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* rtmutex: Document pi chain walkThomas Gleixner2014-06-211-9/+91
| | | | | | | | Add commentry to document the chain walk and the protection mechanisms and their scope. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
* rtmutex: Clarify the boost/deboost partThomas Gleixner2014-06-211-10/+48
| | | | | | | | Add a separate local variable for the boost/deboost logic to make the code more readable. Add comments where appropriate. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
* rtmutex: No need to keep task ref for lock owner checkThomas Gleixner2014-06-211-2/+3
| | | | | | | | | | | There is no point to keep the task ref across the check for lock owner. Drop the ref before that, so the protection context is clear. Found while documenting the chain walk. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
* rtmutex: Simplify and document try_to_take_rtmutex()Thomas Gleixner2014-06-211-45/+88
| | | | | | | | | | | | | | The current implementation of try_to_take_rtmutex() is correct, but requires more than a single brain twist to understand the clever encoded conditionals. Untangle it and document the cases proper. Looks less efficient at the first glance, but actually reduces the binary code size on x8664 by 80 bytes. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
* rtmutex: Simplify rtmutex_slowtrylock()Thomas Gleixner2014-06-211-11/+20
| | | | | | | | | | | | | | | | | | | | | Oleg noticed that rtmutex_slowtrylock() has a pointless check for rt_mutex_owner(lock) != current. To avoid calling try_to_take_rtmutex() we really want to check whether the lock has an owner at all or whether the trylock failed because the owner is NULL, but the RT_MUTEX_HAS_WAITERS bit is set. This covers the lock is owned by caller situation as well. We can actually do this check lockless. trylock is taking a chance whether we take lock->wait_lock to do the check or not. Add comments to the function while at it. Reported-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
* Merge branch 'locking/urgent' into locking/coreThomas Gleixner2014-06-213-35/+218
|\ | | | | | | | | | | | | Reason: Required to add more rtmutex robustness changes on top of those already in mainline. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * rtmutex: Plug slow unlock raceThomas Gleixner2014-06-161-6/+109
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the rtmutex fast path is enabled the slow unlock function can create the following situation: spin_lock(foo->m->wait_lock); foo->m->owner = NULL; rt_mutex_lock(foo->m); <-- fast path free = atomic_dec_and_test(foo->refcnt); rt_mutex_unlock(foo->m); <-- fast path if (free) kfree(foo); spin_unlock(foo->m->wait_lock); <--- Use after free. Plug the race by changing the slow unlock to the following scheme: while (!rt_mutex_has_waiters(m)) { /* Clear the waiters bit in m->owner */ clear_rt_mutex_waiters(m); owner = rt_mutex_owner(m); spin_unlock(m->wait_lock); if (cmpxchg(m->owner, owner, 0) == owner) return; spin_lock(m->wait_lock); } So in case of a new waiter incoming while the owner tries the slow path unlock we have two situations: unlock(wait_lock); lock(wait_lock); cmpxchg(p, owner, 0) == owner mark_rt_mutex_waiters(lock); acquire(lock); Or: unlock(wait_lock); lock(wait_lock); mark_rt_mutex_waiters(lock); cmpxchg(p, owner, 0) != owner enqueue_waiter(); unlock(wait_lock); lock(wait_lock); wakeup_next waiter(); unlock(wait_lock); lock(wait_lock); acquire(lock); If the fast path is disabled, then the simple m->owner = NULL; unlock(m->wait_lock); is sufficient as all access to m->owner is serialized via m->wait_lock; Also document and clarify the wakeup_next_waiter function as suggested by Oleg Nesterov. Reported-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20140611183852.937945560@linutronix.de Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * rtmutex: Detect changes in the pi lock chainThomas Gleixner2014-06-071-24/+71
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we walk the lock chain, we drop all locks after each step. So the lock chain can change under us before we reacquire the locks. That's harmless in principle as we just follow the wrong lock path. But it can lead to a false positive in the dead lock detection logic: T0 holds L0 T0 blocks on L1 held by T1 T1 blocks on L2 held by T2 T2 blocks on L3 held by T3 T4 blocks on L4 held by T4 Now we walk the chain lock T1 -> lock L2 -> adjust L2 -> unlock T1 -> lock T2 -> adjust T2 -> drop locks T2 times out and blocks on L0 Now we continue: lock T2 -> lock L0 -> deadlock detected, but it's not a deadlock at all. Brad tried to work around that in the deadlock detection logic itself, but the more I looked at it the less I liked it, because it's crystal ball magic after the fact. We actually can detect a chain change very simple: lock T1 -> lock L2 -> adjust L2 -> unlock T1 -> lock T2 -> adjust T2 -> next_lock = T2->pi_blocked_on->lock; drop locks T2 times out and blocks on L0 Now we continue: lock T2 -> if (next_lock != T2->pi_blocked_on->lock) return; So if we detect that T2 is now blocked on a different lock we stop the chain walk. That's also correct in the following scenario: lock T1 -> lock L2 -> adjust L2 -> unlock T1 -> lock T2 -> adjust T2 -> next_lock = T2->pi_blocked_on->lock; drop locks T3 times out and drops L3 T2 acquires L3 and blocks on L4 now Now we continue: lock T2 -> if (next_lock != T2->pi_blocked_on->lock) return; We don't have to follow up the chain at that point, because T2 propagated our priority up to T4 already. [ Folded a cleanup patch from peterz ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reported-by: Brad Mouring <bmouring@ni.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20140605152801.930031935@linutronix.de Cc: stable@vger.kernel.org
