summaryrefslogtreecommitdiff
path: root/kernel/time
AgeCommit message (Collapse)AuthorFilesLines
2010-08-04Merge branch 'master' into for-nextJiri Kosina1-12/+9
2010-07-11fix comment/printk typos concerning "already"Uwe Kleine-König1-1/+1
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-07-02Merge branch 'sched-fixes-for-linus' of ↵Linus Torvalds1-8/+8
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sched: Cure nr_iowait_cpu() users init: Fix comment init, sched: Fix race between init and kthreadd
2010-07-01sched: Cure nr_iowait_cpu() usersPeter Zijlstra1-8/+8
Commit 0224cf4c5e (sched: Intoduce get_cpu_iowait_time_us()) broke things by not making sure preemption was indeed disabled by the callers of nr_iowait_cpu() which took the iowait value of the current cpu. This resulted in a heap of preempt warnings. Cure this by making nr_iowait_cpu() take a cpu number and fix up the callers to pass in the right number. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: Maxim Levitsky <maximlevitsky@gmail.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Jiri Slaby <jslaby@suse.cz> Cc: linux-pm@lists.linux-foundation.org LKML-Reference: <1277968037.1868.120.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-06-17nohz: Fix nohz ratelimitPeter Zijlstra1-4/+1
Chris Wedgwood reports that 39c0cbe (sched: Rate-limit nohz) causes a serial console regression, unresponsiveness, and indeed it does. The reason is that the nohz code is skipped even when the tick was already stopped before the nohz_ratelimit(cpu) condition changed. Move the nohz_ratelimit() check to the other conditions which prevent long idle sleeps. Reported-by: Chris Wedgwood <cw@f00f.org> Tested-by: Brian Bloniarz <bmb@athenacr.com> Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Greg KH <gregkh@suse.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Jef Driesen <jefdriesen@telenet.be> LKML-Reference: <1276790557.27822.516.camel@twins> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-05-19Merge branch 'timers-for-linus' of ↵Linus Torvalds3-20/+65
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: clocksource: Add clocksource_register_hz/khz interface posix-cpu-timers: Optimize run_posix_cpu_timers() time: Remove xtime_cache mqueue: Convert message queue timeout to use hrtimers hrtimers: Provide schedule_hrtimeout for CLOCK_REALTIME timers: Introduce the concept of timer slack for legacy timers ntp: Remove tickadj ntp: Make time_adjust static time: Add xtime, wall_to_monotonic to feature-removal-schedule timer: Try to survive timer callback preempt_count leak timer: Split out timer function call timer: Print function name for timer callbacks modifying preemption count time: Clean up warp_clock() cpu-timers: Avoid iterating over all threads in fastpath_timer_check() cpu-timers: Change SIGEV_NONE timer implementation cpu-timers: Return correct previous timer reload value cpu-timers: Cleanup arm_timer() cpu-timers: Simplify RLIMIT_CPU handling
2010-05-10clocksource: Add clocksource_register_hz/khz interfaceJohn Stultz1-0/+48
How to pick good mult/shift pairs has always been difficult to describe to folks writing clocksource drivers, since it requires careful tradeoffs in adjustment accuracy vs overflow limits. Now, with the clocks_calc_mult_shift function, its much easier. However, not many clocksources have converted to using that function, and there is still the issue of the max interval length assumption being made by each clocksource driver independently. So this patch simplifies the registration process by having clocksources be registered with a hz/khz value and the registration function taking care of setting mult/shift. This should take most of the confusion out of writing a clocksource driver. Additionally it also keeps the shift size tradeoff (more accuracy vs longer possible nohz times) centralized so the timekeeping core can keep track of the assumptions being made. [ tglx: Coding style and comments fixed ] Signed-off-by: John Stultz <johnstul@us.ibm.com> LKML-Reference: <1273280858-30143-1-git-send-email-johnstul@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-05-10Merge branch 'linus' into timers/coreThomas Gleixner4-14/+45
Reason: Further posix_cpu_timer patches depend on mainline changes Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-05-09sched: Intoduce get_cpu_iowait_time_us()Arjan van de Ven2-0/+29
For the ondemand cpufreq governor, it is desired that the iowait time is microaccounted in a similar way as idle time is. This patch introduces the infrastructure to account and expose this information via the get_cpu_iowait_time_us() function. [akpm@linux-foundation.org: fix CONFIG_NO_HZ=n build] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: davej@redhat.com LKML-Reference: <20100509082523.284feab6@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-09sched: Eliminate the ts->idle_lastupdate fieldArjan van de Ven1-4/+1
