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2022-03-15Merge tag 'v5.17-rc8' into sched/core, to pick up fixesIngo Molnar1-21/+63
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2022-03-09tracing/osnoise: Force quiescent states while tracingNicolas Saenz Julienne1-0/+20
At the moment running osnoise on a nohz_full CPU or uncontested FIFO priority and a PREEMPT_RCU kernel might have the side effect of extending grace periods too much. This will entice RCU to force a context switch on the wayward CPU to end the grace period, all while introducing unwarranted noise into the tracer. This behaviour is unavoidable as overly extending grace periods might exhaust the system's memory. This same exact problem is what extended quiescent states (EQS) were created for, conversely, rcu_momentary_dyntick_idle() emulates them by performing a zero duration EQS. So let's make use of it. In the common case rcu_momentary_dyntick_idle() is fairly inexpensive: atomically incrementing a local per-CPU counter and doing a store. So it shouldn't affect osnoise's measurements (which has a 1us granularity), so we'll call it unanimously. The uncommon case involve calling rcu_momentary_dyntick_idle() after having the osnoise process: - Receive an expedited quiescent state IPI with preemption disabled or during an RCU critical section. (activates rdp->cpu_no_qs.b.exp code-path). - Being preempted within in an RCU critical section and having the subsequent outermost rcu_read_unlock() called with interrupts disabled. (t->rcu_read_unlock_special.b.blocked code-path). Neither of those are possible at the moment, and are unlikely to be in the future given the osnoise's loop design. On top of this, the noise generated by the situations described above is unavoidable, and if not exposed by rcu_momentary_dyntick_idle() will be eventually seen in subsequent rcu_read_unlock() calls or schedule operations. Link: https://lkml.kernel.org/r/20220307180740.577607-1-nsaenzju@redhat.com Cc: stable@vger.kernel.org Fixes: bce29ac9ce0b ("trace: Add osnoise tracer") Signed-off-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Acked-by: Paul E. McKenney <paulmck@kernel.org> Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-03-09tracing/osnoise: Do not unregister events twiceDaniel Bristot de Oliveira1-0/+11
Nicolas reported that using: # trace-cmd record -e all -M 10 -p osnoise --poll Resulted in the following kernel warning: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1217 at kernel/tracepoint.c:404 tracepoint_probe_unregister+0x280/0x370 [...] CPU: 0 PID: 1217 Comm: trace-cmd Not tainted 5.17.0-rc6-next-20220307-nico+ #19 RIP: 0010:tracepoint_probe_unregister+0x280/0x370 [...] CR2: 00007ff919b29497 CR3: 0000000109da4005 CR4: 0000000000170ef0 Call Trace: <TASK> osnoise_workload_stop+0x36/0x90 tracing_set_tracer+0x108/0x260 tracing_set_trace_write+0x94/0xd0 ? __check_object_size.part.0+0x10a/0x150 ? selinux_file_permission+0x104/0x150 vfs_write+0xb5/0x290 ksys_write+0x5f/0xe0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7ff919a18127 [...] ---[ end trace 0000000000000000 ]--- The warning complains about an attempt to unregister an unregistered tracepoint. This happens on trace-cmd because it first stops tracing, and then switches the tracer to nop. Which is equivalent to: # cd /sys/kernel/tracing/ # echo osnoise > current_tracer # echo 0 > tracing_on # echo nop > current_tracer The osnoise tracer stops the workload when no trace instance is actually collecting data. This can be caused both by disabling tracing or disabling the tracer itself. To avoid unregistering events twice, use the existing trace_osnoise_callback_enabled variable to check if the events (and the workload) are actually active before trying to deactivate them. Link: https://lore.kernel.org/all/c898d1911f7f9303b7e14726e7cc9678fbfb4a0e.camel@redhat.com/ Link: https://lkml.kernel.org/r/938765e17d5a781c2df429a98f0b2e7cc317b022.1646823913.git.bristot@kernel.org Cc: stable@vger.kernel.org Cc: Marcelo Tosatti <mtosatti@redhat.com> Fixes: 2fac8d6486d5 ("tracing/osnoise: Allow multiple instances of the same tracer") Reported-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-03-01sched/tracing: Don't re-read p->state when emitting sched_switch eventValentin Schneider1-1/+3
