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* sched: Add missing call to calc_load_exit_idle()Charles Wang2012-09-04
| | | | | | | | | | | | | | | | | | | | | Azat Khuzhin reported high loadavg in Linux v3.6 After checking the upstream scheduler code, I found Peter's commit: 5167e8d5417b sched/nohz: Rewrite and fix load-avg computation -- again not fully applied, missing the call to calc_load_exit_idle(). After that idle exit in sampling window will always be calculated to non-idle, and the load will be higher than normal. This patch adds the missing call to calc_load_exit_idle(). Signed-off-by: Charles Wang <muming.wq@taobao.com> Cc: stable@kernel.org Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1345449754-27130-1-git-send-email-muming.wq@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* time: Move ktime_t overflow checking into timespec_valid_strictJohn Stultz2012-09-01
| | | | | | | | | | | | | | | | | | | | | | | Andreas Bombe reported that the added ktime_t overflow checking added to timespec_valid in commit 4e8b14526ca7 ("time: Improve sanity checking of timekeeping inputs") was causing problems with X.org because it caused timeouts larger then KTIME_T to be invalid. Previously, these large timeouts would be clamped to KTIME_MAX and would never expire, which is valid. This patch splits the ktime_t overflow checking into a new timespec_valid_strict function, and converts the timekeeping codes internal checking to use this more strict function. Reported-and-tested-by: Andreas Bombe <aeb@debian.org> Cc: Zhouping Liu <zliu@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* time: Avoid making adjustments if we haven't accumulated anythingJohn Stultz2012-08-22
| | | | | | | | | | | | | | If update_wall_time() is called and the current offset isn't large enough to accumulate, avoid re-calling timekeeping_adjust which may change the clock freq and can cause 1ns inconsistencies with CLOCK_REALTIME_COARSE/CLOCK_MONOTONIC_COARSE. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1345595449-34965-5-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* time: Avoid potential shift overflow with large shift valuesJohn Stultz2012-08-22
| | | | | | | | | | | | | | | | Andreas Schwab noticed that the 1 << tk->shift could overflow if the shift value was greater than 30, since 1 would be a 32bit long on 32bit architectures. This issue was introduced by 1e75fa8be (time: Condense timekeeper.xtime into xtime_sec) Use 1ULL instead to ensure we don't overflow on the shift. Reported-by: Andreas Schwab <schwab@linux-m68k.org> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/1345595449-34965-4-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* time: Fix casting issue in timekeeping_forward_nowAndreas Schwab2012-08-22
| | | | | | | | | | | | | | | arch_gettimeoffset returns a u32 value which when shifted by tk->shift can overflow. This issue was introduced with 1e75fa8be (time: Condense timekeeper.xtime into xtime_sec) Cast it to u64 first. Signed-off-by: Andreas Schwab <schwab@linux-m68k.org> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/1345595449-34965-3-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* time: Ensure we normalize the timekeeper in tk_xtime_addJohn Stultz2012-08-22
| | | | | | | | | | | | | | | | | | Andreas noticed problems with resume on specific hardware after commit 1e75fa8b (time: Condense timekeeper.xtime into xtime_sec) combined with commit b44d50dca (time: Fix casting issue in tk_set_xtime and tk_xtime_add) After some digging I realized we aren't normalizing the timekeeper after the add. Add the missing normalize call. Reported-by: Andreas Schwab <schwab@linux-m68k.org> Tested-by: Andreas Schwab <schwab@linux-m68k.org> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/1345595449-34965-2-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* time: Improve sanity checking of timekeeping inputsJohn Stultz2012-08-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Unexpected behavior could occur if the time is set to a value large enough to overflow a 64bit ktime_t (which is something larger then the year 2262). Also unexpected behavior could occur if large negative offsets are injected via adjtimex. So this patch improves the sanity