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* kernel-time: fix s/then/than/ spelling errorsJim Cromie2012-03-241-1/+1
| | | | | | | | Use than for comparisons, like more than. CC: John Stultz <john.stultz@linaro.org> Signed-off-by: Jim Cromie <jim.cromie@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
* Merge branch 'driver-core-next' into Linux 3.2Greg Kroah-Hartman2012-01-061-18/+19
|\ | | | | | | | | | | | | | | | | | | | | | | 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>
| * clocksource: convert sysdev_class to a regular subsystemKay Sievers2011-12-151-18/+19
| | | | | | | | | | | | | | | | | | | | 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>
* | time/clocksource: Fix kernel-doc warningsKusanagi Kouichi2011-12-191-3/+9
| | | | | | | | | | | | | | | | | | 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>
* | clocksource: Fix bug with max_deferment margin calculationYang Honggang (Joseph)2011-12-021-2/+2
| | | | | | | | | | | | | | | | | | 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>
* | clocksource: Avoid selecting mult values that might overflow when adjustedJohn Stultz2011-11-101-10/+48
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* clocksource: Make watchdog reset locklessThomas Gleixner2011-09-131-20/+18
| | | | | | | | | | | | | | | | | | | KGDB needs to trylock watchdog_lock when trying to reset the clocksource watchdog after the system has been stopped to avoid a potential deadlock. When the trylock fails TSC usually becomes unstable. We can be more clever by using an atomic counter and checking it in the clocksource_watchdog callback. We restart the watchdog whenever the counter is > 0 and only decrement the counter when we ran through a full update cycle. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <johnstul@us.ibm.com> Acked-by: Jason Wessel <jason.wessel@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1109121326280.2723@ionos Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: Make watchdog robust vs. interruptionThomas Gleixner2011-06-161-11/+13
| | | | | | | | | | | | | | | The clocksource watchdog code is interruptible and it has been observed that this can trigger false positives which disable the TSC. The reason is that an interrupt storm or a long running interrupt handler between the read of the watchdog source and the read of the TSC brings the two far enough apart that the delta is larger than the unstable treshold. Move both reads into a short interrupt disabled region to avoid that. Reported-and-tested-by: Vernon Mauery <vernux@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@kernel.org
* clockevents/source: Use u64 to make 32bit happyThomas Gleixner2011-05-201-1/+1
| | | | | | unsigned long is not 64bit on 32bit machine. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Merge branch 'timers-clockevents-for-linus' of ↵Linus Torvalds2011-05-201-19/+19
|\ | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-clockevents-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: hpet: Cleanup the clockevents init and register code x86: Convert PIT to clockevents_config_and_register() clockevents: Provide interface to reconfigure an active clock event device clockevents: Provide combined configure and register function clockevents: Restructure clock_event_device members clocksource: Get rid of the hardcoded 5 seconds sleep time limit clocksource: Restructure clocksource struct members
| * clocksource: Get rid of the hardcoded 5 seconds sleep time limitThomas Gleixner2011-05-191-19/+19
| | | | | | | | | | | | | | | | | | | | | | Slow clocksources can have a way longer sleep time than 5 seconds and even fast ones can easily cope with 600 seconds and still maintain proper accuracy. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Reviewed-by: Ingo Molnar <mingo@elte.hu> Link: http://lkml.kernel.org/r/%3C20110518210136.109811585%40linutronix.de%3E
