* 'core-debugobjects-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timer: Use debugobjects to catch deletion of uninitialized timers
timer: Setup uninitialized timer with a stub callback
debugobjects: Extend to assert that an object is initialized
debugobjects: Be smarter about static objects
del_timer_sync() calls debug_object_assert_init() to assert that
a timer has been initialized before calling lock_timer_base().
lock_timer_base() would spin forever on a NULL(uninit-ed) base.
The check is added to del_timer() to prevent silent failure, even
though it would not get stuck in an infinite loop.
[ sboyd@codeaurora.org: Remove WARN, intialize timer function]
Signed-off-by: Christine Chan <cschan@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/1320724108-20788-4-git-send-email-sboyd@codeaurora.org
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Remove the WARN_ON() in timer_fixup_activate() as we now get the
debugobjects printout in the debugobjects activate check.
We also assign a dummy timer callback so that if the timer is
actually set to fire we don't oops.
[ tglx@linutronix.de: Split out the debugobjects vs. the timer change ]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Christine Chan <cschan@codeaurora.org>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1320724108-20788-2-git-send-email-sboyd@codeaurora.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The changed files were only including linux/module.h for the
EXPORT_SYMBOL infrastructure, and nothing else. Revector them
onto the isolated export header for faster compile times.
Nothing to see here but a whole lot of instances of:
-#include <linux/module.h>
+#include <linux/export.h>
This commit is only changing the kernel dir; next targets
will probably be mm, fs, the arch dirs, etc.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
There is an optimization which does not update the timer if the timer
was pending and the expiration time was unchanged.
Since commit 3bbb9ec9 ("timers: Introduce the concept of timer slack
for legacy timers") this optimization is no longer applied for timers
where the expiration time got extended due to the slack value. So we
need to check again after the expiration time might have been updated.
[ tglx: Made it a single check by applying slack first and sorting
out the slack = 0 value (all timeouts < 256 jiffies) early ]
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Link: http://lkml.kernel.org/r/20110521105828.GA29442@Chamillionaire.breakpoint.cc
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (62 commits)
posix-clocks: Check write permissions in posix syscalls
hrtimer: Remove empty hrtimer_init_hres_timer()
hrtimer: Update hrtimer->state documentation
hrtimer: Update base[CLOCK_BOOTTIME].offset correctly
timers: Export CLOCK_BOOTTIME via the posix timers interface
timers: Add CLOCK_BOOTTIME hrtimer base
time: Extend get_xtime_and_monotonic_offset() to also return sleep
time: Introduce get_monotonic_boottime and ktime_get_boottime
hrtimers: extend hrtimer base code to handle more then 2 clockids
ntp: Remove redundant and incorrect parameter check
mn10300: Switch do_timer() to xtimer_update()
posix clocks: Introduce dynamic clocks
posix-timers: Cleanup namespace
posix-timers: Add support for fd based clocks
x86: Add clock_adjtime for x86
posix-timers: Introduce a syscall for clock tuning.
time: Splitout compat timex accessors
ntp: Add ADJ_SETOFFSET mode bit
time: Introduce timekeeping_inject_offset
posix-timer: Update comment
...
Fix up new system-call-related conflicts in
arch/x86/ia32/ia32entry.S
arch/x86/include/asm/unistd_32.h
arch/x86/include/asm/unistd_64.h
arch/x86/kernel/syscall_table_32.S
(name_to_handle_at()/open_by_handle_at() vs clock_adjtime()), and some
due to movement of get_jiffies_64() in:
kernel/time.c
In complex subsystems like mac80211 structures can contain several
timers and work structs, so identifying a specific instance from the
call trace and object type output of debugobjects can be hard.
Allow the subsystems which support debugobjects to provide a hint
function. This function returns a pointer to a kernel address
(preferrably the objects callback function) which is printed along
with the debugobjects type.
Add hint methods for timer_list, work_struct and hrtimer.
[ tglx: Massaged changelog, made it compile ]
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
LKML-Reference: <20110307085809.GA9334@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Twice I had to explain the output about why lockdep gives an error with
locks in IRQ context and with del_timer_sync(). Might as well write it
up and place it in the comments above the code in del_timer_sync().
Perhaps the next time this lockdep dump triggers people will understand
the issues.
