- 24 3月, 2010 1 次提交
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由 John Stultz 提交于
Now that no arches are accessing time_adjust directly, make it static. Signed-off-by: NJohn Stultz <johnstul@us.ibm.com> LKML-Reference: <1268968769-19209-1-git-send-email-johnstul@us.ibm.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 02 3月, 2010 1 次提交
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由 john stultz 提交于
Aaro Koskinen reported an issue in kernel.org bugzilla #15366, where on non-GENERIC_TIME systems, accessing /sys/devices/system/clocksource/clocksource0/current_clocksource results in an oops. It seems the timekeeper/clocksource rework missed initializing the curr_clocksource value in the !GENERIC_TIME case. Thanks to Aaro for reporting and diagnosing the issue as well as testing the fix! Reported-by: NAaro Koskinen <aaro.koskinen@iki.fi> Signed-off-by: NJohn Stultz <johnstul@us.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: stable@kernel.org LKML-Reference: <1267475683.4216.61.camel@localhost.localdomain> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 10 2月, 2010 1 次提交
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由 Jason Wang 提交于
Export getboottime and monotonic_to_bootbased in order to let them could be used by following patch. Cc: stable@kernel.org Signed-off-by: NJason Wang <jasowang@redhat.com> Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
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- 05 2月, 2010 2 次提交
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由 Magnus Damm 提交于
Add a clocksource suspend callback. This callback can be used by the clocksource driver to shutdown and perform any kind of late suspend activities even though the clocksource driver itself is a non-sysdev driver. One example where this is useful is to fix the sh_cmt.c platform driver that today suspends using the platform bus and shuts down the clocksource too early. With this callback in place the sh_cmt driver will suspend using the clocksource and clockevent hooks and leave the platform device pm callbacks unused. Signed-off-by: NMagnus Damm <damm@opensource.se> Cc: Paul Mundt <lethal@linux-sh.org> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Magnus Damm 提交于
Pass the clocksource as an argument to the clocksource resume callback. Needed so we can point out which CMT channel the sh_cmt.c driver shall resume. Signed-off-by: NMagnus Damm <damm@opensource.se> Cc: john stultz <johnstul@us.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 29 1月, 2010 2 次提交
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由 John Stultz 提交于
ntp.c doesn't need to access timekeeping internals directly, so change xtime references to use the get_seconds() timekeeping interface. Signed-off-by: NJohn Stultz <johnstul@us.ibm.com> Cc: richard@rsk.demon.co.uk LKML-Reference: <1264738844-21935-1-git-send-email-johnstul@us.ibm.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 john stultz 提交于
Make time_esterror and time_maxerror static as no one uses them outside of ntp.c Signed-off-by: NJohn Stultz <johnstul@us.ibm.com> Cc: richard@rsk.demon.co.uk LKML-Reference: <1264719761.3437.47.camel@localhost.localdomain> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 26 1月, 2010 1 次提交
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由 Thomas Gleixner 提交于
commit 0f8e8ef7 (clocksource: Simplify clocksource watchdog resume logic) introduced a potential kgdb dead lock. When the kernel is stopped by kgdb inside code which holds watchdog_lock then kgdb dead locks in clocksource_resume_watchdog(). clocksource_resume_watchdog() is called from kbdg via clocksource_touch_watchdog() to avoid that the clock source watchdog marks TSC unstable after the kernel has been stopped. Solve this by replacing spin_lock with a spin_trylock and just return in case the lock is held. Not resetting the watchdog might result in TSC becoming marked unstable, but that's an acceptable penalty for using kgdb. The timekeeping is anyway easily screwed up by kgdb when the system uses either jiffies or a clock source which wraps in short intervals (e.g. pm_timer wraps about every 4.6s), so we really do not have to worry about that occasional TSC marked unstable side effect. The second caller of clocksource_resume_watchdog() is clocksource_resume(). The trylock is safe here as well because the system is UP at this point, interrupts are disabled and nothing else can hold watchdog_lock(). Reported-by: NJason Wessel <jason.wessel@windriver.com> LKML-Reference: <1264480000-6997-4-git-send-email-jason.wessel@windriver.com> Cc: kgdb-bugreport@lists.sourceforge.net Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: John Stultz <johnstul@us.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 18 1月, 2010 1 次提交
