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* [PATCH] Optimize calc_load()Eric Dumazet2006-12-13
| | | | | | | | | | | | | | | | | | | | | | | calc_load() is called by timer interrupt to update avenrun[]. It currently calls nr_active() at each timer tick (HZ per second), while the update of avenrun[] is done only once every 5 seconds. (LOAD_FREQ=5 Hz) nr_active() is quite expensive on SMP machines, since it has to sum up nr_running and nr_uninterruptible of all online CPUS, bringing foreign dirty cache lines. This patch is an optimization of calc_load() so that nr_active() is called only if we need it. The use of unlikely() is welcome since the condition is true only once every 5*HZ time. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: "Siddha, Suresh B" <suresh.b.siddha@intel.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] clocksource: small cleanupDaniel Walker2006-12-10
| | | | | | | | | | | | Mostly changing alignment. Just some general cleanup. [akpm@osdl.org: build fix] Signed-off-by: Daniel Walker <dwalker@mvista.com> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] round_jiffies infrastructureArjan van de Ven2006-12-10
| | | | | | | | | | | | | | | | | | | | | | Introduce a round_jiffies() function as well as a round_jiffies_relative() function. These functions round a jiffies value to the next whole second. The primary purpose of this rounding is to cause all "we don't care exactly when" timers to happen at the same jiffy. This avoids multiple timers firing within the second for no real reason; with dynamic ticks these extra timers cause wakeups from deep sleep CPU sleep states and thus waste power. The exact wakeup moment is skewed by the cpu number, to avoid all cpus from waking up at the exact same time (and hitting the same lock/cachelines there) [akpm@osdl.org: fix variable type] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] kill wall_jiffiesAtsushi Nemoto2006-10-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With 2.6.18-rc4-mm2, now wall_jiffies will always be the same as jiffies. So we can kill wall_jiffies completely. This is just a cleanup and logically should not change any real behavior except for one thing: RTC updating code in (old) ppc and xtensa use a condition "jiffies - wall_jiffies == 1". This condition is never met so I suppose it is just a bug. I just remove that condition only instead of kill the whole "if" block. [heiko.carstens@de.ibm.com: s390 build fix and cleanup] Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Cc: Andi Kleen <ak@muc.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ian Molton <spyro@f2s.com> Cc: Mikael Starvik <starvik@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Hirokazu Takata <takata.hirokazu@renesas.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp> Cc: Richard Curnow <rc@rc0.org.uk> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp> Cc: Chris Zankel <chris@zankel.net> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] ntp: add time_adjust to tick lengthRoman Zippel2006-10-01
| | | | | | | | | | | | This folds update_ntp_one_tick() into second_overflow() and adds time_adjust to the tick length, this makes time_next_adjust unnecessary. This slightly changes the adjtime() behaviour, instead of applying it to the next tick, it's applied to the next second. Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] ntp: add ntp_update_frequencyRoman Zippel2006-10-01
| | | | | | | | | | | | This introduces ntp_update_frequency() and deinlines ntp_clear() (as it's not performance critical). ntp_update_frequency() calculates the base tick length using tick_usec and adds a base adjustment, in case the frequency doesn't divide evenly by HZ. Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] NTP: Move all the NTP related code to ntp.cjohn stultz2006-10-01
| | | | | | | | | | | Move all the NTP related code to ntp.c [akpm@osdl.org: cleanups, build fix] Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] simplify update_times (avoid jiffies/jiffies_64 aliasing problem)Atsushi Nemoto2006-09-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pass ticks to do_timer() and update_times(), and adjust x86_64 and s390 timer interrupt handler with this change. Currently update_times() calculates ticks by "jiffies - wall_jiffies", but callers of do_timer() should know how many ticks to update. Passing ticks get rid of this redundant calculation. Also there are another redundancy pointed out by Martin Schwidefsky. This cleanup make a barrier added by 5aee405c662ca644980c184774277fc6d0769a84 needless. So this patch removes it. As a bonus, this cleanup make wall_jiffies can be removed easily, since now wall_jiffies is always synced with jiffies. (This patch does not really remove wall_jiffies. It would be another cleanup patch) Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Cc: Andi Kleen <ak@muc.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Acked-by: Russell King <rmk@arm.linux.org.uk> Cc: Ian Molton <spyro@f2s.com> Cc: Mikael Starvik <starvik@axis.com> Acked-by: David Howells <dhowells@redhat.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Hirokazu Takata <takata.hirokazu@renesas.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp> Cc: Richard Curnow <rc@rc0.org.uk> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp> Cc: Chris Zankel <chris@zankel.net> Acked-by: "Luck, Tony" <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] check return value of cpu_callbackAkinobu Mita2006-09-29
