Commit Graph

238 Commits

Author SHA1 Message Date
Venkatesh Pallipadi 83cd4fe27a sched: Change nohz idle load balancing logic to push model
In the new push model, all idle CPUs indeed go into nohz mode. There is
still the concept of idle load balancer (performing the load balancing
on behalf of all the idle cpu's in the system). Busy CPU kicks the nohz
balancer when any of the nohz CPUs need idle load balancing.
The kickee CPU does the idle load balancing on behalf of all idle CPUs
instead of the normal idle balance.

This addresses the below two problems with the current nohz ilb logic:
* the idle load balancer continued to have periodic ticks during idle and
  wokeup frequently, even though it did not have any rebalancing to do on
  behalf of any of the idle CPUs.
* On x86 and CPUs that have APIC timer stoppage on idle CPUs, this
  periodic wakeup can result in a periodic additional interrupt on a CPU
  doing the timer broadcast.

Also currently we are migrating the unpinned timers from an idle to the cpu
doing idle load balancing (when all the cpus in the system are idle,
there is no idle load balancing cpu and timers get added to the same idle cpu
where the request was made. So the existing optimization works only on semi idle
system).

And In semi idle system, we no longer have periodic ticks on the idle load
balancer CPU. Using that cpu will add more delays to the timers than intended
(as that cpu's timer base may not be uptodate wrt jiffies etc). This was
causing mysterious slowdowns during boot etc.

For now, in the semi idle case, use the nearest busy cpu for migrating timers
from an idle cpu.  This is good for power-savings anyway.

Signed-off-by: Venkatesh Pallipadi <venki@google.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <1274486981.2840.46.camel@sbs-t61.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-06-09 10:34:52 +02:00
Akinobu Mita 9e506f7adc kernel/: fix BUG_ON checks for cpu notifier callbacks direct call
The commit 80b5184cc5 ("kernel/: convert cpu
notifier to return encapsulate errno value") changed the return value of
cpu notifier callbacks.

Those callbacks don't return NOTIFY_BAD on failures anymore.  But there
are a few callbacks which are called directly at init time and checking
the return value.

I forgot to change BUG_ON checking by the direct callers in the commit.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-06-04 15:21:45 -07:00
Linus Torvalds 29d03fa12b Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  posix_timer: Fix error path in timer_create
  hrtimer: Avoid double seqlock
  timers: Move local variable into else section
  timers: Fix slack calculation really
2010-05-28 10:16:27 -07:00
Akinobu Mita 80b5184cc5 kernel/: convert cpu notifier to return encapsulate errno value
By the previous modification, the cpu notifier can return encapsulate
errno value.  This converts the cpu notifiers for kernel/*.c

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:48 -07:00
Thomas Gleixner 2abfb9e1d4 timers: Move local variable into else section
Fix nit-picking coding style detail.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-05-26 16:07:13 +02:00
Thomas Gleixner 8e63d7795e timers: Fix slack calculation really
commit f00e047ef (timers: Fix slack calculation for expired timers)
fixed the issue of slack on expired timers only partially. Linus
noticed that jiffies is volatile so it is reloaded twice, which
generates bad code.

But its worse. This can defeat the time_after() check if jiffies are
incremented between time_after() and the slack calculation.

Fix it by reading jiffies into a local variable, which prevents the
compiler from loading it twice. While at it make the > -1 check into
>= 0 which is easier to read.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-25 21:07:48 +02:00
Jeff Chua f00e047efd timers: Fix slack calculation for expired timers
commit 3bbb9ec946 (timers: Introduce the concept of timer slack for
legacy timers) does not take the case into account when the timer is
already expired. This broke wireless drivers.

The solution is not to apply slack to already expired timers.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Arjan van de Ven <arjan@linux.intel.com>
2010-05-24 12:10:23 +02:00
Don Zickus 332fbdbca3 lockup_detector: Touch_softlockup cleanups and softlockup_tick removal
Just some code cleanup to make touch_softlockup clearer and remove the
softlockup_tick function as it is no longer needed.

Also remove the /proc softlockup_thres call as it has been changed to
watchdog_thres.

Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
LKML-Reference: <1273266711-18706-3-git-send-email-dzickus@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-05-12 23:55:43 +02:00
Thomas Gleixner dbb6be6d5e Merge branch 'linus' into timers/core
Reason: Further posix_cpu_timer patches depend on mainline changes

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-05-10 14:20:42 +02:00
Arjan van de Ven 3bbb9ec946 timers: Introduce the concept of timer slack for legacy timers
While HR timers have had the concept of timer slack for quite some time
now, the legacy timers lacked this concept, and had to make do with
round_jiffies() and friends.

Timer slack is important for power management; grouping timers reduces the
number of wakeups which in turn reduces power consumption.

This patch introduces timer slack to the legacy timers using the following
pieces:
* A slack field in the timer struct
* An api (set_timer_slack) that callers can use to set explicit timer slack
* A default slack of 0.4% of the requested delay for callers that do not set
  any explicit slack
* Rounding code that is part of mod_timer() that tries to
  group timers around jiffies values every 'power of two'
  (so quick timers will group around every 2, but longer timers
  will group around every 4, 8, 16, 32 etc)

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: johnstul@us.ibm.com
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-04-06 21:50:02 +02:00
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00
Thomas Gleixner 802702e0c2 timer: Try to survive timer callback preempt_count leak
If a timer callback leaks preempt_count we currently assert a
BUG(). That makes it unnecessarily hard to retrieve information about
the problem especially on laptops and headless stations.

There is a decent chance to survive the preempt_count leak by
restoring the preempt_count to the value before the callback. That
allows in many cases to get valuable information about the root cause
of the problem.

We carried that fixup in preempt-rt for years and were able to decode
such wreckage quite a few times.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linux Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arjan van de Veen <arjan@infradead.org>
2010-03-12 22:40:44 +01:00
Thomas Gleixner 576da126a6 timer: Split out timer function call
The ident level is starting to be annoying. More white space than
actual code. Split out the timer function call into its own function.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-03-12 22:40:43 +01:00
Uwe Kleine-König 06f71b922c timer: Print function name for timer callbacks modifying preemption count
A function scheduled with a timer must not exit with a different
preempt count than it was entered. To make helping users running into
the corresponding BUG() easier also print the name of the bad function
not only its address.

[ tglx: Sanitized printk ]

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: johnstul@us.ibm.com
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-03-12 22:40:42 +01:00
Andrew Morton 829b6c1ef4 timer stats: Fix del_timer_sync() and try_to_del_timer_sync()
These functions forgot to run timer_stats_timer_clear_start_info().  It's
unobvious what effect this has and whether it matters much - we won't be
printing it out anyway if the timer's detached.

Untested, just an Ingo trollpatch.