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由 Xiaotian Feng 提交于
Marc reported that the BUG_ON in clockevents_notify() triggers on his system. This happens because the kernel tries to remove an active clock event device (used for broadcasting) from the device list. The handling of devices which can be used as per cpu device and as a global broadcast device is suboptimal. The simplest solution for now (and for stable) is to check whether the device is used as global broadcast device, but this needs to be revisited. [ tglx: restored the cpuweight check and massaged the changelog ] Reported-by: NMarc Dionne <marc.c.dionne@gmail.com> Tested-by: NMarc Dionne <marc.c.dionne@gmail.com> Signed-off-by: NXiaotian Feng <dfeng@redhat.com> LKML-Reference: <1262834564-13033-1-git-send-email-dfeng@redhat.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: stable@kernel.org
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- 23 12月, 2009 1 次提交
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由 Linus Torvalds 提交于
This reverts commit 7bc7d637, as requested by John Stultz. Quoting John: "Petr Titěra reported an issue where he saw odd atime regressions with 2.6.33 where there were a full second worth of nanoseconds in the nanoseconds field. He also reviewed the time code and narrowed down the problem: unhandled overflow of the nanosecond field caused by rounding up the sub-nanosecond accumulated time. Details: * At the end of update_wall_time(), we currently round up the sub-nanosecond portion of accumulated time when storing it into xtime. This was added to avoid time inconsistencies caused when the sub-nanosecond portion was truncated when storing into xtime. Unfortunately we don't handle the possible second overflow caused by that rounding. * Previously the xtime_cache code hid this overflow by normalizing the xtime value when storing into the xtime_cache. * We could try to handle the second overflow after the rounding up, but since this affects the timekeeping's internal state, this would further complicate the next accumulation cycle, causing small errors in ntp steering. As much as I'd like to get rid of it, the xtime_cache code is known to work. * The correct fix is really to include the sub-nanosecond portion in the timekeeping accessor function, so we don't need to round up at during accumulation. This would greatly simplify the accumulation code. Unfortunately, we can't do this safely until the last three non-GENERIC_TIME arches (sparc32, arm, cris) are converted (those patches are in -mm) and we kill off the spots where arches set xtime directly. This is all 2.6.34 material, so I think reverting the xtime_cache change is the best approach for now. Many thanks to Petr for both reporting and finding the issue!" Reported-by: NPetr Titěra <P.Titera@century.cz> Requested-by: Njohn stultz <johnstul@us.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 17 12月, 2009 1 次提交
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由 Rusty Russell 提交于
struct cpumask will be undefined soon with CONFIG_CPUMASK_OFFSTACK=y, to avoid them being declared on the stack. cpumask_bits() does what we want here (of course, this code is crap). Signed-off-by: NRusty Russell <rusty@rustcorp.com.au> To: Thomas Gleixner <tglx@linutronix.de>
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- 16 12月, 2009 1 次提交
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由 Barry Song 提交于
ktime will overflow from 03:14:07 UTC on Tuesday, 19 January 2038, ktime_add() in timecompare_update() will overflow a half earlier. As a result, wrong offset will be gotten, then cause some strange problems. Signed-off-by: NBarry Song <21cnbao@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Patrick Ohly <patrick.ohly@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: John Stultz <johnstul@us.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 15 12月, 2009 3 次提交
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由 Thomas Gleixner 提交于
