IF YOU WOULD LIKE TO GET AN ACCOUNT, please write an
email to Administrator. User accounts are meant only to access repo
and report issues and/or generate pull requests.
This is a purpose-specific Git hosting for
BaseALT
projects. Thank you for your understanding!
Только зарегистрированные пользователи имеют доступ к сервису!
Для получения аккаунта, обратитесь к администратору.
When rcutorture is compiled directly into the kernel
(instead of separately as a module), it is necessary to specify
rcutorture.stat_interval as a kernel command-line parameter, otherwise,
the rcu_torture_stats kthread is never started. However, when working
with the system after it has booted, it is convenient to be able to
change the time between statistic printing, particularly when logged
into the console.
This commit therefore allows the stat_interval parameter to be changed
at runtime.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
There is often a delay between the time that a CPU passes through a
quiescent state and the time that this quiescent state is reported to the
RCU core. It is quite possible that the grace period ended before the
quiescent state could be reported, for example, some other CPU might have
deduced that this CPU passed through dyntick-idle mode. It is critically
important that quiescent state be counted only against the grace period
that was in effect at the time that the quiescent state was detected.
Previously, this was handled by recording the number of the last grace
period to complete when passing through a quiescent state. The RCU
core then checks this number against the current value, and rejects
the quiescent state if there is a mismatch. However, one additional
possibility must be accounted for, namely that the quiescent state was
recorded after the prior grace period completed but before the current
grace period started. In this case, the RCU core must reject the
quiescent state, but the recorded number will match. This is handled
when the CPU becomes aware of a new grace period -- at that point,
it invalidates any prior quiescent state.
This works, but is a bit indirect. The new approach records the current
grace period, and the RCU core checks to see (1) that this is still the
current grace period and (2) that this grace period has not yet ended.
This approach simplifies reasoning about correctness, and this commit
changes over to this new approach.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Add trace events to record grace-period start and end, quiescent states,
CPUs noticing grace-period start and end, grace-period initialization,
call_rcu() invocation, tasks blocking in RCU read-side critical sections,
tasks exiting those same critical sections, force_quiescent_state()
detection of dyntick-idle and offline CPUs, CPUs entering and leaving
dyntick-idle mode (except from NMIs), CPUs coming online and going
offline, and CPUs being kicked for staying in dyntick-idle mode for too
long (as in many weeks, even on 32-bit systems).
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
rcu: Add the rcu flavor to callback trace events
The earlier trace events for registering RCU callbacks and for invoking
them did not include the RCU flavor (rcu_bh, rcu_preempt, or rcu_sched).
This commit adds the RCU flavor to those trace events.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This patch #ifdefs TINY_RCU kthreads out of the kernel unless RCU_BOOST=y,
thus eliminating context-switch overhead if RCU priority boosting has
not been configured.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Add event-trace markers to TREE_RCU kthreads to allow including these
kthread's CPU time in the utilization calculations.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Andi Kleen noticed that one of the RCU_BOOST data declarations was
out of sync with the definition. Move the declarations so that the
compiler can do the checking in the future.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
We now have kthreads only for flavors of RCU that support boosting,
so update the now-misleading comments accordingly.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Add a string to the rcu_batch_start() and rcu_batch_end() trace
messages that indicates the RCU type ("rcu_sched", "rcu_bh", or
"rcu_preempt"). The trace messages for the actual invocations
themselves are not marked, as it should be clear from the
rcu_batch_start() and rcu_batch_end() events before and after.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
In order to allow event tracing to distinguish between flavors of
RCU, we need those names in the relevant RCU data structures. TINY_RCU
has avoided them for memory-footprint reasons, so add them only if
CONFIG_RCU_TRACE=y.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit adds the trace_rcu_utilization() marker that is to be
used to allow postprocessing scripts compute RCU's CPU utilization,
give or take event-trace overhead. Note that we do not include RCU's
dyntick-idle interface because event tracing requires RCU protection,
which is not available in dyntick-idle mode.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
There was recently some controversy about the overhead of invoking RCU
callbacks. Add TRACE_EVENT()s to obtain fine-grained timings for the
start and stop of a batch of callbacks and also for each callback invoked.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_torture_boost() cleanup code destroyed debug-objects state before
waiting for the last RCU callback to be invoked, resulting in rare but
very real debug-objects warnings. Move the destruction to after the
waiting to fix this problem.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Now that the RCU API contains synchronize_rcu_bh(), synchronize_sched(),
call_rcu_sched(), and rcu_bh_expedited()...
