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2012-03-15ntp: Fix integer overflow when setting timeSasha Levin
'long secs' is passed as divisor to div_s64, which accepts a 32bit divisor. On 64bit machines that value is trimmed back from 8 bytes back to 4, causing a divide by zero when the number is bigger than (1 << 32) - 1 and all 32 lower bits are 0. Use div64_long() instead. Signed-off-by: Sasha Levin <levinsasha928@gmail.com> Cc: johnstul@us.ibm.com Link: http://lkml.kernel.org/r/1331829374-31543-2-git-send-email-levinsasha928@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15Merge branch 'fortglx/3.4/time' of git://git.linaro.org/people/jstultz/linux ↵Thomas Gleixner
into timers/core
2012-02-15nohz: Remove ts->Einidle checks before restarting the tickFrederic Weisbecker
ts->inidle is set by tick_nohz_idle_enter() and unset by tick_nohz_idle_exit(). However these two calls are assumed to be always paired. This means that by the time we call tick_nohz_idle_exit(), ts->inidle is supposed to be always set to 1. Remove the checks for ts->inidle in tick_nohz_idle_exit(). This simplifies a bit the code and improves its debuggability (ie: ensure the call is paired with a tick_nohz_idle_enter() call). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Reviewed-by: Yong Zhang <yong.zhang0@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: John Stultz <john.stultz@linaro.org> Cc: Ingo Molnar <mingo@elte.hu> Link: http://lkml.kernel.org/r/1327427984-23282-2-git-send-email-fweisbec@gmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15nohz: Remove update_ts_time_stat from tick_nohz_start_idleMichal Hocko
There is no reason to call update_ts_time_stat from tick_nohz_start_idle anymore (after e0e37c20 sched: Eliminate the ts->idle_lastupdate field) when we updated idle_lastupdate unconditionally. We haven't set idle_active yet and do not provide last_update_time so the whole call end up being just 2 wasted branches. Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: Arjan van de Ven <arjan@linux.intel.com> Link: http://lkml.kernel.org/r/1322755222-6951-1-git-send-email-mhocko@suse.cz Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15clockevents: Leave the broadcast device in shutdown mode when not neededSuresh Siddha
Platforms with Always Running APIC Timer doesn't use the broadcast timer but the kernel is leaving the broadcast timer (HPET in this case) in oneshot mode. On these platforms, before the switch to oneshot mode, broadcast device is actually in shutdown mode. Code checks for empty tick_broadcast_mask and avoids going into the periodic mode. During switch to oneshot mode, add the same tick_broadcast_mask checks in the tick_broadcast_switch_to_oneshot() and avoid the broadcast device going into the oneshot mode. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Cc: john stultz <johnstul@us.ibm.com> Cc: venki@google.com Link: http://lkml.kernel.org/r/1320452301.15071.16.camel@sbsiddha-desk.sc.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-01-27time: Move common updates to a functionThomas Gleixner
CC: Thomas Gleixner <tglx@linutronix.de> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Richard Cochran <richardcochran@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-01-27time: Reorder so the hot data is togetherThomas Gleixner
Keep all the interesting data in a single cache line. CC: Thomas Gleixner <tglx@linutronix.de> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Richard Cochran <richardcochran@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-01-27time: Remove most of xtime_lock usage in timekeeping.cJohn Stultz
Now that ntp.c's locking is reworked, we can remove most of the xtime_lock usage in timekeeping.c The remaining xtime_lock presence is really for jiffies access and the global load calculation. CC: Thomas Gleixner <tglx@linutronix.de> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Richard Cochran <richardcochran@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-01-27ntp: Add ntp_lock to replace xtime_lockingJohn Stultz
Use a ntp_lock spin lock to replace xtime_lock locking in ntp.c CC: Thomas Gleixner <tglx@linutronix.de> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Richard Cochran <richardcochran@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-01-27ntp: Access tick_length variable via ntp_tick_length()John Stultz
Currently the NTP managed tick_length value is accessed globally, in preparations for locking cleanups, make sure it is accessed via a function and mark it as static. CC: Thomas Gleixner <tglx@linutronix.de> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Richard Cochran <richardcochran@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-01-27ntp: Cleanup timex.hJohn Stultz