As of commit c6e7bd7afaeb ("sched/core: Optimize ttwu() spinning on p->on_cpu") the following sequence becomes possible: p->__state = TASK_INTERRUPTIBLE; __schedule() deactivate_task(p); ttwu() READ !p->on_rq p->__state=TASK_WAKING trace_sched_switch() __trace_sched_switch_state() task_state_index() return 0; TASK_WAKING isn't in TASK_REPORT, so the task appears as TASK_RUNNING in the trace event. Prevent this by pushing the value read from __schedule() down the trace event. Reported-by: Abhijeet Dharmapurikar <adharmap@quicinc.com> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Link: https://lore.kernel.org/r/20220120162520.570782-2-valentin.schneider@arm.com
2022-02-25tracing/osnoise: Make osnoise_main to sleep for microsecondsDaniel Bristot de Oliveira1-21/+32
osnoise's runtime and period are in the microseconds scale, but it is currently sleeping in the millisecond's scale. This behavior roots in the usage of hwlat as the skeleton for osnoise. Make osnoise to sleep in the microseconds scale. Also, move the sleep to a specialized function. Link: https://lkml.kernel.org/r/302aa6c7bdf2d131719b22901905e9da122a11b2.1645197336.git.bristot@kernel.org Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-01-16Merge tag 'trace-v5.17' of ↵Linus Torvalds1-6/+17
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing updates from Steven Rostedt: "New: - The Real Time Linux Analysis (RTLA) tool is added to the tools directory. - Can safely filter on user space pointers with: field.ustring ~ "match-string" - eprobes can now be filtered like any other event. - trace_marker(_raw) now uses stream_open() to allow multiple threads to safely write to it. Note, this could possibly break existing user space, but we will not know until we hear about it, and then can revert the change if need be. - New field in events to display when bottom halfs are disabled. - Sorting of the ftrace functions are now done at compile time instead of at bootup. Infrastructure changes to support future efforts: - Added __rel_loc type for trace events. Similar to __data_loc but the offset to the dynamic data is based off of the location of the descriptor and not the beginning of the event. Needed for user defined events. - Some simplification of event trigger code. - Make synthetic events process its callback better to not hinder other event callbacks that are registered. Needed for user defined events. And other small fixes and cleanups" * tag 'trace-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (50 commits) tracing: Add ustring operation to filtering string pointers rtla: Add rtla timerlat hist documentation rtla: Add rtla timerlat top documentation rtla: Add rtla timerlat documentation rtla: Add rtla osnoise hist documentation rtla: Add rtla osnoise top documentation rtla: Add rtla osnoise man page rtla: Add Documentation rtla/timerlat: Add timerlat hist mode rtla: Add timerlat tool and timelart top mode rtla/osnoise: Add the hist mode rtla/osnoise: Add osnoise top mode rtla: Add osnoise tool rtla: Helper functions for rtla rtla: Real-Time Linux Analysis tool tracing/osnoise: Properly unhook events if start_per_cpu_kthreads() fails tracing: Remove duplicate warnings when calling trace_create_file() tracing/kprobes: 'nmissed' not showed correctly for kretprobe tracing: Add test for user space strings when filtering on string pointers tracing: Have syscall trace events use trace_event_buffer_lock_reserve() ...