It is a ticky issue and very subtle, explaining it in detail in the code
may help others understand the issue when they stumble upon the bug
again.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1297186794.23343.19.camel@gandalf.stny.rr.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Both attempts at trying to allow softirq usage for
del_timer_sync() failed (produced bogus warnings),
so revert the commit for this release:
f266a5110d: lockdep, timer: Fix del_timer_sync() annotation
and try again later.
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Yong Zhang <yong.zhang0@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <1297174680.13327.107.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Calling local_bh_enable() will want to actually start processing
softirqs, which isn't a good idea since this can get called with IRQs
disabled.
Cure this by using _local_bh_enable() which doesn't start processing
softirqs, and use raw_local_irq_save() to avoid any softirqs from
happening without letting lockdep think IRQs are in fact disabled.
Reported-by: Nick Bowler <nbowler@elliptictech.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Yong Zhang <yong.zhang0@gmail.com>
LKML-Reference: <20110203141548.039540914@chello.nl>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
do_timer() is primary timekeeping related. calc_global_load() is
called from do_timer() as well, but that's more for historical
reasons.
[ tglx: Fixed up the calc_global_load() reject andmassaged changelog ]
Signed-off-by: Torben Hohn <torbenh@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: johnstul@us.ibm.com
Cc: yong.zhang0@gmail.com
Cc: hch@infradead.org
LKML-Reference: <20110127145855.23248.56933.stgit@localhost>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
MAINTAINERS: Update timer related entries
timers: Use this_cpu_read
timerqueue: Make timerqueue_getnext() static inline
hrtimer: fix timerqueue conversion flub
hrtimers: Convert hrtimers to use timerlist infrastructure
timers: Fixup allmodconfig build issue
timers: Rename timerlist infrastructure to timerqueue
timers: Introduce timerlist infrastructure.
hrtimer: Remove stale comment on curr_timer
timer: Warn when del_timer_sync() is called in hardirq context
timer: Del_timer_sync() can be used in softirq context
timer: Make try_to_del_timer_sync() the same on SMP and UP
posix-timers: Annotate lock_timer()
timer: Permit statically-declared work with deferrable timers
time: Use ARRAY_SIZE macro in timecompare.c
timer: Initialize the field slack of timer_list
timer_list: Remove alignment padding on 64 bit when CONFIG_TIMER_STATS
time: Compensate for rounding on odd-frequency clocksources
Fix up trivial conflict in MAINTAINERS
This fixes a bug as seen on 2.6.32 based kernels where timers got
enqueued on offline cpus.
If a cpu goes offline it might still have pending timers. These will
be migrated during CPU_DEAD handling after the cpu is offline.
However while the cpu is going offline it will schedule the idle task
which will then call tick_nohz_stop_sched_tick().
That function in turn will call get_next_timer_intterupt() to figure
out if the tick of the cpu can be stopped or not. If it turns out that
the next tick is just one jiffy off (delta_jiffies == 1)
tick_nohz_stop_sched_tick() incorrectly assumes that the tick should
not stop and takes an early exit and thus it won't update the load
balancer cpu.
Just afterwards the cpu will be killed and the load balancer cpu could
be the offline cpu.
On 2.6.32 based kernel get_nohz_load_balancer() gets called to decide
on which cpu a timer should be enqueued (see __mod_timer()). Which
leads to the possibility that timers get enqueued on an offline cpu.
These will never expire and can cause a system hang.
This has been observed 2.6.32 kernels. On current kernels
__mod_timer() uses get_nohz_timer_target() which doesn't have that
problem. However there might be other problems because of the too
early exit tick_nohz_stop_sched_tick() in case a cpu goes offline.
The easiest and probably safest fix seems to be to let
get_next_timer_interrupt() just lie and let it say there isn't any
pending timer if the current cpu is offline.
I also thought of moving migrate_[hr]timers() from CPU_DEAD to
CPU_DYING, but seeing that there already have been fixes at least in
the hrtimer code in this area I'm afraid that this could add new
subtle bugs.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20101201091109.GA8984@osiris.boeblingen.de.ibm.com>
Cc: stable@kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There's a long-running regression that proved difficult to fix and
which is hitting certain people and is rather annoying in its effects.
Damien reported that after 74f5187ac8 (sched: Cure load average vs
NO_HZ woes) his load average is unnaturally high, he also noted that
even with that patch reverted the load avgerage numbers are not
correct.
