Commit Graph

32327 Commits

Author SHA1 Message Date
Ahmed S. Darwish
2c8bd58812 time/sched_clock: Expire timer in hardirq context
To minimize latency, PREEMPT_RT kernels expires hrtimers in preemptible
softirq context by default. This can be overriden by marking the timer's
expiry with HRTIMER_MODE_HARD.

sched_clock_timer is missing this annotation: if its callback is preempted
and the duration of the preemption exceeds the wrap around time of the
underlying clocksource, sched clock will get out of sync.

Mark the sched_clock_timer for expiry in hard interrupt context.

Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200309181529.26558-1-a.darwish@linutronix.de
2020-03-19 09:45:08 +01:00
Waiman Long
d441dceb5d tick/common: Make tick_periodic() check for missing ticks
The tick_periodic() function is used at the beginning part of the
bootup process for time keeping while the other clock sources are
being initialized.

The current code assumes that all the timer interrupts are handled in
a timely manner with no missing ticks. That is not actually true. Some
ticks are missed and there are some discrepancies between the tick time
(jiffies) and the timestamp reported in the kernel log.  Some systems,
however, are more prone to missing ticks than the others.  In the extreme
case, the discrepancy can actually cause a soft lockup message to be
printed by the watchdog kthread. For example, on a Cavium ThunderX2
Sabre arm64 system:

 [   25.496379] watchdog: BUG: soft lockup - CPU#14 stuck for 22s!

On that system, the missing ticks are especially prevalent during the
smp_init() phase of the boot process. With an instrumented kernel,
it was found that it took about 24s as reported by the timestamp for
the tick to accumulate 4s of time.

Investigation and bisection done by others seemed to point to the
commit 73f3816609 ("arm64: Advertise mitigation of Spectre-v2, or
lack thereof") as the culprit. It could also be a firmware issue as
new firmware was promised that would fix the issue.

To properly address this problem, stop assuming that there will be no
missing tick in tick_periodic(). Modify it to follow the example of
tick_do_update_jiffies64() by using another reference clock to check for
missing ticks. Since the watchdog timer uses running_clock(), it is used
here as the reference. With this applied, the soft lockup problem in the
affected arm64 system is gone and tick time tracks much more closely to the
timestamp time.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200207193929.27308-1-longman@redhat.com
2020-03-04 10:18:11 +01:00
Wen Yang
38f7b0b131 hrtimer: Cast explicitely to u32t in __ktime_divns()
do_div() does a 64-by-32 division at least on 32bit platforms, while the
divisor 'div' is explicitly casted to unsigned long, thus 64-bit on 64-bit
platforms.

The code already ensures that the divisor is less than 2^32. Hence the
proper cast type is u32.

Signed-off-by: Wen Yang <wenyang@linux.alibaba.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200130130851.29204-1-wenyang@linux.alibaba.com
2020-03-04 10:17:51 +01:00
Wen Yang
4cbbc3a0ee timekeeping: Prevent 32bit truncation in scale64_check_overflow()
While unlikely the divisor in scale64_check_overflow() could be >= 32bit in
scale64_check_overflow(). do_div() truncates the divisor to 32bit at least
on 32bit platforms.

Use div64_u64() instead to avoid the truncation to 32-bit.

[ tglx: Massaged changelog ]

Signed-off-by: Wen Yang <wenyang@linux.alibaba.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200120100523.45656-1-wenyang@linux.alibaba.com
2020-03-04 10:17:51 +01:00
Eric W. Biederman
b95e31c07c posix-cpu-timers: Stop disabling timers on mt-exec
The reasons why the extra posix_cpu_timers_exit_group() invocation has been
added are not entirely clear from the commit message.  Today all that
posix_cpu_timers_exit_group() does is stop timers that are tracking the
task from firing.  Every other operation on those timers is still allowed.

The practical implication of this is posix_cpu_timer_del() which could
not get the siglock after the thread group leader has exited (because
sighand == NULL) would be able to run successfully because the timer
was already dequeued.

With that locking issue fixed there is no point in disabling all of the
timers.  So remove this ``tempoary'' hack.

Fixes: e0a7021710 ("posix-cpu-timers: workaround to suppress the problems with mt exec")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/87o8tityzs.fsf@x220.int.ebiederm.org
2020-03-04 09:54:55 +01:00
Eric W. Biederman
55e8c8eb2c posix-cpu-timers: Store a reference to a pid not a task
posix cpu timers do not handle the death of a process well.

This is most clearly seen when a multi-threaded process calls exec from a
thread that is not the leader of the thread group.  The posix cpu timer code
continues to pin the old thread group leader and is unable to find the
siglock from there.

This results in posix_cpu_timer_del being unable to delete a timer,
posix_cpu_timer_set being unable to set a timer.  Further to compensate for
the problems in posix_cpu_timer_del on a multi-threaded exec all timers
that point at the multi-threaded task are stopped.

The code for the timers fundamentally needs to check if the target
process/thread is alive.  This needs an extra level of indirection. This
level of indirection is already available in struct pid.

So replace cpu.task with cpu.pid to get the needed extra layer of
indirection.

In addition to handling things more cleanly this reduces the amount of
memory a timer can pin when a process exits and then is reaped from
a task_struct to the vastly smaller struct pid.

Fixes: e0a7021710 ("posix-cpu-timers: workaround to suppress the problems with mt exec")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/87wo86tz6d.fsf@x220.int.ebiederm.org
2020-03-04 09:54:55 +01:00
Eric W. Biederman
beb41d9cbe posix-cpu-timers: Pass the task into arm_timer()
The task has been already computed to take siglock before calling
arm_timer. So pass the benefit of that labor into arm_timer().

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/8736auvdt1.fsf@x220.int.ebiederm.org
2020-03-01 11:21:44 +01:00
Eric W. Biederman
60f2ceaa81 posix-cpu-timers: Remove unnecessary locking around cpu_clock_sample_group
As of e78c349679 ("time, signal: Protect resource use statistics
with seqlock") cpu_clock_sample_group no longers needs siglock
protection.  Unfortunately no one realized it at the time.