* | clocksource: Install completely before selectingjohn stultz2011-05-051-2/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | Christian Hoffmann reported that the command line clocksource override with acpi_pm timer fails: Kernel command line: <SNIP> clocksource=acpi_pm hpet clockevent registered Switching to clocksource hpet Override clocksource acpi_pm is not HRT compatible. Cannot switch while in HRT/NOHZ mode. The watchdog code is what enables CLOCK_SOURCE_VALID_FOR_HRES, but we actually end up selecting the clocksource before we enqueue it into the watchdog list, so that's why we see the warning and fail to switch to acpi_pm timer as requested. That's particularly bad when we want to debug timekeeping related problems in early boot. Put the selection call last. Reported-by: Christian Hoffmann <email@christianhoffmann.info> Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: stable@kernel.org # 32... Link: http://lkml.kernel.org/r/%3C1304558210.2943.24.camel%40work-vm%3E Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
*-. Merge branches 'core-fixes-for-linus', 'x86-fixes-for-linus', ↵Linus Torvalds2011-01-151-4/+4
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 'timers-fixes-for-linus' and 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: rcu: avoid pointless blocked-task warnings rcu: demote SRCU_SYNCHRONIZE_DELAY from kernel-parameter status rtmutex: Fix comment about why new_owner can be NULL in wake_futex_pi() * 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, olpc: Add missing Kconfig dependencies x86, mrst: Set correct APB timer IRQ affinity for secondary cpu x86: tsc: Fix calibration refinement conditionals to avoid divide by zero x86, ia64, acpi: Clean up x86-ism in drivers/acpi/numa.c * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: timekeeping: Make local variables static time: Rename misnamed minsec argument of clocks_calc_mult_shift() * 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: tracing: Remove syscall_exit_fields tracing: Only process module tracepoints once perf record: Add "nodelay" mode, disabled by default perf sched: Fix list of events, dropping unsupported ':r' modifier Revert "perf tools: Emit clearer message for sys_perf_event_open ENOENT return" perf top: Fix annotate segv perf evsel: Fix order of event list deletion
| | * time: Rename misnamed minsec argument of clocks_calc_mult_shift()Nicolas Pitre2011-01-121-4/+4
| |/ | | | | | | | | | | | | | | | | | | | | | | | | The minsec argument to clocks_calc_mult_shift() is misnamed. It is used to clamp the magnitude of the mult factor so that a multiplication with any value in the given range won't overflow a 64 bit result. Let's rename it to match the actual usage. Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org> Acked-by: John Stultz <johnstul@us.ibm.com> LKML-Reference: <alpine.LFD.2.00.1101111207140.17086@xanadu.home> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | Merge branch 'for-next' of ↵Linus Torvalds2011-01-131-1/+1
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial * 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (43 commits) Documentation/trace/events.txt: Remove obsolete sched_signal_send. writeback: fix global_dirty_limits comment runtime -> real-time ppc: fix comment typo singal -> signal drivers: fix comment typo diable -> disable. m68k: fix comment typo diable -> disable. wireless: comment typo fix diable -> disable. media: comment typo fix diable -> disable. remove doc for obsolete dynamic-printk kernel-parameter remove extraneous 'is' from Documentation/iostats.txt Fix spelling milisec -> ms in snd_ps3 module parameter description Fix spelling mistakes in comments Revert conflicting V4L changes i7core_edac: fix typos in comments mm/rmap.c: fix comment sound, ca0106: Fix assignment to 'channel'. hrtimer: fix a typo in comment init/Kconfig: fix typo anon_inodes: fix wrong function name in comment fix comment typos concerning "consistent" poll: fix a typo in comment ... Fix up trivial conflicts in: - drivers/net/wireless/iwlwifi/iwl-core.c (moved to iwl-legacy.c) - fs/ext4/ext4.h Also fix missed 'diabled' typo in drivers/net/bnx2x/bnx2x.h while at it.