2022-01-15trace/osnoise: make use of the helper function kthread_run_on_cpu()Cai Huoqing1-2/+1
Replace kthread_create_on_cpu/wake_up_process() with kthread_run_on_cpu() to simplify the code. Link: https://lkml.kernel.org/r/20211022025711.3673-6-caihuoqing@baidu.com Signed-off-by: Cai Huoqing <caihuoqing@baidu.com> Cc: Bernard Metzler <bmt@zurich.ibm.com> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Doug Ledford <dledford@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Joel Fernandes (Google) <joel@joelfernandes.org> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: "Paul E . McKenney" <paulmck@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-13tracing/osnoise: Properly unhook events if start_per_cpu_kthreads() failsNikita Yushchenko1-4/+16
If start_per_cpu_kthreads() called from osnoise_workload_start() returns error, event hooks are left in broken state: unhook_irq_events() called but unhook_thread_events() and unhook_softirq_events() not called, and trace_osnoise_callback_enabled flag not cleared. On the next tracer enable, hooks get not installed due to trace_osnoise_callback_enabled flag. And on the further tracer disable an attempt to remove non-installed hooks happened, hitting a WARN_ON_ONCE() in tracepoint_remove_func(). Fix the error path by adding the missing part of cleanup. While at this, introduce osnoise_unhook_events() to avoid code duplication between this error path and normal tracer disable. Link: https://lkml.kernel.org/r/20220109153459.3701773-1-nikita.yushchenko@virtuozzo.com Cc: stable@vger.kernel.org Fixes: bce29ac9ce0b ("trace: Add osnoise tracer") Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Nikita Yushchenko <nikita.yushchenko@virtuozzo.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2021-12-06tracing: Switch to kvfree_rcu() APIUladzislau Rezki (Sony)1-2/+1
Instead of invoking a synchronize_rcu() to free a pointer after a grace period we can directly make use of new API that does the same but in more efficient way. Link: https://lkml.kernel.org/r/20211124110308.2053-10-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-11-12tracing/osnoise: Make osnoise_instances staticDaniel Bristot de Oliveira1-1/+2
Make the struct list_head osnoise_instances definition static. Link: https://lore.kernel.org/all/202111120052.ZuikQSJi-lkp@intel.com/ Link: https://lkml.kernel.org/r/d001f0eeac66e2b2eeec7d2a15e9e7abede0453a.1636667971.git.bristot@kernel.org Cc: Ingo Molnar <mingo@redhat.com> Fixes: dae181349f1e ("tracing/osnoise: Support a list of trace_array *tr") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-11-01tracing/osnoise: Remove PREEMPT_RT ifdefs from inside functionsDaniel Bristot de Oliveira1-9/+4
Remove CONFIG_PREEMPT_RT from inside functions, avoiding compilation problems in the future. Link: https://lkml.kernel.org/r/37ee0881b033cdc513efc84ebea26cf77880c8c2.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-11-01tracing/osnoise: Remove STACKTRACE ifdefs from inside functionsDaniel Bristot de Oliveira1-15/+29
Remove CONFIG_STACKTRACE from inside functions, avoiding compilation problems in the future. Link: https://lkml.kernel.org/r/3465cca2f28e1ba602a1fc8bdb28d12950b5226e.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-11-01tracing/osnoise: Allow multiple instances of the same tracerDaniel Bristot de Oliveira1-23/+78
Currently, the user can start only one instance of timerlat/osnoise tracers and the tracers cannot run in parallel. As starting point to add more flexibility, let's allow the same tracer to run on different trace instances. The workload will start when the first trace_array (instance) is registered and stop when the last instance is unregistered. So, while this patch allows the same tracer to run in multiple instances (e.g., two instances running osnoise), it still does not allow instances of timerlat and osnoise in parallel (e.g., one timerlat and osnoise). That is because the osnoise: events have different behavior depending on which tracer is enabled (osnoise or timerlat). Enabling the parallel usage of these two tracers is in my TODO list. Link: https://lkml.kernel.org/r/38c8f14b613492a4f3f938d9d3bf0b063b72f0f0.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-11-01tracing/osnoise: Remove TIMERLAT ifdefs from inside functionsDaniel Bristot de Oliveira1-44/+106
