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Adds tracepoints to pm_qos_add_request, pm_qos_update_request,
pm_qos_remove_request, and pm_qos_update_request_timeout.
It's useful for checking pm_qos_class, value, and timeout_us.
Signed-off-by: Sahara <keun-o.park@windriver.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This patch adds tracepoints to pm_qos_update_target and
pm_qos_update_flags. It's useful for checking pm qos action,
previous value and current value.
Signed-off-by: Sahara <keun-o.park@windriver.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This patch keeps track of how long perf's NMI handler is taking,
and also calculates how many samples perf can take a second. If
the sample length times the expected max number of samples
exceeds a configurable threshold, it drops the sample rate.
This way, we don't have a runaway sampling process eating up the
CPU.
This patch can tend to drop the sample rate down to level where
perf doesn't work very well. *BUT* the alternative is that my
system hangs because it spends all of its time handling NMIs.
I'll take a busted performance tool over an entire system that's
busted and undebuggable any day.
BTW, my suspicion is that there's still an underlying bug here.
Using the HPET instead of the TSC is definitely a contributing
factor, but I suspect there are some other things going on.
But, I can't go dig down on a bug like that with my machine
hanging all the time.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: paulus@samba.org
Cc: acme@ghostprotocols.net
Cc: Dave Hansen <dave@sr71.net>
[ Prettified it a bit. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 fixes from Peter Anvin:
"This series fixes a couple of build failures, and fixes MTRR cleanup
and memory setup on very specific memory maps.
Finally, it fixes triggering backtraces on all CPUs, which was
inadvertently disabled on x86."
* 'x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/efi: Fix dummy variable buffer allocation
x86: Fix trigger_all_cpu_backtrace() implementation
x86: Fix section mismatch on load_ucode_ap
x86: fix build error and kconfig for ia32_emulation and binfmt
range: Do not add new blank slot with add_range_with_merge
x86, mtrr: Fix original mtrr range get for mtrr_cleanup
The recent modification in the cpuidle framework consolidated the
timer broadcast code across the different drivers by setting a new
flag in the idle state. It tells the cpuidle core code to enter/exit
the broadcast mode for the cpu when entering a deep idle state. The
broadcast timer enter/exit is no longer handled by the back-end
driver.
This change made the local interrupt to be enabled *before* calling
CLOCK_EVENT_NOTIFY_EXIT.
On a tegra114, a four cores system, when the flag has been introduced
in the driver, the following warning appeared:
WARNING: at kernel/time/tick-broadcast.c:578 tick_broadcast_oneshot_control
CPU: 2 PID: 0 Comm: swapper/2 Not tainted 3.10.0-rc3-next-20130529+ #15
[<c00667f8>] (tick_broadcast_oneshot_control+0x1a4/0x1d0) from [<c0065cd0>] (tick_notify+0x240/0x40c)
[<c0065cd0>] (tick_notify+0x240/0x40c) from [<c0044724>] (notifier_call_chain+0x44/0x84)
[<c0044724>] (notifier_call_chain+0x44/0x84) from [<c0044828>] (raw_notifier_call_chain+0x18/0x20)
[<c0044828>] (raw_notifier_call_chain+0x18/0x20) from [<c00650cc>] (clockevents_notify+0x28/0x170)
[<c00650cc>] (clockevents_notify+0x28/0x170) from [<c033f1f0>] (cpuidle_idle_call+0x11c/0x168)
[<c033f1f0>] (cpuidle_idle_call+0x11c/0x168) from [<c000ea94>] (arch_cpu_idle+0x8/0x38)
[<c000ea94>] (arch_cpu_idle+0x8/0x38) from [<c005ea80>] (cpu_startup_entry+0x60/0x134)
[<c005ea80>] (cpu_startup_entry+0x60/0x134) from [<804fe9a4>] (0x804fe9a4)
I don't have the hardware, so I wasn't able to reproduce the warning
but after looking a while at the code, I deduced the following:
1. the CPU2 enters a deep idle state and sets the broadcast timer
2. the timer expires, the tick_handle_oneshot_broadcast function is
called, setting the tick_broadcast_pending_mask and waking up the
idle cpu CPU2
3. the CPU2 exits idle handles the interrupt and then invokes
tick_broadcast_oneshot_control with CLOCK_EVENT_NOTIFY_EXIT which
runs the following code:
[...]
if (dev->next_event.tv64 == KTIME_MAX)
goto out;
if (cpumask_test_and_clear_cpu(cpu,
tick_broadcast_pending_mask))
goto out;
[...]
