linux-toradex.git/kernel/sched/clock.c, branch v4.9.16

sched/clock: Make local_clock()/cpu_clock() inline

2016-04-13T10:25:22+00:00

The local_clock/cpu_clock functions were changed to prevent a double
identical test with sched_clock_cpu() when HAVE_UNSTABLE_SCHED_CLOCK
is set. That resulted in one line functions.

As these functions are in all the cases one line functions and in the
hot path, it is useful to specify them as static inline in order to
give a strong hint to the compiler.

After verification, it appears the compiler does not inline them
without this hint. Change those functions to static inline.

sched_clock_cpu() is called via the inlined local_clock()/cpu_clock()
functions from sched.h. So any module code including sched.h will
reference sched_clock_cpu(). Thus it must be exported with the
EXPORT_SYMBOL_GPL macro.

Signed-off-by: Daniel Lezcano 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/1460385514-14700-2-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar

sched/clock: Remove pointless test in cpu_clock/local_clock

2016-04-13T10:25:22+00:00

In case the HAVE_UNSTABLE_SCHED_CLOCK config is set, the cpu_clock() version
checks if sched_clock_stable() is not set and calls sched_clock_cpu(),
otherwise it calls sched_clock().

sched_clock_cpu() checks also if sched_clock_stable() is set and, if true,
calls sched_clock().

sched_clock() will be called in sched_clock_cpu() if sched_clock_stable() is
true.

Remove the duplicate test by directly calling sched_clock_cpu() and let the
static key act in this function instead.

Signed-off-by: Daniel Lezcano 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/1460385514-14700-1-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar

sched-clock: Migrate to use new tick dependency mask model

2016-03-02T15:44:57+00:00

Instead of checking sched_clock_stable from the nohz subsystem to verify
its tick dependency, migrate it to the new mask in order to include it
to the all-in-one check.

Reviewed-by: Chris Metcalf 
Cc: Christoph Lameter 
Cc: Chris Metcalf 
Cc: Ingo Molnar 
Cc: Luiz Capitulino 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Thomas Gleixner 
Cc: Viresh Kumar 
Signed-off-by: Frederic Weisbecker

Merge branch 'for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

2016-01-12T02:53:13+00:00

Pull workqueue update from Tejun Heo:
 "Workqueue changes for v4.5.  One cleanup patch and three to improve
  the debuggability.

  Workqueue now has a stall detector which dumps workqueue state if any
  worker pool hasn't made forward progress over a certain amount of time
  (30s by default) and also triggers a warning if a workqueue which can
  be used in memory reclaim path tries to wait on something which can't
  be.

  These should make workqueue hangs a lot easier to debug."

* 'for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: simplify the apply_workqueue_attrs_locked()
  workqueue: implement lockup detector
  watchdog: introduce touch_softlockup_watchdog_sched()
  workqueue: warn if memory reclaim tries to flush !WQ_MEM_RECLAIM workqueue

watchdog: introduce touch_softlockup_watchdog_sched()

2015-12-08T16:29:42+00:00

touch_softlockup_watchdog() is used to tell watchdog that scheduler
stall is expected.  One group of usage is from paths where the task
may not be able to yield for a long time such as performing slow PIO
to finicky device and coming out of suspend.  The other is to account
for scheduler and timer going idle.

For scheduler softlockup detection, there's no reason to distinguish
the two cases; however, workqueue lockup detector is planned and it
can use the same signals from the former group while the latter would
spuriously prevent detection.  This patch introduces a new function
touch_softlockup_watchdog_sched() and convert the latter group to call
it instead.  For now, it just calls touch_softlockup_watchdog() and
there's no functional difference.

Signed-off-by: Tejun Heo 
Cc: Ulrich Obergfell 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Andrew Morton

treewide: Remove old email address

2015-11-23T08:44:58+00:00

There were still a number of references to my old Red Hat email
address in the kernel source. Remove these while keeping the
Red Hat copyright notices intact.

Signed-off-by: Peter Zijlstra (Intel) 
Cc: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Thomas Gleixner 
Cc: Vince Weaver 
Signed-off-by: Ingo Molnar

kernel/sched/clock.c: add another clock for use with the soft lockup watchdog

2015-02-13T02:54:13+00:00

When the hypervisor pauses a virtualised kernel the kernel will observe a
jump in timebase, this can cause spurious messages from the softlockup
detector.

Whilst these messages are harmless, they are accompanied with a stack
trace which causes undue concern and more problematically the stack trace
in the guest has nothing to do with the observed problem and can only be
misleading.

Futhermore, on POWER8 this is completely avoidable with the introduction
of the Virtual Time Base (VTB) register.

This patch (of 2):

This permits the use of arch specific clocks for which virtualised kernels
can use their notion of 'running' time, not the elpased wall time which
will include host execution time.

Signed-off-by: Cyril Bur 
Cc: Michael Ellerman 
Cc: Andrew Jones 
Acked-by: Don Zickus 
Cc: Ingo Molnar 
Cc: Ulrich Obergfell 
Cc: chai wen 
Cc: Fabian Frederick 
Cc: Aaron Tomlin 
Cc: Ben Zhang 
Cc: Martin Schwidefsky 
Cc: John Stultz 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

time: Replace __get_cpu_var uses

2014-08-26T17:45:44+00:00

Convert uses of __get_cpu_var for creating a address from a percpu
offset to this_cpu_ptr.

The two cases where get_cpu_var is used to actually access a percpu
variable are changed to use this_cpu_read/raw_cpu_read.

Reviewed-by: Thomas Gleixner 
Signed-off-by: Christoph Lameter 
Signed-off-by: Tejun Heo

kernel: use macros from compiler.h instead of attribute((...))

2014-04-07T23:36:11+00:00

To increase compiler portability there is  which
provides convenience macros for various gcc constructs.  Eg: __weak for
__attribute__((weak)).  I've replaced all instances of gcc attributes
with the right macro in the kernel subsystem.

Signed-off-by: Gideon Israel Dsouza 
Cc: "Rafael J. Wysocki" 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

sched/clock: Prevent tracing recursion in sched_clock_cpu()

2014-03-11T10:33:48+00:00

Prevent tracing of preempt_disable/enable() in sched_clock_cpu().
When CONFIG_DEBUG_PREEMPT is enabled, preempt_disable/enable() are
traced and this causes trace_clock() users (and probably others) to
go into an infinite recursion. Systems with a stable sched_clock()
are not affected.

This problem is similar to that fixed by upstream commit 95ef1e52922
("KVM guest: prevent tracing recursion with kvmclock").

Signed-off-by: Fernando Luis Vazquez Cao 
Signed-off-by: Peter Zijlstra 
Acked-by: Steven Rostedt 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Link: http://lkml.kernel.org/r/1394083528.4524.3.camel@nexus
Signed-off-by: Ingo Molnar