Convert locks which cannot be sleeping locks in preempt-rt to raw_spinlocks. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Acked-by: NPeter Zijlstra <peterz@infradead.org> Acked-by: NIngo Molnar <mingo@elte.hu>
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由 Thomas Gleixner 提交于
Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Acked-by: NPeter Zijlstra <peterz@infradead.org> Acked-by: NIngo Molnar <mingo@elte.hu>
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由 Thomas Gleixner 提交于
Convert locks which cannot be sleeping locks in preempt-rt to raw_spinlocks. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Acked-by: NPeter Zijlstra <peterz@infradead.org> Acked-by: NIngo Molnar <mingo@elte.hu>
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- 11 12月, 2009 1 次提交
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由 Thomas Gleixner 提交于
Xiaotian Feng triggered a list corruption in the clock events list on CPU hotplug and debugged the root cause. If a CPU registers more than one per cpu clock event device, then only the active clock event device is removed on CPU_DEAD. The unused devices are kept in the clock events device list. On CPU up the clock event devices are registered again, which means that we list_add an already enqueued list_head. That results in list corruption. Resolve this by removing all devices which are associated to the dead CPU on CPU_DEAD. Reported-by: NXiaotian Feng <dfeng@redhat.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Tested-by: NXiaotian Feng <dfeng@redhat.com> Cc: stable@kernel.org
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- 10 12月, 2009 1 次提交
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由 Thomas Gleixner 提交于
The hrtimer_interrupt hang logic adjusts min_delta_ns based on the execution time of the hrtimer callbacks. This is error-prone for virtual machines, where a guest vcpu can be scheduled out during the execution of the callbacks (and the callbacks themselves can do operations that translate to blocking operations in the hypervisor), which in can lead to large min_delta_ns rendering the system unusable. Replace the current heuristics with something more reliable. Allow the interrupt code to try 3 times to catch up with the lost time. If that fails use the total time spent in the interrupt handler to defer the next timer interrupt so the system can catch up with other things which got delayed. Limit that deferment to 100ms. The retry events and the maximum time spent in the interrupt handler are recorded and exposed via /proc/timer_list Inspired by a patch from Marcelo. Reported-by: NMichael Tokarev <mjt@tls.msk.ru> Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Tested-by: NMarcelo Tosatti <mtosatti@redhat.com> Cc: kvm@vger.kernel.org
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- 18 11月, 2009 1 次提交
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由 H Hartley Sweeten 提交于
Include "tick-internal.h" in order to pick up the extern function prototype for clockevents_shutdown(). This quiets the following sparse build noise: warning: symbol 'clockevents_shutdown' was not declared. Should it be static? Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com> LKML-Reference: <BD79186B4FD85F4B8E60E381CAEE190901E24550@mi8nycmail19.Mi8.com> Reviewed-by: NYong Zhang <yong.zhang0@gmail.com> Cc: johnstul@us.ibm.com Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 17 11月, 2009 1 次提交
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由 Lin Ming 提交于
Since commit 0a544198 "timekeeping: Move NTP adjusted clock multiplier to struct timekeeper" the clock multiplier of vsyscall is updated with the unmodified clock multiplier of the clock source and not with the NTP adjusted multiplier of the timekeeper. This causes user space observerable time warps: new CLOCK-warp maximum: 120 nsecs, 00000025c337c537 -> 00000025c337c4bf Add a new argument "mult" to update_vsyscall() and hand in the timekeeping internal NTP adjusted multiplier. Signed-off-by: NLin Ming <ming.m.lin@intel.com> Cc: "Zhang Yanmin" <yanmin_zhang@linux.intel.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Tony Luck <tony.luck@intel.com> LKML-Reference: <1258436990.17765.83.camel@minggr.sh.intel.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 14 11月, 2009 7 次提交
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由 Thomas Gleixner 提交于