So if there is no next event scheduled for CPU2, we fulfil the
first condition and jump out without clearing the
tick_broadcast_pending_mask.
4. CPU2 goes to deep idle again and calls
tick_broadcast_oneshot_control with CLOCK_NOTIFY_EVENT_ENTER but
with the tick_broadcast_pending_mask set for CPU2, triggering the
warning.
The issue only surfaced due to the modifications of the cpuidle
framework, which resulted in interrupts being enabled before the call
to the clockevents code. If the call happens before interrupts have
been enabled, the warning cannot trigger, because there is still the
event pending which caused the broadcast timer expiry.
Move the check for the next event below the check for the pending bit,
so the pending bit gets cleared whether an event is scheduled on the
cpu or not.
[ tglx: Massaged changelog ]
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reported-and-tested-by: Joseph Lo <josephl@nvidia.com>
Cc: Stephen Warren <swarren@nvidia.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linaro-kernel@lists.linaro.org
Link: http://lkml.kernel.org/r/1371485735-31249-1-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Commit a938da06 introduced a useful little log message to tell
users/debuggers which wakeup source aborted a suspend. However,
this message is only printed if the abort happens during the
in-kernel suspend path (after writing /sys/power/state).
The full specification of the /sys/power/wakeup_count facility
allows user-space power managers to double-check if wakeups have
already happened before it actually tries to suspend (e.g. while it
was running user-space pre-suspend hooks), by writing the last known
wakeup_count value to /sys/power/wakeup_count. This patch changes
the sysfs handler for that node to also print said log message if
that write fails, so that we can figure out the offending wakeup
source for both kinds of suspend aborts.
Signed-off-by: Julius Werner <jwerner@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The valid start index for pm_qos_array is not 0, but
PM_QOS_CPU_DMA_LATENCY. There is a null_pm_qos at index 0 of
pm_qos_array. However, null_pm_qos is not created as misc device so
that inclusion of 0 index for checking pm_qos_class especially for
file operations is not proper here.
[rjw: Changelog, a bit]
Signed-off-by: Sahara <keun-o.park@windriver.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Pull scheduler fixes from Ingo Molnar:
"Two smaller fixes - plus a context tracking tracing fix that is a bit
bigger"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
tracing/context-tracking: Add preempt_schedule_context() for tracing
sched: Fix clear NOHZ_BALANCE_KICK
sched/x86: Construct all sibling maps if smt
Pull perf fixes from Ingo Molnar:
"Four fixes. The mmap ones are unfortunately larger than desired -
fuzzing uncovered bugs that needed perf context life time management
changes to fix properly"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86: Fix broken PEBS-LL support on SNB-EP/IVB-EP
perf: Fix mmap() accounting hole
perf: Fix perf mmap bugs
kprobes: Fix to free gone and unused optprobes
Pull cpu idle fixes from Thomas Gleixner:
- Add a missing irq enable. Fallout of the idle conversion
- Fix stackprotector wreckage caused by the idle conversion
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
idle: Enable interrupts in the weak arch_cpu_idle() implementation
idle: Add the stack canary init to cpu_startup_entry()
Pull timer fixes from Thomas Gleixner:
- Fix inconstinant clock usage in virtual time accounting
- Fix a build error in KVM caused by the NOHZ work
- Remove a pointless timekeeping duty assignment which breaks NOHZ
- Use a proper notifier return value to avoid random behaviour
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
tick: Remove useless timekeeping duty attribution to broadcast source
nohz: Fix notifier return val that enforce timekeeping
kvm: Move guest entry/exit APIs to context_tracking
vtime: Use consistent clocks among nohz accounting
This patch simply moves all per-cpu variables into the new
single per-cpu "struct bp_cpuinfo".
To me this looks more logical and clean, but this can also
simplify the further potential changes. In particular, I do not
think this memory should be per-cpu, it is never used "locally".
After this change it is trivial to turn it into, say,
bootmem[nr_cpu_ids].
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20130620155020.GA6350@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
1. register_wide_hw_breakpoint() can use unregister_ if failure,
no need to duplicate the code.
2. "struct perf_event **pevent" adds the unnecesary lever of
indirection and complication, use per_cpu(*cpu_events, cpu).