Move ntp_sycned to ntp.c and mark time_status as static. Also yank function declaration for non-existant function. CC: Thomas Gleixner <tglx@linutronix.de> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Richard Cochran <richardcochran@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-01-27time: Add timekeeper lockJohn Stultz
Now that all the timekeeping variables are stored in the timekeeper structure, add a new lock to protect the structure. For now, this lock nests under the xtime_lock for writes. For readers, we don't need to take xtime_lock anymore. CC: Thomas Gleixner <tglx@linutronix.de> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Richard Cochran <richardcochran@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-01-27time: Cleanup global variables and move them to the topJohn Stultz
Move global xtime_lock and timekeeping_suspended values up to the top of timekeeping.c CC: Thomas Gleixner <tglx@linutronix.de> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Richard Cochran <richardcochran@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-01-27time: Move raw_time into timekeeper structureJohn Stultz
In preparation for locking cleanups, move raw_time into timekeeper structure. CC: Thomas Gleixner <tglx@linutronix.de> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Richard Cochran <richardcochran@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-01-27time: Move xtime into timekeeeper structureJohn Stultz
In preparation for locking cleanups, move xtime into timekeeper structure. CC: Thomas Gleixner <tglx@linutronix.de> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Richard Cochran <richardcochran@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-01-27time: Move wall_to_monotonic into the timekeeper structureJohn Stultz
In preparation for locking cleanups, move wall_to_monotonic into the timekeeper structure. CC: Thomas Gleixner <tglx@linutronix.de> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Richard Cochran <richardcochran@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-01-27time: Move total_sleep_time into the timekeeper structureJohn Stultz
Move total_sleep_time into the timekeeper structure in preparation for locking cleanups CC: Thomas Gleixner <tglx@linutronix.de> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Richard Cochran <richardcochran@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-01-08Merge branch 'for-linus' of ↵Linus Torvalds
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: (53 commits) Kconfig: acpi: Fix typo in comment. misc latin1 to utf8 conversions devres: Fix a typo in devm_kfree comment btrfs: free-space-cache.c: remove extra semicolon. fat: Spelling s/obsolate/obsolete/g SCSI, pmcraid: Fix spelling error in a pmcraid_err() call tools/power turbostat: update fields in manpage mac80211: drop spelling fix types.h: fix comment spelling for 'architectures' typo fixes: aera -> area, exntension -> extension devices.txt: Fix typo of 'VMware'. sis900: Fix enum typo 'sis900_rx_bufer_status' decompress_bunzip2: remove invalid vi modeline treewide: Fix comment and string typo 'bufer' hyper-v: Update MAINTAINERS treewide: Fix typos in various parts of the kernel, and fix some comments. clockevents: drop unknown Kconfig symbol GENERIC_CLOCKEVENTS_MIGR gpio: Kconfig: drop unknown symbol 'CS5535_GPIO' leds: Kconfig: Fix typo 'D2NET_V2' sound: Kconfig: drop unknown symbol ARCH_CLPS7500 ... Fix up trivial conflicts in arch/powerpc/platforms/40x/Kconfig (some new kconfig additions, close to removed commented-out old ones)
2012-01-07Merge branch 'driver-core-next' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core * 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (73 commits) arm: fix up some samsung merge sysdev conversion problems firmware: Fix an oops on reading fw_priv->fw in sysfs loading file Drivers:hv: Fix a bug in vmbus_driver_unregister() driver core: remove __must_check from device_create_file debugfs: add missing #ifdef HAS_IOMEM arm: time.h: remove device.h #include driver-core: remove sysdev.h usage. clockevents: remove sysdev.h arm: convert sysdev_class to a regular subsystem arm: leds: convert sysdev_class to a regular subsystem kobject: remove kset_find_obj_hinted() m86k: gpio - convert sysdev_class to a regular subsystem mips: txx9_sram - convert sysdev_class to a regular subsystem mips: 7segled - convert sysdev_class