powerpc grew a new warning due to the type change of clockevent->mult. The architectures which use parts of the generic time keeping infrastructure tripped over my wrong assumption that clocksource_register is only used when GENERIC_TIME=y. I should have looked and also I should have known better. These renitent Gaul villages are racking my nerves. Some serious deprecating is due. Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Jon Hunter 提交于
In the dynamic tick code, "max_delta_ns" (member of the "clock_event_device" structure) represents the maximum sleep time that can occur between timer events in nanoseconds. The variable, "max_delta_ns", is defined as an unsigned long which is a 32-bit integer for 32-bit machines and a 64-bit integer for 64-bit machines (if -m64 option is used for gcc). The value of max_delta_ns is set by calling the function "clockevent_delta2ns()" which returns a maximum value of LONG_MAX. For a 32-bit machine LONG_MAX is equal to 0x7fffffff and in nanoseconds this equates to ~2.15 seconds. Hence, the maximum sleep time for a 32-bit machine is ~2.15 seconds, where as for a 64-bit machine it will be many years. This patch changes the type of max_delta_ns to be "u64" instead of "unsigned long" so that this variable is a 64-bit type for both 32-bit and 64-bit machines. It also changes the maximum value returned by clockevent_delta2ns() to KTIME_MAX. Hence this allows a 32-bit machine to sleep for longer than ~2.15 seconds. Please note that this patch also changes "min_delta_ns" to be "u64" too and although this is unnecessary, it makes the patch simpler as it avoids to fixup all callers of clockevent_delta2ns(). [ tglx: changed "unsigned long long" to u64 as we use this data type through out the time code ] Signed-off-by: NJon Hunter <jon-hunter@ti.com> Cc: John Stultz <johnstul@us.ibm.com> LKML-Reference: <1250617512-23567-3-git-send-email-jon-hunter@ti.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Thomas Gleixner 提交于
The previous patch which limits the sleep time to the maximum deferment time of the time keeping clocksource has some limitations on SMP machines: if all CPUs are idle then for all CPUs the maximum sleep time is limited. Solve this by keeping track of which cpu had the do_timer() duty assigned last and limit the sleep time only for this cpu. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> LKML-Reference: <new-submission> Cc: Jon Hunter <jon-hunter@ti.com> Cc: John Stultz <johnstul@us.ibm.com>
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由 Jon Hunter 提交于
The dynamic tick allows the kernel to sleep for periods longer than a single tick, but it does not limit the sleep time currently. In the worst case the kernel could sleep longer than the wrap around time of the time keeping clock source which would result in losing track of time. Prevent this by limiting it to the safe maximum sleep time of the current time keeping clock source. The value is calculated when the clock source is registered. [ tglx: simplified the code a bit and massaged the commit msg ] Signed-off-by: NJon Hunter <jon-hunter@ti.com> Cc: John Stultz <johnstul@us.ibm.com> LKML-Reference: <1250617512-23567-2-git-send-email-jon-hunter@ti.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Thomas Gleixner 提交于
On some archs local_softirq_pending() has a data type of unsigned long on others its unsigned int. Type cast it to (unsigned int) in the printk to avoid the compiler warning. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> LKML-Reference: <new-submission>
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由 Thomas Gleixner 提交于
MIPS has two functions to calculcate the mult/shift factors for clock sources and clock events at run time. ARM needs such functions as well. Implement a function which calculates the mult/shift factors based on the frequencies to which and from which is converted. The function also has a parameter to specify the minimum conversion range in seconds. This range is guaranteed not to produce a 64bit overflow when a value is multiplied with the calculated mult factor. The larger the conversion range the less becomes the conversion accuracy. Provide two inline wrappers which handle clock events and clock sources. For clock events the "from" frequency is nano seconds per second which corresponds to 1GHz and "to" is the device frequency. For clock sources "from" is the device frequency and "to" is nano seconds per second. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Tested-by: NMikael Pettersson <mikpe@it.uu.se> Acked-by: NRalf Baechle <ralf@linux-mips.org> Acked-by: NLinus Walleij <linus.walleij@stericsson.com> Cc: John Stultz <johnstul@us.ibm.com> LKML-Reference: <20091111134229.766673305@linutronix.de>