Make rcutorture test synchronize_rcu_bh(), getting rid of the old
rcu_bh_torture_synchronize() workaround. Similarly, make rcutorture test
synchronize_sched(), getting rid of the old sched_torture_synchronize()
workaround. Make rcutorture test call_rcu_sched() instead of wrappering
synchronize_sched(). Also add testing of rcu_bh_expedited().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Pull the code that waits for an RCU grace period into a single function,
which is then called by synchronize_rcu() and friends in the case of
TREE_RCU and TREE_PREEMPT_RCU, and from rcu_barrier() and friends in
the case of TINY_RCU and TINY_PREEMPT_RCU.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
rcutree.c defines rcu_cpu_kthread_cpu as int, not unsigned int,
so the extern has to follow that.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Long ago, using TREE_RCU with PREEMPT would result in "scheduling
while atomic" diagnostics if you blocked in an RCU read-side critical
section. However, PREEMPT now implies TREE_PREEMPT_RCU, which defeats
this diagnostic. This commit therefore adds a replacement diagnostic
based on PROVE_RCU.
Because rcu_lockdep_assert() and lockdep_rcu_dereference() are now being
used for things that have nothing to do with rcu_dereference(), rename
lockdep_rcu_dereference() to lockdep_rcu_suspicious() and add a third
argument that is a string indicating what is suspicious. This third
argument is passed in from a new third argument to rcu_lockdep_assert().
Update all calls to rcu_lockdep_assert() to add an informative third
argument.
Also, add a pair of rcu_lockdep_assert() calls from within
rcu_note_context_switch(), one complaining if a context switch occurs
in an RCU-bh read-side critical section and another complaining if a
context switch occurs in an RCU-sched read-side critical section.
These are present only if the PROVE_RCU kernel parameter is enabled.
Finally, fix some checkpatch whitespace complaints in lockdep.c.
Again, you must enable PROVE_RCU to see these new diagnostics. But you
are enabling PROVE_RCU to check out new RCU uses in any case, aren't you?
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
There are a number of cases where the RCU can find additional work
for the per-CPU kthread within the context of that per-CPU kthread.
In such cases, the per-CPU kthread is already running, so attempting
to wake itself up does nothing except waste CPU cycles. This commit
therefore checks to see if it is in the per-CPU kthread context,
omitting the wakeup in this case.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Commit a26ac2455ffc (move TREE_RCU from softirq to kthread) added
per-CPU kthreads. However, kthread creation uses kthread_create(), which
can put the kthread's stack and task struct on the wrong NUMA node.
Therefore, use kthread_create_on_node() instead of kthread_create()
so that the stacks and task structs are placed on the correct NUMA node.
A similar change was carried out in commit 94dcf29a11b3 (kthread:
use kthread_create_on_node()).
Also change rcutorture's priority-boost-test kthread creation.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Tejun Heo <tj@kernel.org>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Andi Kleen <ak@linux.intel.com>
CC: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Add an event to monitor comm value changes of tasks. Such an event
becomes vital, if someone desires to control threads of a process in
different manner.
A natural characteristic of threads is its comm value, and helpfully
application developers have an opportunity to change it in runtime.
Reporting about such events via proc connector allows to fine-grain
monitoring and control potentials, for instance a process control daemon
listening to proc connector and following comm value policies can place
specific threads to assigned cgroup partitions.
It might be possible to achieve a pale partial one-shot likeness without
this update, if an application changes comm value of a thread generator
task beforehand, then a new thread is cloned, and after that proc
connector listener gets the fork event and reads new thread's comm value
from procfs stat file, but this change visibly simplifies and extends the
matter.
