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1546 Commits

Author SHA1 Message Date
Wanpeng Li 03cbc73263 sched/cputime: Resync steal time when guest & host lose sync 
Commit:

  5743021831 ("sched/cputime: Count actually elapsed irq & softirq time")

... fixed a bug but also triggered a regression:

On an i5 laptop, 4 pCPUs, 4vCPUs for one full dynticks guest, there are four
CPU hog processes(for loop) running in the guest, I hot-unplug the pCPUs
on host one by one until there is only one left, then observe CPU utilization
via 'top' in the guest, it shows:

  100% st for cpu0(housekeeping)
   75% st for other CPUs (nohz full mode)

However, w/o this commit it shows the correct 75% for all four CPUs.

When a guest is interrupted for a longer amount of time, missed clock ticks
are not redelivered later. Because of that, we should not limit the amount
of steal time accounted to the amount of time that the calling functions
think have passed.

However, the interval returned by account_other_time() is NOT rounded down
to the nearest jiffy, while the base interval in get_vtime_delta() it is
subtracted from is, so the max cputime limit is required to avoid underflow.

This patch fixes the regression by limiting the account_other_time() from
get_vtime_delta() to avoid underflow, and lets the other three call sites
(in account_other_time() and steal_account_process_time()) account however
much steal time the host told us elapsed.

Suggested-by: Rik van Riel <riel@redhat.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm@vger.kernel.org
Link: http://lkml.kernel.org/r/1471399546-4069-1-git-send-email-wanpeng.li@hotmail.com
[ Improved the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2016-08-18 11:19:48 +02:00
Peter Zijlstra 173be9a14f sched/cputime: Fix NO_HZ_FULL getrusage() monotonicity regression 
Mike reports:

 Roughly 10% of the time, ltp testcase getrusage04 fails:
 getrusage04    0  TINFO  :  Expected timers granularity is 4000 us
 getrusage04    0  TINFO  :  Using 1 as multiply factor for max [us]time increment (1000+4000us)!
 getrusage04    0  TINFO  :  utime:           0us; stime:         179us
 getrusage04    0  TINFO  :  utime:        3751us; stime:           0us
 getrusage04    1  TFAIL  :  getrusage04.c:133: stime increased > 5000us:

And tracked it down to the case where the task simply doesn't get
_any_ [us]time ticks.

Update the code to assume all rtime is utime when we lack information,
thus ensuring a task that elides the tick gets time accounted.

Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Tested-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Fredrik Markstrom <fredrik.markstrom@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: stable@vger.kernel.org # 4.3+
Fixes: 9d7fb04276 ("sched/cputime: Guarantee stime + utime == rtime")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2016-08-18 10:48:46 +02:00
Frederic Weisbecker 26f2c75cd2 sched/cputime: Fix omitted ticks passed in parameter 
Commit:

  f9bcf1e0e0 ("sched/cputime: Fix steal time accounting")

... fixes a leak on steal time accounting but forgets to account
the ticks passed in parameters, assuming there is only one to
take into account.

Let's consider that parameter back.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Wanpeng Li <kernellwp@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: linux-tip-commits@vger.kernel.org
Link: http://lkml.kernel.org/r/20160811125822.GB4214@lerouge
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2016-08-11 16:34:37 +02:00
Wanpeng Li f9bcf1e0e0 sched/cputime: Fix steal time accounting 
Commit:

  5743021831 ("sched/cputime: Count actually elapsed irq & softirq time")

... didn't take steal time into consideration with passing the noirqtime
kernel parameter.

As Paolo pointed out before:

| Why not? If idle=poll, for example, any time the guest is suspended (and
| thus cannot poll) does count as stolen time.

This patch fixes it by reducing steal time from idle time accounting when
the noirqtime parameter is true. The average idle time drops from 56.8%
to 54.75% for nohz idle kvm guest(noirqtime, idle=poll, four vCPUs running
on one pCPU).

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1470893795-3527-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2016-08-11 11:02:14 +02:00
Wanpeng Li c0c8c9fa21 sched/deadline: Fix lock pinning warning during CPU hotplug 
The following warning can be triggered by hot-unplugging the CPU
on which an active SCHED_DEADLINE task is running on:

  WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3531 lock_release+0x690/0x6a0
  releasing a pinned lock
  Call Trace:
   dump_stack+0x99/0xd0
   __warn+0xd1/0xf0
   ? dl_task_timer+0x1a1/0x2b0
   warn_slowpath_fmt+0x4f/0x60
   ? sched_clock+0x13/0x20
   lock_release+0x690/0x6a0
   ? enqueue_pushable_dl_task+0x9b/0xa0
   ? enqueue_task_dl+0x1ca/0x480
   _raw_spin_unlock+0x1f/0x40
   dl_task_timer+0x1a1/0x2b0
   ? push_dl_task.part.31+0x190/0x190
  WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3649 lock_unpin_lock+0x181/0x1a0
  unpinning an unpinned lock
  Call Trace:
   dump_stack+0x99/0xd0
   __warn+0xd1/0xf0
   warn_slowpath_fmt+0x4f/0x60
   lock_unpin_lock+0x181/0x1a0
   dl_task_timer+0x127/0x2b0
   ? push_dl_task.part.31+0x190/0x190

As per the comment before this code, its safe to drop the RQ lock
here, and since we (potentially) change rq, unpin and repin to avoid
the splat.