[ Nevertheless correct - tglx ]

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: johnstul@us.ibm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-03-12 19:11:29 +01:00
Peter Zijlstra fe432200ab perf: Fix perf_event_do_pending() fallback callsite
Paul questioned the context in which we should call
perf_event_do_pending(). After looking at that I found that it should be
called from IRQ context these days, however the fallback call-site is
placed in softirq context. Ammend this by placing the callback in the IRQ
timer path.

Reported-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1263374859.4244.192.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-01-21 13:40:39 +01:00
Simon Horman cf1e367ee8 timers: Remove duplicate setting of new_base in __mod_timer()
new_base is set using per_cpu(tvec_bases, cpu) after selecting the
desired value of cpu immediately below so this line is a unnecessary.

Signed-off-by: Simon Horman <horms@verge.net.au>
LKML-Reference: <20091217001542.GD25317@verge.net.au>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-12-17 01:30:49 +01:00
Linus Torvalds 31bbb9b58d Merge branch 'timers-for-linus' of 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:
  itimers: Add tracepoints for itimer
  hrtimer: Add tracepoint for hrtimers
  timers: Add tracepoints for timer_list timers
  cputime: Optimize jiffies_to_cputime(1)
  itimers: Simplify arm_timer() code a bit
  itimers: Fix periodic tics precision
  itimers: Merge ITIMER_VIRT and ITIMER_PROF

Trivial header file include conflicts in kernel/fork.c
2009-09-23 09:46:15 -07:00
Ingo Molnar cdd6c482c9 perf: Do the big rename: Performance Counters -> Performance Events
Bye-bye Performance Counters, welcome Performance Events!

In the past few months the perfcounters subsystem has grown out its
initial role of counting hardware events, and has become (and is
becoming) a much broader generic event enumeration, reporting, logging,
monitoring, analysis facility.

Naming its core object 'perf_counter' and naming the subsystem
'perfcounters' has become more and more of a misnomer. With pending
code like hw-breakpoints support the 'counter' name is less and
less appropriate.

All in one, we've decided to rename the subsystem to 'performance
events' and to propagate this rename through all fields, variables
and API names. (in an ABI compatible fashion)

The word 'event' is also a bit shorter than 'counter' - which makes
it slightly more convenient to write/handle as well.

Thanks goes to Stephane Eranian who first observed this misnomer and
suggested a rename.

User-space tooling and ABI compatibility is not affected - this patch
should be function-invariant. (Also, defconfigs were not touched to
keep the size down.)

This patch has been generated via the following script:

  FILES=$(find * -type f | grep -vE 'oprofile|[^K]config')

  sed -i \
    -e 's/PERF_EVENT_/PERF_RECORD_/g' \
    -e 's/PERF_COUNTER/PERF_EVENT/g' \
    -e 's/perf_counter/perf_event/g' \
    -e 's/nb_counters/nb_events/g' \
    -e 's/swcounter/swevent/g' \
    -e 's/tpcounter_event/tp_event/g' \
    $FILES

  for N in $(find . -name perf_counter.[ch]); do
    M=$(echo $N | sed 's/perf_counter/perf_event/g')
    mv $N $M
  done

  FILES=$(find . -name perf_event.*)

  sed -i \
    -e 's/COUNTER_MASK/REG_MASK/g' \
    -e 's/COUNTER/EVENT/g' \
    -e 's/\<event\>/event_id/g' \
    -e 's/counter/event/g' \
    -e 's/Counter/Event/g' \
    $FILES

... to keep it as correct as possible. This script can also be
used by anyone who has pending perfcounters patches - it converts
a Linux kernel tree over to the new naming. We tried to time this
change to the point in time where the amount of pending patches
is the smallest: the end of the merge window.

Namespace clashes were fixed up in a preparatory patch - and some
stylistic fallout will be fixed up in a subsequent patch.

( NOTE: 'counters' are still the proper terminology when we deal
  with hardware registers - and these sed scripts are a bit
  over-eager in renaming them. I've undone some of that, but
  in case there's something left where 'counter' would be
  better than 'event' we can undo that on an individual basis
  instead of touching an otherwise nicely automated patch. )

Suggested-by: Stephane Eranian <eranian@google.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Paul Mackerras <paulus@samba.org>
Reviewed-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <linux-arch@vger.kernel.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-21 14:28:04 +02:00
Linus Torvalds a03fdb7612 Merge branch 'timers-for-linus' of 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: (34 commits)
  time: Prevent 32 bit overflow with set_normalized_timespec()
  clocksource: Delay clocksource down rating to late boot
  clocksource: clocksource_select must be called with mutex locked
  clocksource: Resolve cpu hotplug dead lock with TSC unstable, fix crash
  timers: Drop a function prototype
  clocksource: Resolve cpu hotplug dead lock with TSC unstable
  timer.c: Fix S/390 comments
  timekeeping: Fix invalid getboottime() value
  timekeeping: Fix up read_persistent_clock() breakage on sh
  timekeeping: Increase granularity of read_persistent_clock(), build fix
  time: Introduce CLOCK_REALTIME_COARSE
  x86: Do not unregister PIT clocksource on PIT oneshot setup/shutdown
  clocksource: Avoid clocksource watchdog circular locking dependency
  clocksource: Protect the watchdog rating changes with clocksource_mutex
  clocksource: Call clocksource_change_rating() outside of watchdog_lock
  timekeeping: Introduce read_boot_clock
  timekeeping: Increase granularity of read_persistent_clock()
  timekeeping: Update clocksource with stop_machine
  timekeeping: Add timekeeper read_clock helper functions
  timekeeping: Move NTP adjusted clock multiplier to struct timekeeper
  ...

Fix trivial conflict due to MIPS lemote -> loongson renaming.
2009-09-18 09:15:24 -07:00
Xiao Guangrong 2b022e3d4b timers: Add tracepoints for timer_list timers
Add tracepoints which cover the timer life cycle. The tracepoints are
integrated with the already existing debug_object debug points as far
as possible.

Based on patches from 
Mathieu: http://marc.info/?l=linux-kernel&m=123791201816247&w=2
and 
Anton: http://marc.info/?l=linux-kernel&m=124331396919301&w=2

[ tglx: Fixed timeout value in timer_start tracepoint, massaged
  comments and made the printk's more readable ]

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Zhaolei <zhaolei@cn.fujitsu.com>
LKML-Reference: <4A7F8A9B.3040201@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-08-29 14:10:06 +02:00
Randy Dunlap 90cba64a5f timer.c: Fix S/390 comments
Fix typos and add omitted words.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: akpm <akpm@linux-foundation.org>
Cc: linux390@de.ibm.com
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
LKML-Reference: <20090825143541.43fc2ed8.randy.dunlap@oracle.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-26 08:07:31 +02:00
Paul E. McKenney a157229cab rcu: Simplify rcu_pending()/rcu_check_callbacks() API
All calls from outside RCU are of the form:

	if (rcu_pending(cpu))
		rcu_check_callbacks(cpu, user);

This is silly, instead we put a call to rcu_pending() in
rcu_check_callbacks(), and then make the outside calls be to
rcu_check_callbacks().  This cuts down on the code a bit and
also gives the compiler a better chance of optimizing.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: josht@linux.vnet.ibm.com
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
LKML-Reference: <125097461311-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-23 10:32:39 +02:00
Thomas Gleixner 4cd1993f00 Merge branch 'linus' into timers/core
Reason: Martin's timekeeping cleanup series depends on both
timers/core and mainline changes.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-08-14 15:59:30 +02:00
Martin Schwidefsky 97fd9ed48c timers: Cache __next_timer_interrupt result
Each time a cpu goes to sleep on a NOHZ=y system the timer
wheel is searched for the next timer interrupt. It can take
quite a few cycles to find the next pending timer.