| * rtmutex: Handle deadlock detection smarterThomas Gleixner2014-06-073-5/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Even in the case when deadlock detection is not requested by the caller, we can detect deadlocks. Right now the code stops the lock chain walk and keeps the waiter enqueued, even on itself. Silly not to yell when such a scenario is detected and to keep the waiter enqueued. Return -EDEADLK unconditionally and handle it at the call sites. The futex calls return -EDEADLK. The non futex ones dequeue the waiter, throw a warning and put the task into a schedule loop. Tagged for stable as it makes the code more robust. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Brad Mouring <bmouring@ni.com> Link: http://lkml.kernel.org/r/20140605152801.836501969@linutronix.de Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | Merge tag 'trace-3.16-2' of ↵Linus Torvalds2014-06-123-20/+36
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing cleanups and bugfixes from Steven Rostedt: "One bug fix that goes back to 3.10. Accessing a non existent buffer if "possible cpus" is greater than actual CPUs (including offline CPUs). Namhyung Kim did some reviews of the patches I sent this merge window and found a memory leak and had a few clean ups" * tag 'trace-3.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Fix check of ftrace_trace_arrays list_empty() check tracing: Fix leak of per cpu max data in instances tracing: Cleanup saved_cmdlines_size changes ring-buffer: Check if buffer exists before polling
| * | tracing: Fix check of ftrace_trace_arrays list_empty() checkSteven Rostedt (Red Hat)2014-06-101-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The check that tests if ftrace_trace_arrays is empty in top_trace_array(), uses the .prev pointer: if (list_empty(ftrace_trace_arrays.prev)) instead of testing the variable itself: if (list_empty(&ftrace_trace_arrays)) Although it is technically correct, it is awkward and confusing. Use the proper method. Link: http://lkml.kernel.org/r/87oay1bas8.fsf@sejong.aot.lge.com Reported-by: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | tracing: Fix leak of per cpu max data in instancesSteven Rostedt (Red Hat)2014-06-101-9/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The freeing of an instance, if max data is configured, there will be per cpu data structures created. But these are not freed when the instance is deleted, which causes a memory leak. A new helper function is added that frees the individual buffers within a trace array, instead of duplicating the code. This way changes made for one are applied to the other (normal buffer vs max buffer). Link: http://lkml.kernel.org/r/87k38pbake.fsf@sejong.aot.lge.com Reported-by: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | tracing: Cleanup saved_cmdlines_size changesNamhyung Kim2014-06-101-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The recent addition of saved_cmdlines_size file had some remaining (minor - mostly coding style) issues. Fix them by passing pointer name to sizeof() and using scnprintf(). Link: http://lkml.kernel.org/p/1402384295-23680-1-git-send-email-namhyung@kernel.org Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com> Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | ring-buffer: Check if buffer exists before pollingSteven Rostedt (Red Hat)2014-06-102-7/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The per_cpu buffers are created one per possible CPU. But these do not mean that those CPUs are online, nor do they even exist. With the addition of the ring buffer polling, it assumes that the caller polls on an existing buffer. But this is not the case if the user reads trace_pipe from a CPU that does not exist, and this causes the kernel to crash. Simple fix is to check the cpu against buffer bitmask against to see if the buffer was allocated or not and return -ENODEV if it is not. More updates were done to pass the -ENODEV back up to userspace. Link: http://lkml.kernel.org/r/5393DB61.6060707@oracle.com Reported-by: Sasha Levin <sasha.levin@oracle.com> Cc: stable@vger.kernel.org # 3.10+ Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | | Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2014-06-127-286/+353