to a regular subsystem sh: dma - convert sysdev_class to a regular subsystem sh: intc - convert sysdev_class to a regular subsystem power: suspend - convert sysdev_class to a regular subsystem power: qe_ic - convert sysdev_class to a regular subsystem power: cmm - convert sysdev_class to a regular subsystem s390: time - convert sysdev_class to a regular subsystem ... Fix up conflicts with 'struct sysdev' removal from various platform drivers that got changed: - arch/arm/mach-exynos/cpu.c - arch/arm/mach-exynos/irq-eint.c - arch/arm/mach-s3c64xx/common.c - arch/arm/mach-s3c64xx/cpu.c - arch/arm/mach-s5p64x0/cpu.c - arch/arm/mach-s5pv210/common.c - arch/arm/plat-samsung/include/plat/cpu.h - arch/powerpc/kernel/sysfs.c and fix up cpu_is_hotpluggable() as per Greg in include/linux/cpu.h
2012-01-06Merge branch 'timers-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, tsc: Skip TSC synchronization checks for tsc=reliable clocksource: Convert tcb_clksrc to use clocksource_register_hz/khz clocksource: cris: Convert to clocksource_register_khz clocksource: xtensa: Convert to clocksource_register_hz/khz clocksource: um: Convert to clocksource_register_hz/khz clocksource: parisc: Convert to clocksource_register_hz/khz clocksource: m86k: Convert to clocksource_register_hz/khz time: x86: Replace LATCH with PIT_LATCH in i8253 clocksource driver time: x86: Remove CLOCK_TICK_RATE from acpi_pm clocksource driver time: x86: Remove CLOCK_TICK_RATE from mach_timer.h time: x86: Remove CLOCK_TICK_RATE from tsc code time: Fix spelling mistakes in new comments time: fix bogus comment in timekeeping_get_ns_raw
2012-01-06Merge branch 'driver-core-next' into Linux 3.2Greg Kroah-Hartman
This resolves the conflict in the arch/arm/mach-s3c64xx/s3c6400.c file, and it fixes the build error in the arch/x86/kernel/microcode_core.c file, that the merge did not catch. The microcode_core.c patch was provided by Stephen Rothwell <sfr@canb.auug.org.au> who was invaluable in the merge issues involved with the large sysdev removal process in the driver-core tree. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2012-01-06Merge branch 'sched-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits) sched/tracing: Add a new tracepoint for sleeptime sched: Disable scheduler warnings during oopses sched: Fix cgroup movement of waking process sched: Fix cgroup movement of newly created process sched: Fix cgroup movement of forking process sched: Remove cfs bandwidth period check in tg_set_cfs_period() sched: Fix load-balance lock-breaking sched: Replace all_pinned with a generic flags field sched: Only queue remote wakeups when crossing cache boundaries sched: Add missing rcu_dereference() around ->real_parent usage [S390] fix cputime overflow in uptime_proc_show [S390] cputime: add sparse checking and cleanup sched: Mark parent and real_parent as __rcu sched, nohz: Fix missing RCU read lock sched, nohz: Set the NOHZ_BALANCE_KICK flag for idle load balancer sched, nohz: Fix the idle cpu check in nohz_idle_balance sched: Use jump_labels for sched_feat sched/accounting: Fix parameter passing in task_group_account_field sched/accounting: Fix user/system tick double accounting sched/accounting: Re-use scheduler statistics for the root cgroup ... Fix up conflicts in - arch/ia64/include/asm/cputime.h, include/asm-generic/cputime.h usecs_to_cputime64() vs the sparse cleanups - kernel/sched/fair.c, kernel/time/tick-sched.c scheduler changes in multiple branches
2012-01-06Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits) cpu: Export cpu_up() rcu: Apply ACCESS_ONCE() to rcu_boost() return value Revert "rcu: Permit rt_mutex_unlock() with irqs disabled" docs: Additional LWN links to RCU API rcu: Augment rcu_batch_end tracing for idle and callback state rcu: Add rcutorture tests for srcu_read_lock_raw() rcu: Make rcutorture test for hotpluggability before offlining CPUs driver-core/cpu: Expose hotpluggability to the rest of the kernel rcu: Remove redundant rcu_cpu_stall_suppress declaration rcu: Adaptive dyntick-idle preparation rcu: Keep invoking callbacks if CPU otherwise idle rcu: Irq nesting is always 0 on rcu_enter_idle_common rcu: Don't check irq nesting from rcu idle entry/exit rcu: Permit dyntick-idle with callbacks pending rcu: Document same-context read-side constraints rcu: Identify dyntick-idle CPUs on first force_quiescent_state() pass rcu: Remove dynticks false positives and RCU failures rcu: Reduce latency of rcu_prepare_for_idle() rcu: Eliminate RCU_FAST_NO_HZ grace-period hang rcu: Avoid needlessly IPIing CPUs at GP end ...