This patch adds a field to tvec_base that caches the result of
__next_timer_interrupt.

The hit ratio is around 80% on my thinkpad under normal use, on
a server I've seen hit ratios from 5% to 95% dependent on the
workload.

-v2: jiffies wrap fixes

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Venki Pallipadi <venkatesh.pallipadi@intel.com>
LKML-Reference: <20090721202505.7d56a079@skybase>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-04 20:28:25 +02:00
Pavel Roskin 4841158b26 timer: Avoid reading uninitialized data
timer->expires may be uninitialized, so check timer_pending() before
touching timer->expires to pacify kmemcheck.

Signed-off-by: Pavel Roskin <proski@gnu.org>
LKML-Reference: <20090718204602.5191.360.stgit@mj.roinet.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-07-18 23:11:43 +02:00
Heiko Carstens 507e123151 timer stats: Optimize by adding quick check to avoid function calls
When the kernel is configured with CONFIG_TIMER_STATS but timer
stats are runtime disabled we still get calls to
__timer_stats_timer_set_start_info which initializes some
fields in the corresponding struct timer_list.

So add some quick checks in the the timer stats setup functions
to avoid function calls to __timer_stats_timer_set_start_info
when timer stats are disabled.

In an artificial workload that does nothing but playing ping
pong with a single tcp packet via loopback this decreases cpu
consumption by 1 - 1.5%.

This is part of a modified function trace output on SLES11:

 perl-2497  [00] 28630647177732388 [+  125]: sk_reset_timer <-tcp_v4_rcv
 perl-2497  [00] 28630647177732513 [+  125]: mod_timer <-sk_reset_timer
 perl-2497  [00] 28630647177732638 [+  125]: __timer_stats_timer_set_start_info <-mod_timer
 perl-2497  [00] 28630647177732763 [+  125]: __mod_timer <-mod_timer
 perl-2497  [00] 28630647177732888 [+  125]: __timer_stats_timer_set_start_info <-__mod_timer
 perl-2497  [00] 28630647177733013 [+   93]: lock_timer_base <-__mod_timer

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mustafa Mesanovic <mustafa.mesanovic@de.ibm.com>
Cc: Arjan van de Ven <arjan@infradead.org>
LKML-Reference: <20090623153811.GA4641@osiris.boeblingen.de.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-24 11:15:09 +02:00
Linus Torvalds 19035e5b5d Merge branch 'timers-for-linus-migration' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-for-linus-migration' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  timers: Logic to move non pinned timers
  timers: /proc/sys sysctl hook to enable timer migration
  timers: Identifying the existing pinned timers
  timers: Framework for identifying pinned timers
  timers: allow deferrable timers for intervals tv2-tv5 to be deferred

Fix up conflicts in kernel/sched.c and kernel/timer.c manually
2009-06-15 10:06:19 -07:00
Ingo Molnar 0d5959723e Merge branch 'linus' into x86/mce3
Conflicts:
	arch/x86/kernel/cpu/mcheck/mce_64.c
	arch/x86/kernel/irq.c

Merge reason: Resolve the conflicts above.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-11 23:31:52 +02:00
Ingo Molnar 940010c5a3 Merge branch 'linus' into perfcounters/core
Conflicts:
	arch/x86/kernel/irqinit.c
	arch/x86/kernel/irqinit_64.c
	arch/x86/kernel/traps.c
	arch/x86/mm/fault.c
	include/linux/sched.h
	kernel/exit.c
2009-06-11 17:55:42 +02:00
Andi Kleen a9862e0560 Export add_timer_on for modules
Needed in followon patch.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-05-28 09:24:13 -07:00
Thomas Gleixner 2d02494f5a sched, timers: cleanup avenrun users
avenrun is an rough estimate so we don't have to worry about
consistency of the three avenrun values. Remove the xtime lock
dependency and provide a function to scale the values. Cleanup the
users.

[ Impact: cleanup ]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
2009-05-15 15:32:45 +02:00
Thomas Gleixner dce48a84ad sched, timers: move calc_load() to scheduler
Dimitri Sivanich noticed that xtime_lock is held write locked across
calc_load() which iterates over all online CPUs. That can cause long
latencies for xtime_lock readers on large SMP systems. 

The load average calculation is an rough estimate anyway so there is
no real need to protect the readers vs. the update. It's not a problem
when the avenrun array is updated while a reader copies the values.

Instead of iterating over all online CPUs let the scheduler_tick code
update the number of active tasks shortly before the avenrun update
happens. The avenrun update itself is handled by the CPU which calls
do_timer().

[ Impact: reduce xtime_lock write locked section ]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
2009-05-15 15:32:45 +02:00
Arun R Bharadwaj eea08f32ad timers: Logic to move non pinned timers
* Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-04-16 12:11:36]:

This patch migrates all non pinned timers and hrtimers to the current
idle load balancer, from all the idle CPUs. Timers firing on busy CPUs
are not migrated.

While migrating hrtimers, care should be taken to check if migrating
a hrtimer would result in a latency or not. So we compare the expiry of the
hrtimer with the next timer interrupt on the target cpu and migrate the
hrtimer only if it expires *after* the next interrupt on the target cpu.
So, added a clockevents_get_next_event() helper function to return the
next_event on the target cpu's clock_event_device.

[ tglx: cleanups and simplifications ]

Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-05-13 16:52:42 +02:00
Arun R Bharadwaj 597d027573 timers: Framework for identifying pinned timers
* Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-04-16 12:11:36]:

This patch creates a new framework for identifying cpu-pinned timers
and hrtimers.

This framework is needed because pinned timers are expected to fire on
the same CPU on which they are queued. So it is essential to identify
these and not migrate them, in case there are any.

For regular timers, the currently existing add_timer_on() can be used
queue pinned timers and subsequently mod_timer_pinned() can be used
to modify the 'expires' field.

For hrtimers, new modes HRTIMER_ABS_PINNED and HRTIMER_REL_PINNED are
added to queue cpu-pinned hrtimer.