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
[ Rewrote changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1470274940-17976-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2016-08-10 14:02:55 +02:00
Giovanni Gherdovich 6075620b05 sched/cputime: Mitigate performance regression in times()/clock_gettime() 
Commit:

  6e998916df ("sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency")

fixed a problem whereby clock_nanosleep() followed by clock_gettime() could
allow a task to wake early. It addressed the problem by calling the scheduling
classes update_curr() when the cputimer starts.

Said change induced a considerable performance regression on the syscalls
times() and clock_gettimes(CLOCK_PROCESS_CPUTIME_ID). There are some
debuggers and applications that monitor their own performance that
accidentally depend on the performance of these specific calls.

This patch mitigates the performace loss by prefetching data in the CPU
cache, as stalls due to cache misses appear to be where most time is spent
in our benchmarks.

Here are the performance gain of this patch over v4.7-rc7 on a Sandy Bridge
box with 32 logical cores and 2 NUMA nodes. The test is repeated with a
variable number of threads, from 2 to 4*num_cpus; the results are in
seconds and correspond to the average of 10 runs; the percentage gain is
computed with (before-after)/before so a positive value is an improvement
(it's faster). The improvement varies between a few percents for 5-20
threads and more than 10% for 2 or >20 threads.

pound_clock_gettime:

    threads       4.7-rc7     patched 4.7-rc7
    [num]         [secs]      [secs (percent)]
      2           3.48        3.06 ( 11.83%)
      5           3.33        3.25 (  2.40%)
      8           3.37        3.26 (  3.30%)
     12           3.32        3.37 ( -1.60%)
     21           4.01        3.90 (  2.74%)
     30           3.63        3.36 (  7.41%)
     48           3.71        3.11 ( 16.27%)
     79           3.75        3.16 ( 15.74%)
    110           3.81        3.25 ( 14.80%)
    128           3.88        3.31 ( 14.76%)

pound_times:

    threads       4.7-rc7     patched 4.7-rc7
    [num]         [secs]      [secs (percent)]
      2           3.65        3.25 ( 11.03%)
      5           3.45        3.17 (  7.92%)
      8           3.52        3.22 (  8.69%)
     12           3.29        3.36 ( -2.04%)
     21           4.07        3.92 (  3.78%)
     30           3.87        3.40 ( 12.17%)
     48           3.79        3.16 ( 16.61%)
     79           3.88        3.28 ( 15.42%)
    110           3.90        3.38 ( 13.35%)
    128           4.00        3.38 ( 15.45%)

pound_clock_gettime and pound_clock_gettime are two benchmarks included in
the MMTests framework. They launch a given number of threads which
repeatedly call times() or clock_gettimes(). The results above can be
reproduced with cloning MMTests from github.com and running the "poundtime"
workload:

  $ git clone https://github.com/gormanm/mmtests.git
  $ cd mmtests
  $ cp configs/config-global-dhp__workload_poundtime config
  $ ./run-mmtests.sh --run-monitor $(uname -r)

The above will run "poundtime" measuring the kernel currently running on
the machine; Once a new kernel is installed and the machine rebooted,
running again

  $ cd mmtests
  $ ./run-mmtests.sh --run-monitor $(uname -r)

will produce results to compare with. A comparison table will be output
with:

  $ cd mmtests/work/log
  $ ../../compare-kernels.sh

the table will contain a lot of entries; grepping for "Amean" (as in
"arithmetic mean") will give the tables presented above. The source code
for the two benchmarks is reported at the end of this changelog for
clairity.

The cache misses addressed by this patch were found using a combination of
`perf top`, `perf record` and `perf annotate`. The incriminated lines were
found to be

    struct sched_entity *curr = cfs_rq->curr;

and

    delta_exec = now - curr->exec_start;

in the function update_curr() from kernel/sched/fair.c. This patch
prefetches the data from memory just before update_curr is called in the
interested execution path.

A comparison of the total number of cycles before and after the patch
follows; the data is obtained using `perf stat -r 10 -ddd <program>`
running over the same sequence of number of threads used above (a positive
gain is an improvement):

  threads   cycles before                 cycles after                gain

    2      19,699,563,964  +-1.19%      17,358,917,517  +-1.85%      11.88%
    5      47,401,089,566  +-2.96%      45,103,730,829  +-0.97%       4.85%
    8      80,923,501,004  +-3.01%      71,419,385,977  +-0.77%      11.74%
   12     112,326,485,473  +-0.47%     110,371,524,403  +-0.47%       1.74%
   21     193,455,574,299  +-0.72%     180,120,667,904  +-0.36%       6.89%
   30     315,073,519,013  +-1.64%     271,222,225,950  +-1.29%      13.92%
   48     321,969,515,332  +-1.48%     273,353,977,321  +-1.16%      15.10%
   79     337,866,003,422  +-0.97%     289,462,481,538  +-1.05%      14.33%
  110     338,712,691,920  +-0.78%     290,574,233,170  +-0.77%      14.21%
  128     348,384,794,006  +-0.50%     292,691,648,206  +-0.66%      15.99%