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20130620155018.GA6347@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add the trivial helper which simply returns cpumask_of() or
cpu_possible_mask depending on bp->cpu.
Change fetch_bp_busy_slots() and toggle_bp_slot() to always do
for_each_cpu(cpumask_of_bp) to simplify the code and avoid the
code duplication.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20130620155015.GA6340@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Change toggle_bp_slot() to make "weight" negative if !enable.
This way we can always use "+ weight" without additional "if
(enable)" check and toggle_bp_task_slot() no longer needs this
arg.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20130620155013.GA6337@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The enable/disable logic in toggle_bp_slot() is not symmetrical
and imho very confusing. "old_count" in toggle_bp_task_slot() is
actually new_count because this bp was already removed from the
list.
Change toggle_bp_slot() to always call list_add/list_del after
toggle_bp_task_slot(). This way old_idx is task_bp_pinned() and
this entry should be decremented, new_idx is +/-weight and we
need to increment this element. The code/logic looks obvious.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20130620155011.GA6330@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
trinity fuzzer triggered WARN_ONCE("Can't find any breakpoint
slot") in arch_install_hw_breakpoint() but the problem is not
arch-specific.
The problem is, task_bp_pinned(cpu) checks "cpu == iter->cpu"
but this doesn't account the "all cpus" events with iter->cpu <
0.
This means that, say, register_user_hw_breakpoint(tsk) can
happily create the arbitrary number > HBP_NUM of breakpoints
which can not be activated. toggle_bp_task_slot() is equally
wrong by the same reason and nr_task_bp_pinned[] can have
negative entries.
Simple test:
# perl -e 'sleep 1 while 1' &
# perf record -e mem:0x10,mem:0x10,mem:0x10,mem:0x10,mem:0x10 -p `pidof perl`
Before this patch this triggers the same problem/WARN_ON(),
after the patch it correctly fails with -ENOSPC.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20130620155006.GA6324@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Building full dynticks now implies that all CPUs are forced
into RCU nocb mode through CONFIG_RCU_NOCB_CPU_ALL.
The dynamic check has become useless.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
When the watchdog runs, it prevents the full dynticks
CPUs from stopping their tick because the hard lockup
detector uses perf events internally, which in turn
rely on the periodic tick.
Since this is a rather confusing behaviour that is not
easy to track down and identify for those who want to
test CONFIG_NO_HZ_FULL, let's default disable the
watchdog on boot time when full dynticks is enabled.
The user can still enable it later on runtime using
proc or sysctl.
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Anish Singh <anish198519851985@gmail.com>
We have two very conflicting state variable names in the
watchdog:
* watchdog_enabled: This one reflects the user interface. It's
set to 1 by default and can be overriden with boot options
or sysctl/procfs interface.
* watchdog_disabled: This is the internal toggle state that
tells if watchdog threads, timers and NMI events are currently
running or not. This state mostly depends on the user settings.
It's a convenient state latch.
Now we really need to find clearer names because those
are just too confusing to encourage deep review.
watchdog_enabled now becomes watchdog_user_enabled to reflect
its purpose as an interface.
watchdog_disabled becomes watchdog_running to suggest its
role as a pure internal state.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Anish Singh <anish198519851985@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Don Zickus <dzickus@redhat.com>
Since tp->flags assignment was moved into function enable_trace_probe(),
there is no need to use trace_probe_is_enabled to check flags
in the same function.
Remove the unnecessary checking.
Link: http://lkml.kernel.org/r/51BA7B9E.3040807@huawei.com
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add a traceoff_on_warning option in both the kernel command line as well
as a sysctl option. When set, any WARN*() function that is hit will cause
the tracing_on variable to be cleared, which disables writing to the
ring buffer.
This is useful especially when tracing a bug with function tracing. When
a warning is hit, the print caused by the warning can flood the trace with
the functions that producing the output for the warning. This can make the
resulting trace useless by either hiding where the bug happened, or worse,
by overflowing the buffer and losing the trace of the bug totally.