Remove the extra locking that is for cpu_clock_sample_group and not
for cpu_clock_sample.  This significantly simplifies the code.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/878skmvdts.fsf@x220.int.ebiederm.org
2020-03-01 11:21:44 +01:00
Eric W. Biederman
a2efdbf4fc posix-cpu-timers: cpu_clock_sample_group() no longer needs siglock
As of e78c349679 ("time, signal: Protect resource use statistics with
seqlock") cpu_clock_sample_group() no longer needs siglock protection so
remove the stale comment.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/87eeuevduq.fsf@x220.int.ebiederm.org
2020-03-01 11:21:43 +01:00
Amol Grover
5fb1c2a5bb posix-timers: Pass lockdep expression to RCU lists
head is traversed using hlist_for_each_entry_rcu outside an RCU read-side
critical section but under the protection of hash_lock.

Hence, add corresponding lockdep expression to silence false-positive
lockdep warnings, and harden RCU lists.

[ tglx: Removed the macro and put the condition right where it's used ]

Signed-off-by: Amol Grover <frextrite@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200216074330.GA14025@workstation-portable
2020-02-17 20:12:19 +01:00
Alexander Popov
6e317c32fd timer: Improve the comment describing schedule_timeout()
When working commit 6dcd5d7a7a, a mistake was noticed by Linus:
schedule_timeout() was called without setting the task state to anything
particular.

It calls the scheduler, but doesn't delay anything, because the task stays
runnable. That happens because sched_submit_work() does nothing for tasks
in TASK_RUNNING state.

That turned out to be the intended behavior. Adding a WARN() is not useful
as the task could be woken up right after setting the state and before
reaching schedule_timeout().

Improve the comment about schedule_timeout() and describe that more
explicitly.

Signed-off-by: Alexander Popov <alex.popov@linux.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200117225900.16340-1-alex.popov@linux.com
2020-02-17 20:12:19 +01:00
Thomas Gleixner
2d6b01bd88 lib/vdso: Move VCLOCK_TIMENS to vdso_clock_modes
Move the time namespace indicator clock mode to the other ones for
consistency sake.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lkml.kernel.org/r/20200207124403.656097274@linutronix.de
2020-02-17 20:12:17 +01:00
Thomas Gleixner
c7a18100bd lib/vdso: Avoid highres update if clocksource is not VDSO capable
If the current clocksource is not VDSO capable there is no point in
updating the high resolution parts of the VDSO data.

Replace the architecture specific check with a check for a VDSO capable
clocksource and skip the update if there is none.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lkml.kernel.org/r/20200207124403.563379423@linutronix.de
2020-02-17 20:12:17 +01:00
Thomas Gleixner
f86fd32db7 lib/vdso: Cleanup clock mode storage leftovers
Now that all architectures are converted to use the generic storage the
helpers and conditionals can be removed.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lkml.kernel.org/r/20200207124403.470699892@linutronix.de
2020-02-17 20:12:17 +01:00
Thomas Gleixner
5d51bee725 clocksource: Add common vdso clock mode storage
All architectures which use the generic VDSO code have their own storage
for the VDSO clock mode. That's pointless and just requires duplicate code.

Provide generic storage for it. The new Kconfig symbol is intermediate and
will be removed once all architectures are converted over.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lkml.kernel.org/r/20200207124403.028046322@linutronix.de
2020-02-17 14:40:23 +01:00
Linus Torvalds
ef78e5b7de Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
 "Misc fixes all over the place:

   - Fix NUMA over-balancing between lightly loaded nodes. This is
     fallout of the big load-balancer rewrite.

   - Fix the NOHZ remote loadavg update logic, which fixes anomalies
     like reported 150 loadavg on mostly idle CPUs.

   - Fix XFS performance/scalability

   - Fix throttled groups unbound task-execution bug

   - Fix PSI procfs boundary condition

   - Fix the cpu.uclamp.{min,max} cgroup configuration write checks

   - Fix DocBook annotations

   - Fix RCU annotations

   - Fix overly CPU-intensive housekeeper CPU logic loop on large CPU
     counts"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Fix kernel-doc warning in attach_entity_load_avg()
  sched/core: Annotate curr pointer in rq with __rcu
  sched/psi: Fix OOB write when writing 0 bytes to PSI files
  sched/fair: Allow a per-CPU kthread waking a task to stack on the same CPU, to fix XFS performance regression
  sched/fair: Prevent unlimited runtime on throttled group
  sched/nohz: Optimize get_nohz_timer_target()
  sched/uclamp: Reject negative values in cpu_uclamp_write()
  sched/fair: Allow a small load imbalance between low utilisation SD_NUMA domains
  timers/nohz: Update NOHZ load in remote tick
  sched/core: Don't skip remote tick for idle CPUs
2020-02-15 12:51:22 -08:00
Linus Torvalds
4e03e4e6d2 Power management fixes for 5.6-rc2
Fix three issues related to the handling of wakeup events signaled
 through the ACPI SCI while suspended to idle (Rafael Wysocki) and
 unexport an internal cpufreq variable (Yangtao Li).
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Merge tag 'pm-5.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management fixes from Rafael Wysocki:
 "Fix three issues related to the handling of wakeup events signaled
  through the ACPI SCI while suspended to idle (Rafael Wysocki) and
  unexport an internal cpufreq variable (Yangtao Li)"

* tag 'pm-5.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: PM: s2idle: Prevent spurious SCIs from waking up the system
  ACPICA: Introduce acpi_any_gpe_status_set()
  ACPI: PM: s2idle: Avoid possible race related to the EC GPE
  ACPI: EC: Fix flushing of pending work
  cpufreq: Make cpufreq_global_kobject static
2020-02-14 12:34:30 -08:00
Linus Torvalds
61a7595403 Various fixes:
- Fix an uninitialized variable
 
  - Fix compile bug to bootconfig userspace tool (in tools directory)
 
  - Suppress some error messages of bootconfig userspace tool
 
  - Remove unneded CONFIG_LIBXBC from bootconfig
 
  - Allocate bootconfig xbc_nodes dynamically.
    To ease complaints about taking up static memory at boot up
 
  - Use of parse_args() to parse bootconfig instead of strstr() usage
    Prevents issues of double quotes containing the interested string
 
  - Fix missing ring_buffer_nest_end() on synthetic event error path
 
  - Return zero not -EINVAL on soft disabled synthetic event
    (soft disabling must be the same as hard disabling, which returns zero)
 
  - Consolidate synthetic event code (remove duplicate code)
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Merge tag 'trace-v5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
 "Various fixes:

   - Fix an uninitialized variable

   - Fix compile bug to bootconfig userspace tool (in tools directory)

   - Suppress some error messages of bootconfig userspace tool

   - Remove unneded CONFIG_LIBXBC from bootconfig

   - Allocate bootconfig xbc_nodes dynamically. To ease complaints about
     taking up static memory at boot up