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull more scheduler updates from Ingo Molnar: "Second round of scheduler changes: - try-to-wakeup and IPI reduction speedups, from Andy Lutomirski - continued power scheduling cleanups and refactorings, from Nicolas Pitre - misc fixes and enhancements" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/deadline: Delete extraneous extern for to_ratio() sched/idle: Optimize try-to-wake-up IPI sched/idle: Simplify wake_up_idle_cpu() sched/idle: Clear polling before descheduling the idle thread sched, trace: Add a tracepoint for IPI-less remote wakeups cpuidle: Set polling in poll_idle sched: Remove redundant assignment to "rt_rq" in update_curr_rt(...) sched: Rename capacity related flags sched: Final power vs. capacity cleanups sched: Remove remaining dubious usage of "power" sched: Let 'struct sched_group_power' care about CPU capacity sched/fair: Disambiguate existing/remaining "capacity" usage sched/fair: Change "has_capacity" to "has_free_capacity" sched/fair: Remove "power" from 'struct numa_stats' sched: Fix signedness bug in yield_to() sched/fair: Use time_after() in record_wakee() sched/balancing: Reduce the rate of needless idle load balancing sched/fair: Fix unlocked reads of some cfs_b->quota/period
| * \ \ Merge commit '3cf2f34' into sched/core, to fix build errorIngo Molnar2014-06-1210-27/+92
| |\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix this dependency on the locking tree's smp_mb*() API changes: kernel/sched/idle.c:247:3: error: implicit declaration of function ‘smp_mb__after_atomic’ [-Werror=implicit-function-declaration] Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched/deadline: Delete extraneous extern for to_ratio()Paul Gortmaker2014-06-051-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There was a prototype for it added to kernel/sched/sched.h at the same time the extern was added, so the extern in the C file was never really ever needed. See commit 332ac17ef5bfcff4766dfdfd3b4cdf10b8f8f155 ("sched/deadline: Add bandwidth management for SCHED_DEADLINE tasks") for details. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dario Faggioli <raistlin@linux.it> Link: http://lkml.kernel.org/r/1400013605-18717-1-git-send-email-paul.gortmaker@windriver.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched/idle: Optimize try-to-wake-up IPIPeter Zijlstra2014-06-053-9/+61
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ This series reduces the number of IPIs on Andy's workload by something like 99%. It's down from many hundreds per second to very few. The basic idea behind this series is to make TIF_POLLING_NRFLAG be a reliable indication that the idle task is polling. Once that's done, the rest is reasonably straightforward. ] When enqueueing tasks on remote LLC domains, we send an IPI to do the work 'locally' and avoid bouncing all the cachelines over. However, when the remote CPU is idle (and polling, say x86 mwait), we don't need to send an IPI, we can simply kick the TIF word to wake it up and have the 'idle' loop do the work. So when _TIF_POLLING_NRFLAG is set, but _TIF_NEED_RESCHED is not (yet) set, set _TIF_NEED_RESCHED and avoid sending the IPI. Much-requested-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Peter Zijlstra <peterz@infradead.org> [Edited by Andy Lutomirski, but this is mostly Peter Zijlstra's code.] Signed-off-by: Andy Lutomirski <luto@amacapital.net> Cc: nicolas.pitre@linaro.org Cc: daniel.lezcano@linaro.org Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: umgwanakikbuti@gmail.com Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/ce06f8b02e7e337be63e97597fc4b248d3aa6f9b.1401902905.git.luto@amacapital.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched/idle: Simplify wake_up_idle_cpu()Andy Lutomirski2014-06-051-20/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that rq->idle's polling bit is a reliable indication that the cpu is polling, use it. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: nicolas.pitre@linaro.org Cc: daniel.lezcano@linaro.org Cc: umgwanakikbuti@gmail.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/922f00761445a830ebb23d058e2ae53956ce2d73.1401902905.git.luto@amacapital.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched/idle: Clear polling before descheduling the idle threadAndy Lutomirski2014-06-051-1/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, the only real guarantee provided by the polling bit is that, if you hold rq->lock and the polling bit is set, then you can set need_resched to force a reschedule. The only reason the lock is needed is that the idle thread might not be running at all when setting its need_resched bit, and rq->lock keeps it pinned. This is easy to fix: just clear the polling bit before scheduling. Now the idle thread's polling bit is only ever set when rq->curr == rq->idle. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: nicolas.pitre@linaro.org Cc: daniel.lezcano@linaro.org Cc: umgwanakikbuti@gmail.com Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/b2059fcb4c613d520cb503b6fad6e47033c7c203.1401902905.git.luto@amacapital.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched, trace: Add a tracepoint for IPI-less remote wakeupsAndy Lutomirski2014-06-051-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remote wakeups of polling CPUs are a valuable performance improvement; add a tracepoint to make it much easier to verify that they're working. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: nicolas.pitre@linaro.org Cc: daniel.lezcano@linaro.org Cc: umgwanakikbuti@gmail.com Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/16205aee116772aa686814f9b13bccb562108047.1401902905.git.luto@amacapital.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched: Remove redundant assignment to "rt_rq" in update_curr_rt(...)Giedrius Rekasius2014-06-051-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Variable "rt_rq" is used only in block "for_each_sched_rt_entity" so the value assigned to it at the beginning of the update_curr_rt(...) gets overwritten without ever being read. Remove redundant assignment and move variable declaration to the block in which it is being used. Signed-off-by: Giedrius Rekasius <giedrius.rekasius@gmail.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: kernel-janitors@vger.kernel.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/1401027811-30066-1-git-send-email-giedrius.rekasius@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched: Rename capacity related flagsNicolas Pitre2014-06-053-15/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It is better not to think about compute capacity as being equivalent to "CPU power". The upcoming "power aware" scheduler work may create confusion with the notion of energy consumption if "power" is used too liberally. Let's rename the following feature flags since they do relate to capacity: SD_SHARE_CPUPOWER -> SD_SHARE_CPUCAPACITY ARCH_POWER -> ARCH_CAPACITY NONTASK_POWER -> NONTASK_CAPACITY Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: linaro-kernel@lists.linaro.org Cc: Andy Fleming <afleming@freescale.com> Cc: Anton Blanchard <anton@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Grant Likely <grant.likely@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Rob Herring <robh+dt@kernel.org> Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Cc: Toshi Kani <toshi.kani@hp.com> Cc: Vasant Hegde <hegdevasant@linux.vnet.ibm.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: devicetree@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/n/tip-e93lpnxb87owfievqatey6b5@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched: Final power vs. capacity cleanupsNicolas Pitre2014-06-052-32/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It is better not to think about compute capacity as being equivalent to "CPU power". The upcoming "power aware" scheduler work may create confusion with the notion of energy consumption if "power" is used too liberally. This contains the architecture visible changes. Incidentally, only ARM takes advantage of the available pow^H^H^Hcapacity scaling hooks and therefore those changes outside kernel/sched/ are confined to one ARM specific file. The default arch_scale_smt_power() hook is not overridden by anyone. Replacements are as follows: arch_scale_freq_power --> arch_scale_freq_capacity arch_scale_smt_power --> arch_scale_smt_capacity SCHED_POWER_SCALE --> SCHED_CAPACITY_SCALE SCHED_POWER_SHIFT --> SCHED_CAPACITY_SHIFT The local usage of "power" in arch/arm/kernel/topology.c is also changed to "capacity" as appropriate. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: linaro-kernel@lists.linaro.org Cc: Arnd Bergmann <arnd@arndb.de> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Grant Likely <grant.likely@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mark Brown <broonie@linaro.org> Cc: Rob Herring <robh+dt@kernel.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: devicetree@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/n/tip-48zba9qbznvglwelgq2cfygh@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched: Remove remaining dubious usage of "power"Nicolas Pitre2014-06-053-55/+55
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It is better not to think about compute capacity as being equivalent to "CPU power". The upcoming "power aware" scheduler work may create confusion with the notion of energy consumption if "power" is used too liberally. This is the remaining "power" -> "capacity" rename for local symbols. Those symbols visible to the rest of the kernel are not included yet. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: linaro-kernel@lists.linaro.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/n/tip-yyyhohzhkwnaotr3lx8zd5aa@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched: Let 'struct sched_group_power' care about CPU capacityNicolas Pitre2014-06-053-114/+114