check timekeeping inputs by improving the timespec_valid() check, and then makes better use of timespec_valid() to make sure we don't set the time to an invalid negative value or one that overflows ktime_t. Note: This does not protect from setting the time close to overflowing ktime_t and then letting natural accumulation cause the overflow. Reported-by: CAI Qian <caiqian@redhat.com> Reported-by: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Zhouping Liu <zliu@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1344454580-17031-1-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* time: Fix adjustment cleanup bug in timekeeping_adjust()Ingo Molnar2012-08-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Tetsuo Handa reported that sporadically the system clock starts counting up too quickly which is enough to confuse the hangcheck timer to print a bogus stall warning. Commit 2a8c0883 "time: Move xtime_nsec adjustment underflow handling timekeeping_adjust" overlooked this exit path: } else return; which should really be a proper exit sequence, fixing the bug as a side effect. Also make the flow more readable by properly balancing curly braces. Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> wrote: Tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> wrote: Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: john.stultz@linaro.org Cc: a.p.zijlstra@chello.nl Cc: richardcochran@gmail.com Cc: prarit@redhat.com Link: http://lkml.kernel.org/r/20120804192114.GA28347@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* time: Remove all direct references to timekeeperJohn Stultz2012-07-31
| | | | | | | | | | | | | | | | Ingo noted that the numerous timekeeper.value references made the timekeeping code ugly and caused many long lines that had to be broken up. He recommended replacing timekeeper.value references with tk->value. This patch provides a local tk value for all top level time functions and sets it to &timekeeper. Then all timekeeper access is done via a tk pointer. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Prarit Bhargava <prarit@redhat.com> Link: http://lkml.kernel.org/r/1343414893-45779-6-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* time: Clean up offs_real/wall_to_mono and offs_boot/total_sleep_time updatesJohn Stultz2012-07-31
| | | | | | | | | | | | | | | | | | | | | | | | | | For performance reasons, we maintain ktime_t based duplicates of wall_to_monotonic (offs_real) and total_sleep_time (offs_boot). Since large problems could occur (such as the resume regression on 3.5-rc7, or the leapsecond hrtimer issue) if these value pairs were to be inconsistently updated, this patch this cleans up how we modify these value pairs to ensure we are always consistent. As a side-effect this is also more efficient as we only caulculate the duplicate values when they are changed, rather then every update_wall_time call. This also provides WARN_ONs to detect if future changes break the invariants. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Link: http://lkml.kernel.org/r/1343414893-45779-5-git-send-email-john.stultz@linaro.org [ Cleaned up minor style issues. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
* time: Clean up stray newlinesJohn Stultz2012-07-31
| | | | | | | | | | Ingo noted inconsistent newline usage between functions. This patch cleans those up. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Prarit Bhargava <prarit@redhat.com> Link: http://lkml.kernel.org/r/1343414893-45779-4-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* time/jiffies: Rename ACTHZ to SHIFTED_HZJohn Stultz2012-07-31
| | | | | | | | | | | Ingo noted that ACTHZ is a confusing name, and requested it be renamed, so this patch renames ACTHZ to SHIFTED_HZ to better describe it. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Prarit Bhargava <prarit@redhat.com> Link: http://lkml.kernel.org/r/1343414893-45779-3-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge branch 'linus' into timers/urgentIngo Molnar2012-07-31
|\ | | | | | | | | | | Merge in Linus's branch which already has timers/core merged. Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * Merge branch 'timers-core-for-linus' of ↵Linus Torvalds2012-07-22