   - Use of parse_args() to parse bootconfig instead of strstr() usage
     Prevents issues of double quotes containing the interested string

   - Fix missing ring_buffer_nest_end() on synthetic event error path

   - Return zero not -EINVAL on soft disabled synthetic event (soft
     disabling must be the same as hard disabling, which returns zero)

   - Consolidate synthetic event code (remove duplicate code)"

* tag 'trace-v5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Consolidate trace() functions
  tracing: Don't return -EINVAL when tracing soft disabled synth events
  tracing: Add missing nest end to synth_event_trace_start() error case
  tools/bootconfig: Suppress non-error messages
  bootconfig: Allocate xbc_nodes array dynamically
  bootconfig: Use parse_args() to find bootconfig and '--'
  tracing/kprobe: Fix uninitialized variable bug
  bootconfig: Remove unneeded CONFIG_LIBXBC
  tools/bootconfig: Fix wrong __VA_ARGS__ usage
2020-02-11 16:39:18 -08:00
Randy Dunlap
e9f5490c35 sched/fair: Fix kernel-doc warning in attach_entity_load_avg()
Fix kernel-doc warning in kernel/sched/fair.c, caused by a recent
function parameter removal:

  ../kernel/sched/fair.c:3526: warning: Excess function parameter 'flags' description in 'attach_entity_load_avg'

Fixes: a4f9a0e51b ("sched/fair: Remove redundant call to cpufreq_update_util()")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/cbe964e4-6879-fd08-41c9-ef1917414af4@infradead.org
2020-02-11 13:05:10 +01:00
Madhuparna Bhowmik
4104a562e0 sched/core: Annotate curr pointer in rq with __rcu
This patch fixes the following sparse warnings in sched/core.c
and sched/membarrier.c:

  kernel/sched/core.c:2372:27: error: incompatible types in comparison expression
  kernel/sched/core.c:4061:17: error: incompatible types in comparison expression
  kernel/sched/core.c:6067:9: error: incompatible types in comparison expression
  kernel/sched/membarrier.c:108:21: error: incompatible types in comparison expression
  kernel/sched/membarrier.c:177:21: error: incompatible types in comparison expression
  kernel/sched/membarrier.c:243:21: error: incompatible types in comparison expression

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200201125803.20245-1-madhuparnabhowmik10@gmail.com
2020-02-11 13:00:37 +01:00
Suren Baghdasaryan
6fcca0fa48 sched/psi: Fix OOB write when writing 0 bytes to PSI files
Issuing write() with count parameter set to 0 on any file under
/proc/pressure/ will cause an OOB write because of the access to
buf[buf_size-1] when NUL-termination is performed. Fix this by checking
for buf_size to be non-zero.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: https://lkml.kernel.org/r/20200203212216.7076-1-surenb@google.com
2020-02-11 13:00:02 +01:00
Rafael J. Wysocki
e3728b50cd ACPI: PM: s2idle: Avoid possible race related to the EC GPE
It is theoretically possible for the ACPI EC GPE to be set after the
s2idle_ops->wake() called from s2idle_loop() has returned and before
the subsequent pm_wakeup_pending() check is carried out.  If that
happens, the resulting wakeup event will cause the system to resume
even though it may be a spurious one.

To avoid that race, first make the ->wake() callback in struct
platform_s2idle_ops return a bool value indicating whether or not
to let the system resume and rearrange s2idle_loop() to use that
value instad of the direct pm_wakeup_pending() call if ->wake() is
present.

Next, rework acpi_s2idle_wake() to process EC events and check
pm_wakeup_pending() before re-arming the SCI for system wakeup
to prevent it from triggering prematurely and add comments to
that function to explain the rationale for the new code flow.

Fixes: 56b9918490 ("PM: sleep: Simplify suspend-to-idle control flow")
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-02-11 10:11:02 +01:00
Tom Zanussi
7276531d40 tracing: Consolidate trace() functions
Move the checking, buffer reserve and buffer commit code in
synth_event_trace_start/end() into inline functions
__synth_event_trace_start/end() so they can also be used by
synth_event_trace() and synth_event_trace_array(), and then have all
those functions use them.

Also, change synth_event_trace_state.enabled to disabled so it only
needs to be set if the event is disabled, which is not normally the
case.

Link: http://lkml.kernel.org/r/b1f3108d0f450e58192955a300e31d0405ab4149.1581374549.git.zanussi@kernel.org

Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-10 22:00:21 -05:00
Tom Zanussi
0c62f6cd9e tracing: Don't return -EINVAL when tracing soft disabled synth events
There's no reason to return -EINVAL when tracing a synthetic event if
it's soft disabled - treat it the same as if it were hard disabled and
return normally.

Have synth_event_trace() and synth_event_trace_array() just return
normally, and have synth_event_trace_start set the trace state to
disabled and return.

Link: http://lkml.kernel.org/r/df5d02a1625aff97c9866506c5bada6a069982ba.1581374549.git.zanussi@kernel.org

Fixes: 8dcc53ad95 ("tracing: Add synth_event_trace() and related functions")
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-10 22:00:13 -05:00
Tom Zanussi
d090409abb tracing: Add missing nest end to synth_event_trace_start() error case
If the ring_buffer reserve in synth_event_trace_start() fails, the
matching ring_buffer_nest_end() should be called in the error code,
since nothing else will ever call it in this case.

Link: http://lkml.kernel.org/r/20abc444b3eeff76425f895815380abe7aa53ff8.1581374549.git.zanussi@kernel.org

Fixes: 8dcc53ad95 ("tracing: Add synth_event_trace() and related functions")
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-10 21:58:19 -05:00
Linus Torvalds
0a679e13ea Merge branch 'for-5.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fix from Tejun Heo:
 "I made a mistake while removing cgroup task list lazy init
  optimization making the root cgroup.procs show entries for the
  init_tasks. The zero entries doesn't cause critical failures but does
  make systemd print out warning messages during boot.

  Fix it by omitting init_tasks as they should be"

* 'for-5.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: init_tasks shouldn't be linked to the root cgroup
2020-02-10 17:07:05 -08:00
Gustavo A. R. Silva
10f129cb59 tracing/kprobe: Fix uninitialized variable bug
There is a potential execution path in which variable *ret* is returned
without being properly initialized, previously.

Fix this by initializing variable *ret* to 0.