A comparison of cache miss vs total cache loads ratios, before and after
the patch (again from the `perf stat -r 10 -ddd <program>` tables):

  threads   L1 misses/total*100     L1 misses/total*100            gain
		         before                   after
      2           7.43  +-4.90%           7.36  +-4.70%           0.94%
      5          13.09  +-4.74%          13.52  +-3.73%          -3.28%
      8          13.79  +-5.61%          12.90  +-3.27%           6.45%
     12          11.57  +-2.44%           8.71  +-1.40%          24.72%
     21          12.39  +-3.92%           9.97  +-1.84%          19.53%
     30          13.91  +-2.53%          11.73  +-2.28%          15.67%
     48          13.71  +-1.59%          12.32  +-1.97%          10.14%
     79          14.44  +-0.66%          13.40  +-1.06%           7.20%
    110          15.86  +-0.50%          14.46  +-0.59%           8.83%
    128          16.51  +-0.32%          15.06  +-0.78%           8.78%

As a final note, the following shows the evolution of performance figures
in the "poundtime" benchmark and pinpoints commit 6e998916df
("sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency") as a
major source of degradation, mostly unaddressed to this day (figures
expressed in seconds).

pound_clock_gettime:

  threads   parent of         6e998916df        4.7-rc7
	    6e998916df            itself
    2        2.23          3.68 ( -64.56%)        3.48 (-55.48%)
    5        2.83          3.78 ( -33.42%)        3.33 (-17.43%)
    8        2.84          4.31 ( -52.12%)        3.37 (-18.76%)
    12       3.09          3.61 ( -16.74%)        3.32 ( -7.17%)
    21       3.14          4.63 ( -47.36%)        4.01 (-27.71%)
    30       3.28          5.75 ( -75.37%)        3.63 (-10.80%)
    48       3.02          6.05 (-100.56%)        3.71 (-22.99%)
    79       2.88          6.30 (-118.90%)        3.75 (-30.26%)
    110      2.95          6.46 (-119.00%)        3.81 (-29.24%)
    128      3.05          6.42 (-110.08%)        3.88 (-27.04%)

pound_times:

  threads   parent of         6e998916df        4.7-rc7
	    6e998916df            itself
    2        2.27          3.73 ( -64.71%)        3.65 (-61.14%)
    5        2.78          3.77 ( -35.56%)        3.45 (-23.98%)
    8        2.79          4.41 ( -57.71%)        3.52 (-26.05%)
    12       3.02          3.56 ( -17.94%)        3.29 ( -9.08%)
    21       3.10          4.61 ( -48.74%)        4.07 (-31.34%)
    30       3.33          5.75 ( -72.53%)        3.87 (-16.01%)
    48       2.96          6.06 (-105.04%)        3.79 (-28.10%)
    79       2.88          6.24 (-116.83%)        3.88 (-34.81%)
    110      2.98          6.37 (-114.08%)        3.90 (-31.12%)
    128      3.10          6.35 (-104.61%)        4.00 (-28.87%)

The source code of the two benchmarks follows. To compile the two:

  NR_THREADS=42
  for FILE in pound_times pound_clock_gettime; do
      gcc -lrt -O2 -lpthread -DNUM_THREADS=$NR_THREADS $FILE.c -o $FILE
  done

==== BEGIN pound_times.c ====

struct tms start;

void *pound (void *threadid)
{
  struct tms end;
  int oldutime = 0;
  int utime;
  int i;
  for (i = 0; i < 5000000 / NUM_THREADS; i++) {
          times(&end);
          utime = ((int)end.tms_utime - (int)start.tms_utime);
          if (oldutime > utime) {
            printf("utime decreased, was %d, now %d!\n", oldutime, utime);
          }
          oldutime = utime;
  }
  pthread_exit(NULL);
}

int main()
{
  pthread_t th[NUM_THREADS];
  long i;
  times(&start);
  for (i = 0; i < NUM_THREADS; i++) {
    pthread_create (&th[i], NULL, pound, (void *)i);
  }
  pthread_exit(NULL);
  return 0;
}
==== END pound_times.c ====

==== BEGIN pound_clock_gettime.c ====

void *pound (void *threadid)
{
	struct timespec ts;
	int rc, i;
	unsigned long prev = 0, this = 0;

	for (i = 0; i < 5000000 / NUM_THREADS; i++) {
		rc = clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts);
		if (rc < 0)
			perror("clock_gettime");
		this = (ts.tv_sec * 1000000000) + ts.tv_nsec;
		if (0 && this < prev)
			printf("%lu ns timewarp at iteration %d\n", prev - this, i);
		prev = this;
	}
	pthread_exit(NULL);
}

int main()
{
	pthread_t th[NUM_THREADS];
	long rc, i;
	pid_t pgid;

	for (i = 0; i < NUM_THREADS; i++) {
		rc = pthread_create(&th[i], NULL, pound, (void *)i);
		if (rc < 0)
			perror("pthread_create");
	}

	pthread_exit(NULL);
	return 0;
}
==== END pound_clock_gettime.c ====

Suggested-by: Mike Galbraith <mgalbraith@suse.de>
Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1470385316-15027-2-git-send-email-ggherdovich@suse.cz
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2016-08-10 13:32:56 +02:00
Xunlei Pang b8922125e4 sched/fair: Fix typo in sync_throttle() 
We should update cfs_rq->throttled_clock_task, not
pcfs_rq->throttle_clock_task.