[ tglx: use .._PINNED mode argument instead of creating tons of new
functions ]

Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-05-13 16:52:42 +02:00
Jon Hunter a041988876 timers: allow deferrable timers for intervals tv2-tv5 to be deferred
In the current kernel implementation only kernel timers for time interval
tv1 are being deferred. This patch allows any timer that is configured as
deferrable to be defer regardless of time interval.

This patch was previously discussed in
http://marc.info/?l=linux-kernel&m=123196343531966&w=2 and was acked by
Venki Pallipadi, the author of the original deferrable timer patch.

Signed-off-by: Jon Hunter <jon-hunter@ti.com>
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-05-02 10:36:06 +02:00
Ingo Molnar e7fd5d4b3d Merge branch 'linus' into perfcounters/core
Merge reason: This brach was on -rc1, refresh it to almost-rc4 to pick up
              the latest upstream fixes.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-29 14:47:05 +02:00
Linus Torvalds 422a253483 Merge branches 'core-fixes-for-linus', 'irq-fixes-for-linus' and 'timers-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:
  printk: fix wrong format string iter for printk
  futex: comment requeue key reference semantics

* 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  irq: fix cpumask memory leak on offstack cpumask kernels

* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  posix-timers: fix RLIMIT_CPU && setitimer(CPUCLOCK_PROF)
  posix-timers: fix RLIMIT_CPU && fork()
  timers: add missing kernel-doc
2009-04-09 10:35:30 -07:00
Peter Zijlstra 925d519ab8 perf_counter: unify and fix delayed counter wakeup
While going over the wakeup code I noticed delayed wakeups only work
for hardware counters but basically all software counters rely on
them.

This patch unifies and generalizes the delayed wakeup to fix this
issue.

Since we're dealing with NMI context bits here, use a cmpxchg() based
single link list implementation to track counters that have pending
wakeups.

[ This should really be generic code for delayed wakeups, but since we
  cannot use cmpxchg()/xchg() in generic code, I've let it live in the
  perf_counter code. -- Eric Dumazet could use it to aggregate the
  network wakeups. ]

Furthermore, the x86 method of using TIF flags was flawed in that its
quite possible to end up setting the bit on the idle task, loosing the
wakeup.

The powerpc method uses per-cpu storage and does appear to be
sufficient.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Paul Mackerras <paulus@samba.org>
Orig-LKML-Reference: <20090330171023.153932974@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-06 09:30:36 +02:00
Randy Dunlap 633fe795b8 timers: add missing kernel-doc
Add missing kernel-doc parameter notation and change function
name to its new name:

  Warning(kernel/timer.c:543): No description found for parameter 'name'
  Warning(kernel/timer.c:543): No description found for parameter 'key'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: akpm <akpm@linux-foundation.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
LKML-Reference: <20090401174723.f0bea0eb.randy.dunlap@oracle.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-02 05:54:00 +02:00
Linus Torvalds c4e1aa67ed Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (33 commits)
  lockdep: fix deadlock in lockdep_trace_alloc
  lockdep: annotate reclaim context (__GFP_NOFS), fix SLOB
  lockdep: annotate reclaim context (__GFP_NOFS), fix
  lockdep: build fix for !PROVE_LOCKING
  lockstat: warn about disabled lock debugging
  lockdep: use stringify.h
  lockdep: simplify check_prev_add_irq()
  lockdep: get_user_chars() redo
  lockdep: simplify get_user_chars()
  lockdep: add comments to mark_lock_irq()
  lockdep: remove macro usage from mark_held_locks()
  lockdep: fully reduce mark_lock_irq()
  lockdep: merge the !_READ mark_lock_irq() helpers
  lockdep: merge the _READ mark_lock_irq() helpers
  lockdep: simplify mark_lock_irq() helpers #3
  lockdep: further simplify mark_lock_irq() helpers
  lockdep: simplify the mark_lock_irq() helpers
  lockdep: split up mark_lock_irq()
  lockdep: generate usage strings
  lockdep: generate the state bit definitions
  ...
2009-03-30 17:17:35 -07:00
Ingo Molnar 74019224ac timers: add mod_timer_pending()
Impact: new timer API

Based on an idea from Martin Josefsson with the help of
Patrick McHardy and Stephen Hemminger:

introduce the mod_timer_pending() API which is a mod_timer()
offspring that is an invariant on already removed timers.

(regular mod_timer() re-activates non-pending timers.)

This is useful for the networking code in that it can
allow unserialized mod_timer_pending() timer-forwarding
calls, but a single del_timer*() will stop the timer
from being reactivated again.

Also while at it:

- optimize the regular mod_timer() path some more, the
  timer-stat and a debug check was needlessly duplicated
  in __mod_timer().

- make the exports come straight after the function, as
  most other exports in timer.c already did.

- eliminate __mod_timer() as an external API, change the
  users to mod_timer().

The regular mod_timer() code path is not impacted
significantly, due to inlining optimizations and due to
the simplifications.

Based-on-patch-from: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>
Cc: netdev@vger.kernel.org
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-18 19:26:33 +01:00
Johannes Berg 6f2b9b9a9d timer: implement lockdep deadlock detection
This modifies the timer code in a way to allow lockdep to detect
deadlocks resulting from a lock being taken in the timer function
as well as around the del_timer_sync() call.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
2009-02-14 23:25:52 +01:00
Heiko Carstens 1e7bfb2134 [CVE-2009-0029] System call wrappers part 27
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:29 +01:00
Heiko Carstens dbf040d9d1 [CVE-2009-0029] System call wrappers part 02
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:19 +01:00
Heiko Carstens 58fd3aa288 [CVE-2009-0029] System call wrappers part 01
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:18 +01:00
Heiko Carstens 2ed7c03ec1 [CVE-2009-0029] Convert all system calls to return a long
Convert all system calls to return a long. This should be a NOP since all
converted types should have the same size anyway.
With the exception of sys_exit_group which returned void. But that doesn't
matter since the system call doesn't return.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:14 +01:00
Martin Schwidefsky 79741dd357 [PATCH] idle cputime accounting
The cpu time spent by the idle process actually doing something is
currently accounted as idle time. This is plain wrong, the architectures
that support VIRT_CPU_ACCOUNTING=y can do better: distinguish between the
time spent doing nothing and the time spent by idle doing work. The first
is accounted with account_idle_time and the second with account_system_time.
The architectures that use the account_xxx_time interface directly and not
the account_xxx_ticks interface now need to do the check for the idle
process in their arch code. In particular to improve the system vs true
idle time accounting the arch code needs to measure the true idle time
instead of just testing for the idle process.
To improve the tick based accounting as well we would need an architecture
primitive that can tell us if the pt_regs of the interrupted context
points to the magic instruction that halts the cpu.

In addition idle time is no more added to the stime of the idle process.
This field now contains the system time of the idle process as it should
be. On systems without VIRT_CPU_ACCOUNTING this will always be zero as
every tick that occurs while idle is running will be accounted as idle
time.