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It is better not to think about compute capacity as being equivalent to "CPU power". The upcoming "power aware" scheduler work may create confusion with the notion of energy consumption if "power" is used too liberally. Since struct sched_group_power is really about compute capacity of sched groups, let's rename it to struct sched_group_capacity. Similarly sgp becomes sgc. Related variables and functions dealing with groups are also adjusted accordingly. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: linaro-kernel@lists.linaro.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/n/tip-5yeix833vvgf2uyj5o36hpu9@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched/fair: Disambiguate existing/remaining "capacity" usageNicolas Pitre2014-06-051-21/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have "power" (which should actually become "capacity") and "capacity" which is a scaled down "capacity factor" in terms of unitary tasks. Let's use "capacity_factor" to make room for proper usage of "capacity" later. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: linaro-kernel@lists.linaro.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/n/tip-gk1co8sqdev3763opqm6ovml@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched/fair: Change "has_capacity" to "has_free_capacity"Nicolas Pitre2014-06-051-13/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The capacity of a CPU/group should be some intrinsic value that doesn't change with task placement. It is like a container which capacity is stable regardless of the amount of liquid in it (its "utilization")... unless the container itself is crushed that is, but that's another story. Therefore let's rename "has_capacity" to "has_free_capacity" in order to better convey the wanted meaning. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: linaro-kernel@lists.linaro.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/n/tip-djzkk027jm0e8x8jxy70opzh@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched/fair: Remove "power" from 'struct numa_stats'Nicolas Pitre2014-06-051-6/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It is better not to think about compute capacity as being equivalent to "CPU power". The upcoming "power aware" scheduler work may create confusion with the notion of energy consumption if "power" is used too liberally. To make things explicit and not create more confusion with the existing "capacity" member, let's rename things as follows: power -> compute_capacity capacity -> task_capacity Note: none of those fields are actually used outside update_numa_stats(). Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: linaro-kernel@lists.linaro.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/n/tip-2e2ndymj5gyshyjq8am79f20@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched: Fix signedness bug in yield_to()Dan Carpenter2014-06-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | yield_to() is supposed to return -ESRCH if there is no task to yield to, but because the type is bool that is the same as returning true. The only place I see which cares is kvm_vcpu_on_spin(). Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Raghavendra <raghavendra.kt@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: kvm@vger.kernel.org Link: http://lkml.kernel.org/r/20140523102042.GA7267@mwanda Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched/fair: Use time_after() in record_wakee()Manuel Schölling2014-06-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To be future-proof and for better readability the time comparisons are modified to use time_after() instead of plain, error-prone math. Signed-off-by: Manuel Schölling <manuel.schoelling@gmx.de> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1400780723-24626-1-git-send-email-manuel.schoelling@gmx.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched/balancing: Reduce the rate of needless idle load balancingTim Chen2014-06-051-6/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current no_hz idle load balancer do load balancing for *all* idle cpus, even though the time due to load balance for a particular idle cpu could be still a while in the future. This introduces a much higher load balancing rate than what is necessary. The patch changes the behavior by only doing idle load balancing on behalf of an idle cpu only when it is due for load balancing. On SGI's systems with over 3000 cores, the cpu responsible for idle balancing got overwhelmed with idle balancing, and introduces a lot of OS noise to workloads. This patch fixes the issue. Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Acked-by: Russ Anderson <rja@sgi.com> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Jason Low <jason.low2@hp.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Len Brown <len.brown@intel.com> Cc: Dimitri Sivanich <sivanich@sgi.com> Cc: Hedi Berriche <hedi@sgi.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: MichelLespinasse <walken@google.com> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1400621967.2970.280.camel@schen9-DESK Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched/fair: Fix unlocked reads of some cfs_b->quota/periodBen Segall2014-06-051-19/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sched_cfs_period_timer() reads cfs_b->period without locks before calling do_sched_cfs_period_timer(), and similarly unthrottle_offline_cfs_rqs() would read cfs_b->period without the right lock. Thus a simultaneous change of bandwidth could cause corruption on any platform where ktime_t or u64 writes/reads are not atomic. Extend cfs_b->lock from do_sched_cfs_period_timer() to include the read of cfs_b->period to solve that issue; unthrottle_offline_cfs_rqs() can just use 1 rather than the exact quota, much like distribute_cfs_runtime() does. There is also an unlocked read of cfs_b->runtime_expires, but a race there would only delay runtime expiry by a tick. Still, the comparison should just be != anyway, which clarifies even that problem. Signed-off-by: Ben Segall <bsegall@google.com> Tested-by: Roman Gushchin <klamm@yandex-team.ru> [peterz: Fix compile warn] Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20140519224945.20303.93530.stgit@sword-of-the-dawn.mtv.corp.google.com Cc: pjt@google.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | | Merge branch 'perf-core-for-linus' of ↵Linus Torvalds2014-06-1210-310/+428