Link: http://lkml.kernel.org/r/20200205223404.GA3379@embeddedor

Addresses-Coverity-ID: 1491142 ("Uninitialized scalar variable")
Fixes: 2a588dd1d5 ("tracing: Add kprobe event command generation functions")
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-10 12:07:42 -05:00
Mel Gorman
52262ee567 sched/fair: Allow a per-CPU kthread waking a task to stack on the same CPU, to fix XFS performance regression
The following XFS commit:

  8ab39f11d9 ("xfs: prevent CIL push holdoff in log recovery")

changed the logic from using bound workqueues to using unbound
workqueues. Functionally this makes sense but it was observed at the
time that the dbench performance dropped quite a lot and CPU migrations
were increased.

The current pattern of the task migration is straight-forward. With XFS,
an IO issuer delegates work to xlog_cil_push_work ()on an unbound kworker.
This runs on a nearby CPU and on completion, dbench wakes up on its old CPU
as it is still idle and no migration occurs. dbench then queues the real
IO on the blk_mq_requeue_work() work item which runs on a bound kworker
which is forced to run on the same CPU as dbench. When IO completes,
the bound kworker wakes dbench but as the kworker is a bound but,
real task, the CPU is not considered idle and dbench gets migrated by
select_idle_sibling() to a new CPU. dbench may ping-pong between two CPUs
for a while but ultimately it starts a round-robin of all CPUs sharing
the same LLC. High-frequency migration on each IO completion has poor
performance overall. It has negative implications both in commication
costs and power management. mpstat confirmed that at low thread counts
that all CPUs sharing an LLC has low level of activity.

Note that even if the CIL patch was reverted, there still would
be migrations but the impact is less noticeable. It turns out that
individually the scheduler, XFS, blk-mq and workqueues all made sensible
decisions but in combination, the overall effect was sub-optimal.

This patch special cases the IO issue/completion pattern and allows
a bound kworker waker and a task wakee to stack on the same CPU if
there is a strong chance they are directly related. The expectation
is that the kworker is likely going back to sleep shortly. This is not
guaranteed as the IO could be queued asynchronously but there is a very
strong relationship between the task and kworker in this case that would
justify stacking on the same CPU instead of migrating. There should be
few concerns about kworker starvation given that the special casing is
only when the kworker is the waker.

DBench on XFS
MMTests config: io-dbench4-async modified to run on a fresh XFS filesystem

UMA machine with 8 cores sharing LLC
                          5.5.0-rc7              5.5.0-rc7
                  tipsched-20200124           kworkerstack
Amean     1        22.63 (   0.00%)       20.54 *   9.23%*
Amean     2        25.56 (   0.00%)       23.40 *   8.44%*
Amean     4        28.63 (   0.00%)       27.85 *   2.70%*
Amean     8        37.66 (   0.00%)       37.68 (  -0.05%)
Amean     64      469.47 (   0.00%)      468.26 (   0.26%)
Stddev    1         1.00 (   0.00%)        0.72 (  28.12%)
Stddev    2         1.62 (   0.00%)        1.97 ( -21.54%)
Stddev    4         2.53 (   0.00%)        3.58 ( -41.19%)
Stddev    8         5.30 (   0.00%)        5.20 (   1.92%)
Stddev    64       86.36 (   0.00%)       94.53 (  -9.46%)

NUMA machine, 48 CPUs total, 24 CPUs share cache
                           5.5.0-rc7              5.5.0-rc7
                   tipsched-20200124      kworkerstack-v1r2
Amean     1         58.69 (   0.00%)       30.21 *  48.53%*
Amean     2         60.90 (   0.00%)       35.29 *  42.05%*
Amean     4         66.77 (   0.00%)       46.55 *  30.28%*
Amean     8         81.41 (   0.00%)       68.46 *  15.91%*
Amean     16       113.29 (   0.00%)      107.79 *   4.85%*
Amean     32       199.10 (   0.00%)      198.22 *   0.44%*
Amean     64       478.99 (   0.00%)      477.06 *   0.40%*
Amean     128     1345.26 (   0.00%)     1372.64 *  -2.04%*
Stddev    1          2.64 (   0.00%)        4.17 ( -58.08%)
Stddev    2          4.35 (   0.00%)        5.38 ( -23.73%)
Stddev    4          6.77 (   0.00%)        6.56 (   3.00%)
Stddev    8         11.61 (   0.00%)       10.91 (   6.04%)
Stddev    16        18.63 (   0.00%)       19.19 (  -3.01%)
Stddev    32        38.71 (   0.00%)       38.30 (   1.06%)
Stddev    64       100.28 (   0.00%)       91.24 (   9.02%)
Stddev    128      186.87 (   0.00%)      160.34 (  14.20%)

Dbench has been modified to report the time to complete a single "load
file". This is a more meaningful metric for dbench that a throughput
metric as the benchmark makes many different system calls that are not
throughput-related

Patch shows a 9.23% and 48.53% reduction in the time to process a load
file with the difference partially explained by the number of CPUs sharing
a LLC. In a separate run, task migrations were almost eliminated by the
patch for low client counts. In case people have issue with the metric
used for the benchmark, this is a comparison of the throughputs as
reported by dbench on the NUMA machine.

dbench4 Throughput (misleading but traditional)
                           5.5.0-rc7              5.5.0-rc7
                   tipsched-20200124      kworkerstack-v1r2
Hmean     1        321.41 (   0.00%)      617.82 *  92.22%*
Hmean     2        622.87 (   0.00%)     1066.80 *  71.27%*
Hmean     4       1134.56 (   0.00%)     1623.74 *  43.12%*
Hmean     8       1869.96 (   0.00%)     2212.67 *  18.33%*
Hmean     16      2673.11 (   0.00%)     2806.13 *   4.98%*
Hmean     32      3032.74 (   0.00%)     3039.54 (   0.22%)
Hmean     64      2514.25 (   0.00%)     2498.96 *  -0.61%*
Hmean     128     1778.49 (   0.00%)     1746.05 *  -1.82%*

Note that this is somewhat specific to XFS and ext4 shows no performance
difference as it does not rely on kworkers in the same way. No major
problem was observed running other workloads on different machines although
not all tests have completed yet.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200128154006.GD3466@techsingularity.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-02-10 11:24:37 +01:00
Linus Torvalds
89a47dd1af Kbuild updates for v5.6 (2nd)
- fix randconfig to generate a sane .config
 
  - rename hostprogs-y / always to hostprogs / always-y, which are
    more natual syntax.
 
