- 08 9月, 2011 4 次提交
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由 Martin Schwidefsky 提交于
The automatic increase of the min_delta_ns of a clockevents device should be done in the clockevents code as the minimum delay is an attribute of the clockevents device. In addition not all architectures want the automatic adjustment, on a massively virtualized system it can happen that the programming of a clock event fails several times in a row because the virtual cpu has been rescheduled quickly enough. In that case the minimum delay will erroneously be increased with no way back. The new config symbol GENERIC_CLOCKEVENTS_MIN_ADJUST is used to enable the automatic adjustment. The config option is selected only for x86. Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Cc: john stultz <johnstul@us.ibm.com> Link: http://lkml.kernel.org/r/20110823133142.494157493@de.ibm.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Heiko Carstens 提交于
When performing cpu hotplug tests the kernel printk log buffer gets flooded with pointless "Switched to NOHz mode..." messages. Especially when afterwards analyzing a dump this might have removed more interesting stuff out of the buffer. Assuming that switching to NOHz mode simply works just remove the printk. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Link: http://lkml.kernel.org/r/20110823112046.GB2540@osiris.boeblingen.de.ibm.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Michal Hocko 提交于
get_cpu_{idle,iowait}_time_us update idle/iowait counters unconditionally if the given CPU is in the idle loop. This doesn't work well outside of CPU governors which are singletons so nobody (except for IRQ) can race with them. We will need to use both functions from /proc/stat handler to properly handle nohz idle/iowait times. Make the update depend on a non NULL last_update_time argument. Signed-off-by: NMichal Hocko <mhocko@suse.cz> Cc: Dave Jones <davej@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Alexey Dobriyan <adobriyan@gmail.com> Link: http://lkml.kernel.org/r/11f23179472635ce52e78921d47a20216b872f23.1314172057.git.mhocko@suse.czSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Michal Hocko 提交于
update_ts_time_stat currently updates idle time even if we are in iowait loop at the moment. The only real users of the idle counter (via get_cpu_idle_time_us) are CPU governors and they expect to get cumulative time for both idle and iowait times. The value (idle_sleeptime) is also printed to userspace by print_cpu but it prints both idle and iowait times so the idle part is misleading. Let's clean this up and fix update_ts_time_stat to account both counters properly and update consumers of idle to consider iowait time as well. If we do this we might use get_cpu_{idle,iowait}_time_us from other contexts as well and we will get expected values. Signed-off-by: NMichal Hocko <mhocko@suse.cz> Cc: Dave Jones <davej@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Alexey Dobriyan <adobriyan@gmail.com> Link: http://lkml.kernel.org/r/e9c909c221a8da402c4da07e4cd968c3218f8eb1.1314172057.git.mhocko@suse.czSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 11 8月, 2011 9 次提交
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由 John Stultz 提交于
This allows cleaner detection of the RTC device being registered, rather then probing any time someone calls alarmtimer_get_rtcdev. CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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由 John Stultz 提交于
There's a number of edge cases when cancelling a alarm, so to be sure we accurately do so, introduce try_to_cancel, which returns proper failure errors if it cannot. Also modify cancel to spin until the alarm is properly disabled. CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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由 John Stultz 提交于
In order to allow for functionality like try_to_cancel, add more refined state tracking (similar to hrtimers). CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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由 John Stultz 提交于
Now that periodic alarmtimers are managed by the handler function, remove the period value from the alarm structure and let the handlers manage the interval on their own. CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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由 John Stultz 提交于
Now that the alarmtimers code has been refactored, the interval cap limit can be removed. CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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由 John Stultz 提交于
In order to avoid wasting time expiring and re-adding very high freq periodic alarmtimers, introduce alarm_forward() which is similar to hrtimer_forward and moves the timer to the next future expiration time and returns the number of overruns. CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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由 John Stultz 提交于
This patch pushes the periodic alarmtimer re-arming down into the alarmtimer handler, mimicking how hrtimers handle this. CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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由 John Stultz 提交于