| | | | | | | | | | | | | Spawing ksoftirqd, migration, or watchdog, and calling init_timers_cpu() may fail with small memory. If it happens in initcalls, kernel NULL pointer dereference happens later. This patch makes crash happen immediately in such cases. It seems a bit better than getting kernel NULL pointer dereference later. Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Akinobu Mita <mita@miraclelinux.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Fix kerneldoc comments in kernel/timer.cRolf Eike Beer2006-09-29
| | | | | | | | | | | Some of the kerneldoc comments in this file are ignored since the lead-in is malformed, using either "/*" or "/***" instead of "/**". [rdunlap@xenotime.net: kerneldoc fixes] Signed-off-by: Rolf Eike Beer <eike-kernel@sf-tec.de> Acked-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] timer: add lock annotation to lock_timer_baseJosh Triplett2006-09-29
| | | | | | | | | | | lock_timer_base acquires a lock and returns with that lock held. Add a lock annotation to this function so that sparse can check callers for lock pairing, and so that sparse will not complain about this function since it intentionally uses the lock in this manner. Signed-off-by: Josh Triplett <josh@freedesktop.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] sys_getppid oopses on debug kernelKirill Korotaev2006-08-14
| | | | | | | | | | | | | | | | sys_getppid() optimization can access a freed memory. On kernels with DEBUG_SLAB turned ON, this results in Oops. As Dave Hansen noted, this optimization is also unsafe for memory hotplug. So this patch always takes the lock to be safe. [oleg@tv-sign.ru: simplifications] Signed-off-by: Kirill Korotaev <dev@openvz.org> Cc: <stable@kernel.org> Cc: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* [PATCH] timer: Fix tvec_bases initializerJosh Triplett2006-07-31
| | | | | | | | | | kernel/timer.c defines a (per-cpu) pointer to tvec_base_t, but initializes it using { &a_tvec_base_t }, which sparse warns about; change this to just &a_tvec_base_t. Signed-off-by: Josh Triplett <josh@freedesktop.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] fix bad macro param in timer.cSteven Rostedt2006-07-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have #define INDEX(N) (base->timer_jiffies >> (TVR_BITS + N * TVN_BITS)) & TVN_MASK and it's used via list = varray[i + 1]->vec + (INDEX(i + 1)); So, due to underparenthesisation, this INDEX(i+1) is now a ... (TVR_BITS + i + 1 * TVN_BITS)) ... So this bugfix changes behaviour. It worked before by sheer luck: "If i was anything but 0, it was broken. But this was only used by s390 and arm. Since it was for the next interrupt, could that next interrupt be a problem (going into the second cascade)? But it was probably seldom wrong. That is, this would fail if the next interrupt was in the second cascade, and was wrapped. Which may never of happened. Also if it did happen, it would have just missed the interrupt. If an interrupt was missed, and no one was there to miss it, was it really missed :-)" Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] cpu hotplug: replace __devinit* with __cpuinit* for cpu notificationsChandra Seetharaman2006-07-31
| | | | | | | | | | | | | | | | Few of the callback functions and notifier blocks that are associated with cpu notifications incorrectly have __devinit and __devinitdata. They should be __cpuinit and __cpuinitdata instead. It makes no functional difference but wastes text area when CONFIG_HOTPLUG is enabled and CONFIG_HOTPLUG_CPU is not. This patch fixes all those instances. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Cc: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] improve timekeeping resume robustnessjohn stultz2006-07-15
| | | | | | | | | | | | | | | Resolve problems seen w/ APM suspend. Due to resume initialization ordering, its possible we could get a timer interrupt before the timekeeping resume() function is called. This patch ensures we don't do any timekeeping accounting before we're fully resumed. (akpm: fixes the machine-freezes-on-APM-resume bug) Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] del_timer_sync(): add cpu_relax()Andrew Morton2006-07-15
| | | | | | | Relax the CPU in the del_timer_sync() busywait loop. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] adjust clock for lost ticksRoman Zippel2006-07-10
| | | | | | | | | | | | | | A large number of lost ticks can cause an overadjustment of the clock. To compensate for this we look at the current error and the larger the error already is the more careful we are at adjusting the error. As small extra fix reset the error when the clock is set. Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Acked-by: john stultz <johnstul@us.ibm.com> Cc: Uwe Bugla <uwe.bugla@gmx.de> Cc: James Bottomley <James.Bottomley@SteelEye.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] sched: cleanup, remove task_t, convert to struct task_structIngo Molnar2006-07-03