The effects of this bug was probably occasionally erratic
group scheduling, particularly in cgroups-intense workloads.

Signed-off-by: Xunlei Pang <xlpang@redhat.com>
[ Added changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 55e16d30bd ("sched/fair: Rework throttle_count sync")
Link: http://lkml.kernel.org/r/1468050862-18864-1-git-send-email-xlpang@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2016-08-10 13:32:55 +02:00
Tommaso Cucinotta a23eadfae2 sched/deadline: Fix wrap-around in DL heap 
Current code in cpudeadline.c has a bug in re-heapifying when adding a
new element at the end of the heap, because a deadline value of 0 is
temporarily set in the new elem, then cpudl_change_key() is called
with the actual elem deadline as param.

However, the function compares the new deadline to set with the one
previously in the elem, which is 0.  So, if current absolute deadlines
grew so much to have negative values as s64, the comparison in
cpudl_change_key() makes the wrong decision.  Instead, as from
dl_time_before(), the kernel should handle correctly abs deadlines
wrap-arounds.

This patch fixes the problem with a minimally invasive change that
forces cpudl_change_key() to heapify up in this case.

Signed-off-by: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Luca Abeni <luca.abeni@unitn.it>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1468921493-10054-2-git-send-email-tommaso.cucinotta@sssup.it
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2016-08-10 13:32:55 +02:00
Linus Torvalds 08fd8c1768 Merge tag 'for-linus-4.8-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip 
Pull xen updates from David Vrabel:
 "Features and fixes for 4.8-rc0:

   - ACPI support for guests on ARM platforms.
   - Generic steal time support for arm and x86.
   - Support cases where kernel cpu is not Xen VCPU number (e.g., if
     in-guest kexec is used).
   - Use the system workqueue instead of a custom workqueue in various
     places"

* tag 'for-linus-4.8-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (47 commits)
  xen: add static initialization of steal_clock op to xen_time_ops
  xen/pvhvm: run xen_vcpu_setup() for the boot CPU
  xen/evtchn: use xen_vcpu_id mapping
  xen/events: fifo: use xen_vcpu_id mapping
  xen/events: use xen_vcpu_id mapping in events_base
  x86/xen: use xen_vcpu_id mapping when pointing vcpu_info to shared_info
  x86/xen: use xen_vcpu_id mapping for HYPERVISOR_vcpu_op
  xen: introduce xen_vcpu_id mapping
  x86/acpi: store ACPI ids from MADT for future usage
  x86/xen: update cpuid.h from Xen-4.7
  xen/evtchn: add IOCTL_EVTCHN_RESTRICT
  xen-blkback: really don't leak mode property
  xen-blkback: constify instance of "struct attribute_group"
  xen-blkfront: prefer xenbus_scanf() over xenbus_gather()
  xen-blkback: prefer xenbus_scanf() over xenbus_gather()
  xen: support runqueue steal time on xen
  arm/xen: add support for vm_assist hypercall
  xen: update xen headers
  xen-pciback: drop superfluous variables
  xen-pciback: short-circuit read path used for merging write values
  ...
 2016-07-27 11:35:37 -07:00
Linus Torvalds 6453dbdda3 Merge tag 'pm-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm 
Pull power management updates from Rafael  Wysocki:
 "Again, the majority of changes go into the cpufreq subsystem, but
  there are no big features this time.  The cpufreq changes that stand
  out somewhat are the governor interface rework and improvements
  related to the handling of frequency tables.  Apart from those, there
  are fixes and new device/CPU IDs in drivers, cleanups and an
  improvement of the new schedutil governor.

  Next, there are some changes in the hibernation core, including a fix
  for a nasty problem related to the MONITOR/MWAIT usage by CPU offline
  during resume from hibernation, a few core improvements related to
  memory management during resume, a couple of additional debug features
  and cleanups.

  Finally, we have some fixes and cleanups in the devfreq subsystem,
  generic power domains framework improvements related to system
  suspend/resume, support for some new chips in intel_idle and in the
  power capping RAPL driver, a new version of the AnalyzeSuspend utility
  and some assorted fixes and cleanups.

  Specifics:

   - Rework the cpufreq governor interface to make it more
     straightforward and modify the conservative governor to avoid using
     transition notifications (Rafael Wysocki).

   - Rework the handling of frequency tables by the cpufreq core to make
     it more efficient (Viresh Kumar).

   - Modify the schedutil governor to reduce the number of wakeups it
     causes to occur in cases when the CPU frequency doesn't need to be
     changed (Steve Muckle, Viresh Kumar).