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer core changes from Ingo Molnar: "Continued cleanups of the core time and NTP code, plus more nohz work preparing for tick-less userspace execution." * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: time: Rework timekeeping functions to take timekeeper ptr as argument time: Move xtime_nsec adjustment underflow handling timekeeping_adjust time: Move arch_gettimeoffset() usage into timekeeping_get_ns() time: Refactor accumulation of nsecs to secs time: Condense timekeeper.xtime into xtime_sec time: Explicitly use u32 instead of int for shift values time: Whitespace cleanups per Ingo%27s requests nohz: Move next idle expiry time record into idle logic area nohz: Move ts->idle_calls incrementation into strict idle logic nohz: Rename ts->idle_tick to ts->last_tick nohz: Make nohz API agnostic against idle ticks cputime accounting nohz: Separate idle sleeping time accounting from nohz logic timers: Improve get_next_timer_interrupt() timers: Add accounting of non deferrable timers timers: Consolidate base->next_timer update timers: Create detach_if_pending() and use it
| | * Merge branch 'linus' into timers/coreIngo Molnar2012-07-18
| | |\ | | | | | | | | | | | | | | | | | | | | Resolve semantic conflict in kernel/time/timekeeping.c. Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | \ Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds2012-07-22
| |\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU changes from Ingo Molnar: "Quoting from Paul, the major features of this series are: 1. Preventing latency spikes of more than 200 microseconds for kernels built with NR_CPUS=4096, which is reportedly becoming the default for some distros. This is a first step, as it does not help with systems that actually -have- 4096 CPUs (work on this case is in progress, but is not yet ready for mainline). This category also includes improving concurrency of rcu_barrier(), placed here due to conflicts. Posted to LKML at: https://lkml.org/lkml/2012/6/22/381 Note that patches 18-22 of that series have been defered to 3.7, as they have not yet proven themselves to be mainline-ready (and yes, these are the ones intended to get rid of RCU's latency spikes for systems that actually have 4096 CPUs). 2. Updates to documentation and rcutorture fixes, the latter category including improvements to rcu_barrier() testing. Posted to LKML at http://lkml.indiana.edu/hypermail/linux/kernel/1206.1/04094.html. 3. Miscellaneous fixes posted to LKML at: https://lkml.org/lkml/2012/6/22/500 with the exception of the last commit, which was posted here: http://www.gossamer-threads.com/lists/linux/kernel/1561830 4. RCU_FAST_NO_HZ fixes and improvements. Posted to LKML at: http://lkml.indiana.edu/hypermail/linux/kernel/1206.1/00006.html http://www.gossamer-threads.com/lists/linux/kernel/1561833 The first four patches of the first series went into 3.5 to fix a regression. 5. Code-style fixes. These were posted to LKML at http://lkml.indiana.edu/hypermail/linux/kernel/1205.2/01180.html http://lkml.indiana.edu/hypermail/linux/kernel/1205.2/01181.html" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (48 commits) rcu: Fix broken strings in RCU's source code. rcu: Fix code-style issues involving "else" rcu: Introduce check for callback list/count mismatch rcu: Make RCU_FAST_NO_HZ respect nohz= boot parameter rcu: Fix qlen_lazy breakage rcu: Round FAST_NO_HZ lazy timeout to nearest second rcu: The rcu_needs_cpu() function is not a quiescent state rcu: Dump only the current CPU's buffers for idle-entry/exit warnings rcu: Add check for CPUs going offline with callbacks queued rcu: Disable preemption in rcu_blocking_is_gp() rcu: Prevent uninitialized string in RCU CPU stall info rcu: Fix rcu_is_cpu_idle() #ifdef in TINY_RCU rcu: Split RCU core processing out of __call_rcu() rcu: Prevent __call_rcu() from invoking RCU core on offline CPUs rcu: Make __call_rcu() handle invocation from idle rcu: Remove function versions of __kfree_rcu and __is_kfree_rcu_offset rcu: Consolidate tree/tiny __rcu_read_{,un}lock() implementations rcu: Remove return value from rcu_assign_pointer() key: Remove extraneous parentheses from rcu_assign_keypointer() rcu: Remove return value from RCU_INIT_POINTER() ...