| | | | | | | | | | | | cleanup: remove task_t and convert all the uses to struct task_struct. I introduced it for the scheduler anno and it was a mistake. Conversion was mostly scripted, the result was reviewed and all secondary whitespace and style impact (if any) was fixed up by hand. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] lockdep: annotate timer base locksIngo Molnar2006-07-03
| | | | | | | | | | | | Split the per-CPU timer base locks up into separate lock classes, because they are used recursively. Has no effect on non-lockdep kernels. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] lockdep: locking init debugging improvementIngo Molnar2006-07-03
| | | | | | | | | | | | Locking init improvement: - introduce and use __SPIN_LOCK_UNLOCKED for array initializations, to pass in the name string of locks, used by debugging Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] cpu hotplug: revert initdata patch submitted for 2.6.17Chandra Seetharaman2006-06-27
| | | | | | | | | This patch reverts notifier_block changes made in 2.6.17 Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Cc: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] cpu hotplug: revert init patch submitted for 2.6.17Chandra Seetharaman2006-06-27
| | | | | | | | | | | | | | | | | | | | | In 2.6.17, there was a problem with cpu_notifiers and XFS. I provided a band-aid solution to solve that problem. In the process, i undid all the changes you both were making to ensure that these notifiers were available only at init time (unless CONFIG_HOTPLUG_CPU is defined). We deferred the real fix to 2.6.18. Here is a set of patches that fixes the XFS problem cleanly and makes the cpu notifiers available only at init time (unless CONFIG_HOTPLUG_CPU is defined). If CONFIG_HOTPLUG_CPU is defined then cpu notifiers are available at run time. This patch reverts the notifier_call changes made in 2.6.17 Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Cc: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] fix and optimize clock source updateRoman Zippel2006-06-26
| | | | | | | | | | | This fixes the clock source updates in update_wall_time() to correctly track the time coming in via current_tick_length(). Optimize the fast paths to be as short as possible to keep the overhead low. Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Acked-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] time: rename clocksource functionsjohn stultz2006-06-26
| | | | | | | | | | | As suggested by Roman Zippel, change clocksource functions to use clocksource_xyz rather then xyz_clocksource to avoid polluting the namespace. Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Time: Introduce arch generic time accessorsjohn stultz2006-06-26
| | | | | | | | | Introduces clocksource switching code and the arch generic time accessor functions that use the clocksource infrastructure. Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Time: Use clocksource abstraction for NTP adjustmentsjohn stultz2006-06-26
| | | | | | | | | | | | | | | | | | | | Instead of incrementing xtime by tick_nsec + ntp adjustments, use the clocksource abstraction to increment and scale time. Using the clocksource abstraction allows other clocksources to be used consistently in the face of late or lost ticks, while preserving the existing behavior via the jiffies clocksource. This removes the need to keep time_phase adjustments as we just use the current_tick_length() function as the NTP interface and accumulate time using shifted nanoseconds. The basics of this design was by Roman Zippel, however it is my own interpretation and implementation, so the credit should go to him and the blame to me. Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Time: Let user request precision from current_tick_length()john stultz2006-06-26
| | | | | | | | | | | | Change the current_tick_length() function so it takes an argument which specifies how much precision to return in shifted nanoseconds. This provides a simple way to convert between NTPs internal nanoseconds shifted by (SHIFT_SCALE - 10) to other shifted nanosecond units that are used by the clocksource abstraction. Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Time: Use clocksource infrastructure for update_wall_timejohn stultz2006-06-26
| | | | | | | | | | | | | | | Modify the update_wall_time function so it increments time using the clocksource abstraction instead of jiffies. Since the only clocksource driver currently provided is the jiffies clocksource, this should result in no functional change. Additionally, a timekeeping_init and timekeeping_resume function has been added to initialize and maintain some of the new timekeping state. [hirofumi@mail.parknet.co.jp: fixlet] Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Define __raw_get_cpu_var and use itPaul Mackerras2006-06-25