Now that the only user of ts->idle_lastupdate is update_ts_time_stats(), the entire field can be eliminated. In update_ts_time_stats(), idle_lastupdate is first set to "now", and a few lines later, the only user is an if() statement that assigns a variable either to "now" or to ts->idle_lastupdate, which has the value of "now" at that point. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: davej@redhat.com LKML-Reference: <20100509082439.2fab0b4f@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-09sched: Fold updating of the last_update_time_info into update_ts_time_stats()Arjan van de Ven1-11/+11
This patch folds the updating of the last_update_time into the update_ts_time_stats() function, and updates the callers. This allows for further cleanups that are done in the next patch. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: davej@redhat.com LKML-Reference: <20100509082403.60072967@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-09sched: Update the idle statistics in get_cpu_idle_time_us()Arjan van de Ven1-1/+6
Right now, get_cpu_idle_time_us() only reports the idle statistics upto the point the CPU entered last idle; not what is valid right now. This patch adds an update of the idle statistics to get_cpu_idle_time_us(), so that calling this function always returns statistics that are accurate at the point of the call. This includes resetting the start of the idle time for accounting purposes to avoid double accounting. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: davej@redhat.com LKML-Reference: <20100509082323.2d2f1945@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-09sched: Introduce a function to update the idle statisticsArjan van de Ven1-10/+19
Currently, two places update the idle statistics (and more to come later in this series). This patch creates a helper function for updating these statistics. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: davej@redhat.com LKML-Reference: <20100509082245.163e67ed@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-09sched: Add a comment to get_cpu_idle_time_us()Arjan van de Ven1-0/+14
The exported function get_cpu_idle_time_us() has no comment describing it; add a kerneldoc comment Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: davej@redhat.com LKML-Reference: <20100509082208.7cb721f0@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-04-15Merge branch 'linus' into sched/coreIngo Molnar1-0/+1
Merge reason: merge the latest fixes, update to -rc4. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-04-13time: Remove xtime_cacheJohn Stultz1-19/+16
With the earlier 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 patch also addresses an issue with an earlier version of this change, where xtime_cache was normalizing xtime, which could in some cases be not valid (ie: tv_nsec == NSEC_PER_SEC). This is fixed by handling the edge case in update_wall_time(). Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Petr Titěra <P.Titera@century.cz> LKML-Reference: <1270589451-30773-1-git-send-email-johnstul@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-04-02Merge branch 'linus' into sched/coreIngo Molnar4-14/+48
Merge reason: update to latest upstream Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo1-0/+1
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-23ntp: Make time_adjust staticJohn Stultz1-1/+1
Now that no arches are accessing time_adjust directly, make it static. Signed-off-by: John Stultz <johnstul@us.ibm.com> LKML-Reference: <1268968769-19209-1-git-send-email-johnstul@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-03-23time: Fix accumulation bug triggered by long delay.John Stultz1-1/+2
The logarithmic accumulation done in the timekeeping has some overflow protection that limits the max shift value. That means it will take more then shift loops to accumulate all of the cycles. This causes the shift decrement to underflow, which causes the loop to never exit. The simplest fix would be simply to do a: if (shift) shift--; However that is not optimal, as we know the cycle offset is larger then the interval << shift, the above would make shift drop to zero, then we would be spinning for quite awhile accumulating at interval chunks at a time. Instead, this patch only decreases shift if the offset is smaller then cycle_interval << shift. This makes sure we accumulate using the largest chunks possible without overflowing tick_length, and limits the number of iterations through the loop. This issue was found and reported by Sonic Zhang, who also tested the fix. Many thanks your explanation and testing! Reported-by: Sonic Zhang <sonic.adi@gmail.com> Signed-off-by: John Stultz <johnstul@us.ibm.com> Tested-by: Sonic Zhang <sonic.adi@gmail.com> LKML-Reference: <1268948850-5225-1-git-send-email-johnstul@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-03-12clockevents: Sanitize min_delta_ns adjustment and prevent overflowsThomas Gleixner2-13/+42
The current logic which handles clock events programming failures can increase min_delta_ns unlimited and even can cause overflows. Sanitize it by: - prevent zero increase when min_delta_ns == 1 - limiting min_delta_ns to a jiffie - bail out if the jiffie limit is hit - add retries stats for /proc/timer_list so we can gather data Reported-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-03-11sched: Rate-limit nohzMike Galbraith1-0/+3