| * | tree-wide: fix comment/printk typosUwe Kleine-König2010-11-011-1/+1
| |/ | | | | | | | | | | | | | | | | | | "gadget", "through", "command", "maintain", "maintain", "controller", "address", "between", "initiali[zs]e", "instead", "function", "select", "already", "equal", "access", "management", "hierarchy", "registration", "interest", "relative", "memory", "offset", "already", Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* / Fix rounding in clocks_calc_mult_shift()john stultz2010-12-221-0/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Russell King reports: | On the ARM dev boards, we have a 32-bit counter running at 24MHz. Calling | clocks_calc_mult_shift(&mult, &shift, 24MHz, NSEC_PER_SEC, 60) gives | us a multiplier of 2796202666 and a shift of 26. | | Over a large counter delta, this produces an error - lets take a count | from 362976315 to 4280663372: | | (4280663372-362976315) * 2796202666 / 2^26 - (4280663372-362976315) * (1000/24) | => -38.91872422891230269990 | | Can we do better? | | (4280663372-362976315) * 2796202667 / 2^26 - (4280663372-362976315) * (1000/24) | 19.45936211449532822051 | | which is about twice as good as the 2796202666 multiplier. | | Looking at the equivalent divisions obtained, 2796202666 / 2^26 gives | 41.66666665673255920410ns per tick, whereas 2796202667 / 2^26 gives | 41.66666667163372039794ns. The actual value wanted is 1000/24 = | 41.66666666666666666666ns. Fix this by ensuring we round to nearest when calculating the multiplier. Signed-off-by: John Stultz <john.stultz@linaro.org> Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Tested-by: Will Deacon <will.deacon@arm.com> Tested-by: Mikael Pettersson <mikpe@it.uu.se> Tested-by: Eric Miao <eric.y.miao@gmail.com> Tested-by: Olof Johansson <olof@lixom.net> Tested-by: Jamie Iles <jamie@jamieiles.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* clocksource: Add __clocksource_updatefreq_hz/khz methodsJohn Stultz2010-07-271-5/+24
| | | | | | | | | | | | To properly handle clocksources that change frequencies at the clocksource->enable() point, this patch adds a method that will update the clocksource's mult/shift and max_idle_ns values. Signed-off-by: John Stultz <johnstul@us.ibm.com> LKML-Reference: <1279068988-21864-12-git-send-email-johnstul@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* time: Kill off CONFIG_GENERIC_TIMEJohn Stultz2010-07-271-2/+2
| | | | | | | | | | Now that all arches have been converted over to use generic time via clocksources or arch_gettimeoffset(), we can remove the GENERIC_TIME config option and simplify the generic code. Signed-off-by: John Stultz <johnstul@us.ibm.com> LKML-Reference: <1279068988-21864-4-git-send-email-johnstul@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: Add clocksource_register_hz/khz interfaceJohn Stultz2010-05-101-0/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | | How to pick good mult/shift pairs has always been difficult to describe to folks writing clocksource drivers, since it requires careful tradeoffs in adjustment accuracy vs overflow limits. Now, with the clocks_calc_mult_shift function, its much easier. However, not many clocksources have converted to using that function, and there is still the issue of the max interval length assumption being made by each clocksource driver independently. So this patch simplifies the registration process by having clocksources be registered with a hz/khz value and the registration function taking care of setting mult/shift. This should take most of the confusion out of writing a clocksource driver. Additionally it also keeps the shift size tradeoff (more accuracy vs longer possible nohz times) centralized so the timekeeping core can keep track of the assumptions being made. [ tglx: Coding style and comments fixed ] Signed-off-by: John Stultz <johnstul@us.ibm.com> LKML-Reference: <1273280858-30143-1-git-send-email-johnstul@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* timekeeping: Prevent oops when GENERIC_TIME=njohn stultz2010-03-021-0/+4
| | | | | | | | | | | | | | | | | | | | | Aaro Koskinen reported an issue in kernel.org bugzilla #15366, where on non-GENERIC_TIME systems, accessing /sys/devices/system/clocksource/clocksource0/current_clocksource results in an oops. It seems the timekeeper/clocksource rework missed initializing the curr_clocksource value in the !GENERIC_TIME case. Thanks to Aaro for reporting and diagnosing the issue as well as testing the fix! Reported-by: Aaro Koskinen <aaro.koskinen@iki.fi> Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: stable@kernel.org LKML-Reference: <1267475683.4216.61.camel@localhost.localdomain> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Merge branch 'timers-for-linus' of ↵Linus Torvalds2010-03-011-1/+13
|\ | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: posix-timers.c: Don't export local functions clocksource: start CMT at clocksource resume clocksource: add suspend callback clocksource: add argument to resume callback ntp: Cleanup xtime references in ntp.c ntp: Make time_esterror and time_maxerror static
