From ed1ac6e91a3ff7c561008ba57747cd6cbc49385e Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 11 Jan 2013 13:37:33 +0100 Subject: PM: don't use [delayed_]work_pending() There's no need to test whether a (delayed) work item is pending before queueing, flushing or cancelling it, so remove work_pending() tests used in those cases. Signed-off-by: Tejun Heo Signed-off-by: Rafael J. Wysocki --- kernel/power/autosleep.c | 2 +- kernel/power/qos.c | 9 +++------ 2 files changed, 4 insertions(+), 7 deletions(-) (limited to 'kernel/power') diff --git a/kernel/power/autosleep.c b/kernel/power/autosleep.c index ca304046..c6422ff 100644 --- a/kernel/power/autosleep.c +++ b/kernel/power/autosleep.c @@ -66,7 +66,7 @@ static DECLARE_WORK(suspend_work, try_to_suspend); void queue_up_suspend_work(void) { - if (!work_pending(&suspend_work) && autosleep_state > PM_SUSPEND_ON) + if (autosleep_state > PM_SUSPEND_ON) queue_work(autosleep_wq, &suspend_work); } diff --git a/kernel/power/qos.c b/kernel/power/qos.c index 9322ff7..587ddde 100644 --- a/kernel/power/qos.c +++ b/kernel/power/qos.c @@ -359,8 +359,7 @@ void pm_qos_update_request(struct pm_qos_request *req, return; } - if (delayed_work_pending(&req->work)) - cancel_delayed_work_sync(&req->work); + cancel_delayed_work_sync(&req->work); if (new_value != req->node.prio) pm_qos_update_target( @@ -386,8 +385,7 @@ void pm_qos_update_request_timeout(struct pm_qos_request *req, s32 new_value, "%s called for unknown object.", __func__)) return; - if (delayed_work_pending(&req->work)) - cancel_delayed_work_sync(&req->work); + cancel_delayed_work_sync(&req->work); if (new_value != req->node.prio) pm_qos_update_target( @@ -416,8 +414,7 @@ void pm_qos_remove_request(struct pm_qos_request *req) return; } - if (delayed_work_pending(&req->work)) - cancel_delayed_work_sync(&req->work); + cancel_delayed_work_sync(&req->work); pm_qos_update_target(pm_qos_array[req->pm_qos_class]->constraints, &req->node, PM_QOS_REMOVE_REQ, -- cgit v1.1 From 9f3b795a626ee79574595e06d1437fe0c7d51d29 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Micha=C5=82=20Miros=C5=82aw?= Date: Fri, 1 Feb 2013 20:40:17 +0100 Subject: driver-core: constify data for class_find_device() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit All in-kernel users of class_find_device() don't really need mutable data for match callback. In two places (kernel/power/suspend_test.c, drivers/scsi/osd/osd_uld.c) this patch changes match callbacks to use const search data. The const is propagated to rtc_class_open() and power_supply_get_by_name() parameters. Note that there's a dev reference leak in suspend_test.c that's not touched in this patch. Signed-off-by: Michał Mirosław Acked-by: Grant Likely Signed-off-by: Greg Kroah-Hartman --- kernel/power/suspend_test.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) (limited to 'kernel/power') diff --git a/kernel/power/suspend_test.c b/kernel/power/suspend_test.c index 25596e4..9b2a1d5 100644 --- a/kernel/power/suspend_test.c +++ b/kernel/power/suspend_test.c @@ -112,7 +112,7 @@ static void __init test_wakealarm(struct rtc_device *rtc, suspend_state_t state) rtc_set_alarm(rtc, &alm); } -static int __init has_wakealarm(struct device *dev, void *name_ptr) +static int __init has_wakealarm(struct device *dev, const void *data) { struct rtc_device *candidate = to_rtc_device(dev); @@ -121,7 +121,6 @@ static int __init has_wakealarm(struct device *dev, void *name_ptr) if (!device_may_wakeup(candidate->dev.parent)) return 0; - *(const char **)name_ptr = dev_name(dev); return 1; } @@ -159,8 +158,8 @@ static int __init test_suspend(void) static char warn_no_rtc[] __initdata = KERN_WARNING "PM: no wakealarm-capable RTC driver is ready\n"; - char *pony = NULL; struct rtc_device *rtc = NULL; + struct device *dev; /* PM is initialized by now; is that state testable? */ if (test_state == PM_SUSPEND_ON) @@ -171,9 +170,9 @@ static int __init test_suspend(void) } /* RTCs have initialized by now too ... can we use one? */ - class_find_device(rtc_class, NULL, &pony, has_wakealarm); - if (pony) - rtc = rtc_class_open(pony); + dev = class_find_device(rtc_class, NULL, NULL, has_wakealarm); + if (dev) + rtc = rtc_class_open(dev_name(dev)); if (!rtc) { printk(warn_no_rtc); goto done; -- cgit v1.1 From 7e73c5ae6e7991a6c01f6d096ff8afaef4458c36 Mon Sep 17 00:00:00 2001 From: Zhang Rui Date: Wed, 6 Feb 2013 13:00:36 +0100 Subject: PM: Introduce suspend state PM_SUSPEND_FREEZE PM_SUSPEND_FREEZE state is a general