  - optimize scripts/kallsyms
 
  - fix yes2modconfig and mod2yesconfig
 
  - make multiple directory targets ('make foo/ bar/') work
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Merge tag 'kbuild-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull more Kbuild updates from Masahiro Yamada:

 - fix randconfig to generate a sane .config

 - rename hostprogs-y / always to hostprogs / always-y, which are more
   natual syntax.

 - optimize scripts/kallsyms

 - fix yes2modconfig and mod2yesconfig

 - make multiple directory targets ('make foo/ bar/') work

* tag 'kbuild-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: make multiple directory targets work
  kconfig: Invalidate all symbols after changing to y or m.
  kallsyms: fix type of kallsyms_token_table[]
  scripts/kallsyms: change table to store (strcut sym_entry *)
  scripts/kallsyms: rename local variables in read_symbol()
  kbuild: rename hostprogs-y/always to hostprogs/always-y
  kbuild: fix the document to use extra-y for vmlinux.lds
  kconfig: fix broken dependency in randconfig-generated .config
2020-02-09 16:05:50 -08:00
Linus Torvalds
1a2a76c268 A set of fixes for X86:
- Ensure that the PIT is set up when the local APIC is disable or
    configured in legacy mode. This is caused by an ordering issue
    introduced in the recent changes which skip PIT initialization when the
    TSC and APIC frequencies are already known.
 
  - Handle malformed SRAT tables during early ACPI parsing which caused an
    infinite loop anda boot hang.
 
  - Fix a long standing race in the affinity setting code which affects PCI
    devices with non-maskable MSI interrupts. The problem is caused by the
    non-atomic writes of the MSI address (destination APIC id) and data
    (vector) fields which the device uses to construct the MSI message. The
    non-atomic writes are mandated by PCI.
 
    If both fields change and the device raises an interrupt after writing
    address and before writing data, then the MSI block constructs a
    inconsistent message which causes interrupts to be lost and subsequent
    malfunction of the device.
 
    The fix is to redirect the interrupt to the new vector on the current
    CPU first and then switch it over to the new target CPU. This allows to
    observe an eventually raised interrupt in the transitional stage (old
    CPU, new vector) to be observed in the APIC IRR and retriggered on the
    new target CPU and the new vector. The potential spurious interrupts
    caused by this are harmless and can in the worst case expose a buggy
    driver (all handlers have to be able to deal with spurious interrupts as
    they can and do happen for various reasons).
 
  - Add the missing suspend/resume mechanism for the HYPERV hypercall page
    which prevents resume hibernation on HYPERV guests. This change got
    lost before the merge window.
 
  - Mask the IOAPIC before disabling the local APIC to prevent potentially
    stale IOAPIC remote IRR bits which cause stale interrupt lines after
    resume.
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Merge tag 'x86-urgent-2020-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Thomas Gleixner:
 "A set of fixes for X86:

   - Ensure that the PIT is set up when the local APIC is disable or
     configured in legacy mode. This is caused by an ordering issue
     introduced in the recent changes which skip PIT initialization when
     the TSC and APIC frequencies are already known.

   - Handle malformed SRAT tables during early ACPI parsing which caused
     an infinite loop anda boot hang.

   - Fix a long standing race in the affinity setting code which affects
     PCI devices with non-maskable MSI interrupts. The problem is caused
     by the non-atomic writes of the MSI address (destination APIC id)
     and data (vector) fields which the device uses to construct the MSI
     message. The non-atomic writes are mandated by PCI.

     If both fields change and the device raises an interrupt after
     writing address and before writing data, then the MSI block
     constructs a inconsistent message which causes interrupts to be
     lost and subsequent malfunction of the device.

     The fix is to redirect the interrupt to the new vector on the
     current CPU first and then switch it over to the new target CPU.
     This allows to observe an eventually raised interrupt in the
     transitional stage (old CPU, new vector) to be observed in the APIC
     IRR and retriggered on the new target CPU and the new vector.

     The potential spurious interrupts caused by this are harmless and
     can in the worst case expose a buggy driver (all handlers have to
     be able to deal with spurious interrupts as they can and do happen
     for various reasons).

   - Add the missing suspend/resume mechanism for the HYPERV hypercall
     page which prevents resume hibernation on HYPERV guests. This
     change got lost before the merge window.

   - Mask the IOAPIC before disabling the local APIC to prevent
     potentially stale IOAPIC remote IRR bits which cause stale
     interrupt lines after resume"

* tag 'x86-urgent-2020-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/apic: Mask IOAPIC entries when disabling the local APIC
  x86/hyperv: Suspend/resume the hypercall page for hibernation
  x86/apic/msi: Plug non-maskable MSI affinity race
  x86/boot: Handle malformed SRAT tables during early ACPI parsing
  x86/timer: Don't skip PIT setup when APIC is disabled or in legacy mode
2020-02-09 12:11:12 -08:00
Linus Torvalds
f41377609a Two fixes for the SMP related functionality:
- Make the UP version of smp_call_function_single() match SMP semantics
    when called for a not available CPU.  Instead of emitting a warning and
    assuming that the function call target is CPU0, return a proper error
    code like the SMP version does.
 
  - Remove a superfluous check in smp_call_function_many_cond()
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Merge tag 'smp-urgent-2020-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull SMP fixes from Thomas Gleixner:
 "Two fixes for the SMP related functionality:

   - Make the UP version of smp_call_function_single() match SMP
     semantics when called for a not available CPU. Instead of emitting
     a warning and assuming that the function call target is CPU0,
     return a proper error code like the SMP version does.

   - Remove a superfluous check in smp_call_function_many_cond()"

* tag 'smp-urgent-2020-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  smp/up: Make smp_call_function_single() match SMP semantics
  smp: Remove superfluous cond_func check in smp_call_function_many_cond()
2020-02-09 12:09:43 -08:00
Linus Torvalds
ca21b9b370 A set of fixes and improvements for the perf subsystem:
- Kernel fixes:
 
    - Install cgroup events to the correct CPU context to prevent a
      potential list double add
 
    - Prevent am intgeer underflow in the perf mlock acounting
 
    - Add a missing prototyp for arch_perf_update_userpage()
 
  - Tooling:
 
    - Add a missing unlock in the error path of maps__insert() in perf maps.
 