| | * | | rcu: Make RCU_FAST_NO_HZ respect nohz= boot parameterPaul E. McKenney2012-07-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the nohz= boot parameter disables nohz, then RCU_FAST_NO_HZ needs to also disable itself. This commit therefore checks for tick_nohz_enabled being zero, disabling rcu_prepare_for_idle() if so. This commit assumes that tick_nohz_enabled can change at runtime: If this is not the case, then a simpler approach suffices. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| * | | | Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds2012-07-18
| |\ \ \ \ | | |_|_|/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip One more time/ntp fix pulled from Ingo Molnar. * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: ntp: Fix STA_INS/DEL clearing bug
| * | | | timekeeping: Add missing update call in timekeeping_resume()Thomas Gleixner2012-07-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The leap second rework unearthed another issue of inconsistent data. On timekeeping_resume() the timekeeper data is updated, but nothing calls timekeeping_update(), so now the update code in the timer interrupt sees stale values. This has been the case before those changes, but then the timer interrupt was using stale data as well so this went unnoticed for quite some time. Add the missing update call, so all the data is consistent everywhere. Reported-by: Andreas Schwab <schwab@linux-m68k.org> Reported-and-tested-by: "Rafael J. Wysocki" <rjw@sisk.pl> Reported-and-tested-by: Martin Steigerwald <Martin@lichtvoll.de> Cc: LKML <linux-kernel@vger.kernel.org> Cc: Linux PM list <linux-pm@vger.kernel.org> Cc: John Stultz <johnstul@us.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>, Cc: Prarit Bhargava <prarit@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | | time: Fix casting issue in tk_set_xtime and tk_xtime_addJohn Stultz2012-07-24
| |_|_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 1e75fa8b (time: Condense timekeeper.xtime into xtime_sec) introduced helper functions which apply a timespec to the core internal timekeeper data. The internal storage type is u64. The timespec tv_nsec value must be shifted before set or added to the internal value. tv_nsec is a long, which is 32bit on a 32bit system, so without casting tv_nsec to u64 we lose the bits which are shifted over the 32bit boundary. Add the proper typecasts. Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Acked-by: Prarit Bhargava <prarit@redhat.com> Link: http://lkml.kernel.org/r/1343074957-16541-1-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | | time: Rework timekeeping functions to take timekeeper ptr as argumentJohn Stultz2012-07-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As part of cleaning up the timekeeping code, this patch converts a number of internal functions to takei a timekeeper ptr as an argument, so that the internal functions don't access the global timekeeper structure directly. This allows for further optimizations to reduce lock hold time later. This patch has been updated to include more consistent usage of the timekeeper value, by making sure it is always passed as a argument to non top-level functions. Signed-off-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Link: http://lkml.kernel.org/r/1342156917-25092-9-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | | time: Move xtime_nsec adjustment underflow handling timekeeping_adjustJohn Stultz2012-07-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we make adjustments speeding up the clock, its possible for xtime_nsec to underflow. We already handle this properly, but we do so from update_wall_time() instead of the more logical timekeeping_adjust(), where the possible underflow actually occurs. Thus, move the correction logic to the timekeeping_adjust, which is the function that causes the issue. Making update_wall_time() more readable. Signed-off-by: John Stultz <johnstul@us.ibm.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Link: http://lkml.kernel.org/r/1342156917-25092-8-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | | time: Move arch_gettimeoffset() usage into timekeeping_get_ns()John Stultz2012-07-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since we call arch_gettimeoffset() in all the accessor functions, move arch_gettimeoffset() calls into timekeeping_get_ns() and timekeeping_get_ns_raw() to simplify the code. This also makes the code easier to maintain as we don't have to worry about forgetting the arch_gettimeoffset() as has happened in the past. Signed-off-by: John Stultz <johnstul@us.ibm.