| | | | | | | | | | | | | | | | | | | | | | | There are several instances of per_cpu(foo, raw_smp_processor_id()), which is semantically equivalent to __get_cpu_var(foo) but without the warning that smp_processor_id() can give if CONFIG_DEBUG_PREEMPT is enabled. For those architectures with optimized per-cpu implementations, namely ia64, powerpc, s390, sparc64 and x86_64, per_cpu() turns into more and slower code than __get_cpu_var(), so it would be preferable to use __get_cpu_var on those platforms. This defines a __raw_get_cpu_var(x) macro which turns into per_cpu(x, raw_smp_processor_id()) on architectures that use the generic per-cpu implementation, and turns into __get_cpu_var(x) on the architectures that have an optimized per-cpu implementation. Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] When CONFIG_BASE_SMALL=1, cascade() may enter an infinite loopPorpoise2006-06-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When CONFIG_BASE_SAMLL=1, cascade() in may enter the infinite loop. Because of CONFIG_BASE_SMALL=1(TVR_BITS=6 and TVN_BITS=4), the list base->tv5 may cascade into base->tv5. So, the kernel enters the infinite loop in the function cascade(). I created a test module to verify this bug, and a patch to fix it. #include <linux/kernel.h> #include <linux/module.h> #include <linux/init.h> #include <linux/timer.h> #if 0 #include <linux/kdb.h> #else #define kdb_printf printk #endif #define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6) #define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8) #define TVN_SIZE (1 << TVN_BITS) #define TVR_SIZE (1 << TVR_BITS) #define TVN_MASK (TVN_SIZE - 1) #define TVR_MASK (TVR_SIZE - 1) #define TV_SIZE(N) (N*TVN_BITS + TVR_BITS) struct timer_list timer0; struct timer_list dummy_timer1; struct timer_list dummy_timer2; void dummy_timer_fun(unsigned long data) { } unsigned long j=0; void check_timer_base(unsigned long data) { kdb_printf("check_timer_base %08x\n",jiffies); mod_timer(&timer0,(jiffies & (~0xFFF)) + 0x1FFF); } int init_module(void) { init_timer(&timer0); timer0.data = (unsigned long)0; timer0.function = check_timer_base; mod_timer(&timer0,jiffies+1); init_timer(&dummy_timer1); dummy_timer1.data = (unsigned long)0; dummy_timer1.function = dummy_timer_fun; init_timer(&dummy_timer2); dummy_timer2.data = (unsigned long)0; dummy_timer2.function = dummy_timer_fun; j=jiffies; j&=(~((1<<TV_SIZE(3))-1)); j+=(1<<TV_SIZE(3)); j+=(1<<TV_SIZE(4)); kdb_printf("mod_timer %08x\n",j); mod_timer(&dummy_timer1, j ); mod_timer(&dummy_timer2, j ); return 0; } void cleanup_module() { del_timer_sync(&timer0); del_timer_sync(&dummy_timer1); del_timer_sync(&dummy_timer2); } (Cleanups from Oleg) [oleg@tv-sign.ru: use list_replace_init()] Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] list: use list_replace_init() instead of list_splice_init()Oleg Nesterov2006-06-23
| | | | | | | | | | list_splice_init(list, head) does unneeded job if it is known that list_empty(head) == 1. We can use list_replace_init() instead. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Fix a NO_IDLE_HZ timer bugZachary Amsden2006-05-21
| | | | | | | | | | | | | | | | | | | | | | | | Under certain timing conditions, a race during boot occurs where timer ticks are being processed on remote CPUs. The remote timer ticks can increment jiffies, and if this happens during a window when a timeout is very close to expiring but a local tick has not yet been delivered, you can end up with 1) No softirq pending 2) A local timer wheel which is not synced to jiffies 3) No high resolution timer active 4) A local timer which is supposed to fire before the current jiffies value. In this circumstance, the comparison in next_timer_interrupt overflows, because the base of the comparison for high resolution timers is jiffies, but for the softirq timer wheel, it is relative the the current base of the wheel (jiffies_base). Signed-off-by: Zachary Amsden <zach@vmware.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Remove __devinit and __cpuinit from notifier_call definitionsChandra Seetharaman2006-04-26
| | | | | | | | | | | | | Few of the notifier_chain_register() callers use __init in the definition of notifier_call. It is incorrect as the function definition should be available after the initializations (they do not unregister them during initializations). This patch fixes all such usages to _not_ have the notifier_call __init section. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Remove __devinitdata from notifier block definitionsChandra Seetharaman2006-04-26
| | | | | | | | | | | | | | | | Few of the notifier_chain_register() callers use __devinitdata in the definition of notifier_block data structure. It is incorrect as the data structure should be available after the initializations (they do not unregister them during initializations). This was leading to an oops when notifier_chain_register() call is invoked for those callback chains after initialization. This patch fixes all such usages to _not_ have the notifier_block data structure in the init data section. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] timer initialisation fixAndrew Morton2006-04-11