    - Fix the build with the latest libbfd
 
    - Fix the perf parser so it does not delete parse event terms, which
      caused a regression for using perf with the ARM CoreSight as the sink
      confuguration was missing due to the deletion.
 
    - Fix the double free in the perf CPU map merging test case
 
    - Add the missing ustring support for the perf probe command
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Merge tag 'perf-urgent-2020-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf fixes from Thomas Gleixner:
 "A set of fixes and improvements for the perf subsystem:

  Kernel fixes:

   - Install cgroup events to the correct CPU context to prevent a
     potential list double add

   - Prevent an integer underflow in the perf mlock accounting

   - Add a missing prototype for arch_perf_update_userpage()

  Tooling:

   - Add a missing unlock in the error path of maps__insert() in perf
     maps.

   - Fix the build with the latest libbfd

   - Fix the perf parser so it does not delete parse event terms, which
     caused a regression for using perf with the ARM CoreSight as the
     sink configuration was missing due to the deletion.

   - Fix the double free in the perf CPU map merging test case

   - Add the missing ustring support for the perf probe command"

* tag 'perf-urgent-2020-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf maps: Add missing unlock to maps__insert() error case
  perf probe: Add ustring support for perf probe command
  perf: Make perf able to build with latest libbfd
  perf test: Fix test case Merge cpu map
  perf parse: Copy string to perf_evsel_config_term
  perf parse: Refactor 'struct perf_evsel_config_term'
  kernel/events: Add a missing prototype for arch_perf_update_userpage()
  perf/cgroups: Install cgroup events to correct cpuctx
  perf/core: Fix mlock accounting in perf_mmap()
2020-02-09 12:04:09 -08:00
Linus Torvalds
2fbc23c738 Two small fixes for the time(r) subsystem:
- Handle a subtle race between the clocksource watchdog and a concurrent
     clocksource watchdog stop/start sequence correctly to prevent a timer
     double add bug.
 
   - Fix the file path for the core time namespace file.
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Merge tag 'timers-urgent-2020-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer fixes from Thomas Gleixner:
 "Two small fixes for the time(r) subsystem:

   - Handle a subtle race between the clocksource watchdog and a
     concurrent clocksource watchdog stop/start sequence correctly to
     prevent a timer double add bug.

   - Fix the file path for the core time namespace file"

* tag 'timers-urgent-2020-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource: Prevent double add_timer_on() for watchdog_timer
  MAINTAINERS: Correct path to time namespace source file
2020-02-09 12:00:12 -08:00
Linus Torvalds
f06bed87d7 A set of fixes for the interrupt subsystem:
- Provision only ACPI enabled redistributors on GICv3
 
  - Use the proper command colums when building the INVALL command for the
    GICv3-ITS
 
  - Ensure the allocation of the L2 vPE table for GICv4.1
 
  - Correct the GICv4.1 VPROBASER programming so it uses the proper size
 
  - A set of small GICv4.1 tidy up patches
 
  - Configuration cleanup for C-SKY interrupt chip
 
  - Clarify the function documentation for irq_set_wake() to document that
    the wakeup functionality is orthogonal to the irq disable/enable
    mechanism.
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Merge tag 'irq-urgent-2020-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull interrupt fixes from Thomas Gleixner:
 "A set of fixes for the interrupt subsystem:

   - Provision only ACPI enabled redistributors on GICv3

   - Use the proper command colums when building the INVALL command for
     the GICv3-ITS

   - Ensure the allocation of the L2 vPE table for GICv4.1

   - Correct the GICv4.1 VPROBASER programming so it uses the proper
     size

   - A set of small GICv4.1 tidy up patches

   - Configuration cleanup for C-SKY interrupt chip

   - Clarify the function documentation for irq_set_wake() to document
     that the wakeup functionality is orthogonal to the irq
     disable/enable mechanism"

* tag 'irq-urgent-2020-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/gic-v3-its: Rename VPENDBASER/VPROPBASER accessors
  irqchip/gic-v3-its: Remove superfluous WARN_ON
  irqchip/gic-v4.1: Drop 'tmp' in inherit_vpe_l1_table_from_rd()
  irqchip/gic-v4.1: Ensure L2 vPE table is allocated at RD level
  irqchip/gic-v4.1: Set vpe_l1_base for all redistributors
  irqchip/gic-v4.1: Fix programming of GICR_VPROPBASER_4_1_SIZE
  genirq: Clarify that irq wake state is orthogonal to enable/disable
  irqchip/gic-v3-its: Reference to its_invall_cmd descriptor when building INVALL
  irqchip: Some Kconfig cleanup for C-SKY
  irqchip/gic-v3: Only provision redistributors that are enabled in ACPI
2020-02-09 11:56:41 -08:00
Linus Torvalds
291abfea47 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from David Miller:

 1) Unbalanced locking in mwifiex_process_country_ie, from Brian Norris.

 2) Fix thermal zone registration in iwlwifi, from Andrei
    Otcheretianski.

 3) Fix double free_irq in sgi ioc3 eth, from Thomas Bogendoerfer.

 4) Use after free in mptcp, from Florian Westphal.

 5) Use after free in wireguard's root_remove_peer_lists, from Eric
    Dumazet.

 6) Properly access packets heads in bonding alb code, from Eric
    Dumazet.

 7) Fix data race in skb_queue_len(), from Qian Cai.

 8) Fix regression in r8169 on some chips, from Heiner Kallweit.

 9) Fix XDP program ref counting in hv_netvsc, from Haiyang Zhang.

10) Certain kinds of set link netlink operations can cause a NULL deref
    in the ipv6 addrconf code. Fix from Eric Dumazet.