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull more perf updates from Ingo Molnar: "A second round of perf updates: - wide reaching kprobes sanitization and robustization, with the hope of fixing all 'probe this function crashes the kernel' bugs, by Masami Hiramatsu. - uprobes updates from Oleg Nesterov: tmpfs support, corner case fixes and robustization work. - perf tooling updates and fixes from Jiri Olsa, Namhyung Ki, Arnaldo et al: * Add support to accumulate hist periods (Namhyung Kim) * various fixes, refactorings and enhancements" * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (101 commits) perf: Differentiate exec() and non-exec() comm events perf: Fix perf_event_comm() vs. exec() assumption uprobes/x86: Rename arch_uprobe->def to ->defparam, minor comment updates perf/documentation: Add description for conditional branch filter perf/x86: Add conditional branch filtering support perf/tool: Add conditional branch filter 'cond' to perf record perf: Add new conditional branch filter 'PERF_SAMPLE_BRANCH_COND' uprobes: Teach copy_insn() to support tmpfs uprobes: Shift ->readpage check from __copy_insn() to uprobe_register() perf/x86: Use common PMU interrupt disabled code perf/ARM: Use common PMU interrupt disabled code perf: Disable sampled events if no PMU interrupt perf: Fix use after free in perf_remove_from_context() perf tools: Fix 'make help' message error perf record: Fix poll return value propagation perf tools: Move elide bool into perf_hpp_fmt struct perf tools: Remove elide setup for SORT_MODE__MEMORY mode perf tools: Fix "==" into "=" in ui_browser__warning assignment perf tools: Allow overriding sysfs and proc finding with env var perf tools: Consider header files outside perf directory in tags target ...
| * | | | | perf: Differentiate exec() and non-exec() comm eventsAdrian Hunter2014-06-061-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | perf tools like 'perf report' can aggregate samples by comm strings, which generally works. However, there are other potential use-cases. For example, to pair up 'calls' with 'returns' accurately (from branch events like Intel BTS) it is necessary to identify whether the process has exec'd. Although a comm event is generated when an 'exec' happens it is also generated whenever the comm string is changed on a whim (e.g. by prctl PR_SET_NAME). This patch adds a flag to the comm event to differentiate one case from the other. In order to determine whether the kernel supports the new flag, a selection bit named 'exec' is added to struct perf_event_attr. The bit does nothing but will cause perf_event_open() to fail if the bit is set on kernels that do not have it defined. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/537D9EBE.7030806@intel.com Cc: Paul Mackerras <paulus@samba.org> Cc: Dave Jones <davej@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | Merge branch 'perf/urgent' into perf/core, to resolve conflict and to ↵Ingo Molnar2014-06-0623-250/+377
| |\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | prepare for new patches Conflicts: arch/x86/kernel/traps.c Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | | | perf: Fix perf_event_comm() vs. exec() assumptionPeter Zijlstra2014-06-061-12/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | perf_event_comm() assumes that set_task_comm() is only called on exec(), and in particular that its only called on current. Neither are true, as Dave reported a WARN triggered by set_task_comm() being called on !current. Separate the exec() hook from the comm hook. Reported-by: Dave Jones <davej@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/20140521153219.GH5226@laptop.programming.kicks-ass.net [ Build fix. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | uprobes: Teach copy_insn() to support tmpfsOleg Nesterov2014-06-051-5/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | tmpfs is widely used but as Denys reports shmem_aops doesn't have ->readpage() and thus you can't probe a binary on this filesystem. As Hugh suggested we can use shmem_read_mapping_page() in this case, just we need to check shmem_mapping() if ->readpage == NULL. Reported-by: Denys Vlasenko <dvlasenk@redhat.com> Suggested-by: Hugh Dickins <hughd@google.