2011-12-30Revert "clockevents: Set noop handler in clockevents_exchange_device()"Linus Torvalds
This reverts commit de28f25e8244c7353abed8de0c7792f5f883588c. It results in resume problems for various people. See for example http://thread.gmane.org/gmane.linux.kernel/1233033 http://thread.gmane.org/gmane.linux.kernel/1233389 http://thread.gmane.org/gmane.linux.kernel/1233159 http://thread.gmane.org/gmane.linux.kernel/1227868/focus=1230877 and the fedora and ubuntu bug reports https://bugzilla.redhat.com/show_bug.cgi?id=767248 https://bugs.launchpad.net/ubuntu/+source/linux/+bug/904569 which got bisected down to the stable version of this commit. Reported-by: Jonathan Nieder <jrnieder@gmail.com> Reported-by: Phil Miller <mille121@illinois.edu> Reported-by: Philip Langdale <philipl@overt.org> Reported-by: Tim Gardner <tim.gardner@canonical.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Greg KH <gregkh@suse.de> Cc: stable@kernel.org # for stable kernels that applied the original Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-12-22clockevents: remove sysdev.hKay Sievers
This isn't needed in the clockevents.c file, and the header file is going away soon, so just remove the #include Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-12-19time/clocksource: Fix kernel-doc warningsKusanagi Kouichi
Fix various KernelDoc build warnings. Signed-off-by: Kusanagi Kouichi <slash@ac.auone-net.jp> Cc: John Stultz <johnstul@us.ibm.com> Link: http://lkml.kernel.org/r/20111219091320.0D5AF6FC03D@msa105.auone-net.jp Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-15Merge commit 'v3.2-rc5' into sched/coreIngo Molnar
Merge reason: Pick up the latest fixes. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-14clocksource: convert sysdev_class to a regular subsystemKay Sievers
After all sysdev classes are ported to regular driver core entities, the sysdev implementation will be entirely removed from the kernel. Cc: John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-12-11nohz: Remove tick_nohz_idle_enter_norcu() / tick_nohz_idle_exit_norcu()Frederic Weisbecker
Those two APIs were provided to optimize the calls of tick_nohz_idle_enter() and rcu_idle_enter() into a single irq disabled section. This way no interrupt happening in-between would needlessly process any RCU job. Now we are talking about an optimization for which benefits have yet to be measured. Let's start simple and completely decouple idle rcu and dyntick idle logics to simplify. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-12-11nohz: Allow rcu extended quiescent state handling seperately from tick stopFrederic Weisbecker
It is assumed that rcu won't be used once we switch to tickless mode and until we restart the tick. However this is not always true, as in x86-64 where we dereference the idle notifiers after the tick is stopped. To prepare for fixing this, add two new APIs: tick_nohz_idle_enter_norcu() and tick_nohz_idle_exit_norcu(). If no use of RCU is made in the idle loop between tick_nohz_enter_idle() and tick_nohz_exit_idle() calls, the arch must instead call the new *_norcu() version such that the arch doesn't need to call rcu_idle_enter() and rcu_idle_exit(). Otherwise the arch must call tick_nohz_enter_idle() and tick_nohz_exit_idle() and also call explicitly: - rcu_idle_enter() after its last use of RCU before the CPU is put to sleep. - rcu_idle_exit() before the first use of RCU after the CPU is woken up. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-12-11nohz: Separate out irq exit and idle loop dyntick logicFrederic Weisbecker