   - Fix some minor issues and clean up code in the cpufreq core and
     governors (Rafael Wysocki, Viresh Kumar).

   - Add Intel Broxton support to the intel_pstate driver (Srinivas
     Pandruvada).

   - Fix problems related to the config TDP feature and to the validity
     of the MSR_HWP_INTERRUPT register in intel_pstate (Jan Kiszka,
     Srinivas Pandruvada).

   - Make intel_pstate update the cpu_frequency tracepoint even if the
     frequency doesn't change to avoid confusing powertop (Rafael
     Wysocki).

   - Clean up the usage of __init/__initdata in intel_pstate, mark some
     of its internal variables as __read_mostly and drop an unused
     structure element from it (Jisheng Zhang, Carsten Emde).

   - Clean up the usage of some duplicate MSR symbols in intel_pstate
     and turbostat (Srinivas Pandruvada).

   - Update/fix the powernv, s3c24xx and mvebu cpufreq drivers (Akshay
     Adiga, Viresh Kumar, Ben Dooks).

   - Fix a regression (introduced during the 4.5 cycle) in the
     pcc-cpufreq driver by reverting the problematic commit (Andreas
     Herrmann).

   - Add support for Intel Denverton to intel_idle, clean up Broxton
     support in it and make it explicitly non-modular (Jacob Pan, Jan
     Beulich, Paul Gortmaker).

   - Add support for Denverton and Ivy Bridge server to the Intel RAPL
     power capping driver and make it more careful about the handing of
     MSRs that may not be present (Jacob Pan, Xiaolong Wang).

   - Fix resume from hibernation on x86-64 by making the CPU offline
     during resume avoid using MONITOR/MWAIT in the "play dead" loop
     which may lead to an inadvertent "revival" of a "dead" CPU and a
     page fault leading to a kernel crash from it (Rafael Wysocki).

   - Make memory management during resume from hibernation more
     straightforward (Rafael Wysocki).

   - Add debug features that should help to detect problems related to
     hibernation and resume from it (Rafael Wysocki, Chen Yu).

   - Clean up hibernation core somewhat (Rafael Wysocki).

   - Prevent KASAN from instrumenting the hibernation core which leads
     to large numbers of false-positives from it (James Morse).

   - Prevent PM (hibernate and suspend) notifiers from being called
     during the cleanup phase if they have not been called during the
     corresponding preparation phase which is possible if one of the
     other notifiers returns an error at that time (Lianwei Wang).

   - Improve suspend-related debug printout in the tasks freezer and
     clean up suspend-related console handling (Roger Lu, Borislav
     Petkov).

   - Update the AnalyzeSuspend script in the kernel sources to version
     4.2 (Todd Brandt).

   - Modify the generic power domains framework to make it handle system
     suspend/resume better (Ulf Hansson).

   - Make the runtime PM framework avoid resuming devices synchronously
     when user space changes the runtime PM settings for them and
     improve its error reporting (Rafael Wysocki, Linus Walleij).

   - Fix error paths in devfreq drivers (exynos, exynos-ppmu,
     exynos-bus) and in the core, make some devfreq code explicitly
     non-modular and change some of it into tristate (Bartlomiej
     Zolnierkiewicz, Peter Chen, Paul Gortmaker).

   - Add DT support to the generic PM clocks management code and make it
     export some more symbols (Jon Hunter, Paul Gortmaker).

   - Make the PCI PM core code slightly more robust against possible
     driver errors (Andy Shevchenko).

   - Make it possible to change DESTDIR and PREFIX in turbostat (Andy
     Shevchenko)"

* tag 'pm-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (89 commits)
  Revert "cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency"
  PM / hibernate: Introduce test_resume mode for hibernation
  cpufreq: export cpufreq_driver_resolve_freq()
  cpufreq: Disallow ->resolve_freq() for drivers providing ->target_index()
  PCI / PM: check all fields in pci_set_platform_pm()
  cpufreq: acpi-cpufreq: use cached frequency mapping when possible
  cpufreq: schedutil: map raw required frequency to driver frequency
  cpufreq: add cpufreq_driver_resolve_freq()
  cpufreq: intel_pstate: Check cpuid for MSR_HWP_INTERRUPT
  intel_pstate: Update cpu_frequency tracepoint every time
  cpufreq: intel_pstate: clean remnant struct element
  PM / tools: scripts: AnalyzeSuspend v4.2
  x86 / hibernate: Use hlt_play_dead() when resuming from hibernation
  cpufreq: powernv: Replacing pstate_id with frequency table index
  intel_pstate: Fix MSR_CONFIG_TDP_x addressing in core_get_max_pstate()
  PM / hibernate: Image data protection during restoration
  PM / hibernate: Add missing braces in __register_nosave_region()
  PM / hibernate: Clean up comments in snapshot.c
  PM / hibernate: Clean up function headers in snapshot.c
  PM / hibernate: Add missing braces in hibernate_setup()
  ...
 2016-07-26 17:29:07 -07:00
Linus Torvalds 766fd5f6cd Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 
Pull NOHZ updates from Ingo Molnar:

 - fix system/idle cputime leaked on cputime accounting (all nohz
   configs) (Rik van Riel)

 - remove the messy, ad-hoc irqtime account on nohz-full and make it
   compatible with CONFIG_IRQ_TIME_ACCOUNTING=y instead (Rik van Riel)

 - cleanups (Frederic Weisbecker)

 - remove unecessary irq disablement in the irqtime code (Rik van Riel)

* 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/cputime: Drop local_irq_save/restore from irqtime_account_irq()
  sched/cputime: Reorganize vtime native irqtime accounting headers
  sched/cputime: Clean up the old vtime gen irqtime accounting completely
  sched/cputime: Replace VTIME_GEN irq time code with IRQ_TIME_ACCOUNTING code
  sched/cputime: Count actually elapsed irq & softirq time
 2016-07-25 14:43:00 -07:00
Linus Torvalds cca08cd66c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 
Pull scheduler updates from Ingo Molnar:

 - introduce and use task_rcu_dereference()/try_get_task_struct() to fix
   and generalize task_struct handling (Oleg Nesterov)

 - do various per entity load tracking (PELT) fixes and optimizations
   (Peter Zijlstra)

 - cputime virt-steal time accounting enhancements/fixes (Wanpeng Li)

 - introduce consolidated cputime output file cpuacct.usage_all and
   related refactorings (Zhao Lei)

 - ... plus misc fixes and enhancements

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/core: Panic on scheduling while atomic bugs if kernel.panic_on_warn is set
  sched/cpuacct: Introduce cpuacct.usage_all to show all CPU stats together
  sched/cpuacct: Use loop to consolidate code in cpuacct_stats_show()
  sched/cpuacct: Merge cpuacct_usage_index and cpuacct_stat_index enums
  sched/fair: Rework throttle_count sync
  sched/core: Fix sched_getaffinity() return value kerneldoc comment
  sched/fair: Reorder cgroup creation code
  sched/fair: Apply more PELT fixes
  sched/fair: Fix PELT integrity for new tasks
  sched/cgroup: Fix cpu_cgroup_fork() handling
  sched/fair: Fix PELT integrity for new groups
  sched/fair: Fix and optimize the fork() path
  sched/cputime: Add steal time support to full dynticks CPU time accounting
  sched/cputime: Fix prev steal time accouting during CPU hotplug
  KVM: Fix steal clock warp during guest CPU hotplug
  sched/debug: Always show 'nr_migrations'
  sched/fair: Use task_rcu_dereference()
  sched/api: Introduce task_rcu_dereference() and try_get_task_struct()
  sched/idle: Optimize the generic idle loop
  sched/fair: Fix the wrong throttled clock time for cfs_rq_clock_task()
 2016-07-25 13:59:34 -07:00
Linus Torvalds c86ad14d30 Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 
Pull locking updates from Ingo Molnar:
 "The locking tree was busier in this cycle than the usual pattern - a
  couple of major projects happened to coincide.

  The main changes are:

   - implement the atomic_fetch_{add,sub,and,or,xor}() API natively
     across all SMP architectures (Peter Zijlstra)

   - add atomic_fetch_{inc/dec}() as well, using the generic primitives
     (Davidlohr Bueso)

   - optimize various aspects of rwsems (Jason Low, Davidlohr Bueso,
     Waiman Long)

   - optimize smp_cond_load_acquire() on arm64 and implement LSE based
     atomic{,64}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}()
     on arm64 (Will Deacon)

   - introduce smp_acquire__after_ctrl_dep() and fix various barrier
     mis-uses and bugs (Peter Zijlstra)

   - after discovering ancient spin_unlock_wait() barrier bugs in its
     implementation and usage, strengthen its semantics and update/fix
     usage sites (Peter Zijlstra)

   - optimize mutex_trylock() fastpath (Peter Zijlstra)