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Link: http://lkml.kernel.org/r/1342156917-25092-7-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | | time: Refactor accumulation of nsecs to secsJohn Stultz2012-07-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We do the exact same logic moving nsecs to secs in the timekeeper in multiple places, so condense this into a single function. Signed-off-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Link: http://lkml.kernel.org/r/1342156917-25092-6-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | | time: Condense timekeeper.xtime into xtime_secJohn Stultz2012-07-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The timekeeper struct has a xtime_nsec, which keeps the sub-nanosecond remainder. This ends up being somewhat duplicative of the timekeeper.xtime.tv_nsec value, and we have to do extra work to keep them apart, copying the full nsec portion out and back in over and over. This patch simplifies some of the logic by taking the timekeeper xtime value and splitting it into timekeeper.xtime_sec and reuses the timekeeper.xtime_nsec for the sub-second portion (stored in higher res shifted nanoseconds). This simplifies some of the accumulation logic. And will allow for more accurate timekeeping once the vsyscall code is updated to use the shifted nanosecond remainder. Signed-off-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Link: http://lkml.kernel.org/r/1342156917-25092-5-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | | time: Explicitly use u32 instead of int for shift valuesJohn Stultz2012-07-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ingo noted that using a u32 instead of int for shift values would be better to make sure the compiler doesn't unnecessarily use complex signed arithmetic. Signed-off-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Link: http://lkml.kernel.org/r/1342156917-25092-4-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | | time: Whitespace cleanups per Ingo%27s requestsJohn Stultz2012-07-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ingo noted a number of places where there is inconsistent use of whitespace. This patch tries to address the main culprits. Signed-off-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Link: http://lkml.kernel.org/r/1342156917-25092-3-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | | Merge branch 'timers/urgent' into timers/coreThomas Gleixner2012-07-15
|\ \ \ \ | | |/ / | |/| | | | | | | | | | | | | | | | | | Reason: Update to upstream changes to avoid further conflicts. Fixup a trivial merge conflict in kernel/time/tick-sched.c Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | ntp: Fix STA_INS/DEL clearing bugJohn Stultz2012-07-15
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In commit 6b43ae8a619d17c4935c3320d2ef9e92bdeed05d, I introduced a bug that kept the STA_INS or STA_DEL bit from being cleared from time_status via adjtimex() without forcing STA_PLL first. Usually once the STA_INS is set, it isn't cleared until the leap second is applied, so its unlikely this affected anyone. However during testing I noticed it took some effort to cancel a leap second once STA_INS was set. Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> CC: stable@vger.kernel.org # 3.4 Link: http://lkml.kernel.org/r/1342156917-25092-2-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| | |
| | \
| *-. \ Merge branches 'core-urgent-for-linus', 'perf-urgent-for-linus' and ↵Linus Torvalds2012-07-14
| |\ \ \ | | | |/ | | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU, perf, and scheduler fixes from Ingo Molnar. The RCU fix is a revert for an optimization that could cause deadlocks. One of the scheduler commits (164c33c6adee "sched: Fix fork() error path to not crash") is correct but not complete (some architectures like Tile are not covered yet) - the resulting additional fixes are still WIP and Ingo did not want to delay these pending fixes. See this thread on lkml: [PATCH] fork: fix error handling in dup_task() The perf fixes are just trivial oneliners. * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Revert "rcu: Move PREEMPT_RCU preemption to switch_to() invocation" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf kvm: Fix segfault with report and mixed guestmount use perf kvm: Fix regression with guest machine creation perf script: Fix format regression due to libtraceevent merge ring-buffer: Fix accounting of entries when removing pages ring-buffer: Fix crash due to uninitialized new_pages list head * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: MAINTAINERS/sched: Update scheduler file pattern sched/nohz: Rewrite and fix load-avg computation -- again sched: Fix fork() error path to not crash
| | | * sched/nohz: Rewrite and fix load-avg computation -- againPeter Zijlstra2012-07-05
| | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Thanks to Charles Wang for spotting the defects in the current code: - If we go idle during the sample window -- after sampling, we get a negative bias because we can negate our own sample. - If we wake up during the sample window we get a positive bias because we push the sample to a known active period. So rewrite the entire nohz load-avg muck once again, now adding copious documentation to the code. Reported-and-tested-by: Doug Smythies <dsmythies@telus.net> Reported-and-tested-by: Charles Wang <muming.wq@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: stable@kernel.org Link: http://lkml.kernel.org/r/1340373782.18025.74.camel@twins [ minor edits ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | timekeeping: Provide hrtimer update functionThomas Gleixner2012-07-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To finally fix the infamous leap second issue and other race windows caused by functions which change the offsets between the various time bases (CLOCK_MONOTONIC, CLOCK_REALTIME and CLOCK_BOOTTIME) we need a function which atomically gets the current monotonic time and updates the offsets of CLOCK_REALTIME and CLOCK_BOOTTIME with minimalistic overhead. The previous patch which provides ktime_t offsets allows us to make this function almost as cheap as ktime_get() which is going to be replaced in hrtimer_interrupt(). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Prarit Bhargava <prarit@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: John Stultz <johnstul@us.ibm.com> Link: http://lkml.kernel.org/r/1341960205-56738-7-git-send-email-johnstul@us.ibm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | timekeeping: Maintain ktime_t based offsets for hrtimersThomas Gleixner2012-07-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We need to update the hrtimer clock offsets from the hrtimer interrupt context. To avoid conversions from timespec to ktime_t maintain a ktime_t based representation of those offsets in the timekeeper. This puts the conversion overhead into the code which updates the underlying offsets and provides fast accessible values in the hrtimer interrupt. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <johnstul@us.ibm.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Prarit Bhargava <prarit@redhat.com> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1341960205-56738-4-git-send-email-johnstul@us.ibm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | timekeeping: Fix leapsecond triggered load spike issueJohn Stultz2012-07-11
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The timekeeping code misses an update of the hrtimer subsystem after a leap second happened. Due to that timers based on CLOCK_REALTIME are either expiring a second early or late depending on whether a leap second has been inserted or deleted until an operation is initiated which causes that update. Unless the update happens by some other means this discrepancy between the timekeeping and the hrtimer data stays forever and timers are expired either early or late. The reported immediate workaround - $ data -s "`date`" - is causing a call to clock_was_set() which updates the hrtimer data structures. See: http://www.sheeri.com/content/mysql-and-leap-second-high-cpu-and-fix Add the missing clock_was_set() call to update_wall_time() in case of a leap second event. The actual update is deferred to softirq context as the necessary smp function call cannot be invoked from hard interrupt context. Signed-off-by: John Stultz <johnstul@us.ibm.com> Reported-by: Jan Engelhardt <jengelh@inai.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Prarit Bhargava <prarit@redhat.com> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1341960205-56738-3-git-send-email-johnstul@us.ibm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * Merge branch 'core-urgent-for-linus' of ↵Linus Torvalds2012-06-15
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull core updates (RCU and locking) from Ingo Molnar: "Most of the diffstat comes from the RCU slow boot regression fixes, but there's also a debuggability improvements/fixes." * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: memblock: Document memblock_is_region_{memory,reserved}() rcu: Precompute RCU_FAST_NO_HZ timer offsets rcu: Move RCU_FAST_NO_HZ per-CPU variables to rcu_dynticks structure rcu: Update RCU_FAST_NO_HZ tracing for lazy callbacks rcu: RCU_FAST_NO_HZ detection of callback adoption spinlock: Indicate that a lockup is only suspected kdump: Execute kmsg_dump(KMSG_DUMP_PANIC) after smp_send_stop() panic: Make panic_on_oops configurable
| | * Merge branch 'rcu/urgent' of ↵Ingo Molnar2012-06-11
| | |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/urgent Merge RCU fixes from Paul E. McKenney: " This series has four patches, the major point of which is to eliminate some slowdowns (including boot-time slowdowns) resulting from some RCU_FAST_NO_HZ changes. The issue with the changes is that posting timers from the idle loop has no effect if the CPU has entered dyntick-idle mode because the CPU has already computed its wakeup time, and posting a timer does not cause it to be recomputed. The short-term fix is for RCU to precompute the timeout value so that the CPU's calculation is correct. " Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | | * rcu: Precompute RCU_FAST_NO_HZ timer offsetsPaul E. McKenney2012-06-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a CPU is entering dyntick-idle mode, tick_nohz_stop_sched_tick() calls rcu_needs_cpu() see if RCU needs that CPU, and, if not, computes the next wakeup time based on the timer wheels. Only later, when actually entering the idle loop, rcu_prepare_for_idle() will be invoked. In some cases, rcu_prepare_for_idle() will post timers to wake the CPU back up. But all for naught: The next wakeup time for the CPU has already been computed, and posting a timer afterwards does not force that wakeup time to be recomputed. This means that rcu_prepare_for_idle()'s have no effect. This is not a problem on a busy system because something else will wake up the CPU soon enough. However, on lightly loaded systems, the CPU might stay asleep for a considerable length of time. If that CPU has a callback that the rest of the system is waiting on, the system might run very slowly or (in theory) even hang. This commit avoids this problem by having rcu_needs_cpu() give tick_nohz_stop_sched_tick() an estimate of when RCU will need the CPU to wake back up, which tick_nohz_stop_sched_tick() takes into account when programming the CPU's wakeup time. An alternative approach is for rcu_prepare_for_idle() to use hrtimers instead of normal timers, but timers are much more efficient than are hrtimers for frequently and repeatedly posting and cancelling a given timer, which is exactly what RCU_FAST_NO_HZ does. Reported-by: Pascal Chapperon <pascal.chapperon@wanadoo.fr> Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com> Tested-by: Pascal Chapperon <pascal.chapperon@wanadoo.fr>