In order to properly fix the denial of service issue with high freq periodic alarm timers, we need to push the re-arming logic into the alarm timer handler, much as the hrtimer code does. This patch introduces alarmtimer_restart enum and changes the alarmtimer handler declarations to use it as a return value. Further, to ease following changes, it extends the alarmtimer handler functions to also take the time at expiration. No logic is yet modified. CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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由 John Stultz 提交于
Its possible to jam up the alarm timers by setting very small interval timers, which will cause the alarmtimer subsystem to spend all of its time firing and restarting timers. This can effectivly lock up a box. A deeper fix is needed, closely mimicking the hrtimer code, but for now just cap the interval to 100us to avoid userland hanging the system. CC: Thomas Gleixner <tglx@linutronix.de> CC: stable@kernel.org Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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- 10 8月, 2011 2 次提交
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由 John Stultz 提交于
Following common_timer_get, zero out the itimerspec passed in. CC: Thomas Gleixner <tglx@linutronix.de> CC: stable@kernel.org Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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由 John Stultz 提交于
We don't check if old_setting is non null before assigning it, so correct this. CC: Thomas Gleixner <tglx@linutronix.de> CC: stable@kernel.org Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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- 21 7月, 2011 1 次提交
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由 John Stultz 提交于
Terribly embarassing. Don't know how I committed this, but its KERN_WARNING not KERN_WARN. This fixes the following compile error: kernel/time/timekeeping.c: In function ‘__timekeeping_inject_sleeptime’: kernel/time/timekeeping.c:608: error: ‘KERN_WARN’ undeclared (first use in this function) kernel/time/timekeeping.c:608: error: (Each undeclared identifier is reported only once kernel/time/timekeeping.c:608: error: for each function it appears in.) kernel/time/timekeeping.c:608: error: expected ‘)’ before string constant make[2]: *** [kernel/time/timekeeping.o] Error 1 Reported-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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- 22 6月, 2011 4 次提交
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由 John Stultz 提交于
Because the read_persistent_clock interface is usually backed by only a second granular interface, each time we read from the persistent clock for suspend/resume, we introduce a half second (on average) of error. In order to avoid this error accumulating as the system is suspended over and over, this patch measures the time delta between the persistent clock and the system CLOCK_REALTIME. If the delta is less then 2 seconds from the last suspend, we compensate by using the previous time delta (keeping it close). If it is larger then 2 seconds, we assume the clock was set or has been changed, so we do no correction and update the delta. Note: If NTP is running, ths could seem to "fight" with the NTP corrected time, where as if the system time was off by 1 second, and NTP slewed the value in, a suspend/resume cycle could undo this correction, by trying to restore the previous offset from the persistent clock. However, without this patch, since each read could cause almost a full second worth of error, its possible to get almost 2 seconds of error just from the suspend/resume cycle alone, so this about equal to any offset added by the compensation. Further on systems that suspend/resume frequently, this should keep time closer then NTP could compensate for if the errors were allowed to accumulate. Credits to Arve Hjønnevåg for suggesting this solution. CC: Arve Hjønnevåg <arve@android.com> CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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由 John Stultz 提交于
Arve suggested making sure we catch possible negative sleep time intervals that could be passed into timekeeping_inject_sleeptime. CC: Arve Hjønnevåg <arve@android.com> CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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由 John Stultz 提交于
Toralf Förster and Richard Weinberger noted that if there is no RTC device, the alarm timers core prints out an annoying "ALARM timers will not wake from suspend" message. This warning has been removed in a previous patch, however the issue still remains: The original idea was to support alarm timers even if there was no rtc device, as long as the system didn't go into suspend. However, after further consideration, communicating to the application that alarmtimers are not fully functional seems like the better solution. So this patch makes it so we return -ENOTSUPP to any posix _ALARM clockid calls if there is no backing RTC device on the system. Further this changes the behavior where when there is no rtc device we will check for one on clock_getres, clock_gettime, timer_create, and timer_nsleep instead of on suspend. CC: Toralf Förster <toralf.foerster@gmx.de> CC: Richard Weinberger <richard@nod.at CC: Peter Zijlstra <peterz@infradead.org> CC: Thomas Gleixner <tglx@linutronix.de> Reported-by: NToralf Förster <toralf.foerster@gmx.de> Reported by: Richard Weinberger <richard@nod.at> Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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由 John Stultz 提交于