11) Don't cancel uninitialized work queue in drop monitor, from Ido
    Schimmel.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (84 commits)
  net: thunderx: use proper interface type for RGMII
  mt76: mt7615: fix max_nss in mt7615_eeprom_parse_hw_cap
  bpf: Improve bucket_log calculation logic
  selftests/bpf: Test freeing sockmap/sockhash with a socket in it
  bpf, sockhash: Synchronize_rcu before free'ing map
  bpf, sockmap: Don't sleep while holding RCU lock on tear-down
  bpftool: Don't crash on missing xlated program instructions
  bpf, sockmap: Check update requirements after locking
  drop_monitor: Do not cancel uninitialized work item
  mlxsw: spectrum_dpipe: Add missing error path
  mlxsw: core: Add validation of hardware device types for MGPIR register
  mlxsw: spectrum_router: Clear offload indication from IPv6 nexthops on abort
  selftests: mlxsw: Add test cases for local table route replacement
  mlxsw: spectrum_router: Prevent incorrect replacement of local table routes
  net: dsa: microchip: enable module autoprobe
  ipv6/addrconf: fix potential NULL deref in inet6_set_link_af()
  dpaa_eth: support all modes with rate adapting PHYs
  net: stmmac: update pci platform data to use phy_interface
  net: stmmac: xgmac: fix missing IFF_MULTICAST checki in dwxgmac2_set_filter
  net: stmmac: fix missing IFF_MULTICAST check in dwmac4_set_filter
  ...
2020-02-08 17:15:08 -08:00
Linus Torvalds
c9d35ee049 Merge branch 'merge.nfs-fs_parse.1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs file system parameter updates from Al Viro:
 "Saner fs_parser.c guts and data structures. The system-wide registry
  of syntax types (string/enum/int32/oct32/.../etc.) is gone and so is
  the horror switch() in fs_parse() that would have to grow another case
  every time something got added to that system-wide registry.

  New syntax types can be added by filesystems easily now, and their
  namespace is that of functions - not of system-wide enum members. IOW,
  they can be shared or kept private and if some turn out to be widely
  useful, we can make them common library helpers, etc., without having
  to do anything whatsoever to fs_parse() itself.

  And we already get that kind of requests - the thing that finally
  pushed me into doing that was "oh, and let's add one for timeouts -
  things like 15s or 2h". If some filesystem really wants that, let them
  do it. Without somebody having to play gatekeeper for the variants
  blessed by direct support in fs_parse(), TYVM.

  Quite a bit of boilerplate is gone. And IMO the data structures make a
  lot more sense now. -200LoC, while we are at it"

* 'merge.nfs-fs_parse.1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (25 commits)
  tmpfs: switch to use of invalfc()
  cgroup1: switch to use of errorfc() et.al.
  procfs: switch to use of invalfc()
  hugetlbfs: switch to use of invalfc()
  cramfs: switch to use of errofc() et.al.
  gfs2: switch to use of errorfc() et.al.
  fuse: switch to use errorfc() et.al.
  ceph: use errorfc() and friends instead of spelling the prefix out
  prefix-handling analogues of errorf() and friends
  turn fs_param_is_... into functions
  fs_parse: handle optional arguments sanely
  fs_parse: fold fs_parameter_desc/fs_parameter_spec
  fs_parser: remove fs_parameter_description name field
  add prefix to fs_context->log
  ceph_parse_param(), ceph_parse_mon_ips(): switch to passing fc_log
  new primitive: __fs_parse()
  switch rbd and libceph to p_log-based primitives
  struct p_log, variants of warnf() et.al. taking that one instead
  teach logfc() to handle prefices, give it saner calling conventions
  get rid of cg_invalf()
  ...
2020-02-08 13:26:41 -08:00
David S. Miller
2696e1146d Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Daniel Borkmann says:

====================
pull-request: bpf 2020-02-07

The following pull-request contains BPF updates for your *net* tree.

We've added 15 non-merge commits during the last 10 day(s) which contain
a total of 12 files changed, 114 insertions(+), 31 deletions(-).

The main changes are:

1) Various BPF sockmap fixes related to RCU handling in the map's tear-
   down code, from Jakub Sitnicki.

2) Fix macro state explosion in BPF sk_storage map when calculating its
   bucket_log on allocation, from Martin KaFai Lau.

3) Fix potential BPF sockmap update race by rechecking socket's established
   state under lock, from Lorenz Bauer.

4) Fix crash in bpftool on missing xlated instructions when kptr_restrict
   sysctl is set, from Toke Høiland-Jørgensen.

5) Fix i40e's XSK wakeup code to return proper error in busy state and
   various misc fixes in xdpsock BPF sample code, from Maciej Fijalkowski.

6) Fix the way modifiers are skipped in BTF in the verifier while walking
   pointers to avoid program rejection, from Alexei Starovoitov.

7) Fix Makefile for runqslower BPF tool to i) rebuild on libbpf changes and
   ii) to fix undefined reference linker errors for older gcc version due to
   order of passed gcc parameters, from Yulia Kartseva and Song Liu.

8) Fix a trampoline_count BPF kselftest warning about missing braces around
   initializer, from Andrii Nakryiko.

9) Fix up redundant "HAVE" prefix from large INSN limit kernel probe in
   bpftool, from Michal Rostecki.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-08 15:01:03 +01:00
Stephen Boyd
f9f21cea31 genirq: Clarify that irq wake state is orthogonal to enable/disable
There's some confusion around if an irq that's disabled with disable_irq()
can still wake the system from sleep states such as "suspend to RAM".

Clarify this in the kernel documentation for irq_set_irq_wake() so that
it's clear that an irq can be disabled and still wake the system if it has
been marked for wakeup.

Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lkml.kernel.org/r/20200206191521.94559-1-swboyd@chromium.org
2020-02-07 21:37:08 +01:00
Al Viro
58c025f0e8 cgroup1: switch to use of errorfc() et.al.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-02-07 14:48:43 -05:00
Al Viro
d7167b1499 fs_parse: fold fs_parameter_desc/fs_parameter_spec
The former contains nothing but a pointer to an array of the latter...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-02-07 14:48:37 -05:00
Eric Sandeen
96cafb9ccb fs_parser: remove fs_parameter_description name field
Unused now.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-02-07 14:48:36 -05:00
Al Viro
fbc2d1686d get rid of cg_invalf()
pointless alias for invalf()...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-02-07 14:48:31 -05:00
Paul E. McKenney
1e474b28e7 smp/up: Make smp_call_function_single() match SMP semantics
In CONFIG_SMP=y kernels, smp_call_function_single() returns -ENXIO when
invoked for a non-existent CPU.  In contrast, in CONFIG_SMP=n kernels,
a splat is emitted and smp_call_function_single() otherwise silently
ignores its "cpu" argument, instead pretending that the caller intended
to have something happen on CPU 0.  Given that there is now code that
expects smp_call_function_single() to return an error if a bad CPU was
specified, this difference in semantics needs to be addressed.

Bring the semantics of the CONFIG_SMP=n version of
smp_call_function_single() into alignment with its CONFIG_SMP=y
counterpart.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200205143409.GA7021@paulmck-ThinkPad-P72
2020-02-07 15:34:12 +01:00
Linus Torvalds
d854b2d639 kgdb fixes for 5.6-rc1
One of the simplifications added for 5.6-rc1 has caused build
 regressions on some platforms (it was reported for sparc64).
 This pull request fixes it with a direct revert.
 
 Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
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Merge tag 'kgdb-fixes-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux

Pull kgdb fix from Daniel Thompson:
 "One of the simplifications added for 5.6-rc1 has caused build
  regressions on some platforms (it was reported for sparc64).

  This fixes it with a revert"

* tag 'kgdb-fixes-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux:
  Revert "kdb: Get rid of confusing diag msg from "rd" if current task has no regs"
2020-02-06 09:05:42 -08:00
Daniel Thompson
fcf2736c82 Revert "kdb: Get rid of confusing diag msg from "rd" if current task has no regs"
This reverts commit bbfceba15f.

When DBG_MAX_REG_NUM is zero then a number of symbols are conditionally
defined. It is therefore not possible to check it using C expressions.

Reported-by: Anatoly Pugachev <matorola@gmail.com>
Acked-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-02-06 11:40:09 +00:00
Linus Torvalds
e310396bb8 Tracing updates:
- Added new "bootconfig".
    Looks for a file appended to initrd to add boot config options.
    This has been discussed thoroughly at Linux Plumbers.
    Very useful for adding kprobes at bootup.
    Only enabled if "bootconfig" is on the real kernel command line.
 
  - Created dynamic event creation.
    Merges common code between creating synthetic events and
      kprobe events.
 
  - Rename perf "ring_buffer" structure to "perf_buffer"
 
  - Rename ftrace "ring_buffer" structure to "trace_buffer"
    Had to rename existing "trace_buffer" to "array_buffer"
 
  - Allow trace_printk() to work withing (some) tracing code.
 
  - Sort of tracing configs to be a little better organized
 
  - Fixed bug where ftrace_graph hash was not being protected properly
 
  - Various other small fixes and clean ups
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Merge tag 'trace-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:

 - Added new "bootconfig".

   This looks for a file appended to initrd to add boot config options,
   and has been discussed thoroughly at Linux Plumbers.

   Very useful for adding kprobes at bootup.

   Only enabled if "bootconfig" is on the real kernel command line.

 - Created dynamic event creation.

   Merges common code between creating synthetic events and kprobe
   events.

 - Rename perf "ring_buffer" structure to "perf_buffer"

 - Rename ftrace "ring_buffer" structure to "trace_buffer"

   Had to rename existing "trace_buffer" to "array_buffer"

 - Allow trace_printk() to work withing (some) tracing code.

 - Sort of tracing configs to be a little better organized

 - Fixed bug where ftrace_graph hash was not being protected properly

 - Various other small fixes and clean ups

* tag 'trace-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (88 commits)
  bootconfig: Show the number of nodes on boot message
  tools/bootconfig: Show the number of bootconfig nodes
  bootconfig: Add more parse error messages
  bootconfig: Use bootconfig instead of boot config
  ftrace: Protect ftrace_graph_hash with ftrace_sync
  ftrace: Add comment to why rcu_dereference_sched() is open coded
  tracing: Annotate ftrace_graph_notrace_hash pointer with __rcu
  tracing: Annotate ftrace_graph_hash pointer with __rcu
  bootconfig: Only load bootconfig if "bootconfig" is on the kernel cmdline
  tracing: Use seq_buf for building dynevent_cmd string
  tracing: Remove useless code in dynevent_arg_pair_add()
  tracing: Remove check_arg() callbacks from dynevent args
  tracing: Consolidate some synth_event_trace code
  tracing: Fix now invalid var_ref_vals assumption in trace action
  tracing: Change trace_boot to use synth_event interface
  tracing: Move tracing selftests to bottom of menu
  tracing: Move mmio tracer config up with the other tracers
  tracing: Move tracing test module configs together
  tracing: Move all function tracing configs together
  tracing: Documentation for in-kernel synthetic event API
  ...
2020-02-06 07:12:11 +00:00
Steven Rostedt (VMware)
54a16ff6f2 ftrace: Protect ftrace_graph_hash with ftrace_sync
As function_graph tracer can run when RCU is not "watching", it can not be
protected by synchronize_rcu() it requires running a task on each CPU before
it can be freed. Calling schedule_on_each_cpu(ftrace_sync) needs to be used.

Link: https://lore.kernel.org/r/20200205131110.GT2935@paulmck-ThinkPad-P72

Cc: stable@vger.kernel.org
Fixes: b9b0c831be ("ftrace: Convert graph filter to use hash tables")
Reported-by: "Paul E. McKenney" <paulmck@kernel.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-05 17:16:42 -05:00
Steven Rostedt (VMware)
16052dd5bd ftrace: Add comment to why rcu_dereference_sched() is open coded
Because the function graph tracer can execute in sections where RCU is not
"watching", the rcu_dereference_sched() for the has needs to be open coded.
This is fine because the RCU "flavor" of the ftrace hash is protected by
its own RCU handling (it does its own little synchronization on every CPU
and does not rely on RCU sched).

Acked-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-05 17:15:57 -05:00
Amol Grover
fd0e6852c4 tracing: Annotate ftrace_graph_notrace_hash pointer with __rcu
Fix following instances of sparse error
kernel/trace/ftrace.c:5667:29: error: incompatible types in comparison
kernel/trace/ftrace.c:5813:21: error: incompatible types in comparison
kernel/trace/ftrace.c:5868:36: error: incompatible types in comparison
kernel/trace/ftrace.c:5870:25: error: incompatible types in comparison

Use rcu_dereference_protected to dereference the newly annotated pointer.

Link: http://lkml.kernel.org/r/20200205055701.30195-1-frextrite@gmail.com

Signed-off-by: Amol Grover <frextrite@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-05 17:14:37 -05:00
Amol Grover
24a9729f83 tracing: Annotate ftrace_graph_hash pointer with __rcu
Fix following instances of sparse error
kernel/trace/ftrace.c:5664:29: error: incompatible types in comparison
kernel/trace/ftrace.c:5785:21: error: incompatible types in comparison
kernel/trace/ftrace.c:5864:36: error: incompatible types in comparison
kernel/trace/ftrace.c:5866:25: error: incompatible types in comparison

Use rcu_dereference_protected to access the __rcu annotated pointer.

Link: http://lkml.kernel.org/r/20200201072703.17330-1-frextrite@gmail.com

Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Amol Grover <frextrite@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-05 17:14:26 -05:00