* | | | nohz: Move next idle expiry time record into idle logic areaFrederic Weisbecker2012-06-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The next idle expiry time record and idle sleeps tracking are statistics that only concern idle. Since we want the nohz APIs to become usable further idle context, let's pull up the handling of these statistics to the callers in idle. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Avi Kivity <avi@redhat.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@ti.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de>
* | | | nohz: Move ts->idle_calls incrementation into strict idle logicFrederic Weisbecker2012-06-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since we want to prepare for making the nohz API to work further the idle case, we need to pull ts->idle_calls incrementation up to the callers in idle. To perform this, we split tick_nohz_stop_sched_tick() in two parts: a first one that checks if we can really stop the tick for idle, and another that actually stops it. Then from the callers in idle, we check if we can stop the tick and only then we increment idle_calls and finally relay to the nohz API that won't care about these details anymore. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Avi Kivity <avi@redhat.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@ti.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de>
* | | | nohz: Rename ts->idle_tick to ts->last_tickFrederic Weisbecker2012-06-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that idle and nohz logics are going to be independant each others, ts->idle_tick becomes too much a biased name to describe the field that saves the last scheduled tick on top of which we re-calculate the next tick to schedule when the timer is restarted. We want to reuse this even to stop the tick outside idle cases. So let's rename it to some more generic name: ts->last_tick. This changes a bit the timer list stat export so we need to increase its version. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Avi Kivity <avi@redhat.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@ti.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de>
* | | | nohz: Make nohz API agnostic against idle ticks cputime accountingFrederic Weisbecker2012-06-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the timer tick fires, it accounts the new jiffy as either part of system, user or idle time. This is how we record the cputime statistics. But when the tick is stopped from the idle task, we still need to record the number of jiffies spent tickless until we restart the tick and fall back to traditional tick-based cputime accounting. To do this, we take a snapshot of jiffies when the tick is stopped and compute the difference against the new value of jiffies when the tick is restarted. Then we account this whole difference to the idle cputime. However we are preparing to be able to stop the tick from other places than idle. So this idle time accounting needs to be performed from the callers of nohz APIs, not from the nohz APIs themselves because we now want them to be agnostic against places that stop/restart tick. Therefore, we pull the tickless idle time accounting out of generic nohz helpers up to idle entry/exit callers. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Avi Kivity <avi@redhat.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@ti.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de>
* | | | nohz: Separate idle sleeping time accounting from nohz logicFrederic Weisbecker2012-06-11
|/ / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As we plan to be able to stop the tick outside the idle task, we need to prepare for separating nohz logic from idle. As a start, this pulls the idle sleeping time accounting out of the tick stop/restart API to the callers on idle entry/exit. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Avi Kivity <avi@redhat.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@ti.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de>
* | | Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds2012-06-08
|\ \ \ | |/ / |/| | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull leap second timer fix from Thomas Gleixner. * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timekeeping: Fix CLOCK_MONOTONIC inconsistency during leapsecond
| * | timekeeping: Fix CLOCK_MONOTONIC inconsistency during leapsecondJohn Stultz2012-06-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 6b43ae8a61 (ntp: Fix leap-second hrtimer livelock) broke the leapsecond update of CLOCK_MONOTONIC. The missing leapsecond update to wall_to_monotonic causes discontinuities in CLOCK_MONOTONIC. Adjust wall_to_monotonic when NTP inserted a leapsecond. Reported-by: Richard Cochran <richardcochran@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Tested-by: Richard Cochran <richardcochran@gmail.com> Cc: stable@kernel.org Link: http://lkml.kernel.org/r/1338400497-12420-1-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds2012-06-05