Signed-off-by: Vladimir Zapolskiy <vzapolskiy@gmail.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch introduces 3 trace points to prepare for tracing
rpm_idle/rpm_suspend/rpm_resume functions, so we can use these
trace points to replace the current dev_dbg().
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
The caller already checks for nr_running > 1, therefore we don't have
to do so again.
Signed-off-by: Wang Xingchao <xingchao.wang@intel.com>
Reviewed-by: Paul Turner <pjt@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1316194552-12019-1-git-send-email-xingchao.wang@intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Commit c259e01a1ec ("sched: Separate the scheduler entry for
preemption") contained a boo-boo wrecking wchan output. It forgot to
put the new schedule() function in the __sched section and thereby
doesn't get properly ignored for things like wchan.
Tested-by: Simon Kirby <sim@hostway.ca>
Cc: stable@kernel.org # 2.6.39+
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110923000346.GA25425@hostway.ca
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If PTRACE_LISTEN fails after lock_task_sighand() it doesn't drop ->siglock.
Reported-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Implements syscore_ops in cpu_pm to call the cpu and
cpu cluster notifiers during suspend and resume,
allowing drivers receiving the notifications to
avoid implementing syscore_ops.
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-and-Acked-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Vishwanath BS <vishwanath.bs@ti.com>
During some CPU power modes entered during idle, hotplug and
suspend, peripherals located in the CPU power domain, such as
the GIC, localtimers, and VFP, may be powered down. Add a
notifier chain that allows drivers for those peripherals to
be notified before and after they may be reset.
Notified drivers can include VFP co-processor, interrupt controller
and it's PM extensions, local CPU timers context save/restore which
shouldn't be interrupted. Hence CPU PM event APIs must be called
with interrupts disabled.
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-and-Acked-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Kevin Hilman <khilman@ti.com>
Tested-by: Vishwanath BS <vishwanath.bs@ti.com>
If irqs are disabled when preemption count reaches zero, the
preemptirqsoff tracer should not flag that as the end.
When interrupts are enabled and preemption count is not zero
the preemptirqsoff correctly continues its tracing.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The parameter's origin type is long. On an i386 architecture, it can
easily be larger than 0x80000000, causing this function to convert it
to a sign-extended u64 type.
Change the type to unsigned long so we get the correct result.
Signed-off-by: hank <pyu@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: <stable@kernel.org>
[ build fix ]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'irq-fixes-for-linus' of git://tesla.tglx.de/git/linux-2.6-tip:
x86, iommu: Mark DMAR IRQ as non-threaded
genirq: Make irq_shutdown() symmetric vs. irq_startup again
Even with just the interface limited to admin, there really is little to
reason to give byte-per-byte counts for taskstats. So round it down to
something less intrusive.
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ok, this isn't optimal, since it means that 'iotop' needs admin
capabilities, and we may have to work on this some more. But at the
same time it is very much not acceptable to let anybody just read
anybody elses IO statistics quite at this level.
Use of the GENL_ADMIN_PERM suggested by Johannes Berg as an alternative
to checking the capabilities by hand.
Reported-by: Vasiliy Kulikov <segoon@openwall.com>
Cc: Johannes Berg <johannes.berg@intel.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When debugging tight race conditions, it can be helpful to have a
synchronized tracing method. Although in most cases the global clock
provides this functionality, if timings is not the issue, it is more
comforting to know that the order of events really happened in a precise
order.
Instead of using a clock, add a "counter" that is simply an incrementing
atomic 64bit counter that orders the events as they are perceived to
happen.
The trace_clock_counter() is added from the attempt by Peter Zijlstra
trying to convert the trace_clock_global() to it. I took Peter's counter
code and made trace_clock_counter() instead, and added it to the choice
of clocks. Just echo counter > /debug/tracing/trace_clock to activate
it.