| * clocksource: add suspend callbackMagnus Damm2010-02-051-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a clocksource suspend callback. This callback can be used by the clocksource driver to shutdown and perform any kind of late suspend activities even though the clocksource driver itself is a non-sysdev driver. One example where this is useful is to fix the sh_cmt.c platform driver that today suspends using the platform bus and shuts down the clocksource too early. With this callback in place the sh_cmt driver will suspend using the clocksource and clockevent hooks and leave the platform device pm callbacks unused. Signed-off-by: Magnus Damm <damm@opensource.se> Cc: Paul Mundt <lethal@linux-sh.org> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * clocksource: add argument to resume callbackMagnus Damm2010-02-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | Pass the clocksource as an argument to the clocksource resume callback. Needed so we can point out which CMT channel the sh_cmt.c driver shall resume. Signed-off-by: Magnus Damm <damm@opensource.se> Cc: john stultz <johnstul@us.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | clocksource: Prevent potential kgdb dead lockThomas Gleixner2010-01-261-3/+15
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 0f8e8ef7 (clocksource: Simplify clocksource watchdog resume logic) introduced a potential kgdb dead lock. When the kernel is stopped by kgdb inside code which holds watchdog_lock then kgdb dead locks in clocksource_resume_watchdog(). clocksource_resume_watchdog() is called from kbdg via clocksource_touch_watchdog() to avoid that the clock source watchdog marks TSC unstable after the kernel has been stopped. Solve this by replacing spin_lock with a spin_trylock and just return in case the lock is held. Not resetting the watchdog might result in TSC becoming marked unstable, but that's an acceptable penalty for using kgdb. The timekeeping is anyway easily screwed up by kgdb when the system uses either jiffies or a clock source which wraps in short intervals (e.g. pm_timer wraps about every 4.6s), so we really do not have to worry about that occasional TSC marked unstable side effect. The second caller of clocksource_resume_watchdog() is clocksource_resume(). The trylock is safe here as well because the system is UP at this point, interrupts are disabled and nothing else can hold watchdog_lock(). Reported-by: Jason Wessel <jason.wessel@windriver.com> LKML-Reference: <1264480000-6997-4-git-send-email-jason.wessel@windriver.com> Cc: kgdb-bugreport@lists.sourceforge.net Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: John Stultz <johnstul@us.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Merge branch 'for-linus' of ↵Linus Torvalds2009-12-101-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (42 commits) tree-wide: fix misspelling of "definition" in comments reiserfs: fix misspelling of "journaled" doc: Fix a typo in slub.txt. inotify: remove superfluous return code check hdlc: spelling fix in find_pvc() comment doc: fix regulator docs cut-and-pasteism mtd: Fix comment in Kconfig doc: Fix IRQ chip docs tree-wide: fix assorted typos all over the place drivers/ata/libata-sff.c: comment spelling fixes fix typos/grammos in Documentation/edac.txt sysctl: add missing comments fs/debugfs/inode.c: fix comment typos sgivwfb: Make use of ARRAY_SIZE. sky2: fix sky2_link_down copy/paste comment error tree-wide: fix typos "couter" -> "counter" tree-wide: fix typos "offest" -> "offset" fix kerneldoc for set_irq_msi() spidev: fix double "of of" in comment comment typo fix: sybsystem -> subsystem ...
| * tree-wide: fix typos "selct" + "slect" -> "select"Uwe Kleine-König2009-11-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | This patch was generated by git grep -E -i -l 's(le|el)ct' | xargs -r perl -p -i -e 's/([Ss])(le|el)ct/$1elect/ with only skipping net/netfilter/xt_SECMARK.c and include/linux/netfilter/xt_SECMARK.h which have a struct member called selctx. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* | Merge branch 'timers-for-linus' of ↵Linus Torvalds2009-12-091-0/+97
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: timers, init: Limit the number of per cpu calibration bootup messages posix-cpu-timers: optimize and document timer_create callback clockevents: Add missing include to pacify sparse x86: vmiclock: Fix printk format x86: Fix printk format due to variable type change sparc: fix printk for change of variable type clocksource/events: Fix fallout of generic code changes nohz: Allow 32-bit machines to sleep for more than 2.15 seconds nohz: Track last do_timer() cpu nohz: Prevent clocksource wrapping during idle nohz: Type cast printk argument mips: Use generic mult/shift factor calculation for clocks clocksource: Provide a generic mult/shift factor calculation clockevents: Use u32 for mult and shift factors nohz: Introduce arch_needs_cpu nohz: Reuse ktime in sub-functions of tick_check_idle. time: Remove xtime_cache time: Implement logarithmic time accumulation