Entering nohz code on every micro-idle is costing ~10% throughput for netperf TCP_RR when scheduling cross-cpu. Rate limiting entry fixes this, but raises ticks a bit. On my Q6600, an idle box goes from ~85 interrupts/sec to 128. The higher the context switch rate, the more nohz entry costs. With this patch and some cycle recovery patches in my tree, max cross cpu context switch rate is improved by ~16%, a large portion of which of which is this ratelimiting. Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1268301003.6785.28.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-02timekeeping: Prevent oops when GENERIC_TIME=njohn stultz1-0/+4
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: Aaro Koskinen <aaro.koskinen@iki.fi> Signed-off-by: John 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: Thomas Gleixner <tglx@linutronix.de>
2010-03-01Merge branch 'timers-for-linus' of ↵Linus Torvalds3-6/+19
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: posix-timers.c: Don't export local functions clocksource: start CMT at clocksource resume clocksource: add suspend callback clocksource: add argument to resume callback ntp: Cleanup xtime references in ntp.c ntp: Make time_esterror and time_maxerror static
2010-02-09Export the symbol of getboottime and mmonotonic_to_bootbasedJason Wang1-0/+2
Export getboottime and monotonic_to_bootbased in order to let them could be used by following patch. Cc: stable@kernel.org Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-02-05clocksource: add suspend callbackMagnus Damm2-0/+13
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: Magnus Damm <damm@opensource.se> Cc: Paul Mundt <lethal@linux-sh.org> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-02-05clocksource: add argument to resume callbackMagnus Damm1-1/+1
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: Magnus Damm <damm@opensource.se> Cc: john stultz <johnstul@us.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-01-29ntp: Cleanup xtime references in ntp.cJohn Stultz1-3/+3
ntp.c doesn't need to access timekeeping internals directly, so change xtime references to use the get_seconds() timekeeping interface. Signed-off-by: John 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: Thomas Gleixner <tglx@linutronix.de>
2010-01-29ntp: Make time_esterror and time_maxerror staticjohn stultz1-2/+2
Make time_esterror and time_maxerror static as no one uses them outside of ntp.c Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: richard@rsk.demon.co.uk LKML-Reference: <1264719761.3437.47.camel@localhost.localdomain> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-01-26clocksource: Prevent potential kgdb dead lockThomas Gleixner1-3/+15
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: Jason 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: Thomas Gleixner <tglx@linutronix.de>
2010-01-18clockevent: Don't remove broadcast device when cpu is deadXiaotian Feng1-1/+2
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: Marc Dionne <marc.c.dionne@gmail.com> Tested-by: Marc Dionne <marc.c.dionne@gmail.com> Signed-off-by: Xiaotian Feng <dfeng@redhat.com> LKML-Reference: <1262834564-13033-1-git-send-email-dfeng@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@kernel.org
2009-12-22Revert "time: Remove xtime_cache"Linus Torvalds1-4/+23
This reverts commit 7bc7d637452383d56ba4368d4336b0dde1bb476d, 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: Petr Titěra <P.Titera@century.cz> Requested-by: john stultz <johnstul@us.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-19Merge branch 'timers-fixes-for-linus' of ↵Linus Torvalds1-3/+15
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: timers: Remove duplicate setting of new_base in __mod_timer() clockevents: Prevent clockevent_devices list corruption on cpu hotplug
2009-12-17cpumask: avoid dereferencing struct cpumaskRusty Russell1-2/+2
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: Rusty Russell <rusty@rustcorp.com.au> To: Thomas Gleixner <tglx@linutronix.de>
2009-12-16timecompare: fix half-Y2K38 problem in timecompare_update while calculating ↵Barry Song1-1/+1
offset 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: Barry 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-14clockevents: Convert to raw_spinlockThomas Gleixner3-38/+38
Convert locks which cannot be sleeping locks in preempt-rt to raw_spinlocks. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Ingo Molnar <mingo@elte.hu>
2009-12-14clockevents: Make tick_device_lock staticThomas Gleixner2-2/+1
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Ingo Molnar <mingo@elte.hu>
2009-12-14hrtimers: Convert to raw_spinlocksThomas Gleixner2-11/+12
Convert locks which cannot be sleeping locks in preempt-rt to raw_spinlocks. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Ingo Molnar <mingo@elte.hu>
2009-12-14Merge branch 'for-linus' of ↵Linus Torvalds1-5/+6