The tick_nohz_stop_sched_tick() function, which tries to delay the next timer tick as long as possible, can be called from two places: - From the idle loop to start the dytick idle mode - From interrupt exit if we have interrupted the dyntick idle mode, so that we reprogram the next tick event in case the irq changed some internal state that requires this action. There are only few minor differences between both that are handled by that function, driven by the ts->inidle cpu variable and the inidle parameter. The whole guarantees that we only update the dyntick mode on irq exit if we actually interrupted the dyntick idle mode, and that we enter in RCU extended quiescent state from idle loop entry only. Split this function into: - tick_nohz_idle_enter(), which sets ts->inidle to 1, enters dynticks idle mode unconditionally if it can, and enters into RCU extended quiescent state. - tick_nohz_irq_exit() which only updates the dynticks idle mode when ts->inidle is set (ie: if tick_nohz_idle_enter() has been called). To maintain symmetry, tick_nohz_restart_sched_tick() has been renamed into tick_nohz_idle_exit(). This simplifies the code and micro-optimize the irq exit path (no need for local_irq_save there). This also prepares for the split between dynticks and rcu extended quiescent state logics. We'll need this split to further fix illegal uses of RCU in extended quiescent states in the idle loop. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-12-11rcu: Track idleness independent of idle tasksPaul E. McKenney
Earlier versions of RCU used the scheduling-clock tick to detect idleness by checking for the idle task, but handled idleness differently for CONFIG_NO_HZ=y. But there are now a number of uses of RCU read-side critical sections in the idle task, for example, for tracing. A more fine-grained detection of idleness is therefore required. This commit presses the old dyntick-idle code into full-time service, so that rcu_idle_enter(), previously known as rcu_enter_nohz(), is always invoked at the beginning of an idle loop iteration. Similarly, rcu_idle_exit(), previously known as rcu_exit_nohz(), is always invoked at the end of an idle-loop iteration. This allows the idle task to use RCU everywhere except between consecutive rcu_idle_enter() and rcu_idle_exit() calls, in turn allowing architecture maintainers to specify exactly where in the idle loop that RCU may be used. Because some of the userspace upcall uses can result in what looks to RCU like half of an interrupt, it is not possible to expect that the irq_enter() and irq_exit() hooks will give exact counts. This patch therefore expands the ->dynticks_nesting counter to 64 bits and uses two separate bitfields to count process/idle transitions and interrupt entry/exit transitions. It is presumed that userspace upcalls do not happen in the idle loop or from usermode execution (though usermode might do a system call that results in an upcall). The counter is hard-reset on each process/idle transition, which avoids the interrupt entry/exit error from accumulating. Overflow is avoided by the 64-bitness of the ->dyntick_nesting counter. This commit also adds warnings if a non-idle task asks RCU to enter idle state (and these checks will need some adjustment before applying Frederic's OS-jitter patches (http://lkml.org/lkml/2011/10/7/246). In addition, validation of ->dynticks and ->dynticks_nesting is added. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-12-06alarmtimers: Fix time comparisonThomas Gleixner
The expiry function compares the timer against current time and does not expire the timer when the expiry time is >= now. That's wrong. If the timer is set for now, then it must expire. Make the condition expiry > now for breaking out the loop. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: John Stultz <john.stultz@linaro.org> Cc: stable@kernel.org
2011-12-06sched, nohz: Track nr_busy_cpus in the sched_group_powerSuresh Siddha
Introduce nr_busy_cpus in the struct sched_group_power [Not in sched_group because sched groups are duplicated for the SD_OVERLAP scheduler domain] and for each cpu that enters and exits idle, this parameter will be updated in each scheduler group of the scheduler domain that this cpu belongs to. To avoid the frequent update of this state as the cpu enters and exits idle, the update of the stat during idle exit is delayed to the first timer tick that happens after the cpu becomes busy. This is done using NOHZ_IDLE flag in the struct rq's nohz_flags. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20111202010832.555984323@sbsiddha-desk.sc.intel.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-06Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: clockevents: Set noop handler in clockevents_exchange_device() tick-broadcast: Stop active broadcast device when replacing it clocksource: Fix bug with max_deferment margin calculation rtc: Fix some bugs that allowed accumulating time drift in suspend/resume rtc: Disable the alarm in the hardware