| * | clocksource/events: Fix fallout of generic code changesThomas Gleixner2009-11-141-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | powerpc grew a new warning due to the type change of clockevent->mult. The architectures which use parts of the generic time keeping infrastructure tripped over my wrong assumption that clocksource_register is only used when GENERIC_TIME=y. I should have looked and also I should have known better. These renitent Gaul villages are racking my nerves. Some serious deprecating is due. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | nohz: Prevent clocksource wrapping during idleJon Hunter2009-11-131-0/+44
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The dynamic tick allows the kernel to sleep for periods longer than a single tick, but it does not limit the sleep time currently. In the worst case the kernel could sleep longer than the wrap around time of the time keeping clock source which would result in losing track of time. Prevent this by limiting it to the safe maximum sleep time of the current time keeping clock source. The value is calculated when the clock source is registered. [ tglx: simplified the code a bit and massaged the commit msg ] Signed-off-by: Jon Hunter <jon-hunter@ti.com> Cc: John Stultz <johnstul@us.ibm.com> LKML-Reference: <1250617512-23567-2-git-send-email-jon-hunter@ti.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | clocksource: Provide a generic mult/shift factor calculationThomas Gleixner2009-11-131-0/+53
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | MIPS has two functions to calculcate the mult/shift factors for clock sources and clock events at run time. ARM needs such functions as well. Implement a function which calculates the mult/shift factors based on the frequencies to which and from which is converted. The function also has a parameter to specify the minimum conversion range in seconds. This range is guaranteed not to produce a 64bit overflow when a value is multiplied with the calculated mult factor. The larger the conversion range the less becomes the conversion accuracy. Provide two inline wrappers which handle clock events and clock sources. For clock events the "from" frequency is nano seconds per second which corresponds to 1GHz and "to" is the device frequency. For clock sources "from" is the device frequency and "to" is nano seconds per second. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Mikael Pettersson <mikpe@it.uu.se> Acked-by: Ralf Baechle <ralf@linux-mips.org> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Cc: John Stultz <johnstul@us.ibm.com> LKML-Reference: <20091111134229.766673305@linutronix.de>
* / clocksource/timecompare: Fix symbol exports to be GPL'd.David S. Miller2009-11-121-3/+3
|/ | | | | | Noticed by Thomas GLeixner. Signed-off-by: David S. Miller <davem@davemloft.net>
* clocksource: Resume clocksource without taking the clocksource mutexMartin Schwidefsky2009-09-241-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git commit 75c5158f70c065b9 converted the clocksource spinlock to a mutex. This causes the following BUG: BUG: sleeping function called from invalid context at kernel/mutex.c:280 in_atomic(): 0, irqs_disabled(): 1, pid: 2473, name: pm-suspend 2 locks held by pm-suspend/2473: #0: (&buffer->mutex){......}, at: [<ffffffff8115ab13>] sysfs_write_file+0x3c/0x137 #1: (pm_mutex){......}, at: [<ffffffff810865b5>] enter_state+0x39/0x130 Pid: 2473, comm: pm-suspend Not tainted 2.6.31 #1 Call Trace: [<ffffffff810792f0>] ? __debug_show_held_locks+0x22/0x24 [<ffffffff8104a2ef>] __might_sleep+0x107/0x10b [<ffffffff8141fca9>] mutex_lock_nested+0x25/0x43 [<ffffffff81073537>] clocksource_resume+0x1c/0x60 [<ffffffff81072902>] timekeeping_resume+0x1e/0x1c8 [<ffffffff812aee62>] __sysdev_resume+0x25/0xcf [<ffffffff812aef79>] sysdev_resume+0x6d/0xae [<ffffffff810864f8>] suspend_devices_and_enter+0x12b/0x1af [<ffffffff8108665b>] enter_state+0xdf/0x130 [<ffffffff81085dc3>] state_store+0xb6/0xd3 [<ffffffff81204c73>] kobj_attr_store+0x17/0x19 [<ffffffff8115abd2>] sysfs_write_file+0xfb/0x137 [<ffffffff811057d2>] vfs_write+0xae/0x10b [<ffffffff81208392>] ? __up_read+0x1a/0x7f [<ffffffff811058ef>] sys_write+0x4a/0x6e [<ffffffff81011b82>] system_call_fastpath+0x16/0x1b clocksource_resume is called early in the resume process, there is only one cpu, no processes are running and the interrupts are disabled. It is therefore possible to resume the clocksources without taking the clocksource mutex. Reported-by: Xiaotian Feng <xtfeng@gmail.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Tested-by: Michal Schmidt <mschmidt@redhat.com> Cc: Xiaotian Feng <xtfeng@gmail.com> Cc: John Stultz <johnstul@us.ibm.com> LKML-Reference: <20090924172952.49697825@mschwide.boeblingen.de.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* clocksource: Delay clocksource down rating to late bootThomas Gleixner2009-09-141-10/+18
