b/kernel/power/main.c index 1c16f91..453ead1 100644 --- a/kernel/power/main.c +++ b/kernel/power/main.c @@ -553,6 +553,30 @@ power_attr(pm_trace_dev_match); #endif /* CONFIG_PM_TRACE */ +#ifdef CONFIG_FREEZER +static ssize_t pm_freeze_timeout_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%u\n", sys_freeze_process_timeout_msecs); +} + +static ssize_t pm_freeze_timeout_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t n) +{ + unsigned long val; + + if (kstrtoul(buf, 10, &val)) + return -EINVAL; + + sys_freeze_process_timeout_msecs = val; + return n; +} + +power_attr(pm_freeze_timeout); + +#endif /* CONFIG_FREEZER*/ + static struct attribute * g[] = { &state_attr.attr, #ifdef CONFIG_PM_TRACE @@ -576,6 +600,9 @@ static struct attribute * g[] = { &pm_print_times_attr.attr, #endif #endif +#ifdef CONFIG_FREEZER + &pm_freeze_timeout_attr.attr, +#endif NULL, }; diff --git a/kernel/power/process.c b/kernel/power/process.c index d5a258b..ba45a26 100644 --- a/kernel/power/process.c +++ b/kernel/power/process.c @@ -21,7 +21,7 @@ /* * Timeout for stopping processes */ -#define TIMEOUT (20 * HZ) +unsigned int __read_mostly sys_freeze_process_timeout_msecs = 20000; static int try_to_freeze_tasks(bool user_only) { @@ -36,7 +36,7 @@ static int try_to_freeze_tasks(bool user_only) do_gettimeofday(&start); - end_time = jiffies + TIMEOUT; + end_time = jiffies + msecs_to_jiffies(sys_freeze_process_timeout_msecs); if (!user_only) freeze_workqueues_begin();