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
There are some cases when filtering on a set flag of a field of a tracepoint
is useful. But currently the only filtering commands for numbered fields
is ==, !=, <, <=, >, >=. This does not help when you just want to trace if
a specific flag is set. For example:
> # sudo trace-cmd record -e brcmfmac:brcmf_dbg -f 'level & 0x40000'
> disable all
> enable brcmfmac:brcmf_dbg
> path = /sys/kernel/debug/tracing/events/brcmfmac/brcmf_dbg/enable
> (level & 0x40000)
> ^
> parse_error: Invalid operator
>
When trying to trace brcmf_dbg when level has its 1 << 18 bit set, the
filter fails to perform.
By allowing a binary '&' operation, this gives the user the ability to
test a bit.
Note, a binary '|' is not added, as it doesn't make sense as fields must
be compared to constants (for now), and ORing a constant will always return
true.
Link: http://lkml.kernel.org/r/1371057385.9844.261.camel@gandalf.local.home
Suggested-by: Arend van Spriel <arend@broadcom.com>
Tested-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The user activation/deactivation of the watchdog through boot parameters
or systcl is currently implemented with a dance involving kthreads parking
and unparking methods: the threads are unconditionally registered on
boot and they park as soon as the user want the watchdog to be disabled.
This method involves a few noisy details to handle though: the watchdog
kthreads may be unparked anytime due to hotplug operations, after which
the watchdog internals have to decide to park again if it is user-disabled.
As a result the setup() and unpark() methods need to be able to request a
reparking. This is not currently supported in the kthread infrastructure
so this piece of the watchdog code only works halfway.
Besides, unparking/reparking the watchdog kthreads consume unnecessary
cputime on hotplug operations when those could be simply ignored in the
first place.
As suggested by Srivatsa, let's instead only register the watchdog
threads when they are needed. This way we don't need to think about
hotplug operations and we don't burden the CPU onlining when the watchdog
is simply disabled.
Suggested-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Anish Singh <anish198519851985@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Don Zickus <dzickus@redhat.com>
If the user configures NO_HZ_FULL and defines nohz_full=XXX on the
kernel command line, or enables NO_HZ_FULL_ALL, but nohz fails
due to the machine having a unstable clock, warn about it.
We do not want users thinking that they are getting the benefit
of nohz when their machine can not support it.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Pull RCU changes from Paul E. McKenney:
"The major changes for this series are:
1. Simplify RCU's grace-period and callback processing based on
the new numbering for callbacks. These were posted to LKML at
https://lkml.org/lkml/2013/5/20/330.
2. Documentation updates. These were posted to LKML at
https://lkml.org/lkml/2013/5/20/348.
3. Miscellaneous fixes, including converting a few remaining printk()
calls to pr_*(). These were posted to LKML at
https://lkml.org/lkml/2013/5/20/324.
4. SRCU-related changes and fixes. These were posted to LKML at
https://lkml.org/lkml/2013/5/20/425.
5. Removal of TINY_PREEMPT_RCU in favor of TREE_PREEMPT_RCU for
single-CPU low-latency systems. These were posted to LKML at
https://lkml.org/lkml/2013/5/20/427."
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Just use struct ctl_table.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1371063336.2069.22.camel@joe-AO722
Signed-off-by: Ingo Molnar <mingo@kernel.org>
sd can't be NULL in init_sched_groups_power() and so checking it for NULL isn't
useful. In case it is required, then also we need to rearrange the code a bit as
we already accessed invalid pointer sd to get sg: sg = sd->groups.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/2bbe633cd74b431c05253a8ce61fdfd5066a531b.1370948150.git.viresh.kumar@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In build_sched_groups() we don't need to call get_group() for cpus
which are already covered in previous iterations. Calling get_group()
would mark the group used and eventually leak it since we wouldn't
connect it and not find it again to free it.
This will happen only in cases where sg->cpumask contained more than
one cpu (For any topology level). This patch would free sg's memory
for all cpus leaving the group leader as the group isn't marked used
now.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/7a61e955abdcbb1dfa9fe493f11a5ec53a11ddd3.1370948150.git.viresh.kumar@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In the beginning of build_sched_groups() we called sched_domain_span() and
cached its return value in span. Few statements later we are calling it again to
get the same pointer.
Lets use the cached value instead as it hasn't changed in between.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/834ecd507071ad88aff039352dbc7e063dd996a7.1370948150.git.viresh.kumar@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For loop for traversing sched_domain_topology was used at multiple placed in
core.c. This patch removes code redundancy by creating for_each_sd_topology().