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由 Thomas Gleixner 提交于
The mult and shift factors of clock events differ in their data type from those of clock sources for no reason. u32 is sufficient for both. shift is always <= 32 and mult is limited to 2^32-1 to avoid 64bit multiplication overflows in the conversion. Preparatory patch for a generic mult/shift factor calculation function. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Tested-by: NMikael Pettersson <mikpe@it.uu.se> Acked-by: NRalf Baechle <ralf@linux-mips.org> Acked-by: NLinus Walleij <linus.walleij@stericsson.com> Cc: John Stultz <johnstul@us.ibm.com> LKML-Reference: <20091111134229.725664788@linutronix.de>
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- 12 11月, 2009 1 次提交
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由 David S. Miller 提交于
Noticed by Thomas GLeixner. Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 09 11月, 2009 1 次提交
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由 Uwe Kleine-König 提交于
This patch was generated by git grep -E -i -l 's(le|el)ct' | xargs -r perl -p -i -e 's/([Ss])(le|el)ct/$1elect/ with only skipping net/netfilter/xt_SECMARK.c and include/linux/netfilter/xt_SECMARK.h which have a struct member called selctx. Signed-off-by: NUwe Kleine-Knig <u.kleine-koenig@pengutronix.de> Signed-off-by: NJiri Kosina <jkosina@suse.cz>
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- 05 11月, 2009 2 次提交
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由 Martin Schwidefsky 提交于
Allow the architecture to request a normal jiffy tick when the system goes idle and tick_nohz_stop_sched_tick is called . On s390 the hook is used to prevent the system going fully idle if there has been an interrupt other than a clock comparator interrupt since the last wakeup. On s390 the HiperSockets response time for 1 connection ping-pong goes down from 42 to 34 microseconds. The CPU cost decreases by 27%. Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> LKML-Reference: <20090929122533.402715150@de.ibm.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Martin Schwidefsky 提交于
On a system with NOHZ=y tick_check_idle calls tick_nohz_stop_idle and tick_nohz_update_jiffies. Given the right conditions (ts->idle_active and/or ts->tick_stopped) both function get a time stamp with ktime_get. The same time stamp can be reused if both function require one. On s390 this change has the additional benefit that gcc inlines the tick_nohz_stop_idle function into tick_check_idle. The number of instructions to execute tick_check_idle drops from 225 to 144 (without the ktime_get optimization it is 367 vs 215 instructions). before: 0) | tick_check_idle() { 0) | tick_nohz_stop_idle() { 0) | ktime_get() { 0) | read_tod_clock() { 0) 0.601 us | } 0) 1.765 us | } 0) 3.047 us | } 0) | ktime_get() { 0) | read_tod_clock() { 0) 0.570 us | } 0) 1.727 us | } 0) | tick_do_update_jiffies64() { 0) 0.609 us | } 0) 8.055 us | } after: 0) | tick_check_idle() { 0) | ktime_get() { 0) | read_tod_clock() { 0) 0.617 us | } 0) 1.773 us | } 0) | tick_do_update_jiffies64() { 0) 0.593 us | } 0) 4.477 us | } Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Cc: john stultz <johnstul@us.ibm.com> LKML-Reference: <20090929122533.206589318@de.ibm.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 29 10月, 2009 1 次提交
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由 Tejun Heo 提交于
This patch updates percpu related symbols under kernel/ and mm/ such that percpu symbols are unique and don't clash with local symbols. This serves two purposes of decreasing the possibility of global percpu symbol collision and allowing dropping per_cpu__ prefix from percpu symbols. * kernel/lockdep.c: s/lock_stats/cpu_lock_stats/ * kernel/sched.c: s/init_rq_rt/init_rt_rq_var/ (any better idea?) s/sched_group_cpus/sched_groups/ * kernel/softirq.c: s/ksoftirqd/run_ksoftirqd/a * kernel/softlockup.c: s/(*)_timestamp/softlockup_\1_ts/ s/watchdog_task/softlockup_watchdog/ s/timestamp/ts/ for local variables * kernel/time/timer_stats: s/lookup_lock/tstats_lookup_lock/ * mm/slab.c: s/reap_work/slab_reap_work/ s/reap_node/slab_reap_node/ * mm/vmstat.c: local variable changed to avoid collision with vmstat_work Partly based on Rusty Russell's "alloc_percpu: rename percpu vars which cause name clashes" patch. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: N(slab/vmstat) Christoph Lameter <cl@linux-foundation.org> Reviewed-by: NChristoph Lameter <cl@linux-foundation.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Nick Piggin <npiggin@suse.de>