This patch contains the necessary common code changes to be able to
distinguish idle system time and true idle time. The architectures with
support for VIRT_CPU_ACCOUNTING need some changes to exploit this.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-31 15:11:46 +01:00
Martin Schwidefsky 457533a7d3 [PATCH] fix scaled & unscaled cputime accounting
The utimescaled / stimescaled fields in the task structure and the
global cpustat should be set on all architectures. On s390 the calls
to account_user_time_scaled and account_system_time_scaled never have
been added. In addition system time that is accounted as guest time
to the user time of a process is accounted to the scaled system time
instead of the scaled user time.
To fix the bugs and to prevent future forgetfulness this patch merges
account_system_time_scaled into account_system_time and
account_user_time_scaled into account_user_time.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Michael Neuling <mikey@neuling.org>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-31 15:11:46 +01:00
James Morris 2b82892565 Merge branch 'master' into next
Conflicts:
	security/keys/internal.h
	security/keys/process_keys.c
	security/keys/request_key.c

Fixed conflicts above by using the non 'tsk' versions.

Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 11:29:12 +11:00
David Howells 76aac0e9a1 CRED: Wrap task credential accesses in the core kernel
Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.

Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-audit@redhat.com
Cc: containers@lists.linux-foundation.org
Cc: linux-mm@kvack.org
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:12 +11:00
Alan Stern 9c133c469d Add round_jiffies_up and related routines
This patch (as1158b) adds round_jiffies_up() and friends.  These
routines work like the analogous round_jiffies() functions, except
that they will never round down.

The new routines will be useful for timeouts where we don't care
exactly when the timer expires, provided it doesn't expire too soon.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-11-06 08:42:48 +01:00
Thomas Gleixner c465a76af6 Merge branches 'timers/clocksource', 'timers/hrtimers', 'timers/nohz', 'timers/ntp', 'timers/posixtimers' and 'timers/debug' into v28-timers-for-linus 2008-10-20 13:14:06 +02:00
Oleg Nesterov d82f0b0f6f migrate_timers: add comment, use spinlock_irq()
Add the comment to explain why the double lock in migrate_timers()
can't deadlock.

Change the code to use spinlock_irq() instead of local_irq_disable()
+ spin_lock().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-21 13:34:54 +02:00
Peter Zijlstra b845b517b5 printk: robustify printk
Avoid deadlocks against rq->lock and xtime_lock by deferring the klogd
wakeup by polling from the timer tick.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-11 13:46:53 +02:00
Linus Torvalds 85082fd7cb Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm
* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (241 commits)
  [ARM] 5171/1: ep93xx: fix compilation of modules using clocks
  [ARM] 5133/2: at91sam9g20 defconfig file
  [ARM] 5130/4: Support for the at91sam9g20
  [ARM] 5160/1: IOP3XX: gpio/gpiolib support
  [ARM] at91: Fix NAND FLASH timings for at91sam9x evaluation kits.
  [ARM] 5084/1: zylonite: Register AC97 device
  [ARM] 5085/2: PXA: Move AC97 over to the new central device declaration model
  [ARM] 5120/1: pxa: correct platform driver names for PXA25x and PXA27x UDC drivers
  [ARM] 5147/1: pxaficp_ir: drop pxa_gpio_mode calls, as pin setting
  [ARM] 5145/1: PXA2xx: provide api to control IrDA pins state
  [ARM] 5144/1: pxaficp_ir: cleanup includes
  [ARM] pxa: remove pxa_set_cken()
  [ARM] pxa: allow clk aliases
  [ARM] Feroceon: don't disable BPU on boot
  [ARM] Orion: LED support for HP mv2120
  [ARM] Orion: add RD88F5181L-FXO support
  [ARM] Orion: add RD88F5181L-GE support
  [ARM] Orion: add Netgear WNR854T support
  [ARM] s3c2410_defconfig: update for current build
  [ARM] Acer n30: Minor style and indentation fixes.
  ...
2008-07-14 16:06:58 -07:00
Carlos R. Mafra 962cf36c5b Remove argument from open_softirq which is always NULL
As git-grep shows, open_softirq() is always called with the last argument
being NULL

block/blk-core.c:       open_softirq(BLOCK_SOFTIRQ, blk_done_softirq, NULL);
kernel/hrtimer.c:       open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq, NULL);
kernel/rcuclassic.c:    open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL);
kernel/rcupreempt.c:    open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL);
kernel/sched.c: open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL);
kernel/softirq.c:       open_softirq(TASKLET_SOFTIRQ, tasklet_action, NULL);
kernel/softirq.c:       open_softirq(HI_SOFTIRQ, tasklet_hi_action, NULL);
kernel/timer.c: open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);
net/core/dev.c: open_softirq(NET_TX_SOFTIRQ, net_tx_action, NULL);
net/core/dev.c: open_softirq(NET_RX_SOFTIRQ, net_rx_action, NULL);

This observation has already been made by Matthew Wilcox in June 2002
(http://www.cs.helsinki.fi/linux/linux-kernel/2002-25/0687.html)

"I notice that none of the current softirq routines use the data element
passed to them."

and the situation hasn't changed since them. So it appears we can safely
remove that extra argument to save 128 (54) bytes of kernel data (text).

Signed-off-by: Carlos R. Mafra <crmafra@ift.unesp.br>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-25 07:43:15 +02:00
Russell King ee9c578527 dyntick: Remove last reminants of dyntick support
Remove the last reminants of dyntick support from the generic kernel.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-05-12 17:39:14 +01:00
Thomas Gleixner c6f3a97f86 debugobjects: add timer specific object debugging code
Add calls to the generic object debugging infrastructure and provide fixup
functions which allow to keep the system alive when recoverable problems have
been detected by the object debugging core code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Greg KH <greg@kroah.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 08:29:53 -07:00
Oleg Nesterov 0d180406f2 timers: simplify lockdep handling
In order to avoid the false positive from lockdep, each per-cpu base->lock has
the separate lock class and migrate_timers() uses double_spin_lock().

This all is overcomplicated: except for migrate_timers() we never take 2 locks
at once, and migrate_timers() can use spin_lock_nested().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-04-17 12:22:31 +02:00
Thomas Gleixner 06d8308c61 NOHZ: reevaluate idle sleep length after add_timer_on()
add_timer_on() can add a timer on a CPU which is currently in a long
idle sleep, but the timer wheel is not reevaluated by the nohz code on
that CPU. So a timer can be delayed for quite a long time. This
triggered a false positive in the clocksource watchdog code.

To avoid this we need to wake up the idle CPU and enforce the
reevaluation of the timer wheel for the next timer event.

Add a function, which checks a given CPU for idle state, marks the
idle task with NEED_RESCHED and sends a reschedule IPI to notify the
other CPU of the change in the timer wheel.