state that does not need any platform specific support, it equals frozen processes + suspended devices + idle processors. Compared with PM_SUSPEND_MEMORY, PM_SUSPEND_FREEZE saves less power because the system is still in a running state. PM_SUSPEND_FREEZE has less resume latency because it does not touch BIOS, and the processors are in idle state. Compared with RTPM/idle, PM_SUSPEND_FREEZE saves more power as 1. the processor has longer sleep time because processes are frozen. The deeper c-state the processor supports, more power saving we can get. 2. PM_SUSPEND_FREEZE uses system suspend code path, thus we can get more power saving from the devices that does not have good RTPM support. This state is useful for 1) platforms that do not have STR, or have a broken STR. 2) platforms that have an extremely low power idle state, which can be used to replace STR. The following describes how PM_SUSPEND_FREEZE state works. 1. echo freeze > /sys/power/state 2. the processes are frozen. 3. all the devices are suspended. 4. all the processors are blocked by a wait queue 5. all the processors idles and enters (Deep) c-state. 6. an interrupt fires. 7. a processor is woken up and handles the irq. 8. if it is a general event, a) the irq handler runs and quites. b) goto step 4. 9. if it is a real wake event, say, power button pressing, keyboard touch, mouse moving, a) the irq handler runs and activate the wakeup source b) wakeup_source_activate() notifies the wait queue. c) system starts resuming from PM_SUSPEND_FREEZE 10. all the devices are resumed. 11. all the processes are unfrozen. 12. system is back to working. Known Issue: The wakeup of this new PM_SUSPEND_FREEZE state may behave differently from the previous suspend state. Take ACPI platform for example, there are some GPEs that only enabled when the system is in sleep state, to wake the system backk from S3/S4. But we are not touching these GPEs during transition to PM_SUSPEND_FREEZE. This means we may lose some wake event. But on the other hand, as we do not disable all the Interrupts during PM_SUSPEND_FREEZE, we may get some extra "wakeup" Interrupts, that are not available for S3/S4. The patches has been tested on an old Sony laptop, and here are the results: Average Power: 1. RPTM/idle for half an hour: 14.8W, 12.6W, 14.1W, 12.5W, 14.4W, 13.2W, 12.9W 2. Freeze for half an hour: 11W, 10.4W, 9.4W, 11.3W 10.5W 3. RTPM/idle for three hours: 11.6W 4. Freeze for three hours: 10W 5. Suspend to Memory: 0.5~0.9W Average Resume Latency: 1. RTPM/idle with a black screen: (From pressing keyboard to screen back) Less than 0.2s 2. Freeze: (From pressing power button to screen back) 2.50s 3. Suspend to Memory: (From pressing power button to screen back) 4.33s >From the results, we can see that all the platforms should benefit from this patch, even if it does not have Low Power S0. Signed-off-by: Zhang Rui Signed-off-by: Rafael J. Wysocki --- kernel/power/main.c | 2 +- kernel/power/suspend.c | 69 ++++++++++++++++++++++++++++++++++++++++---------- 2 files changed, 57 insertions(+), 14 deletions(-) (limited to 'kernel/power') diff --git a/kernel/power/main.c b/kernel/power/main.c index 1c16f91..b1c26a9 100644 --- a/kernel/power/main.c +++ b/kernel/power/main.c @@ -313,7 +313,7 @@ static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr, static suspend_state_t decode_state(const char *buf, size_t n) { #ifdef CONFIG_SUSPEND - suspend_state_t state = PM_SUSPEND_STANDBY; + suspend_state_t state = PM_SUSPEND_MIN; const char * const *s; #endif char *p; diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index c8b7446..d4feda0 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -30,12 +30,38 @@ #include "power.h" const char *const pm_states[PM_SUSPEND_MAX] = { + [PM_SUSPEND_FREEZE] = "freeze", [PM_SUSPEND_STANDBY] = "standby", [PM_SUSPEND_MEM] = "mem", }; static const struct platform_suspend_ops *suspend_ops; +static bool need_suspend_ops(suspend_state_t state) +{ + return !!