| | | | | | | | | | | | | | | | | | We need the boot CPU's tvec_bases[] entry to be initialised super-early in boot, for early_serial_setup(). That runs within setup_arch(), before even per-cpu areas are initialised. The patch changes tvec_bases to use compile-time initialisation, and adds a separate array `tvec_base_done' to keep track of which CPU has had its tvec_bases[] entry initialised (because we can no longer use the zeroness of that tvec_bases[] entry to determine whether it has been initialised). Thanks to Eugene Surovegin <ebs@ebshome.net> for diagnosing this. Cc: Eugene Surovegin <ebs@ebshome.net> Cc: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] x86_64: Fix drift with HPET timer enabledJordan Hargrave2006-04-09
| | | | | | | | | | | | | | | | | | | | If the HPET timer is enabled, the clock can drift by ~3 seconds a day. This is due to the HPET timer not being initialized with the correct setting (still using PIT count). If HZ changes, this drift can become even more pronounced. HPET patch initializes tick_nsec with correct tick_nsec settings for HPET timer. Vojtech comments: "It's not entirely correct (it assumes the HPET ticks totally exactly), but it's significantly better than assuming the PIT error there." Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* BUG_ON() Conversion in kernel/signal.cEric Sesterhenn2006-04-02
| | | | | | | | this changes if() BUG(); constructs to BUG_ON() which is cleaner, contains unlikely() and can better optimized away. Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [PATCH] sched: reduce overhead of calc_loadJack Steiner2006-03-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, count_active_tasks() calls both nr_running() & nr_interruptible(). Each of these functions does a "for_each_cpu" & reads values from the runqueue of each cpu. Although this is not a lot of instructions, each runqueue may be located on different node. Depending on the architecture, a unique TLB entry may be required to access each runqueue. Since there may be more runqueues than cpu TLB entries, a scan of all runqueues can trash the TLB. Each memory reference incurs a TLB miss & refill. In addition, the runqueue cacheline that contains nr_running & nr_uninterruptible may be evicted from the cache between the two passes. This causes unnecessary cache misses. Combining nr_running() & nr_interruptible() into a single function substantially reduces the TLB & cache misses on large systems. This should have no measureable effect on smaller systems. On a 128p IA64 system running a memory stress workload, the new function reduced the overhead of calc_load() from 605 usec/call to 324 usec/call. Signed-off-by: Jack Steiner <steiner@sgi.com> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] __mod_timer: simplify ->base changingOleg Nesterov2006-03-31
| | | | | | | | | | Since base and new_base are of the same type now, we can save one 'if' branch and simplify the code a bit. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] kill __init_timer_base in favor of boot_tvec_basesOleg Nesterov2006-03-31
| | | | | | | | | | | | | Commit a4a6198b80cf82eb8160603c98da218d1bd5e104: [PATCH] tvec_bases too large for per-cpu data introduced "struct tvec_t_base_s boot_tvec_bases" which is visible at compile time. This means we can kill __init_timer_base and move timer_base_s's content into tvec_t_base_s. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] remove pps supportRoman Zippel2006-03-25
| | | | | | | | | | | | | | This removes the support for pps. It's completely unused within the kernel and is basically in the way for further cleanups. It should be easier to readd proper support for it after the rest has been converted to NTP4 (where the pps mechanisms are quite different from NTP3 anyway). Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Cc: Adrian Bunk <bunk@stusta.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] sys_alarm() unsigned signed conversion fixupThomas Gleixner2006-03-25
| | | | | | | | | | | | | | | | | | | | | | | | | alarm() calls the kernel with an unsigend int timeout in seconds. The value is stored in the tv_sec field of a struct timeval to setup the itimer. The tv_sec field of struct timeval is of type long, which causes the tv_sec value to be negative on 32 bit machines if seconds > INT_MAX. Before the hrtimer merge (pre 2.6.16) such a negative value was converted to the maximum jiffies timeout by the timeval_to_jiffies conversion. It's not clear whether this was intended or just happened to be done by the timeval_to_jiffies code. hrtimers expect a timeval in canonical form and treat a negative timeout as already expired. This breaks the legitimate usage of alarm() with a timeout value > INT_MAX seconds. For 32 bit machines it is therefor necessary to limit the internal seconds value to avoid API breakage. Instead of doing this in all implementations of sys_alarm the duplicated sys_alarm code is moved into a common function in itimer.c Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] timer-irq-driven soft-watchdog, cleanupsIngo Molnar2006-03-24
| | | | | | | | | | | | | | | Make the softlockup detector purely timer-interrupt driven, removing softirq-context (timer) dependencies. This means that if the softlockup watchdog triggers, it has truly observed a longer than 10 seconds scheduling delay of a SCHED_FIFO prio 99 task. (the patch also turns off the softlockup detector during the initial bootup phase and does small style fixes) Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] tvec_bases too large for per-cpu dataJan Beulich2006-03-24