|\ \ \ | |/ / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Ingo Molnar. * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched: Remove NULL assignment of dattr_cur sched: Remove the last NULL entry from sched_feat_names sched: Make sched_feat_names const sched/rt: Fix SCHED_RR across cgroups sched: Move nr_cpus_allowed out of 'struct sched_rt_entity' sched: Make sure to not re-read variables after validation sched: Fix SD_OVERLAP sched: Don't try allocating memory from offline nodes sched/nohz: Fix rq->cpu_load calculations some more sched/x86: Use cpu_llc_shared_mask(cpu) for coregroup_mask
| * | sched/nohz: Fix rq->cpu_load calculations some morePeter Zijlstra2012-05-30
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Follow up on commit 556061b00 ("sched/nohz: Fix rq->cpu_load[] calculations") since while that fixed the busy case it regressed the mostly idle case. Add a callback from the nohz exit to also age the rq->cpu_load[] array. This closes the hole where either there was no nohz load balance pass during the nohz, or there was a 'significant' amount of idle time between the last nohz balance and the nohz exit. So we'll update unconditionally from the tick to not insert any accidental 0 load periods while busy, and we try and catch up from nohz idle balance and nohz exit. Both these are still prone to missing a jiffy, but that has always been the case. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: pjt@google.com Cc: Venkatesh Pallipadi <venki@google.com> Link: http://lkml.kernel.org/n/tip-kt0trz0apodbf84ucjfdbr1a@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | tick: Move skew_tick option into the HIGH_RES_TIMER sectionThomas Gleixner2012-05-25
| | | | | | | | | | | | | | | | | | | | | | commit 5307c95 (tick: Add tick skew boot option) broke the !CONFIG_HIGH_RES_TIMERS build. Move the boot option parsing into the CONFIG_HIGH_RES_TIMERS section. Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Mike Galbraith <mgalbraith@suse.de>
* | clockevents: Make clockevents_config() a global symbolMagnus Damm2012-05-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make clockevents_config() into a global symbol to allow it to be used by compiled-in clockevent drivers. This is needed by drivers that want to update the timer frequency after registration time. Signed-off-by: Magnus Damm <damm@opensource.se> Tested-by: Simon Horman <horms@verge.net.au> Cc: arnd@arndb.de Cc: johnstul@us.ibm.com Cc: rjw@sisk.pl Cc: lethal@linux-sh.org Cc: gregkh@linuxfoundation.org Cc: olof@lixom.net Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20120509143934.27521.46553.sendpatchset@w520 Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | tick: Add tick skew boot optionMike Galbraith2012-05-24
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Let the user decide whether power consumption or jitter is the more important consideration for their machines. Quoting removal commit af5ab277ded04bd9bc6b048c5a2f0e7d70ef0867: "Historically, Linux has tried to make the regular timer tick on the various CPUs not happen at the same time, to avoid contention on xtime_lock. Nowadays, with the tickless kernel, this contention no longer happens since time keeping and updating are done differently. In addition, this skew is actually hurting power consumption in a measurable way on many-core systems." Problems: - Contrary to the above, systems do encounter contention on both xtime_lock and RCU structure locks when the tick is synchronized. - Moderate sized RT systems suffer intolerable jitter due to the tick being synchronized. - SGI reports the same for their large systems. - Fully utilized systems reap no power saving benefit from skew removal, but do suffer from resulting induced lock contention. - 0209f649 rcu: limit rcu_node leaf-level fanout This patch was born to combat lock contention which testing showed to have been _induced by_ skew removal. Skew the tick, contention disappeared virtually completely. Signed-off-by: Mike Galbraith <mgalbraith@suse.de> Link: http://lkml.kernel.org/r/1336472458.21924.78.camel@marge.simpson.net Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Merge branch 'timers-core-for-linus' of ↵Linus Torvalds2012-05-24
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner. Various trivial conflict fixups in arch Kconfig due to addition of unrelated entries nearby. And one slightly more subtle one for sparc32 (new user of GENERIC_CLOCKEVENTS), fixed up as per Thomas. * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits) timekeeping: Fix a few minor newline issues. time: remove obsolete declaration ntp: Fix a stale comment and a few stray newlines. ntp: Correct TAI offset during leap second timers: Fixup the Kconfig consolidation fallout x86: Use generic time config unicore32: Use generic time config um: Use generic time config tile: Use generic time config sparc: Use: generic time config sh: Use generic time config score: Use generic time config s390: Use generic time config openrisc: Use generic time config powerpc: Use generic time config mn10300: Use generic time config mips: Use generic time config microblaze: Use generic time config m68k: Use generic time config m32r: Use generic time config ...
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