2011-12-05Merge branch 'fortglx/3.3/tip/timers/core' of ↵Thomas Gleixner
git://git.linaro.org/people/jstultz/linux into timers/core
2011-12-02clockevents: Set noop handler in clockevents_exchange_device()Thomas Gleixner
If a device is shutdown, then there might be a pending interrupt, which will be processed after we reenable interrupts, which causes the original handler to be run. If the old handler is the (broadcast) periodic handler the shutdown state might hang the kernel completely. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org
2011-12-02tick-broadcast: Stop active broadcast device when replacing itThomas Gleixner
When a better rated broadcast device is installed, then the current active device is not disabled, which results in two running broadcast devices. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org
2011-12-01clocksource: Fix bug with max_deferment margin calculationYang Honggang (Joseph)
In order to leave a margin of 12.5% we should >> 3 not >> 5. CC: stable@kernel.org Signed-off-by: Yang Honggang (Joseph) <eagle.rtlinux@gmail.com> [jstultz: Modified commit subject] Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-11-29clockevents: drop unknown Kconfig symbol GENERIC_CLOCKEVENTS_MIGRPaul Bolle
There's no Kconfig symbol GENERIC_CLOCKEVENTS_MIGR, so the check for it will always fail. Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-11-28Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: hrtimer: Fix extra wakeups from __remove_hrtimer() timekeeping: add arch_offset hook to ktime_get functions clocksource: Avoid selecting mult values that might overflow when adjusted time: Improve documentation of timekeeeping_adjust()
2011-11-22time: Fix spelling mistakes in new commentsJohn Stultz
Fixup spelling issues caught by Richard CC: Richard Cochran <richardcochran@gmail.com> CC: Chen Jie <chenj@lemote.com> CC: Steven Rostedt <rostedt@goodmis.org> CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-11-22time: fix bogus comment in timekeeping_get_ns_rawDan McGee
The whole point of this function is to return a value not touched by NTP; unfortunately the comment got copied wholesale without adjustment from the timekeeping_get_ns function above. Signed-off-by: Dan McGee <dpmcgee@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-11-17timekeeping: add arch_offset hook to ktime_get functionsHector Palacios
ktime_get and ktime_get_ts were calling timekeeping_get_ns() but later they were not calling arch_gettimeoffset() so architectures using this mechanism returned 0 ns when calling these functions. This happened for example when running Busybox's ping which calls syscall(__NR_clock_gettime, CLOCK_MONOTONIC, ts) which eventually calls ktime_get. As a result the returned ping travel time was zero. CC: stable@kernel.org Signed-off-by: Hector Palacios <hector.palacios@digi.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-11-11Merge branch 'formingo/3.2/tip/timers/core' of ↵Ingo Molnar
git://git.linaro.org/people/jstultz/linux into timers/core Conflicts: kernel/time/timekeeping.c
2011-11-10clocksource: Avoid selecting mult values that might overflow when adjustedJohn Stultz