| | | | | | | | | | | | | | | The down rating of clock sources in the early boot process via the clock source watchdog mechanism can happen way before the per cpu event queues are initialized. This leads to a boot crash on x86 when the TSC is marked unstable in the SMP bring up. The selection of a clock source for time keeping happens in the late boot process so we can safely delay the list manipulation until clocksource_done_booting() is called. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <new-submission> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
* clocksource: clocksource_select must be called with mutex lockedThomas Gleixner2009-09-141-0/+2
| | | | | | | | | The callers of clocksource_select must hold clocksource_mutex to protect the clocksource_list. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <new-submission> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
* clocksource: Resolve cpu hotplug dead lock with TSC unstable, fix crashMartin Schwidefsky2009-09-111-2/+3
| | | | | | | | | | | | | | | | | The watchdog timer is started after the watchdog clocksource and at least one watched clocksource have been registered. The clocksource work element watchdog_work is initialized just before the clocksource timer is started. This is too late for the clocksource_mark_unstable call from native_cpu_up. To fix this use a static initializer for watchdog_work. This resolves a boot crash reported by multiple people. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: John Stultz <johnstul@us.ibm.com> LKML-Reference: <20090911153305.3fe9a361@skybase> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* clocksource: Resolve cpu hotplug dead lock with TSC unstableThomas Gleixner2009-08-281-3/+30
| | | | | | | | | | | | | | | | | | | | | Martin Schwidefsky analyzed it: To register a clocksource the clocksource_mutex is acquired and if necessary timekeeping_notify is called to install the clocksource as the timekeeper clock. timekeeping_notify uses stop_machine which needs to take cpu_add_remove_lock mutex. Starting a new cpu is done with the cpu_add_remove_lock mutex held. native_cpu_up checks the tsc of the new cpu and if the tsc is no good clocksource_change_rating is called. Which needs the clocksource_mutex and the deadlock is complete. The solution is to replace the TSC via the clocksource watchdog mechanism. Mark the TSC as unstable and schedule the watchdog work so it gets removed in the watchdog thread context. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <new-submission> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: John Stultz <johnstul@us.ibm.com>
* clocksource: Avoid clocksource watchdog circular locking dependencyMartin Schwidefsky2009-08-191-3/+16
| | | | | | | | | | | | | stop_machine from a multithreaded workqueue is not allowed because of a circular locking dependency between cpu_down and the workqueue execution. Use a kernel thread to do the clocksource downgrade. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: john stultz <johnstul@us.ibm.com> LKML-Reference: <20090818170942.3ab80c91@skybase> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: Protect the watchdog rating changes with clocksource_mutexThomas Gleixner2009-08-191-5/+13
| | | | | | | | | | | | | | | | | | | Martin pointed out that commit 6ea41d2529 (clocksource: Call clocksource_change_rating() outside of watchdog_lock) has a theoretical reference count problem. The calls to clocksource_change_rating() are now done outside of the clocksource mutex and outside of the watchdog lock. A concurrent clocksource_unregister() could remove the clock. Split out the code which changes the rating from clocksource_change_rating() into __clocksource_change_rating(). Protect the clocksource_watchdog_work() code sequence with the clocksource_mutex() and call __clocksource_change_rating(). LKML-Reference: <alpine.LFD.2.00.0908171038420.2782@localhost.localdomain> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
* clocksource: Call clocksource_change_rating() outside of watchdog_lockThomas Gleixner2009-08-151-2/+9
| | | | | | | | The changes to the watchdog logic introduced a lock inversion between watchdog_lock and clocksource_mutex. Change the rating outside of watchdog_lock to avoid it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* timekeeping: Update clocksource with stop_machineMartin Schwidefsky2009-08-151-68/+44
| | | | | | | | | | | | | | update_wall_time calls change_clocksource HZ times per second to check if a new clock source is available. In close to 100% of all calls there is no new clock. Replace the tick based check by an update done with stop_machine. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134810.711836357@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* timekeeping: Introduce struct timekeeperMartin Schwidefsky2009-08-151-2/+4