The alarmtimers code currently picks a rtc device to use at late init time. However, if your rtc driver is loaded as a module, it may be registered after the alarmtimers late init code, leaving the alarmtimers nonfunctional. This patch moves the the rtcdevice selection to when we actually try to use it, allowing us to make use of rtc modules that may have been loaded at any point since bootup. CC: Thomas Gleixner <tglx@linutronix.de> CC: Meelis Roos <mroos@ut.ee> Reported-by: NMeelis Roos <mroos@ut.ee> Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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- 17 6月, 2011 1 次提交
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由 Thomas Gleixner 提交于
The clocksource watchdog code is interruptible and it has been observed that this can trigger false positives which disable the TSC. The reason is that an interrupt storm or a long running interrupt handler between the read of the watchdog source and the read of the TSC brings the two far enough apart that the delta is larger than the unstable treshold. Move both reads into a short interrupt disabled region to avoid that. Reported-and-tested-by: NVernon Mauery <vernux@us.ibm.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: stable@kernel.org
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- 03 6月, 2011 1 次提交
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由 Thomas Gleixner 提交于
For UP it's stupid to request an initialized cpumask for the clock event devices. Though we need the mask set even on UP to avoid a horrible ifdeffery especially in the broadcast code. For SMP we can at least try to survive with a warning and set the cpumask of the cpu we're running on. That gives a decent chance to bring the machine up and retrieve the debug info. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: Linus Walleij <linus.walleij@linaro.org Cc: Lee Jones <lee.jones@linaro.org> Cc: Russell King - ARM Linux <linux@arm.linux.org.uk> Cc: Stephen Boyd <sboyd@codeaurora.org>
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- 23 5月, 2011 1 次提交
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由 Thomas Gleixner 提交于
Instead of iterating over all possible timer bases avoid it by marking the active bases in the cpu base. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Reviewed-by: NPeter Zijlstra <peterz@infradead.org>
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- 20 5月, 2011 1 次提交
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由 Thomas Gleixner 提交于
unsigned long is not 64bit on 32bit machine. Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 19 5月, 2011 3 次提交
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由 Thomas Gleixner 提交于
Some ARM SoCs have clock event devices which have their frequency modified due to frequency scaling. Provide an interface which allows to reconfigure an active device. After reconfiguration reprogram the current pending event. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: LAK <linux-arm-kernel@lists.infradead.org> Cc: John Stultz <john.stultz@linaro.org> Acked-by: NLinus Walleij <linus.walleij@linaro.org> Reviewed-by: NIngo Molnar <mingo@elte.hu> Link: http://lkml.kernel.org/r/%3C20110518210136.437459958%40linutronix.de%3E
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由 Thomas Gleixner 提交于
All clockevent devices have the same open coded initialization functions. Provide an interface which does all necessary initialization in the core code. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Reviewed-by: NIngo Molnar <mingo@elte.hu> Link: http://lkml.kernel.org/r/%3C20110518210136.331975870%40linutronix.de%3E
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由 Thomas Gleixner 提交于
Slow clocksources can have a way longer sleep time than 5 seconds and even fast ones can easily cope with 600 seconds and still maintain proper accuracy. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Reviewed-by: NIngo Molnar <mingo@elte.hu> Link: http://lkml.kernel.org/r/%3C20110518210136.109811585%40linutronix.de%3E
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- 17 5月, 2011 1 次提交
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由 Thomas Gleixner 提交于
The first cpu which switches from periodic to oneshot mode switches also the broadcast device into oneshot mode. The broadcast device serves as a backup for per cpu timers which stop in deeper C-states. To avoid starvation of the cpus which might be in idle and depend on broadcast mode it marks the other cpus as broadcast active and sets the brodcast expiry value of those cpus to the next tick. The oneshot mode broadcast bit for the other cpus is sticky and gets only cleared when those cpus exit idle. If a cpu was not idle while the bit got set in consequence the bit prevents that the broadcast device is armed on behalf of that cpu when it enters idle for the first time after it switched to oneshot mode. In most cases that goes unnoticed as one of the other cpus has usually a timer pending which keeps the broadcast device armed with a short timeout. Now if the only cpu which has a short timer active has the bit set then the broadcast device will not be armed on behalf of that cpu and will fire way after the expected timer expiry. In the case of Christians bug report it took ~145 seconds which is about half of the wrap around time of HPET (the limit for that device) due to the fact that all other cpus had no timers armed which expired before the 145 seconds timeframe. The solution is simply to clear the broadcast active bit unconditionally when a cpu switches to oneshot mode after the first cpu switched the broadcast device over. It's not idle at that point otherwise it would not be executing that code. [ I fundamentally hate that broadcast crap. Why the heck thought some folks that when going into deep idle it's a brilliant concept to switch off the last device which brings the cpu back from that state? ] Thanks to Christian for providing all the valuable debug information! Reported-and-tested-by: NChristian Hoffmann <email@christianhoffmann.info> Cc: John Stultz <johnstul@us.ibm.com> Link: http://lkml.kernel.org/r/%3Calpine.LFD.2.02.1105161105170.3078%40ionos%3E Cc: stable@kernel.org Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 05 5月, 2011 2 次提交