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140519184136.GB6750@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | uprobes: Shift ->readpage check from __copy_insn() to uprobe_register()Oleg Nesterov2014-06-051-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | copy_insn() fails with -EIO if ->readpage == NULL, but this error is not propagated unless uprobe_register() path finds ->mm which already mmaps this file. In this case (say) "perf record" does not actually install the probe, but the user can't know about this. Move this check into uprobe_register() so that this problem can be detected earlier and reported to user. Note: this is still not perfect, - copy_insn() and arch_uprobe_analyze_insn() should be called by uprobe_register() but this is not simple, we need vm_file for read_mapping_page() (although perhaps we can pass NULL), and we need ->mm for is_64bit_mm() (although this logic is broken anyway). - uprobe_register() should be called by create_trace_uprobe(), not by probe_event_enable(), so that an error can be detected at "perf probe -x" time. This also needs more changes in the core uprobe code, uprobe register/unregister interface was poorly designed from the very beginning. Reported-by: Denys Vlasenko <dvlasenk@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Hugh Dickins <hughd@google.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140519184054.GA6750@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | perf: Disable sampled events if no PMU interruptVince Weaver2014-06-051-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add common code to generate -ENOTSUPP at event creation time if an architecture attempts to create a sampled event and PERF_PMU_NO_INTERRUPT is set. This adds a new pmu->capabilities flag. Initially we only support PERF_PMU_NO_INTERRUPT (to indicate a PMU has no support for generating hardware interrupts) but there are other capabilities that can be added later. Signed-off-by: Vince Weaver <vincent.weaver@maine.edu> Acked-by: Will Deacon <will.deacon@arm.com> [peterz: rename to PERF_PMU_CAP_* and moved the pmu::capabilities word into a hole] Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1405161708060.11099@vincent-weaver-1.umelst.maine.edu Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | perf: Fix use after free in perf_remove_from_context()Peter Zijlstra2014-06-051-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While that mutex should guard the elements, it doesn't guard against the use-after-free that's from list_for_each_entry_rcu(). __perf_event_exit_task() can actually free the event. And because list addition/deletion is guarded by both ctx->mutex and ctx->lock, holding ctx->mutex is sufficient for reading the list, so we don't actually need the rcu list iteration. Fixes: 3a497f48637e ("perf: Simplify perf_event_exit_task_context()") Reported-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Dave Jones <davej@redhat.com> Cc: acme@ghostprotocols.net Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140529170024.GA2315@laptop.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | Merge branch 'perf/kprobes' into perf/coreIngo Molnar2014-06-058-254/+343
| |\ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/x86/kernel/traps.c The kprobes enhancements are fully cooked, ship them upstream. Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | | | | kprobes: Show blacklist entries via debugfsMasami Hiramatsu2014-04-241-8/+53
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Show blacklist entries (function names with the address range) via /sys/kernel/debug/kprobes/blacklist. Note that at this point the blacklist supports only in vmlinux, not module. So the list is fixed and not updated. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S. Miller <davem@davemloft.net> Link: http://lkml.kernel.org/r/20140417081849.26341.11609.stgit@ltc230.yrl.intra.hitachi.co.jp Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | | | | kprobes, sched: Use NOKPROBE_SYMBOL macro in schedMasami Hiramatsu2014-04-241-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use NOKPROBE_SYMBOL macro to protect functions from kprobes instead of __kprobes annotation in sched/core.c. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/20140417081842.26341.83959.stgit@ltc230.yrl.intra.hitachi.co.jp
| | * | | | | | kprobes, notifier: Use NOKPROBE_SYMBOL macro in notifierMasami Hiramatsu2014-04-241-9/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use NOKPROBE_SYMBOL macro to protect functions from kprobes instead of __kprobes annotation in notifier. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/20140417081835.26341.56128.stgit@ltc230.yrl.intra.hitachi.co.jp Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | | | | kprobes, ftrace: Use NOKPROBE_SYMBOL macro in ftraceMasami Hiramatsu2014-04-244-65/+82