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/e0e04542f54e9464bd9da54f5ccfe62ec6c4c0bc.1370861520.git.viresh.kumar@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Memory for sd is allocated with kzalloc_node() which will initialize its fields
with zero. In build_sched_domain() we are setting sd->child to child even if
child is NULL, which isn't required.
Lets do it only if child isn't NULL.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/f4753a1730051341003ad2ad29a3229c7356678e.1370861520.git.viresh.kumar@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We are saving first scheduling domain for a cpu in build_sched_domains() by
iterating over the nested sd->child list. We don't actually need to do it this
way.
tl will be equal to sched_domain_topology for the first iteration and so we can
set *per_cpu_ptr(d.sd, i) based on that. So, save pointer to first SD while
running the iteration loop over tl's.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/fc473527cbc4dfa0b8eeef2a59db74684eb59a83.1370436120.git.viresh.kumar@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Most of the stuff from kernel/sched.c was moved to kernel/sched/core.c long time
back and the comments/Documentation never got updated.
I figured it out when I was going through sched-domains.txt and so thought of
fixing it globally.
I haven't crossed check if the stuff that is referenced in sched/core.c by all
these files is still present and hasn't changed as that wasn't the motive behind
this patch.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/cdff76a265326ab8d71922a1db5be599f20aad45.1370329560.git.viresh.kumar@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
default_cfs_period(), do_sched_cfs_period_timer(), do_sched_cfs_slack_timer()
already defined previously, no need to declare again.
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51AD8808.7020608@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Directly use rq to save some code.
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51AD87EB.1070605@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[ Peter, this is based off of some of my work, I ran it though a few
tests and it passed. I also reviewed it, and added my SOB as I am
somewhat a co-author to it. ]
Based on the patch by Steven Rostedt from previous year:
https://lkml.org/lkml/2012/4/18/517
1)Simplify pull_rt_task() logic: search in pushable tasks of dest runqueue.
The only pullable tasks are the tasks which are pushable in their local rq,
and no others.
2)Remove .leaf_rt_rq_list member of struct rt_rq and functions connected
with it: nobody uses it since now.
Signed-off-by: Kirill Tkhai <tkhai@yandex.ru>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/287571370557898@web7d.yandex.ru
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Dave Jones hit the following bug report:
===============================
[ INFO: suspicious RCU usage. ]
3.10.0-rc2+ #1 Not tainted
-------------------------------
include/linux/rcupdate.h:771 rcu_read_lock() used illegally while idle!
other info that might help us debug this:
RCU used illegally from idle CPU! rcu_scheduler_active = 1, debug_locks = 0
RCU used illegally from extended quiescent state!
2 locks held by cc1/63645:
#0: (&rq->lock){-.-.-.}, at: [<ffffffff816b39fd>] __schedule+0xed/0x9b0
#1: (rcu_read_lock){.+.+..}, at: [<ffffffff8109d645>] cpuacct_charge+0x5/0x1f0
CPU: 1 PID: 63645 Comm: cc1 Not tainted 3.10.0-rc2+ #1 [loadavg: 40.57 27.55 13.39 25/277 64369]
Hardware name: Gigabyte Technology Co., Ltd. GA-MA78GM-S2H/GA-MA78GM-S2H, BIOS F12a 04/23/2010
0000000000000000 ffff88010f78fcf8 ffffffff816ae383 ffff88010f78fd28
ffffffff810b698d ffff88011c092548 000000000023d073 ffff88011c092500
0000000000000001 ffff88010f78fd60 ffffffff8109d7c5 ffffffff8109d645
Call Trace:
[<ffffffff816ae383>] dump_stack+0x19/0x1b
[<ffffffff810b698d>] lockdep_rcu_suspicious+0xfd/0x130
[<ffffffff8109d7c5>] cpuacct_charge+0x185/0x1f0
[<ffffffff8109d645>] ? cpuacct_charge+0x5/0x1f0
[<ffffffff8108dffc>] update_curr+0xec/0x240
[<ffffffff8108f528>] put_prev_task_fair+0x228/0x480
[<ffffffff816b3a71>] __schedule+0x161/0x9b0
[<ffffffff816b4721>] preempt_schedule+0x51/0x80
[<ffffffff816b4800>] ? __cond_resched_softirq+0x60/0x60
[<ffffffff816b6824>] ? retint_careful+0x12/0x2e
[<ffffffff810ff3cc>] ftrace_ops_control_func+0x1dc/0x210
[<ffffffff816be280>] ftrace_call+0x5/0x2f
[<ffffffff816b681d>] ? retint_careful+0xb/0x2e
[<ffffffff816b4805>] ? schedule_user+0x5/0x70
[<ffffffff816b4805>] ? schedule_user+0x5/0x70
[<ffffffff816b6824>] ? retint_careful+0x12/0x2e
------------[ cut here ]------------
What happened was that the function tracer traced the schedule_user() code
that tells RCU that the system is coming back from userspace, and to
add the CPU back to the RCU monitoring.