Remove CONFIG_TIMERLAT_TRACER from inside functions, avoiding compilation problems in the future. Link: https://lkml.kernel.org/r/8245abb5a112d249f5da6c1df499244ad9e647bc.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-11-01tracing/osnoise: Support a list of trace_array *trDaniel Bristot de Oliveira1-69/+192
osnoise/timerlat were built to run a single instance, and for this, a single variable is enough to store the current struct trace_array *tr with information about the tracing instance. This is done via the *osnoise_trace variable. A trace_array represents a trace instance. In preparation to support multiple instances, replace the *osnoise_trace variable with an RCU protected list of instances. The operations that refer to an instance now propagate to all elements of the list (all instances). Also, replace the osnoise_busy variable with a check if the list has elements (busy). No functional change is expected with this patch, i.e., only one instance is allowed yet. Link: https://lkml.kernel.org/r/91d006e889b9a5d1ff258fe6077f021ae3f26372.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-11-01tracing/osnoise: Use start/stop_per_cpu_kthreads() on osnoise_cpus_write()Daniel Bristot de Oliveira1-5/+2
When writing a new CPU mask via osnoise/cpus, if the tracer is running, the workload is restarted to follow the new cpumask. The restart is currently done using osnoise_workload_start/stop(), which disables the workload *and* the instrumentation. However, disabling the instrumentation is not necessary. Calling start/stop_per_cpu_kthreads() is enough to apply the new osnoise/cpus config. Link: https://lkml.kernel.org/r/ee633e82867c5b88851aa6040522a799c0034486.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-11-01tracing/osnoise: Split workload start from the tracer startDaniel Bristot de Oliveira1-23/+36
In preparation from supporting multiple trace instances, create workload start/stop specific functions. No functional change. Link: https://lkml.kernel.org/r/74b090971e9acdd13625be1c28ef3270d2275e77.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-11-01tracing/osnoise: Improve comments about barrier need for NMI callbacksDaniel Bristot de Oliveira1-1/+7
trace_osnoise_callback_enabled is used by ftrace_nmi_enter/exit() to know when to call the NMI callback. The barrier is used to avoid having callbacks enabled before the resetting date during the start or to touch the values after stopping the tracer. Link: https://lkml.kernel.org/r/a413b8f14aa9312fbd1ba99f96225a8aed831053.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-11-01tracing/osnoise: Do not follow tracing_cpumaskDaniel Bristot de Oliveira1-18/+6
In preparation to support multiple instances, decouple the osnoise/timelat workload from instance-specific tracing_cpumask. Different instances can have conflicting cpumasks, making osnoise workload management needlessly complex. Osnoise already has its global cpumask. I also thought about using the first instance mask, but the "first" instance could be removed before the others. This also fixes the problem that changing the tracing_mask was not re-starting the trace. Link: https://lkml.kernel.org/r/169a71bcc919ce3ab53ae6f9ca5cde57fffaf9c6.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-10-25trace/timerlat: Add migrate-disabled field to the timerlat headerDaniel Bristot de Oliveira1-5/+6
Since "54357f0c9149 tracing: Add migrate-disabled counter to tracing output," the migrate disabled field is also printed in the !PREEMPR_RT kernel config. While this information was added to the vast majority of tracers, osnoise and timerlat were not updated (because they are new tracers). Fix timerlat header by adding the information about migrate disabled. Link: https://lkml.kernel.org/r/bc0c234ab49946cdd63effa6584e1d5e8662cb44.1634308385.git.bristot@kernel.org Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: x86@kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Fixes: 54357f0c9149 ("tracing: Add migrate-disabled counter to tracing output.") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-10-25trace/osnoise: Add migrate-disabled field to the osnoise headerDaniel Bristot de Oliveira1-7/+7