git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (34 commits) m68k: rename global variable vmalloc_end to m68k_vmalloc_end percpu: add missing per_cpu_ptr_to_phys() definition for UP percpu: Fix kdump failure if booted with percpu_alloc=page percpu: make misc percpu symbols unique percpu: make percpu symbols in ia64 unique percpu: make percpu symbols in powerpc unique percpu: make percpu symbols in x86 unique percpu: make percpu symbols in xen unique percpu: make percpu symbols in cpufreq unique percpu: make percpu symbols in oprofile unique percpu: make percpu symbols in tracer unique percpu: make percpu symbols under kernel/ and mm/ unique percpu: remove some sparse warnings percpu: make alloc_percpu() handle array types vmalloc: fix use of non-existent percpu variable in put_cpu_var() this_cpu: Use this_cpu_xx in trace_functions_graph.c this_cpu: Use this_cpu_xx for ftrace this_cpu: Use this_cpu_xx in nmi handling this_cpu: Use this_cpu operations in RCU this_cpu: Use this_cpu ops for VM statistics ... Fix up trivial (famous last words) global per-cpu naming conflicts in arch/x86/kvm/svm.c mm/slab.c
2009-12-11clockevents: Prevent clockevent_devices list corruption on cpu hotplugThomas Gleixner1-3/+15
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: Xiaotian Feng <dfeng@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Xiaotian Feng <dfeng@redhat.com> Cc: stable@kernel.org
2009-12-10hrtimer: Tune hrtimer_interrupt hang logicThomas Gleixner1-1/+4
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: Michael Tokarev <mjt@tls.msk.ru> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Marcelo Tosatti <mtosatti@redhat.com> Cc: kvm@vger.kernel.org
2009-12-09Merge branch 'for-linus' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (42 commits) tree-wide: fix misspelling of "definition" in comments reiserfs: fix misspelling of "journaled" doc: Fix a typo in slub.txt. inotify: remove superfluous return code check hdlc: spelling fix in find_pvc() comment doc: fix regulator docs cut-and-pasteism mtd: Fix comment in Kconfig doc: Fix IRQ chip docs tree-wide: fix assorted typos all over the place drivers/ata/libata-sff.c: comment spelling fixes fix typos/grammos in Documentation/edac.txt sysctl: add missing comments fs/debugfs/inode.c: fix comment typos sgivwfb: Make use of ARRAY_SIZE. sky2: fix sky2_link_down copy/paste comment error tree-wide: fix typos "couter" -> "counter" tree-wide: fix typos "offest" -> "offset" fix kerneldoc for set_irq_msi() spidev: fix double "of of" in comment comment typo fix: sybsystem -> subsystem ...
2009-12-08Merge branch 'timers-for-linus-urgent' of ↵Linus Torvalds1-3/+3
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-for-linus-urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: hrtimer: Fix /proc/timer_list regression itimers: Fix racy writes to cpu_itimer fields timekeeping: Fix clock_gettime vsyscall time warp
2009-12-08Merge branch 'timers-for-linus' of ↵Linus Torvalds6-111/+273
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: timers, init: Limit the number of per cpu calibration bootup messages posix-cpu-timers: optimize and document timer_create callback clockevents: Add missing include to pacify sparse x86: vmiclock: Fix printk format x86: Fix printk format due to variable type change sparc: fix printk for change of variable type clocksource/events: Fix fallout of generic code changes nohz: Allow 32-bit machines to sleep for more than 2.15 seconds nohz: Track last do_timer() cpu nohz: Prevent clocksource wrapping during idle nohz: Type cast printk argument mips: Use generic mult/shift factor calculation for clocks clocksource: Provide a generic mult/shift factor calculation clockevents: Use u32 for mult and shift factors nohz: Introduce arch_needs_cpu nohz: Reuse ktime in sub-functions of tick_check_idle. time: Remove xtime_cache time: Implement logarithmic time accumulation
2009-11-18Merge branch 'master' of ↵David S. Miller2-2/+8
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/sfc/sfe4001.c drivers/net/wireless/libertas/cmd.c drivers/staging/Kconfig drivers/staging/Makefile drivers/staging/rtl8187se/Kconfig drivers/staging/rtl8192e/Kconfig
2009-11-18clockevents: Add missing include to pacify sparseH Hartley Sweeten1-0/+2
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: H Hartley Sweeten <hsweeten@visionengravers.com> LKML-Reference: <BD79186B4FD85F4B8E60E381CAEE190901E24550@mi8nycmail19.Mi8.com> Reviewed-by: Yong Zhang <yong.zhang0@gmail.com> Cc: johnstul@us.ibm.com Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-11-17timekeeping: Fix clock_gettime vsyscall time warpLin Ming1-3/+3
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: Lin 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: Thomas Gleixner <tglx@linutronix.de>
2009-11-14clocksource/events: Fix fallout of generic code changesThomas Gleixner1-2/+2
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: Thomas Gleixner <tglx@linutronix.de>
2009-11-13nohz: Allow 32-bit machines to sleep for more than 2.15 secondsJon Hunter3-10/+11
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: Jon 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: Thomas Gleixner <tglx@linutronix.de>
2009-11-13nohz: Track last do_timer() cpuThomas Gleixner1-24/+28
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: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <new-submission> Cc: Jon Hunter <jon-hunter@ti.com> Cc: John Stultz <johnstul@us.ibm.com>