Because the function tracer does a preempt_disable/enable_notrace() calls
the preempt_enable_notrace() checks the NEED_RESCHED flag. If it is set,
then preempt_schedule() is called. But this is called before the user_exit()
function can inform the kernel that the CPU is no longer in user mode and
needs to be accounted for by RCU.
The fix is to create a new preempt_schedule_context() that checks if
the kernel is still in user mode and if so to switch it to kernel mode
before calling schedule. It also switches back to user mode coming back
from schedule in need be.
The only user of this currently is the preempt_enable_notrace(), which is
only used by the tracing subsystem.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1369423420.6828.226.camel@gandalf.local.home
Signed-off-by: Ingo Molnar <mingo@kernel.org>
I have faced a sequence where the Idle Load Balance was sometime not
triggered for a while on my platform, in the following scenario:
CPU 0 and CPU 1 are running tasks and CPU 2 is idle
CPU 1 kicks the Idle Load Balance
CPU 1 selects CPU 2 as the new Idle Load Balancer
CPU 2 sets NOHZ_BALANCE_KICK for CPU 2
CPU 2 sends a reschedule IPI to CPU 2
While CPU 3 wakes up, CPU 0 or CPU 1 migrates a waking up task A on CPU 2
CPU 2 finally wakes up, runs task A and discards the Idle Load Balance
task A quickly goes back to sleep (before a tick occurs on CPU 2)
CPU 2 goes back to idle with NOHZ_BALANCE_KICK set
Whenever CPU 2 will be selected as the ILB, no reschedule IPI will be sent
because NOHZ_BALANCE_KICK is already set and no Idle Load Balance will be
performed.
We must wait for the sched softirq to be raised on CPU 2 thanks to another
part the kernel to come back to clear NOHZ_BALANCE_KICK.
The proposed solution clears NOHZ_BALANCE_KICK in schedule_ipi if
we can't raise the sched_softirq for the Idle Load Balance.
Change since V1:
- move the clear of NOHZ_BALANCE_KICK in got_nohz_idle_kick if the ILB
can't run on this CPU (as suggested by Peter)
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1370419991-13870-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This allows us to use pdev->name for registering a PMU device.
IMO the name is not supposed to be changed anyway.
Signed-off-by: Mischa Jonker <mjonker@synopsys.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1370339148-5566-1-git-send-email-mjonker@synopsys.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit 2b923c8 perf/x86: Check branch sampling priv level in generic code
was missing the check for the hypervisor (HV) priv level, so add it back.
With this patch, we get the following correct behavior:
# echo 2 >/proc/sys/kernel/perf_event_paranoid
$ perf record -j any,k noploop 1
Error:
You may not have permission to collect stats.
Consider tweaking /proc/sys/kernel/perf_event_paranoid:
-1 - Not paranoid at all
0 - Disallow raw tracepoint access for unpriv
1 - Disallow cpu events for unpriv
2 - Disallow kernel profiling for unpriv
$ perf record -j any,hv noploop 1
Error:
You may not have permission to collect stats.
Consider tweaking /proc/sys/kernel/perf_event_paranoid:
-1 - Not paranoid at all
0 - Disallow raw tracepoint access for unpriv
1 - Disallow cpu events for unpriv
2 - Disallow kernel profiling for unpriv
Signed-off-by: Stephane Eranian <eranian@google.com>
Acked-by: Petr Matousek <pmatouse@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130606090204.GA3725@quad
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Vince's fuzzer once again found holes. This time it spotted a leak in
the locked page accounting.
When an event had redirected output and its close() was the last
reference to the buffer we didn't have a vm context to undo accounting.
Change the code to destroy the buffer on the last munmap() and detach
all redirected events at that time. This provides us the right context
to undo the vm accounting.
Reported-and-tested-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130604084421.GI8923@twins.programming.kicks-ass.net
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