(state > PM_SUSPEND_FREEZE); +} + +static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head); +static bool suspend_freeze_wake; + +static void freeze_begin(void) +{ + suspend_freeze_wake = false; +} + +static void freeze_enter(void) +{ + wait_event(suspend_freeze_wait_head, suspend_freeze_wake); +} + +void freeze_wake(void) +{ + suspend_freeze_wake = true; + wake_up(&suspend_freeze_wait_head); +} +EXPORT_SYMBOL_GPL(freeze_wake); + /** * suspend_set_ops - Set the global suspend method table. * @ops: Suspend operations to use. @@ -50,8 +76,11 @@ EXPORT_SYMBOL_GPL(suspend_set_ops); bool valid_state(suspend_state_t state) { + if (state == PM_SUSPEND_FREEZE) + return true; /* - * All states need lowlevel support and need to be valid to the lowlevel + * PM_SUSPEND_STANDBY and PM_SUSPEND_MEMORY states need lowlevel + * support and need to be valid to the lowlevel * implementation, no valid callback implies that none are valid. */ return suspend_ops && suspend_ops->valid && suspend_ops->valid(state); @@ -89,11 +118,11 @@ static int suspend_test(int level) * hibernation). Run suspend notifiers, allocate the "suspend" console and * freeze processes. */ -static int suspend_prepare(void) +static int suspend_prepare(suspend_state_t state) { int error; - if (!suspend_ops || !suspend_ops->enter) + if (need_suspend_ops(state) && (!suspend_ops || !suspend_ops->enter)) return -EPERM; pm_prepare_console(); @@ -137,7 +166,7 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) { int error; - if (suspend_ops->prepare) { + if (need_suspend_ops(state) && suspend_ops->prepare) { error = suspend_ops->prepare(); if (error) goto Platform_finish; @@ -149,12 +178,23 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) goto Platform_finish; } - if (suspend_ops->prepare_late) { + if (need_suspend_ops(state) && suspend_ops->prepare_late) { error = suspend_ops->prepare_late(); if (error) goto Platform_wake; } + /* + * PM_SUSPEND_FREEZE equals + * frozen processes + suspended devices + idle processors. + * Thus we should invoke freeze_enter() soon after + * all the devices are suspended. + */ + if (state == PM_SUSPEND_FREEZE) { + freeze_enter(); + goto Platform_wake; + } + if (suspend_test(TEST_PLATFORM)) goto Platform_wake; @@ -182,13 +222,13 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) enable_nonboot_cpus(); Platform_wake: - if (suspend_ops->wake) + if (need_suspend_ops(state) && suspend_ops->wake) suspend_ops->wake(); dpm_resume_start(PMSG_RESUME); Platform_finish: - if (suspend_ops->finish) + if (need_suspend_ops(state) && suspend_ops->finish) suspend_ops->finish(); return error; @@ -203,11 +243,11 @@ int suspend_devices_and_enter(suspend_state_t state) int error; bool wakeup = false; - if (!suspend_ops) + if (need_suspend_ops(state) && !suspend_ops) return -ENOSYS; trace_machine_suspend(state); - if (suspend_ops->begin) { + if (need_suspend_ops(state) && suspend_ops->begin) { error = suspend_ops->begin(state); if (error) goto Close; @@ -226,7 +266,7 @@ int suspend_devices_and_enter(suspend_state_t state) do { error = suspend_enter(state, &wakeup); - } while (!error && !wakeup + } while (!error && !wakeup && need_suspend_ops(state) && suspend_ops->suspend_again && suspend_ops->suspend_again()); Resume_devices: @@ -236,13 +276,13 @@ int suspend_devices_and_enter(suspend_state_t state) ftrace_start(); resume_console(); Close: - if (suspend_ops->end) + if (need_suspend_ops(state) && suspend_ops->end) suspend_ops->end(); trace_machine_suspend(PWR_EVENT_EXIT); return error; Recover_platform: - if (suspend_ops->recover) + if (need_suspend_ops(state) && suspend_ops->recover) suspend_ops->recover(); goto Resume_devices; } @@ -278,12 +318,15 @@ static int enter_state(suspend_state_t state) if (!mutex_trylock(&pm_mutex)) return -EBUSY; + if (state == PM_SUSPEND_FREEZE) + freeze_begin(); + printk(KERN_INFO "PM: Syncing filesystems ... "); sys_sync(); printk("done.\n"); pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]); - error = suspend_prepare(); + error = suspend_prepare(state); if (error) goto Unlock; -- cgit v1.1 From 957d1282bb8c07e682e142b9237cd9fcb8348a0b Mon Sep 17 00:00:00 2001 From: Li Fei Date: Fri, 1 Feb 2013 08:56:03 +0000 Subject: suspend: enable freeze timeout configuration through sys 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 Signed-off-by: Rafael J. Wysocki --- kernel/power/main.c | 27 +++++++++++++++++++++++++++ kernel/power/process.c | 4 ++-- 2 files changed, 29 insertions(+), 2 deletions(-) (limited to 'kernel/power') diff --git a/kernel/power/main.c b/kernel/power/main.c index b1c26a9..d77663b 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", freeze_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; + + freeze_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..98088e0 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 freeze_timeout_msecs = 20 * MSEC_PER_SEC; 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(freeze_timeout_msecs); if (!user_only) freeze_workqueues_begin(); -- cgit v1.1