   - ... misc fixes and cleanups"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (67 commits)
  locking/atomic: Introduce inc/dec variants for the atomic_fetch_$op() API
  locking/barriers, arch/arm64: Implement LDXR+WFE based smp_cond_load_acquire()
  locking/static_keys: Fix non static symbol Sparse warning
  locking/qspinlock: Use __this_cpu_dec() instead of full-blown this_cpu_dec()
  locking/atomic, arch/tile: Fix tilepro build
  locking/atomic, arch/m68k: Remove comment
  locking/atomic, arch/arc: Fix build
  locking/Documentation: Clarify limited control-dependency scope
  locking/atomic, arch/rwsem: Employ atomic_long_fetch_add()
  locking/atomic, arch/qrwlock: Employ atomic_fetch_add_acquire()
  locking/atomic, arch/mips: Convert to _relaxed atomics
  locking/atomic, arch/alpha: Convert to _relaxed atomics
  locking/atomic: Remove the deprecated atomic_{set,clear}_mask() functions
  locking/atomic: Remove linux/atomic.h:atomic_fetch_or()
  locking/atomic: Implement atomic{,64,_long}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}()
  locking/atomic: Fix atomic64_relaxed() bits
  locking/atomic, arch/xtensa: Implement atomic_fetch_{add,sub,and,or,xor}()
  locking/atomic, arch/x86: Implement atomic{,64}_fetch_{add,sub,and,or,xor}()
  locking/atomic, arch/tile: Implement atomic{,64}_fetch_{add,sub,and,or,xor}()
  locking/atomic, arch/sparc: Implement atomic{,64}_fetch_{add,sub,and,or,xor}()
  ...
 2016-07-25 12:41:29 -07:00
Rafael J. Wysocki 9def970ead Merge branch 'pm-cpufreq' 
* pm-cpufreq: (41 commits)
  Revert "cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency"
  cpufreq: export cpufreq_driver_resolve_freq()
  cpufreq: Disallow ->resolve_freq() for drivers providing ->target_index()
  cpufreq: acpi-cpufreq: use cached frequency mapping when possible
  cpufreq: schedutil: map raw required frequency to driver frequency
  cpufreq: add cpufreq_driver_resolve_freq()
  cpufreq: intel_pstate: Check cpuid for MSR_HWP_INTERRUPT
  intel_pstate: Update cpu_frequency tracepoint every time
  cpufreq: intel_pstate: clean remnant struct element
  cpufreq: powernv: Replacing pstate_id with frequency table index
  intel_pstate: Fix MSR_CONFIG_TDP_x addressing in core_get_max_pstate()
  cpufreq: Reuse new freq-table helpers
  cpufreq: Handle sorted frequency tables more efficiently
  cpufreq: Drop redundant check from cpufreq_update_current_freq()
  intel_pstate: Declare pid_params/pstate_funcs/hwp_active __read_mostly
  intel_pstate: add __init/__initdata marker to some functions/variables
  intel_pstate: Fix incorrect placement of __initdata
  cpufreq: mvebu: fix integer to pointer cast
  cpufreq: intel_pstate: Broxton support
  cpufreq: conservative: Do not use transition notifications
  ...
 2016-07-25 13:46:08 +02:00
Steve Muckle 5cbea46984 cpufreq: schedutil: map raw required frequency to driver frequency 
The slow-path frequency transition path is relatively expensive as it
requires waking up a thread to do work. Should support be added for
remote CPU cpufreq updates that is also expensive since it requires an
IPI. These activities should be avoided if they are not necessary.

To that end, calculate the actual driver-supported frequency required by
the new utilization value in schedutil by using the recently added
cpufreq_driver_resolve_freq API. If it is the same as the previously
requested driver frequency then there is no need to continue with the
update assuming the cpu frequency limits have not changed. This will
have additional benefits should the semantics of the rate limit be
changed to apply solely to frequency transitions rather than to
frequency calculations in schedutil.

The last raw required frequency is cached. This allows the driver
frequency lookup to be skipped in the event that the new raw required
frequency matches the last one, assuming a frequency update has not been
forced due to limits changing (indicated by a next_freq value of
UINT_MAX, see sugov_should_update_freq).

Signed-off-by: Steve Muckle <smuckle@linaro.org>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 2016-07-21 22:28:21 +02:00
Rik van Riel 553bf6bbfd sched/cputime: Drop local_irq_save/restore from irqtime_account_irq() 
Paolo pointed out that irqs are already blocked when irqtime_account_irq()
is called. That means there is no reason to call local_irq_save/restore()
again.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1468421405-20056-6-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2016-07-14 10:42:35 +02:00
Frederic Weisbecker 0cfdf9a198 sched/cputime: Clean up the old vtime gen irqtime accounting completely 
Vtime generic irqtime accounting has been removed but there are a few
remnants to clean up:

* The vtime_accounting_cpu_enabled() check in irq entry was only used
  by CONFIG_VIRT_CPU_ACCOUNTING_GEN. We can safely remove it.

* Without the vtime_accounting_cpu_enabled(), we no longer need to
  have a vtime_common_account_irq_enter() indirect function.

* Move vtime_account_irq_enter() implementation under
  CONFIG_VIRT_CPU_ACCOUNTING_NATIVE which is the last user.

* The vtime_account_user() call was only used on irq entry for
  CONFIG_VIRT_CPU_ACCOUNTING_GEN. We can remove that too.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1468421405-20056-4-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2016-07-14 10:42:35 +02:00
Rik van Riel b58c358405 sched/cputime: Replace VTIME_GEN irq time code with IRQ_TIME_ACCOUNTING code 
The CONFIG_VIRT_CPU_ACCOUNTING_GEN irq time tracking code does not
appear to currently work right.

On CPUs without nohz_full=, only tick based irq time sampling is
done, which breaks down when dealing with a nohz_idle CPU.

On firewalls and similar systems, no ticks may happen on a CPU for a
while, and the irq time spent may never get accounted properly. This
can cause issues with capacity planning and power saving, which use
the CPU statistics as inputs in decision making.

Remove the VTIME_GEN vtime irq time code, and replace it with the
IRQ_TIME_ACCOUNTING code, when selected as a config option by the user.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1468421405-20056-3-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2016-07-14 10:42:34 +02:00
Rik van Riel 5743021831 sched/cputime: Count actually elapsed irq & softirq time 
Currently, if there was any irq or softirq time during 'ticks'
jiffies, the entire period will be accounted as irq or softirq
time.