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由 Andi Kleen 提交于
Avoid taking broadcast_lock in the idle path for systems where the timer doesn't stop in C3. [ tglx: Removed the stale label and added comment ] Signed-off-by: NAndi Kleen <ak@linux.intel.com> Cc: Dave Kleikamp <dkleikamp@gmail.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: lenb@kernel.org Cc: paulmck@us.ibm.com Link: http://lkml.kernel.org/r/%3C20110504234806.GF2925%40one.firstfloor.org%3ESigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 john stultz 提交于
Christian Hoffmann reported that the command line clocksource override with acpi_pm timer fails: Kernel command line: <SNIP> clocksource=acpi_pm hpet clockevent registered Switching to clocksource hpet Override clocksource acpi_pm is not HRT compatible. Cannot switch while in HRT/NOHZ mode. The watchdog code is what enables CLOCK_SOURCE_VALID_FOR_HRES, but we actually end up selecting the clocksource before we enqueue it into the watchdog list, so that's why we see the warning and fail to switch to acpi_pm timer as requested. That's particularly bad when we want to debug timekeeping related problems in early boot. Put the selection call last. Reported-by: NChristian Hoffmann <email@christianhoffmann.info> Signed-off-by: NJohn Stultz <johnstul@us.ibm.com> Cc: stable@kernel.org # 32... Link: http://lkml.kernel.org/r/%3C1304558210.2943.24.camel%40work-vm%3ESigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 04 5月, 2011 2 次提交
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由 Thomas Gleixner 提交于
class_find_device() takes a refcount on the rtc device. rtc_open() takes another one, so we can drop it after the rtc_open() call. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org>
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由 Thomas Gleixner 提交于
alarmtimer_late_init() uses class_find_device() to find a alarm capable rtc device. The match callback stores a pointer to the name in the char pointer handed in from the call site. alarmtimer_late_init() checks the char pointer for NULL, but the pointer is on the stack and not initialized to NULL before the call. So it can have random content when the match function did not identify a device, which leads to random access in the following rtc_open() call where the pointer is dereferenced Instead of relying on the char pointer, check the return value of class_find_device. If a device is found then the name pointer is valid as well. Reported-by: NIngo Molnar <mingo@elte.hu> Cc: John Stultz <john.stultz@linaro.org> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 03 5月, 2011 3 次提交
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由 Thomas Gleixner 提交于
Some applications must be aware of clock realtime being set backward. A simple example is a clock applet which arms a timer for the next minute display. If clock realtime is set backward then the applet displays a stale time for the amount of time which the clock was set backwards. Due to that applications poll the time because we don't have an interface. Extend the timerfd interface by adding a flag which puts the timer onto a different internal realtime clock. All timers on this clock are expired whenever the clock was set. The timerfd core records the monotonic offset when the timer is created. When the timer is armed, then the current offset is compared to the previous recorded offset. When it has changed, then timerfd_settime returns -ECANCELED. When a timer is read the offset is compared and if it changed -ECANCELED returned to user space. Periodic timers are not rearmed in the cancelation case. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Acked-by: NJohn Stultz <johnstul@us.ibm.com> Cc: Chris Friesen <chris.friesen@genband.com> Tested-by: NKay Sievers <kay.sievers@vrfy.org> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Davide Libenzi <davidel@xmailserver.org> Reviewed-by: NAlexander Shishkin <virtuoso@slind.org> Link: http://lkml.kernel.org/r/%3Calpine.LFD.2.02.1104271359580.3323%40ionos%3ESigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Thomas Gleixner 提交于
Make clock_was_set() unconditional and rename hres_timers_resume to hrtimers_resume. This is a preparatory patch for hrtimers which are cancelled when clock realtime was set. Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 John Stultz 提交于
Ingo pointed out that the alarmtimers won't build if CONFIG_RTC_CLASS=n. This patch adds proper ifdefs to the alarmtimer code to disable the rtc usage if it is not built in. Reported-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NJohn Stultz <john.stultz@linaro.org> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 29 4月, 2011 2 次提交