The problem is that the previous patch only solved half the NO_HZ
problem, it addressed the part of going into NO_HZ mode, not of
comming out of NO_HZ mode. This patch implements that missing half.
When comming out of NO_HZ mode there are two important things to take
care of:
- Folding the pending idle delta into the global active count.
- Correctly aging the averages for the idle-duration.
So with this patch the NO_HZ interaction should be complete and
behaviour between CONFIG_NO_HZ=[yn] should be equivalent.
Furthermore, this patch slightly changes the load average computation
by adding a rounding term to the fixed point multiplication.
Reported-by: Damien Wyart <damien.wyart@free.fr>
Reported-by: Tim McGrath <tmhikaru@gmail.com>
Tested-by: Damien Wyart <damien.wyart@free.fr>
Tested-by: Orion Poplawski <orion@cora.nwra.com>
Tested-by: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: stable@kernel.org
Cc: Chase Douglas <chase.douglas@canonical.com>
LKML-Reference: <1291129145.32004.874.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Actually we have used del_timer_sync() in softirq context for a long time,
e.g. in __dst_free()::cancel_delayed_work().
So change the comments of it to warn on hardirq context only, and make
lockdep know about this change.
Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
On UP try_to_del_timer_sync() is mapped to del_timer() which does not
take the running timer callback into account, so it has different
semantics.
Remove the SMP dependency of try_to_del_timer_sync() by using
base->running_timer in the UP case as well.
[ tglx: Removed set_running_timer() inline and tweaked the changelog ]
Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Currently, you have to just define a delayed_work uninitialised, and then
initialise it before first use. That's a tad clumsy. At risk of playing
mind-games with the compiler, fooling it into doing pointer arithmetic
with compile-time-constants, this lets clients properly initialise delayed
work with deferrable timers statically.
This patch was inspired by the issues which lead Artem Bityutskiy to
commit 8eab945c56 ("sunrpc: make the cache cleaner workqueue
deferrable").
Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com>
Acked-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Provide a mechanism that allows running code in IRQ context. It is
most useful for NMI code that needs to interact with the rest of the
system -- like wakeup a task to drain buffers.
Perf currently has such a mechanism, so extract that and provide it as
a generic feature, independent of perf so that others may also
benefit.
The IRQ context callback is generated through self-IPIs where
possible, or on architectures like powerpc the decrementer (the
built-in timer facility) is set to generate an interrupt immediately.
Architectures that don't have anything like this get to do with a
callback from the timer tick. These architectures can call
irq_work_run() at the tail of any IRQ handlers that might enqueue such
work (like the perf IRQ handler) to avoid undue latencies in
processing the work.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
[ various fixes ]
Signed-off-by: Huang Ying <ying.huang@intel.com>
LKML-Reference: <1287036094.7768.291.camel@yhuang-dev>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
Documentation: Add timers/timers-howto.txt
timer: Added usleep_range timer
Revert "timer: Added usleep[_range] timer"
clockevents: Remove the per cpu tick skew
posix_timer: Move copy_to_user(created_timer_id) down in timer_create()
timer: Added usleep[_range] timer
timers: Document meaning of deferrable timer
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (27 commits)
sched: Use correct macro to display sched_child_runs_first in /proc/sched_debug
sched: No need for bootmem special cases
sched: Revert nohz_ratelimit() for now
sched: Reduce update_group_power() calls
sched: Update rq->clock for nohz balanced cpus
sched: Fix spelling of sibling
sched, cpuset: Drop __cpuexit from cpu hotplug callbacks
sched: Fix the racy usage of thread_group_cputimer() in fastpath_timer_check()
sched: run_posix_cpu_timers: Don't check ->exit_state, use lock_task_sighand()
sched: thread_group_cputime: Simplify, document the "alive" check
sched: Remove the obsolete exit_state/signal hacks
sched: task_tick_rt: Remove the obsolete ->signal != NULL check
sched: __sched_setscheduler: Read the RLIMIT_RTPRIO value lockless
sched: Fix comments to make them DocBook happy
sched: Fix fix_small_capacity
powerpc: Exclude arch_sd_sibiling_asym_packing() on UP
powerpc: Enable asymmetric SMT scheduling on POWER7
sched: Add asymmetric group packing option for sibling domain
sched: Fix capacity calculations for SMT4
sched: Change nohz idle load balancing logic to push model
...