Requested-by: Thomas Gleixner <tglx@linutronix.de>
Requested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-By: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When the watchdog thread exits it runs through the exit path with FIFO
priority. There is no point in doing so. Switch back to SCHED_NORMAL
before exiting.
Cc: Don Zickus <dzickus@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1109121337461.2723@ionos
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Andrew requested I comment all the lockdep WARN()s to help other people
figure out wth is wrong..
Requested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1315301493.3191.9.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Commit 43fa5460fe60dea5c610490a1d263415419c60f6 ("sched: Try not to
migrate higher priority RT tasks") also introduced a change in behavior
which keeps RT tasks on the same CPU if there is an equal priority RT
task currently running even if there are empty CPUs available.
This can cause unnecessary wakeup latencies, and can prevent the
scheduler from balancing all RT tasks across available CPUs.
This change causes an RT task to search for a new CPU if an equal
priority RT task is already running on wakeup. Lower priority tasks
will still have to wait on higher priority tasks, but the system should
still balance out because there is always the possibility that if there
are both a high and low priority RT tasks on a given CPU that the high
priority task could wakeup while the low priority task is running and
force it to search for a better runqueue.
Signed-off-by: Shawn Bohrer <sbohrer@rgmadvisors.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Tested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: stable@kernel.org # 37+
Link: http://lkml.kernel.org/r/1315837684-18733-1-git-send-email-sbohrer@rgmadvisors.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Change a single occurrence of "unlcoked" into "unlocked".
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Cc: Darren Hart <dvhltc@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
The variables here are really not used uninitialized.
kernel/futex.c: In function 'fixup_pi_state_owner.clone.17':
kernel/futex.c:1582:6: warning: 'curval' may be used uninitialized in this function
kernel/futex.c: In function 'handle_futex_death':
kernel/futex.c:2486:6: warning: 'nval' may be used uninitialized in this function
kernel/futex.c: In function 'do_futex':
kernel/futex.c:863:11: warning: 'curval' may be used uninitialized in this function
kernel/futex.c:828:6: note: 'curval' was declared here
kernel/futex.c:898:5: warning: 'oldval' may be used uninitialized in this function
kernel/futex.c:890:6: note: 'oldval' was declared here
Signed-off-by: Vitaliy Ivanov <vitalivanov@gmail.com>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
The variables here are really not used uninitialized.
kernel/async.c: In function 'async_synchronize_cookie_domain':
kernel/async.c:270:10: warning: 'starttime.tv64' may be used uninitialized in this function
kernel/async.c: In function 'async_run_entry_fn':
kernel/async.c:122:10: warning: 'calltime.tv64' may be used uninitialized in this function
Signed-off-by: Vitaliy Ivanov <vitalivanov@gmail.com>
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Take cwq->gcwq->lock to avoid racing between drain_workqueue checking to
make sure the workqueues are empty and cwq_dec_nr_in_flight decrementing
and then incrementing nr_active when it activates a delayed work.
We discovered this when a corner case in one of our drivers resulted in
us trying to destroy a workqueue in which the remaining work would
always requeue itself again in the same workqueue. We would hit this
race condition and trip the BUG_ON on workqueue.c:3080.
Signed-off-by: Thomas Tuttle <ttuttle@chromium.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
commit 8bc0daf (alarmtimers: Rework RTC device selection using class
interface) did not implement required error checks. Add them.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The latency_lock is lock can be taken in the guts of the
scheduler code and therefore cannot be preempted on -rt -
annotate it.
In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The table_lock lock can be taken in atomic context and therefore
cannot be preempted on -rt - annotate it.
In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.
Reported-by: Andreas Sundebo <kernel@sundebo.dk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Andreas Sundebo <kernel@sundebo.dk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There is no reason to have the spin_lock protecting the semaphore
preemptible on -rt. Annotate it as a raw_spinlock.
In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.
( On rt this also solves lockdep complaining about the
rt_mutex.wait_lock being not initialized. )
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The thread_group_cputimer lock can be taken in atomic context and therefore
cannot be preempted on -rt - annotate it.
In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