| | | | | | | | | | | | | | | | | | Add struct timekeeper to keep the internal values timekeeping.c needs in regard to the currently selected clock source. This moves the timekeeping intervals, xtime_nsec and the ntp error value from struct clocksource to struct timekeeper. The raw_time is removed from the clocksource as well. It gets treated like xtime as a global variable. Eventually xtime raw_time should be moved to struct timekeeper. [ tglx: minor cleanup ] Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134809.613209842@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: Move watchdog downgrade to a work queue threadMartin Schwidefsky2009-08-151-17/+39
| | | | | | | | | | | | | Move the downgrade of an unstable clocksource from the timer interrupt context into the process context of a work queue thread. This is needed to be able to do the clocksource switch with stop_machine. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134809.354926067@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: Refactor clocksource watchdogMartin Schwidefsky2009-08-151-28/+69
| | | | | | | | | | | | | Refactor clocksource watchdog code to make it more readable. Add clocksource_dequeue_watchdog to remove a clocksource from the watchdog list when it is unregistered. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134809.110881699@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: Simplify clocksource watchdog resume logicMartin Schwidefsky2009-08-151-8/+15
| | | | | | | | | | | | To resume the clocksource watchdog just remove the CLOCK_SOURCE_WATCHDOG bit from the watched clocksource. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134808.880925790@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: Delay clocksource watchdog highres enablementMartin Schwidefsky2009-08-151-25/+22
| | | | | | | | | | | | | | The clocksource watchdog marks a clock as highres capable before it checked the deviation from the watchdog clocksource even for a single time. Make sure that the deviation is at least checked once before doing the switch to highres mode. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134808.627795883@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: Cleanup clocksource selectionMartin Schwidefsky2009-08-151-83/+51
| | | | | | | | | | | | | | | | | | | | | | If a non high-resolution clocksource is first set as override clock and then registered it becomes active even if the system is in one-shot mode. Move the override check from sysfs_override_clocksource to the clocksource selection. That fixes the bug and simplifies the code. The check in clocksource_register for double registration of the same clocksource is removed without replacement. To find the initial clocksource a new weak function in jiffies.c is defined that returns the jiffies clocksource. The architecture code can then override the weak function with a more suitable clocksource, e.g. the TOD clock on s390. [ tglx: Folded in a fix from John Stultz ] Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134808.388024160@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: Prevent NULL pointer dereferenceThomas Gleixner2009-07-191-1/+1
| | | | | | | | | | Writing a zero length string to sys/.../current_clocksource will cause a NULL pointer dereference if the clock events system is in one shot (highres or nohz) mode. Pointed-out-by: Dan Carpenter <error27@gmail.com> LKML-Reference: <alpine.DEB.2.00.0907191545580.12306@bicker> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: prevent selection of low resolution clocksourse also for nohz=onThomas Gleixner2009-06-131-8/+10
| | | | | | | | | | | | | | commit 3f68535adad (clocksource: sanity check sysfs clocksource changes) prevents selection of non high resolution capable clocksources when high resolution mode is active, but did not take into account that the same rules apply for highres=off nohz=on. Check the tick device mode instead of hrtimer_hres_active() to verify whether the system needs to be protected from a switch to jiffies or other non highres capable clock sources. Reported-by: Luming Yu <luming.yu@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: sanity check sysfs clocksource changesjohn stultz2009-06-111-1/+17
| | | | | | | | | | | | | | | Thomas, Andrew and Ingo pointed out that we don't have any safety checks in the clocksource sysfs entries to make sure sysadmins don't try to change the clocksource to a non high-res timer capable clocksource (such as jiffies) when high-res timers (HRT) is enabled. Doing so will likely hang a system. Correct this by filtering non HRT clocksources from available_clocksources and not accepting non HRT clocksources with HRT enabled. Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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