Call this function from add_timer_on().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: stable@kernel.org

--
 include/linux/sched.h |    6 ++++++
 kernel/sched.c        |   43 +++++++++++++++++++++++++++++++++++++++++++
 kernel/timer.c        |   10 +++++++++-
 3 files changed, 58 insertions(+), 1 deletion(-)
2008-03-26 08:28:55 +01:00
Harvey Harrison 7ad5b3a505 kernel: remove fastcall in kernel/*
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:31 -08:00
Pavel Emelyanov 6c5f3e7b43 Pidns: make full use of xxx_vnr() calls
Some time ago the xxx_vnr() calls (e.g.  pid_vnr or find_task_by_vpid) were
_all_ converted to operate on the current pid namespace.  After this each call
like xxx_nr_ns(foo, current->nsproxy->pid_ns) is nothing but a xxx_vnr(foo)
one.

Switch all the xxx_nr_ns() callers to use the xxx_vnr() calls where
appropriate.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Reviewed-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:29 -08:00
Michael Neuling 06b8e878a9 taskstats scaled time cleanup
This moves the ability to scale cputime into generic code.  This allows us
to fix the issue in kernel/timer.c (noticed by Balbir) where we could only
add an unscaled value to the scaled utime/stime.

This adds a cputime_to_scaled function.  As before, the POWERPC version
does the scaling based on the last SPURR/PURR ratio calculated.  The
generic and s390 (only other arch to implement asm/cputime.h) versions are
both NOPs.

Also moves the SPURR and PURR snapshots closer.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Cc: Jay Lan <jlan@engr.sgi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06 10:41:00 -08:00
Linus Torvalds 75659ca0c1 Merge branch 'task_killable' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc
* 'task_killable' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc: (22 commits)
  Remove commented-out code copied from NFS
  NFS: Switch from intr mount option to TASK_KILLABLE
  Add wait_for_completion_killable
  Add wait_event_killable
  Add schedule_timeout_killable
  Use mutex_lock_killable in vfs_readdir
  Add mutex_lock_killable
  Use lock_page_killable
  Add lock_page_killable
  Add fatal_signal_pending
  Add TASK_WAKEKILL
  exit: Use task_is_*
  signal: Use task_is_*
  sched: Use task_contributes_to_load, TASK_ALL and TASK_NORMAL
  ptrace: Use task_is_*
  power: Use task_is_*
  wait: Use TASK_NORMAL
  proc/base.c: Use task_is_*
  proc/array.c: Use TASK_REPORT
  perfmon: Use task_is_*
  ...

Fixed up conflicts in NFS/sunrpc manually..
2008-02-01 11:45:47 +11:00
Pavel Machek 4c9dc64122 time: timer cleanups
Small cleanups to tick-related code. Wrong preempt count is followed
by BUG(), so it is hardly KERN_WARNING.

Signed-off-by: Pavel Machek <pavel@suse.cz>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:30:00 +01:00
Pavel Machek a6fa8e5a61 time: clean hungarian notation from timers
Clean up hungarian notation from timer code.

Signed-off-by: Pavel Machek <pavel@suse.cz>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:30:00 +01:00
Peter Zijlstra d3d74453c3 hrtimer: fixup the HRTIMER_CB_IRQSAFE_NO_SOFTIRQ fallback
Currently all highres=off timers are run from softirq context, but
HRTIMER_CB_IRQSAFE_NO_SOFTIRQ timers expect to run from irq context.

Fix this up by splitting it similar to the highres=on case.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-01-25 21:08:31 +01:00
Randy Dunlap 48ccf3dac3 timer: fix section mismatch
The caller is __cpuinit.
Also, this code block and its caller are inside #ifdef CONFIG_HOTPLUG_CPU
blocks, so this code should reflect that config symbol's usage.

WARNING: vmlinux.o(.text+0x4252f): Section mismatch: reference to .init.text: (between 'timer_cpu_notify' and 'msleep')

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@akpm@linux-foundation.org>
2008-01-21 19:39:41 -08:00
Roland McGrath 84427eaef1 remove task_ppid_nr_ns
task_ppid_nr_ns is called in three places.  One of these should never
have called it.  In the other two, using it broke the existing
semantics.  This was presumably accidental.  If the function had not
been there, it would have been much more obvious to the eye that those
patches were changing the behavior.  We don't need this function.

In task_state, the pid of the ptracer is not the ppid of the ptracer.

In do_task_stat, ppid is the tgid of the real_parent, not its pid.
I also moved the call outside of lock_task_sighand, since it doesn't
need it.

In sys_getppid, ppid is the tgid of the real_parent, not its pid.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-01-13 09:56:43 -08:00
Adrian Bunk b4be625852 timer: kernel/timer.c section fixes
This patch fixes the following section mismatches with CONFIG_HOTPLUG=n,
CONFIG_HOTPLUG_CPU=y:

...
WARNING: vmlinux.o(.text+0x41cd3): Section mismatch: reference to .init.data:tvec_base_done.22610 (between 'timer_cpu_notify' and 'run_timer_softirq')
WARNING: vmlinux.o(.text+0x41d67): Section mismatch: reference to .init.data:tvec_base_done.22610 (between 'timer_cpu_notify' and 'run_timer_softirq')
...

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2007-12-18 18:05:58 +01:00
Matthew Wilcox 294d5cc233 Add schedule_timeout_killable
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
2007-12-06 17:40:07 -05:00
Paul Mackerras fa13a5a1f2 sched: restore deterministic CPU accounting on powerpc
Since powerpc started using CONFIG_GENERIC_CLOCKEVENTS, the
deterministic CPU accounting (CONFIG_VIRT_CPU_ACCOUNTING) has been
broken on powerpc, because we end up counting user time twice: once in
timer_interrupt() and once in update_process_times().

This fixes the problem by pulling the code in update_process_times
that updates utime and stime into a separate function called
account_process_tick.  If CONFIG_VIRT_CPU_ACCOUNTING is not defined,
there is a version of account_process_tick in kernel/timer.c that
simply accounts a whole tick to either utime or stime as before.  If
CONFIG_VIRT_CPU_ACCOUNTING is defined, then arch code gets to
implement account_process_tick.

This also lets us simplify the s390 code a bit; it means that the s390
timer interrupt can now call update_process_times even when
CONFIG_VIRT_CPU_ACCOUNTING is turned on, and can just implement a
suitable account_process_tick().

account_process_tick() now takes the task_struct * as an argument.
Tested both with and without CONFIG_VIRT_CPU_ACCOUNTING.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-11-09 22:39:38 +01:00
Li Zefan 8dce39c231 time: fix inconsistent function names in comments
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-11-05 15:12:33 -08:00
Pavel Emelyanov b488893a39 pid namespaces: changes to show virtual ids to user
This is the largest patch in the set. Make all (I hope) the places where
the pid is shown to or get from user operate on the virtual pids.