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由 John Stultz 提交于
Thomas asked about the delayed irq work in the alarmtimers code, and I realized that it was a legacy from when the alarmtimer base lock was a mutex (due to concerns that we'd be interacting with the RTC device, which is protected by mutexes). Since the alarmtimer base is now protected by a spinlock, we can simply execute alarmtimer functions directly from the hrtimer callback. Should any future alarmtimer functions sleep, they can simply manage scheduling any delayed work themselves. CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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由 John Stultz 提交于
This patch addresses a number of minor comment improvements and other minor issues from Thomas' review of the alarmtimers code. CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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- 27 4月, 2011 3 次提交
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由 John Stultz 提交于
This patch exposes alarm-timers to userland via the posix clock and timers interface, using two new clockids: CLOCK_REALTIME_ALARM and CLOCK_BOOTTIME_ALARM. Both clockids behave identically to CLOCK_REALTIME and CLOCK_BOOTTIME, respectively, but timers set against the _ALARM suffixed clockids will wake the system if it is suspended. Some background can be found here: https://lwn.net/Articles/429925/ The concept for Alarm-timers was inspired by the Android Alarm driver (by Arve Hjønnevåg) found in the Android kernel tree. See: http://android.git.kernel.org/?p=kernel/common.git;a=blob;f=drivers/rtc/alarm.c;h=1250edfbdf3302f5e4ea6194847c6ef4bb7beb1c;hb=android-2.6.36 While the in-kernel interface is pretty similar between alarm-timers and Android alarm driver, the user-space interface for the Android alarm driver is via ioctls to a new char device. As mentioned above, I've instead chosen to export this functionality via the posix interface, as it seemed a little simpler and avoids creating duplicate interfaces to things like CLOCK_REALTIME and CLOCK_MONOTONIC under alternate names (ie:ANDROID_ALARM_RTC and ANDROID_ALARM_SYSTEMTIME). The semantics of the Android alarm driver are different from what this posix interface provides. For instance, threads other then the thread waiting on the Android alarm driver are able to modify the alarm being waited on. Also this interface does not allow the same wakelock semantics that the Android driver provides (ie: kernel takes a wakelock on RTC alarm-interupt, and holds it through process wakeup, and while the process runs, until the process either closes the char device or calls back in to wait on a new alarm). One potential way to implement similar semantics may be via the timerfd infrastructure, but this needs more research. There may also need to be some sort of sysfs system level policy hooks that allow alarm timers to be disabled to keep them from firing at inappropriate times (ie: laptop in a well insulated bag, mid-flight). CC: Arve Hjønnevåg <arve@android.com> CC: Thomas Gleixner <tglx@linutronix.de> CC: Alessandro Zummo <a.zummo@towertech.it> Acked-by: NArnd Bergmann <arnd@arndb.de> Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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由 John Stultz 提交于
This provides the in kernel interface and infrastructure for alarm-timers. Alarm-timers are a hybrid style timer, similar to hrtimers, but when the system is suspended, the RTC device is set to fire and wake the system for when the soonest alarm-timer expires. The concept for Alarm-timers was inspired by the Android Alarm driver (by Arve Hjønnevåg) found in the Android kernel tree. See: http://android.git.kernel.org/?p=kernel/common.git;a=blob;f=drivers/rtc/alarm.c;h=1250edfbdf3302f5e4ea6194847c6ef4bb7beb1c;hb=android-2.6.36 This in-kernel interface should be fairly compatible with the Android alarm driver in-kernel interface, but has the advantage of utilizing the new RTC timerqueue code instead of doing direct RTC manipulation. CC: Arve Hjønnevåg <arve@android.com> CC: Thomas Gleixner <tglx@linutronix.de> CC: Alessandro Zummo <a.zummo@towertech.it> Acked-by: NArnd Bergmann <arnd@arndb.de> Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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由 John Stultz 提交于
Some platforms cannot implement read_persistent_clock, as their RTC devices are only accessible when interrupts are enabled. This keeps them from being used by the timekeeping code on resume to measure the time in suspend. The RTC layer tries to work around this, by calling do_settimeofday on resume after irqs are reenabled to set the time properly. However, this only corrects CLOCK_REALTIME, and does not properly adjust the sleep time value. This causes btime in /proc/stat to be incorrect as well as making the new CLOCK_BOTTTIME inaccurate. This patch resolves the issue by introducing a new timekeeping hook to allow the RTC layer to inject the sleep time on resume. The code also checks to make sure that read_persistent_clock is nonfunctional before setting the sleep time, so that should the RTC's HCTOSYS option be configured in on a system that does support read_persistent_clock we will not increase the total_sleep_time twice. CC: Arve Hjønnevåg <arve@android.com> CC: Thomas Gleixner <tglx@linutronix.de> Acked-by: NArnd Bergmann <arnd@arndb.de> Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
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