Since "54357f0c9149 tracing: Add migrate-disabled counter to tracing output," the migrate disabled field is also printed in the !PREEMPR_RT kernel config. While this information was added to the vast majority of tracers, osnoise and timerlat were not updated (because they are new tracers). Fix osnoise header by adding the information about migrate disabled. Link: https://lkml.kernel.org/r/9cb3d54e29e0588dbba12e81486bd8a09adcd8ca.1634308385.git.bristot@kernel.org Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: x86@kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Fixes: 54357f0c9149 ("tracing: Add migrate-disabled counter to tracing output.") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-10-08tracing: Disable "other" permission bits in the tracefs filesSteven Rostedt (VMware)1-7/+7
When building the files in the tracefs file system, do not by default set any permissions for OTH (other). This will make it easier for admins who want to define a group for accessing tracefs and not having to first disable all the permission bits for "other" in the file system. As tracing can leak sensitive information, it should never by default allowing all users access. An admin can still set the permission bits for others to have access, which may be useful for creating a honeypot and seeing who takes advantage of it and roots the machine. Link: https://lkml.kernel.org/r/20210818153038.864149276@goodmis.org Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-09-08tracing/osnoise: Fix missed cpus_read_unlock() in start_per_cpu_kthreads()Qiang.Zhang1-3/+3
When start_kthread() return error, the cpus_read_unlock() need to be called. Link: https://lkml.kernel.org/r/20210831022919.27630-1-qiang.zhang@windriver.com Cc: <stable@vger.kernel.org> Fixes: c8895e271f79 ("trace/osnoise: Support hotplug operations") Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Qiang.Zhang <qiang.zhang@windriver.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-08-17tracing: Replace deprecated CPU-hotplug functions.Sebastian Andrzej Siewior1-8/+8
The functions get_online_cpus() and put_online_cpus() have been deprecated during the CPU hotplug rework. They map directly to cpus_read_lock() and cpus_read_unlock(). Replace deprecated CPU-hotplug functions with the official version. The behavior remains unchanged. Link: https://lkml.kernel.org/r/20210803141621.780504-37-bigeasy@linutronix.de Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-08-12trace/osnoise: Print a stop tracing messageDaniel Bristot de Oliveira1-1/+5
When using osnoise/timerlat with stop tracing, sometimes it is not clear in which CPU the stop condition was hit, mainly when using some extra events. Print a message informing in which CPU the trace stopped, like in the example below: <idle>-0 [006] d.h. 2932.676616: #1672599 context irq timer_latency 34689 ns <idle>-0 [006] dNh. 2932.676618: irq_noise: local_timer:236 start 2932.676615639 duration 2391 ns <idle>-0 [006] dNh. 2932.676620: irq_noise: virtio0-output.0:47 start 2932.676620180 duration 86 ns <idle>-0 [003] d.h. 2932.676621: #1673374 context irq timer_latency 1200 ns <idle>-0 [006] d... 2932.676623: thread_noise: swapper/6:0 start 2932.676615964 duration 4339 ns <idle>-0 [003] dNh. 2932.676623: irq_noise: local_timer:236 start 2932.676620597 duration 1881 ns <idle>-0 [006] d... 2932.676623: sched_switch: prev_comm=swapper/6 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=timerlat/6 next_pid=852 next_prio=4 timerlat/6-852 [006] .... 2932.676623: #1672599 context thread timer_latency 41931 ns <idle>-0 [003] d... 2932.676623: thread_noise: swapper/3:0 start 2932.676620854 duration 880 ns <idle>-0 [003] d... 2932.676624: sched_switch: prev_comm=swapper/3 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=timerlat/3 next_pid=849 next_prio=4 timerlat/6-852 [006] .... 2932.676624: timerlat_main: stop tracing hit on cpu 6 timerlat/3-849 [003] .... 2932.676624: #1673374 context thread timer_latency 4310 ns Link: https://lkml.kernel.org/r/b30a0d7542adba019185f44ee648e60e14923b11.1626598844.git.bristot@kernel.org Cc: Tom Zanussi <zanussi@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-08-12trace/timerlat: Add a header with PREEMPT_RT additional fieldsDaniel Bristot de Oliveira1-0/+19