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- 12 10月, 2009 1 次提交
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由 Alexey Dobriyan 提交于
After m68k's task_thread_info() doesn't refer to current, it's possible to remove sched.h from interrupt.h and not break m68k! Many thanks to Heiko Carstens for allowing this. Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
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- 07 10月, 2009 1 次提交
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由 Eero Nurkkala 提交于
Commit f2e21c96 had unfortunate side effects with cpufreq governors on some systems. If the system did not switch into NOHZ mode ts->inidle is not set when tick_nohz_stop_sched_tick() is called from the idle routine. Therefor all subsequent calls from irq_exit() to tick_nohz_stop_sched_tick() fail to call tick_nohz_start_idle(). This results in bogus idle accounting information which is passed to cpufreq governors. Set the inidle flag unconditionally of the NOHZ active state to keep the idle time accounting correct in any case. [ tglx: Added comment and tweaked the changelog ] Reported-by: NSteven Noonan <steven@uplinklabs.net> Signed-off-by: NEero Nurkkala <ext-eero.nurkkala@nokia.com> Cc: Rik van Riel <riel@redhat.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Greg KH <greg@kroah.com> Cc: Steven Noonan <steven@uplinklabs.net> Cc: stable@kernel.org LKML-Reference: <1254907901.30157.93.camel@eenurkka-desktop> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 05 10月, 2009 2 次提交
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由 john stultz 提交于
With the prior logarithmic time accumulation patch, xtime will now always be within one "tick" of the current time, instead of possibly half a second off. This removes the need for the xtime_cache value, which always stored the time at the last interrupt, so this patch cleans that up removing the xtime_cache related code. This is a bit simpler, but still could use some wider testing. Signed-off-by: NJohn Stultz <johnstul@us.ibm.com> Acked-by: NThomas Gleixner <tglx@linutronix.de> Reviewed-by: NJohn Kacur <jkacur@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <1254525855.7741.95.camel@localhost.localdomain> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 john stultz 提交于
Accumulating one tick at a time works well unless we're using NOHZ. Then it can be an issue, since we may have to run through the loop a few thousand times, which can increase timer interrupt caused latency. The current solution was to accumulate in half-second intervals with NOHZ. This kept the number of loops down, however it did slightly change how we make NTP adjustments. While not an issue with NTPd users, as NTPd makes adjustments over a longer period of time, other adjtimex() users have noticed the half-second granularity with which we can apply frequency changes to the clock. For instance, if a application tries to apply a 100ppm frequency correction for 20ms to correct a 2us offset, with NOHZ they either get no correction, or a 50us correction. Now, there will always be some granularity error for applying frequency corrections. However with users sensitive to this error have seen a 50-500x increase with NOHZ compared to running without NOHZ. So I figured I'd try another approach then just simply increasing the interval. My approach is to consume the time interval logarithmically. This reduces the number of times through the loop needed keeping latency down, while still preserving the original granularity error for adjtimex() changes. Further, this change allows us to remove the xtime_cache code (patch to follow), as xtime is always within one tick of the current time, instead of the half-second updates it saw before. An earlier version of this patch has been shipping to x86 users in the RedHat MRG releases for awhile without issue, but I've reworked this version to be even more careful about avoiding possible overflows if the shift value gets too large. Signed-off-by: NJohn Stultz <johnstul@us.ibm.com> Acked-by: NThomas Gleixner <tglx@linutronix.de> Reviewed-by: NJohn Kacur <jkacur@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <1254525473.7741.88.camel@localhost.localdomain> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 02 10月, 2009 1 次提交