| | | | | | | | | | | | | | | | With internal Xen-enabled kernels we see the kernel's static per-cpu data area exceed the limit of 32k on x86-64, and even native x86-64 kernels get fairly close to that limit. I generally question whether it is reasonable to have data structures several kb in size allocated as per-cpu data when the space there is rather limited. The biggest arch-independent consumer is tvec_bases (over 4k on 32-bit archs, over 8k on 64-bit ones), which now gets converted to use dynamically allocated memory instead. Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] time_interpolator: add __read_mostlyChristoph Lameter2006-03-17
| | | | | | | | | | The pointer to the current time interpolator and the current list of time interpolators are typically only changed during bootup. Adding __read_mostly takes them away from possibly hot cachelines. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] time: add barrier after updating jiffies_64Atsushi Nemoto2006-03-06
| | | | | | | | | | | Add a compiler barrier so that we don't read jiffies before updating jiffies_64. Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] fix next_timer_interrupt() for hrtimerTony Lindgren2006-03-06
| | | | | | | | | | | | | | | | | | | | | Also from Thomas Gleixner <tglx@linutronix.de> Function next_timer_interrupt() got broken with a recent patch 6ba1b91213e81aa92b5cf7539f7d2a94ff54947c as sys_nanosleep() was moved to hrtimer. This broke things as next_timer_interrupt() did not check hrtimer tree for next event. Function next_timer_interrupt() is needed with dyntick (CONFIG_NO_IDLE_HZ, VST) implementations, as the system can be in idle when next hrtimer event was supposed to happen. At least ARM and S390 currently use next_timer_interrupt(). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] time_interpolator: Use readq_relaxed() instead of readq().Christoph Lameter2006-03-02
| | | | | | | | | | | | | | | | On some platforms readq performs additional work to make sure I/O is done in a coherent way. This is not needed for time retrieval as done by the time interpolator. So we can use readq_relaxed instead which will improve performance. It affects sparc64 and ia64 only. Apparently it makes a significant difference on ia64. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: john stultz <johnstul@us.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Provide an interface for getting the current tick lengthPaul Mackerras2006-02-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This provides an interface for arch code to find out how many nanoseconds are going to be added on to xtime by the next call to do_timer. The value returned is a fixed-point number in 52.12 format in nanoseconds. The reason for this format is that it gives the full precision that the timekeeping code is using internally. The motivation for this is to fix a problem that has arisen on 32-bit powerpc in that the value returned by do_gettimeofday drifts apart from xtime if NTP is being used. PowerPC is now using a lockless do_gettimeofday based on reading the timebase register and performing some simple arithmetic. (This method of getting the time is also exported to userspace via the VDSO.) However, the factor and offset it uses were calculated based on the nominal tick length and weren't being adjusted when NTP varied the tick length. Note that 64-bit powerpc has had the lockless do_gettimeofday for a long time now. It also had an extremely hairy routine that got called from the 32-bit compat routine for adjtimex, which adjusted the factor and offset according to what it thought the timekeeping code was going to do. Not only was this only called if a 32-bit task did adjtimex (i.e. not if a 64-bit task did adjtimex), it was also duplicating computations from kernel/timer.c and it wasn't clear that it was (still) correct. The simple solution is to ask the timekeeping code how long the current jiffy will be on each timer interrupt, after calling do_timer. If this jiffy will be a different length from the last one, we then need to compute new values for the factor and offset used in the lockless do_gettimeofday. In this way we can keep xtime and do_gettimeofday in sync, even when NTP is varying the tick length. Note that when adjtimex varies the tick length, it almost always introduces the variation from the next tick on. The only case I could see where adjtimex would vary the length of the current tick is when an old-style adjtime adjustment is being cancelled. (It's not clear to me why the adjustment has to be cancelled immediately rather than from the next tick on.) Thus I don't see any real need for a hook in adjtimex; the rare case of an old-style adjustment being cancelled can be fixed up at the next tick. Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: john stultz <johnstul@us.ibm.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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