Some extra flags are printed to the trace header when using the PREEMPT_RT config. The extra flags are: need-resched-lazy, preempt-lazy-depth, and migrate-disable. Without printing these fields, the timerlat specific fields are shifted by three positions, for example: # tracer: timerlat # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # || / # |||| ACTIVATION # TASK-PID CPU# |||| TIMESTAMP ID CONTEXT LATENCY # | | | |||| | | | | <idle>-0 [000] d..h... 3279.798871: #1 context irq timer_latency 830 ns <...>-807 [000] ....... 3279.798881: #1 context thread timer_latency 11301 ns Add a new header for timerlat with the missing fields, to be used when the PREEMPT_RT is enabled. Link: https://lkml.kernel.org/r/babb83529a3211bd0805be0b8c21608230202c55.1626598844.git.bristot@kernel.org Cc: Tom Zanussi <zanussi@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-08-12trace/osnoise: Add a header with PREEMPT_RT additional fieldsDaniel Bristot de Oliveira1-0/+31
Some extra flags are printed to the trace header when using the PREEMPT_RT config. The extra flags are: need-resched-lazy, preempt-lazy-depth, and migrate-disable. Without printing these fields, the osnoise specific fields are shifted by three positions, for example: # tracer: osnoise # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth MAX # || / SINGLE Interference counters: # |||| RUNTIME NOISE %% OF CPU NOISE +-----------------------------+ # TASK-PID CPU# |||| TIMESTAMP IN US IN US AVAILABLE IN US HW NMI IRQ SIRQ THREAD # | | | |||| | | | | | | | | | | <...>-741 [000] ....... 1105.690909: 1000000 234 99.97660 36 21 0 1001 22 3 <...>-742 [001] ....... 1105.691923: 1000000 281 99.97190 197 7 0 1012 35 14 <...>-743 [002] ....... 1105.691958: 1000000 1324 99.86760 118 11 0 1016 155 143 <...>-744 [003] ....... 1105.691998: 1000000 109 99.98910 21 4 0 1004 33 7 <...>-745 [004] ....... 1105.692015: 1000000 2023 99.79770 97 37 0 1023 52 18 Add a new header for osnoise with the missing fields, to be used when the PREEMPT_RT is enabled. Link: https://lkml.kernel.org/r/1f03289d2a51fde5a58c2e7def063dc630820ad1.1626598844.git.bristot@kernel.org Cc: Tom Zanussi <zanussi@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-06-29trace/timerlat: Fix indentation on timerlat_main()Daniel Bristot de Oliveira1-3/+3
Dan Carpenter reported that: The patch a955d7eac177: "trace: Add timerlat tracer" from Jun 22, 2021, leads to the following static checker warning: kernel/trace/trace_osnoise.c:1400 timerlat_main() warn: inconsistent indenting here: 1389 while (!kthread_should_stop()) { 1390 now = ktime_to_ns(hrtimer_cb_get_time(&tlat->timer)); 1391 diff = now - tlat->abs_period; 1392 1393 s.seqnum = tlat->count; 1394 s.timer_latency = diff; 1395 s.context = THREAD_CONTEXT; 1396 1397 trace_timerlat_sample(&s); 1398 1399 #ifdef CONFIG_STACKTRACE 1400 if (osnoise_data.print_stack) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This should be indented another tab? 1401 if (osnoise_data.print_stack <= time_to_us(diff)) 1402 timerlat_dump_stack(); 1403 #endif /* CONFIG_STACKTRACE */ 1404 1405 tlat->tracing_thread = false; 1406 if (osnoise_data.stop_tracing_total) 1407 if (time_to_us(diff) >= osnoise_data.stop_tracing_total) 1408 osnoise_stop_tracing(); 1409 1410 wait_next_period(tlat); 1411 } And the static checker is right. Fix the indentation. Link: https://lkml.kernel.org/r/3d5d8c9258fbdcfa9d3c7362941b3d13a2a28d9d.1624986368.git.bristot@redhat.com Cc: Ingo Molnar <mingo@redhat.com> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: linux-kernel@vger.kernel.org Fixes: a955d7eac177 ("trace: Add timerlat tracer") Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-06-29trace/osnoise: Make 'noise' variable s64 in run_osnoise()Daniel Bristot de Oliveira1-2/+3
Dab Carpenter reported that: The patch bce29ac9ce0b: "trace: Add osnoise tracer" from Jun 22, 2021, leads to the following static checker warning: kernel/trace/trace_osnoise.c:1103 run_osnoise() warn: unsigned 'noise' is never less than zero. In this part of the code: 1100 /* 1101 * This shouldn't happen. 1102 */ 1103 if (noise < 0) { ^^^^^^^^^ 1104 osnoise_taint("negative noise!"); 1105 goto out; 1106 } 1107 And the static checker is right because 'noise' is u64. Make noise s64 and keep the check. It is important to check if the time read is behaving correctly - so we can trust the results. I also re-arranged some variable declarations. Link: https://lkml.kernel.org/r/acd7cd6e7d56b798a298c3bc8139a390b3c4ab52.1624986368.git.bristot@redhat.com Cc: Ingo Molnar <mingo@redhat.com> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: linux-kernel@vger.kernel.org Fixes: bce29ac9ce0b ("trace: Add osnoise tracer") Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-06-28trace/osnoise: Fix return value on osnoise_init_hotplug_supportDaniel Bristot de Oliveira1-1/+1