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由 Alexey Dobriyan 提交于
[akpm@linux-foundation.org: fix KVM] Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com> Acked-by: NMike Frysinger <vapier@gentoo.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 25 9月, 2009 1 次提交
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由 Martin Schwidefsky 提交于
git commit 75c5158f converted the clocksource spinlock to a mutex. This causes the following BUG: BUG: sleeping function called from invalid context at kernel/mutex.c:280 in_atomic(): 0, irqs_disabled(): 1, pid: 2473, name: pm-suspend 2 locks held by pm-suspend/2473: #0: (&buffer->mutex){......}, at: [<ffffffff8115ab13>] sysfs_write_file+0x3c/0x137 #1: (pm_mutex){......}, at: [<ffffffff810865b5>] enter_state+0x39/0x130 Pid: 2473, comm: pm-suspend Not tainted 2.6.31 #1 Call Trace: [<ffffffff810792f0>] ? __debug_show_held_locks+0x22/0x24 [<ffffffff8104a2ef>] __might_sleep+0x107/0x10b [<ffffffff8141fca9>] mutex_lock_nested+0x25/0x43 [<ffffffff81073537>] clocksource_resume+0x1c/0x60 [<ffffffff81072902>] timekeeping_resume+0x1e/0x1c8 [<ffffffff812aee62>] __sysdev_resume+0x25/0xcf [<ffffffff812aef79>] sysdev_resume+0x6d/0xae [<ffffffff810864f8>] suspend_devices_and_enter+0x12b/0x1af [<ffffffff8108665b>] enter_state+0xdf/0x130 [<ffffffff81085dc3>] state_store+0xb6/0xd3 [<ffffffff81204c73>] kobj_attr_store+0x17/0x19 [<ffffffff8115abd2>] sysfs_write_file+0xfb/0x137 [<ffffffff811057d2>] vfs_write+0xae/0x10b [<ffffffff81208392>] ? __up_read+0x1a/0x7f [<ffffffff811058ef>] sys_write+0x4a/0x6e [<ffffffff81011b82>] system_call_fastpath+0x16/0x1b clocksource_resume is called early in the resume process, there is only one cpu, no processes are running and the interrupts are disabled. It is therefore possible to resume the clocksources without taking the clocksource mutex. Reported-by: NXiaotian Feng <xtfeng@gmail.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Tested-by: NMichal Schmidt <mschmidt@redhat.com> Cc: Xiaotian Feng <xtfeng@gmail.com> Cc: John Stultz <johnstul@us.ibm.com> LKML-Reference: <20090924172952.49697825@mschwide.boeblingen.de.ibm.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 24 9月, 2009 1 次提交
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由 Zhaolei 提交于
There are many similar code in kernel for one object: convert time between calendar time and broken-down time. Here is some source I found: fs/ncpfs/dir.c fs/smbfs/proc.c fs/fat/misc.c fs/udf/udftime.c fs/cifs/netmisc.c net/netfilter/xt_time.c drivers/scsi/ips.c drivers/input/misc/hp_sdc_rtc.c drivers/rtc/rtc-lib.c arch/ia64/hp/sim/boot/fw-emu.c arch/m68k/mac/misc.c arch/powerpc/kernel/time.c arch/parisc/include/asm/rtc.h ... We can make a common function for this type of conversion, At least we can get following benefit: 1: Make kernel simple and unify 2: Easy to fix bug in converting code 3: Reduce clone of code in future For example, I'm trying to make ftrace display walltime, this patch will make me easy. This code is based on code from glibc-2.6 Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Pavel Machek <pavel@ucw.cz> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 15 9月, 2009 2 次提交
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由 Thomas Gleixner 提交于
The down rating of clock sources in the early boot process via the clock source watchdog mechanism can happen way before the per cpu event queues are initialized. This leads to a boot crash on x86 when the TSC is marked unstable in the SMP bring up. The selection of a clock source for time keeping happens in the late boot process so we can safely delay the list manipulation until clocksource_done_booting() is called. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> LKML-Reference: <new-submission> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
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由 Thomas Gleixner 提交于
The callers of clocksource_select must hold clocksource_mutex to protect the clocksource_list. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> LKML-Reference: <new-submission> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
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