This is inaccurate if only a subset of the time was actually spent
handling irqs, and could conceivably mis-count all of the ticks during
a period as irq time, when there was some irq and some softirq time.

This can actually happen when irqtime_account_process_tick is called
from account_idle_ticks, which can pass a larger number of ticks down
all at once.

Fix this by changing irqtime_account_hi_update(), irqtime_account_si_update(),
and steal_account_process_ticks() to work with cputime_t time units, and
return the amount of time spent in each mode.

Rename steal_account_process_ticks() to steal_account_process_time(), to
reflect that time is now accounted in cputime_t, instead of ticks.

Additionally, have irqtime_account_process_tick() take into account how
much time was spent in each of steal, irq, and softirq time.

The latter could help improve the accuracy of cputime
accounting when returning from idle on a NO_HZ_IDLE CPU.

Properly accounting how much time was spent in hardirq and
softirq time will also allow the NO_HZ_FULL code to re-use
these same functions for hardirq and softirq accounting.

Signed-off-by: Rik van Riel <riel@redhat.com>
[ Make nsecs_to_cputime64() actually return cputime64_t. ]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1468421405-20056-2-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2016-07-14 10:42:34 +02:00
Thomas Gleixner d60585c576 sched/core: Correct off by one bug in load migration calculation 
The move of calc_load_migrate() from CPU_DEAD to CPU_DYING did not take into
account that the function is now called from a thread running on the outgoing
CPU. As a result a cpu unplug leakes a load of 1 into the global load
accounting mechanism.

Fix it by adjusting for the currently running thread which calls
calc_load_migrate().

Reported-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Cc: rt@linutronix.de
Cc: shreyas@linux.vnet.ibm.com
Fixes: e9cd8fa4fc: ("sched/migration: Move calc_load_migrate() into CPU_DYING")
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1607121744350.4083@nanos
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2016-07-13 14:58:20 +02:00
Daniel Bristot de Oliveira 748c7201e6 sched/core: Panic on scheduling while atomic bugs if kernel.panic_on_warn is set 
Currently, a schedule while atomic error prints the stack trace to the
kernel log and the system continue running.

Although it is possible to collect the kernel log messages and analyze
it, often more information are needed. Furthermore, keep the system
running is not always the best choice. For example, when the preempt
count underflows the system will not stop to complain about scheduling
while atomic, so the kernel log can wrap around overwriting the first
stack trace, tuning the analysis even more challenging.

This patch uses the kernel.panic_on_warn sysctl to help out on these
more complex situations.

When kernel.panic_on_warn is set to 1, the kernel will panic() in the
schedule while atomic detection.

The default value of the sysctl is 0, maintaining the current behavior.

Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Reviewed-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/e8f7b80f353aa22c63bd8557208163989af8493d.1464983675.git.bristot@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2016-07-10 20:17:27 +02:00
Zhao Lei 277a13e4f0 sched/cpuacct: Introduce cpuacct.usage_all to show all CPU stats together 
In current code, we can get cpuacct data from several files,
but each file has various limitations.

For example:

 - We can get CPU usage in user and kernel mode via cpuacct.stat,
   but we can't get detailed data about each CPU.

 - We can get each CPU's kernel mode usage in cpuacct.usage_percpu_sys,
   but we can't get user mode usage data at the same time.

This patch introduces cpuacct.usage_all, to show all detailed CPU
accounting data together:

 # cat cpuacct.usage_all
 cpu user system
 0 3809760299 5807968992
 1 3250329855 454612211
 ..

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/7744460969edd7caaf0e903592ee52353ed9bdd6.1466415271.git.zhaolei@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2016-07-09 13:56:15 +02:00
Zhao Lei 8e546bfafb sched/cpuacct: Use loop to consolidate code in cpuacct_stats_show() 
In cpuacct_stats_show() we currently we have copies of similar code,
for each cpustat(system/user) variant.

Use a loop instead to consolidate the code. This will also work better
if we extend the CPUACCT_STAT_NSTATS type.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/b0597d4224655e9f333f1a6224ed9654c7d7d36a.1466415271.git.zhaolei@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2016-07-09 13:56:15 +02:00
Zhao Lei 9acacc2ac5 sched/cpuacct: Merge cpuacct_usage_index and cpuacct_stat_index enums 
These two types have similar function, no need to separate them.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/436748885270d64363c7dc67167507d486c2057a.1466415271.git.zhaolei@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2016-07-09 13:56:15 +02:00
Juergen Gross ecb23dc6f2 xen: add steal_clock support on x86 
The pv_time_ops structure contains a function pointer for the
"steal_clock" functionality used only by KVM and Xen on ARM. Xen on x86
uses its own mechanism to account for the "stolen" time a thread wasn't
able to run due to hypervisor scheduling.

Add support in Xen arch independent time handling for this feature by
moving it out of the arm arch into drivers/xen and remove the x86 Xen
hack.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
 2016-07-06 10:34:48 +01:00