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use NOKPROBE_SYMBOL macro to protect functions from kprobes instead of __kprobes annotation in ftrace. This applies nokprobe_inline annotation for some cases, because NOKPROBE_SYMBOL() will inhibit inlining by referring the symbol address. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20140417081828.26341.55152.stgit@ltc230.yrl.intra.hitachi.co.jp Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | | | | kprobes: Use NOKPROBE_SYMBOL macro instead of __kprobesMasami Hiramatsu2014-04-241-26/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use NOKPROBE_SYMBOL macro to protect functions from kprobes instead of __kprobes annotation. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S. Miller <davem@davemloft.net> Link: http://lkml.kernel.org/r/20140417081821.26341.40362.stgit@ltc230.yrl.intra.hitachi.co.jp Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | | | | kprobes, ftrace: Allow probing on some functionsMasami Hiramatsu2014-04-243-15/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is no need to prohibit probing on the functions used for preparation and uprobe only fetch functions. Those are safely probed because those are not invoked from kprobe's breakpoint/fault/debug handlers. So there is no chance to cause recursive exceptions. Following functions are now removed from the kprobes blacklist: update_bitfield_fetch_param free_bitfield_fetch_param kprobe_register FETCH_FUNC_NAME(stack, type) in trace_uprobe.c FETCH_FUNC_NAME(memory, type) in trace_uprobe.c FETCH_FUNC_NAME(memory, string) in trace_uprobe.c FETCH_FUNC_NAME(memory, string_size) in trace_uprobe.c FETCH_FUNC_NAME(file_offset, type) in trace_uprobe.c Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20140417081800.26341.56504.stgit@ltc230.yrl.intra.hitachi.co.jp Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | | | | kprobes: Allow probe on some kprobe functionsMasami Hiramatsu2014-04-241-77/+76
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is no need to prohibit probing on the functions used for preparation, registeration, optimization, controll etc. Those are safely probed because those are not invoked from breakpoint/fault/debug handlers, there is no chance to cause recursive exceptions. Following functions are now removed from the kprobes blacklist: add_new_kprobe aggr_kprobe_disabled alloc_aggr_kprobe alloc_aggr_kprobe arm_all_kprobes __arm_kprobe arm_kprobe arm_kprobe_ftrace check_kprobe_address_safe collect_garbage_slots collect_garbage_slots collect_one_slot debugfs_kprobe_init __disable_kprobe disable_kprobe disarm_all_kprobes __disarm_kprobe disarm_kprobe disarm_kprobe_ftrace do_free_cleaned_kprobes do_optimize_kprobes do_unoptimize_kprobes enable_kprobe force_unoptimize_kprobe free_aggr_kprobe free_aggr_kprobe __free_insn_slot __get_insn_slot get_optimized_kprobe __get_valid_kprobe init_aggr_kprobe init_aggr_kprobe in_nokprobe_functions kick_kprobe_optimizer kill_kprobe kill_optimized_kprobe kprobe_addr kprobe_optimizer kprobe_queued kprobe_seq_next kprobe_seq_start kprobe_seq_stop kprobes_module_callback kprobes_open optimize_all_kprobes optimize_kprobe prepare_kprobe prepare_optimized_kprobe register_aggr_kprobe register_jprobe register_jprobes register_kprobe register_kprobes register_kretprobe register_kretprobe register_kretprobes register_kretprobes report_probe show_kprobe_addr try_to_optimize_kprobe unoptimize_all_kprobes unoptimize_kprobe unregister_jprobe unregister_jprobes unregister_kprobe __unregister_kprobe_bottom unregister_kprobes __unregister_kprobe_top unregister_kretprobe unregister_kretprobe unregister_kretprobes unregister_kretprobes wait_for_kprobe_optimizer I tested those functions by putting kprobes on all instructions in the functions with the bash script I sent to LKML. See: https://lkml.org/lkml/2014/3/27/33 Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Link: http://lkml.kernel.org/r/20140417081753.26341.57889.stgit@ltc230.yrl.intra.hitachi.co.jp Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: fche@redhat.com Cc: systemtap@sourceware.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | | | | kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklistMasami Hiramatsu2014-04-242-48/+53
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce NOKPROBE_SYMBOL() macro which builds a kprobes blacklist at kernel build time. The usage of this macro is similar to EXPORT_SYMBOL(), placed after the function definition: NOKPROBE_SYMBOL(function); Since this macro will inhibit inlining of static/inline functions, this patch also introduces a nokprobe_inline macro for static/inline functions. In this case, we must use NOKPROBE_SYMBOL() for the inline function caller. When CONFIG_KPROBES=y, the macro stores the given function address in the "_kprobe_blacklist" section. Since the data structures are not fully initialized by the macro (because there is no "size" information), those are re-initialized at boot time by using kallsyms. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Link: http://lkml.kernel.org/r/20140417081705.26341.96719.stgit@ltc230.yrl.intra.hitachi.co.jp Cc: Alok Kataria <akataria@vmware.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christopher Li <sparse@chrisli.org> Cc: Chris Wright <chrisw@sous-sol.org> Cc: David S. Miller <davem@davemloft.net> Cc: Jan-Simon Möller <dl9pf@gmx.de> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: linux-arch@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-sparse@vger.kernel.org Cc: virtualization@lists.linux-foundation.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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