For some frequencies, the clocks_calc_mult_shift() function will unfortunately select mult values very close to 0xffffffff. This has the potential to overflow when NTP adjusts the clock, adding to the mult value. This patch adds a clocksource.maxadj value, which provides an approximation of an 11% adjustment(NTP limits adjustments to 500ppm and the tick adjustment is limited to 10%), which could be made to the clocksource.mult value. This is then used to both check that the current mult value won't overflow/underflow, as well as warning us if the timekeeping_adjust() code pushes over that 11% boundary. v2: Fix max_adjustment calculation, and improve WARN_ONCE messages. v3: Don't warn before maxadj has actually been set CC: Yong Zhang <yong.zhang0@gmail.com> CC: David Daney <ddaney.cavm@gmail.com> CC: Thomas Gleixner <tglx@linutronix.de> CC: Chen Jie <chenj@lemote.com> CC: zhangfx <zhangfx@lemote.com> CC: stable@kernel.org Reported-by: Chen Jie <chenj@lemote.com> Reported-by: zhangfx <zhangfx@lemote.com> Tested-by: Yong Zhang <yong.zhang0@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-10-31kernel: Fix files explicitly needing EXPORT_SYMBOL infrastructurePaul Gortmaker
These files were getting <linux/module.h> via an implicit non-obvious path, but we want to crush those out of existence since they cost time during compiles of processing thousands of lines of headers for no reason. Give them the lightweight header that just contains the EXPORT_SYMBOL infrastructure. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-28time: Improve documentation of timekeeeping_adjust()John Stultz
After getting a number of questions in private emails about the math around admittedly very complex timekeeping_adjust() and timekeeping_big_adjust(), I figure the code needs some better comments. Hopefully the explanations are clear enough and don't muddy the water any worse. Still needs documentation for ntp_error, but I couldn't recall exactly the full explanation behind the code that's there (although I do recall once working it out when Roman first proposed it). Given a bit more time I can probably work it out, but I don't want to hold back this documentation until then. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Chen Jie <chenj@lemote.com> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1319764362-32367-1-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-10-26Merge branch 'timers-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits) time, s390: Get rid of compile warning dw_apb_timer: constify clocksource name time: Cleanup old CONFIG_GENERIC_TIME references that snuck in time: Change jiffies_to_clock_t() argument type to unsigned long alarmtimers: Fix error handling clocksource: Make watchdog reset lockless posix-cpu-timers: Cure SMP accounting oddities s390: Use direct ktime path for s390 clockevent device clockevents: Add direct ktime programming function clockevents: Make minimum delay adjustments configurable nohz: Remove "Switched to NOHz mode" debugging messages proc: Consider NO_HZ when printing idle and iowait times nohz: Make idle/iowait counter update conditional nohz: Fix update_ts_time_stat idle accounting cputime: Clean up cputime_to_usecs and usecs_to_cputime macros alarmtimers: Rework RTC device selection using class interface alarmtimers: Add try_to_cancel functionality alarmtimers: Add more refined alarm state tracking alarmtimers: Remove period from alarm structure alarmtimers: Remove interval cap limit hack ...
2011-10-26Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (45 commits) rcu: Move propagation of ->completed from rcu_start_gp() to rcu_report_qs_rsp() rcu: Remove rcu_needs_cpu_flush() to avoid false quiescent states rcu: Wire up RCU_BOOST_PRIO for rcutree rcu: Make rcu_torture_boost() exit loops at end of test rcu: Make rcu_torture_fqs() exit loops at end of test rcu: Permit rt_mutex_unlock() with irqs disabled rcu: Avoid having just-onlined CPU resched itself when RCU is idle rcu: Suppress NMI backtraces when stall ends before dump rcu: Prohibit grace periods during early boot rcu: Simplify unboosting checks rcu: Prevent early boot set_need_resched() from __rcu_pending() rcu: Dump local stack if cannot dump all CPUs' stacks rcu: Move __rcu_read_unlock()'s barrier() within if-statement rcu: Improve rcu_assign_pointer() and RCU_INIT_POINTER() documentation rcu: Make rcu_assign_pointer() unconditionally insert a memory barrier rcu: Make rcu_implicit_dynticks_qs() locals be correct size rcu: Eliminate in_irq() checks in rcu_enter_nohz() nohz: Remove nohz_cpu_mask rcu: Document interpretation of RCU-lockdep splats rcu: Allow rcutorture's stat_interval parameter to be changed at runtime ...