The idea is:
 - all in-kernel data structures must store either struct pid itself
   or the pid's global nr, obtained with pid_nr() call;
 - when seeking the task from kernel code with the stored id one
   should use find_task_by_pid() call that works with global pids;
 - when showing pid's numerical value to the user the virtual one
   should be used, but however when one shows task's pid outside this
   task's namespace the global one is to be used;
 - when getting the pid from userspace one need to consider this as
   the virtual one and use appropriate task/pid-searching functions.

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: nuther build fix]
[akpm@linux-foundation.org: yet nuther build fix]
[akpm@linux-foundation.org: remove unneeded casts]
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:40 -07:00
Michael Neuling c66f08be7e Add scaled time to taskstats based process accounting
This adds items to the taststats struct to account for user and system
time based on scaling the CPU frequency and instruction issue rates.

Adds account_(user|system)_time_scaled callbacks which architectures
can use to account for time using this mechanism.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-18 14:37:28 -07:00
Daniel Walker 5b4db0c2f2 whitespace fixes: system timers
Signed-off-by: Daniel Walker <dwalker@mvista.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-18 14:37:26 -07:00
Tony Luck c36c282b88 Pull ia64-clocksource into release branch 2007-07-20 11:26:47 -07:00
Bob Picco 1f564ad6d4 [IA64] remove time interpolator
Remove time_interpolator code (This is generic code, but
only user was ia64.  It has been superseded by the
CONFIG_GENERIC_TIME code).

Signed-off-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Peter Keilty <peter.keilty@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2007-07-20 11:23:02 -07:00
Thomas Gleixner 6819457d2c timer.c: cleanup recently introduced whitespace damage
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 10:04:52 -07:00
Christoph Lameter 94f6030ca7 Slab allocators: Replace explicit zeroing with __GFP_ZERO
kmalloc_node() and kmem_cache_alloc_node() were not available in a zeroing
variant in the past.  But with __GFP_ZERO it is possible now to do zeroing
while allocating.

Use __GFP_ZERO to remove the explicit clearing of memory via memset whereever
we can.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 10:23:02 -07:00
Venki Pallipadi c5c061b8f9 Add a flag to indicate deferrable timers in /proc/timer_stats
Add a flag in /proc/timer_stats to indicate deferrable timers.  This will
let developers/users to differentiate between types of tiemrs in
/proc/timer_stats.

Deferrable timer and normal timer will appear in /proc/timer_stats as below.
  10D,     1 swapper          queue_delayed_work_on (delayed_work_timer_fn)
   10,     1 swapper          queue_delayed_work_on (delayed_work_timer_fn)

Also version of timer_stats changes from v0.1 to v0.2

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:45 -07:00
Tomas Janousek d62141414a Use boot based time for uptime in /proc
Commit 411187fb05 caused uptime not to increase
during suspend.  This may cause confusion so I restore the old behaviour by
using the boot based time instead of monotonic for uptime.

Signed-off-by: Tomas Janousek <tjanouse@redhat.com>
Acked-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:41 -07:00
Thomas Gleixner eaad084bb0 NOHZ: prevent multiplication overflow - stop timer for huge timeouts
get_next_timer_interrupt() returns a delta of (LONG_MAX > 1) in case
there is no timer pending. On 64 bit machines this results in a
multiplication overflow in tick_nohz_stop_sched_tick().

Reported by: Dave Miller <davem@davemloft.net>

Make the return value a constant and limit the return value to a 32 bit
value.

When the max timeout value is returned, we can safely stop the tick
timer device. The max jiffies delta results in a 12 days timeout for
HZ=1000.

In the long term the get_next_timer_interrupt() code needs to be
reworked to return ktime instead of jiffies, but we have to wait until
the last users of the original NO_IDLE_HZ code are converted.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-29 18:11:10 -07:00
Thomas Gleixner d10ff3fb62 timekeeping fix patch got mis-applied
The time keeping code move to kernel/time/timekeeping.c broke the
clocksource resume logic patch, which got applied to the old file by a
fuzzy application.  Fix it up and move the clocksource_resume() call to
the appropriate place.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[ tssk, tssk, everybody should use --fuzz=0 ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-14 12:13:11 -07:00
akpm@linux-foundation.org e9910846fd timer: revert parenthesis fix in tbase_get_deferrable() etc
On 09-05-2007 21:10, Pallipadi, Venkatesh wrote:
...
> On a 64 bit system, converting pointer to int causes unnecessary
> compiler warning, and intermediate long conversion was to avoid that.
> I will have to rephrase my comment to remove 32 bit value and use int,
> as that is what the function returns.

So, this patch reverts all changes done by my previous patch.

I apologize for my wrong comment about "logical error" here.

Cc: "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>
Cc: Satyam Sharma <satyam.sharma@gmail.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-10 09:26:53 -07:00
Thomas Gleixner b52f52a093 clocksource: fix resume logic
We need to make sure that the clocksources are resumed, when timekeeping is
resumed.  The current resume logic does not guarantee this.

Add a resume function pointer to the clocksource struct, so clocksource
drivers which need to reinitialize the clocksource can provide a resume
function.

Add a resume function, which calls the maybe available clocksource resume
functions and resets the watchdog function, so a stable TSC can be used
accross suspend/resume.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:56 -07:00
Rafael J. Wysocki 8bb7844286 Add suspend-related notifications for CPU hotplug
Since nonboot CPUs are now disabled after tasks and devices have been
frozen and the CPU hotplug infrastructure is used for this purpose, we need
special CPU hotplug notifications that will help the CPU-hotplug-aware
subsystems distinguish normal CPU hotplug events from CPU hotplug events
related to a system-wide suspend or resume operation in progress.  This
patch introduces such notifications and causes them to be used during
suspend and resume transitions.  It also changes all of the
CPU-hotplug-aware subsystems to take these notifications into consideration
(for now they are handled in the same way as the corresponding "normal"
ones).

[oleg@tv-sign.ru: cleanups]
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:56 -07:00
Jarek Poplawski 38a23e311b timer: parenthesis fix in tbase_get_deferrable() etc
Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:55 -07:00
Pavel Emelianov b5e618181a Introduce a handy list_first_entry macro
There are many places in the kernel where the construction like

   foo = list_entry(head->next, struct foo_struct, list);

are used.
The code might look more descriptive and neat if using the macro

   list_first_entry(head, type, member) \
             list_entry((head)->next, type, member)

Here is the macro itself and the examples of its usage in the generic code.
 If it will turn out to be useful, I can prepare the set of patches to
inject in into arch-specific code, drivers, networking, etc.

Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Zach Brown <zach.brown@oracle.com>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:11 -07:00
john stultz 8524070b79 Move timekeeping code to timekeeping.c
Move the timekeeping code out of kernel/timer.c and into
kernel/time/timekeeping.c.  I made no cleanups or other changes in transit.

[akpm@linux-foundation.org: build fix]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:06 -07:00
Venki Pallipadi 6e453a6751 Add support for deferrable timers
Introduce a new flag for timers - deferrable: Timers that work normally
when system is busy.  But, will not cause CPU to come out of idle (just to
service this timer), when CPU is idle.  Instead, this timer will be
serviced when CPU eventually wakes up with a subsequent non-deferrable
timer.

The main advantage of this is to avoid unnecessary timer interrupts when
CPU is idle.  If the routine currently called by a timer can wait until
next event without any issues, this new timer can be used to setup timer
event for that routine.  This, with dynticks, allows CPUs to be lazy,
allowing them to stay in idle for extended period of time by reducing
unnecesary wakeup and thereby reducing the power consumption.

This patch:

Builds this new timer on top of existing timer infrastructure.  It uses
last bit in 'base' pointer of timer_list structure to store this deferrable
timer flag.  __next_timer_interrupt() function skips over these deferrable
timers when CPU looks for next timer event for which it has to wake up.

This is exported by a new interface init_timer_deferrable() that can be
called in place of regular init_timer().

[akpm@linux-foundation.org: Privatise a #define]
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:05 -07:00
David Howells e19dff1fdd [AF_RXRPC]: Make it possible to merely try to cancel timers from a module
Export try_to_del_timer_sync() for use by the AF_RXRPC module.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-26 15:46:56 -07:00
Ingo Molnar 995f054f2a [PATCH] high-res timers: resume fix
Soeren Sonnenburg reported that upon resume he is getting
this backtrace:

 [<c0119637>] smp_apic_timer_interrupt+0x57/0x90
 [<c0142d30>] retrigger_next_event+0x0/0xb0
 [<c0104d30>] apic_timer_interrupt+0x28/0x30
 [<c0142d30>] retrigger_next_event+0x0/0xb0
 [<c0140068>] __kfifo_put+0x8/0x90
 [<c0130fe5>] on_each_cpu+0x35/0x60
 [<c0143538>] clock_was_set+0x18/0x20
 [<c0135cdc>] timekeeping_resume+0x7c/0xa0
 [<c02aabe1>] __sysdev_resume+0x11/0x80
 [<c02ab0c7>] sysdev_resume+0x47/0x80
 [<c02b0b05>] device_power_up+0x5/0x10

it turns out that on resume we mistakenly re-enable interrupts too
early.  Do the timer retrigger only on the current CPU.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Soeren Sonnenburg <kernel@nn7.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-04-07 10:03:43 -07:00
Thomas Gleixner 9501b6cf55 [PATCH] dynticks: fix hrtimer rounding error in next_timer_interrupt
The rework of next_timer_interrupt() fixed the timer wheel bugs, but
invented a rounding error versus the next hrtimer event. This is caused
by the conversion of the hrtimer internal representation to relative
jiffies.

This causes bug #8100:
http://bugzilla.kernel.org/show_bug.cgi?id=8100

next_timer_interrupt() returns "now" in such a case and causes the code
in tick_nohz_stop_sched_tick() to trigger the timer softirq, which is
bogus as no timer is due for expiry. This results in an endless context
switching between idle and ksoftirqd until a timer is due for expiry.

Modify the hrtimer evaluation so that, it returns now + 1, when the
conversion results in a delta < 1 jiffie.

It's confirmed to resolve bug #8100

Reported-by: Emil Karlson <jkarlson@cc.hut.fi>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-25 14:57:34 -07:00
Daniel Walker 90675a27fa [PATCH] fix vsyscall settimeofday
I've only seen this on x86_64.

The vsyscall state only gets updated when a timer interrupts comes in.  So
if the time is set long before the next timer, there will be a period when
a gettimeofday() won't reflect the correct time.

I added an explicit update_vsyscall() during the settimeofday(), that way
the vsyscall state doesn't get stale.

Signed-off-by: Daniel Walker <dwalker@mvista.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-06 09:30:25 -08:00
Thomas Gleixner 6321dd60c7 [PATCH] Save/restore periodic tick information over suspend/resume
The programming of periodic tick devices needs to be saved/restored
across suspend/resume - otherwise we might end up with a system coming
up that relies on getting a PIT (or HPET) interrupt, while those devices
default to 'no interrupts' after powerup. (To confuse things it worked
to a certain degree on some systems because the lapic gets initialized
as a side-effect of SMP bootup.)

This suspend / resume thing was dropped unintentionally during the
last-minute -mm code reshuffling.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-06 09:30:24 -08:00
Heiko Carstens e81ce1f7ec [PATCH] timer/hrtimer: take per cpu locks in sane order
Doing something like this on a two cpu system

  # echo 0 > /sys/devices/system/cpu/cpu0/online
  # echo 1 > /sys/devices/system/cpu/cpu0/online
  # echo 0 > /sys/devices/system/cpu/cpu1/online

will give me this:

  =======================================================
  [ INFO: possible circular locking dependency detected ]
  2.6.21-rc2-g562aa1d4-dirty #7
  -------------------------------------------------------
  bash/1282 is trying to acquire lock:
   (&cpu_base->lock_key){.+..}, at: [<000000000005f17e>] hrtimer_cpu_notify+0xc6/0x240

  but task is already holding lock:
   (&cpu_base->lock_key#2){.+..}, at: [<000000000005f174>] hrtimer_cpu_notify+0xbc/0x240

  which lock already depends on the new lock.

This happens because we have the following code in kernel/hrtimer.c:

  migrate_hrtimers(int cpu)
  [...]
  old_base = &per_cpu(hrtimer_bases, cpu);
  new_base = &get_cpu_var(hrtimer_bases);
  [...]
  spin_lock(&new_base->lock);
  spin_lock(&old_base->lock);

Which means the spinlocks are taken in an order which depends on which cpu
gets shut down from which other cpu. Therefore lockdep complains that there
might be an ABBA deadlock. Since migrate_hrtimers() gets only called on
cpu hotplug it's safe to assume that it isn't executed concurrently on a

The same problem exists in kernel/timer.c: migrate_timers().

As pointed out by Christian Borntraeger one possible solution to avoid
the locking order complaints would be to make sure that the locks are
always taken in the same order. E.g. by taking the lock of the cpu with
the lower number first.

To achieve this we introduce two new spinlock functions double_spin_lock
and double_spin_unlock which lock or unlock two locks in a given order.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Christian Borntraeger <cborntra@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-05 07:57:53 -08:00
Randy Dunlap 05fb6bf0b2 [PATCH] kernel-doc fixes for 2.6.20-git15 (non-drivers)
Fix kernel-doc warnings in 2.6.20-git15 (lib/, mm/, kernel/, include/).

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-01 14:53:37 -08:00
Daniel Walker 9d63463114 [PATCH] update timekeeping_is_continuous comment
Signed-off-by: Daniel Walker <dwalker@mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-01 14:53:36 -08:00