kernel test robot reported: >> kernel/trace/trace_osnoise.c:1584:2: error: void function 'osnoise_init_hotplug_support' should not return a value [-Wreturn-type] return 0; When !CONFIG_HOTPLUG_CPU. Fix it problem by removing the return value. Link: https://lkml.kernel.org/r/c7fc67f1a117cc88bab2e508c898634872795341.1624872608.git.bristot@redhat.com Fixes: c8895e271f79 ("trace/osnoise: Support hotplug operations") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-06-28trace/osnoise: Make interval u64 on osnoise_mainDaniel Bristot de Oliveira1-1/+1
kernel test robot reported: >> kernel/trace/trace_osnoise.c:966:3: warning: comparison of distinct pointer types ('typeof ((interval)) *' (aka 'long long *') and 'uint64_t *' (aka 'unsigned long long *')) [-Wcompare-distinct-pointer-types] do_div(interval, USEC_PER_MSEC); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/asm-generic/div64.h:228:28: note: expanded from macro 'do_div' (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \ ~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~ As interval cannot be negative because sample_period >= sample_runtime, making interval u64 on osnoise_main() is enough to fix this problem. Link: https://lkml.kernel.org/r/4ae1e7780563598563de079a3ef6d4d10b5f5546.1624872608.git.bristot@redhat.com Fixes: bce29ac9ce0b ("trace: Add osnoise tracer") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-06-28trace/osnoise: Fix 'no previous prototype' warningsDaniel Bristot de Oliveira1-9/+11
kernel test robot reported some osnoise functions with "no previous prototype." Fix these warnings by making local functions static, and by adding: void osnoise_trace_irq_entry(int id); void osnoise_trace_irq_exit(int id, const char *desc); to include/linux/trace.h. Link: https://lkml.kernel.org/r/e40d3cb4be8bde921f4b40fa6a095cf85ab807bd.1624872608.git.bristot@redhat.com Fixes: bce29ac9ce0b ("trace: Add osnoise tracer") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-06-28tracing: Have osnoise_main() add a quiescent state for task rcuSteven Rostedt (VMware)1-1/+4
ftracetest triggered: INFO: rcu_tasks detected stalls on tasks: 00000000b92b832d: .. nvcsw: 1/1 holdout: 1 idle_cpu: -1/7 task:osnoise/7 state:R running task stack: 0 pid: 2133 ppid: 2 flags:0x00004000 Call Trace: ? asm_sysvec_apic_timer_interrupt+0x12/0x20 ? asm_sysvec_apic_timer_interrupt+0x12/0x20 ? trace_hardirqs_on+0x2b/0xe0 ? asm_sysvec_apic_timer_interrupt+0x12/0x20 ? trace_clock_local+0xc/0x20 ? osnoise_main+0x10e/0x450 ? trace_softirq_entry_callback+0x50/0x50 ? kthread+0x153/0x170 ? __kthread_bind_mask+0x60/0x60 ? ret_from_fork+0x22/0x30 While running osnoise tracer with other tracers that rely on synchronize_rcu_tasks(), where that just hung. The reason is that osnoise_main() never schedules out if the interval is less than 1, and this will cause synchronize_rcu_tasks() to never return. Link: https://lkml.kernel.org/r/20210628114953.6dc06a91@oasis.local.home Fixes: bce29ac9ce0bb ("trace: Add osnoise tracer") Acked-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-06-25trace/osnoise: Support hotplug operationsDaniel Bristot de Oliveira1-30/+135
Enable and disable osnoise/timerlat thread during on CPU hotplug online and offline operations respectivelly. Link: https://lore.kernel.org/linux-doc/20210621134636.5b332226@oasis.local.home/ Link: https://lkml.kernel.org/r/39f98590b3caeb3c32f09526214058efe0e9272a.1624372313.git.bristot@redhat.com Cc: Phil Auld <pauld@redhat.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Kate Carcia <kcarcia@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Alexandre Chartre <alexandre.chartre@oracle.com> Cc: Clark Willaims <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: x86@kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Suggested-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-06-25trace: Add timerlat tracerDaniel Bristot de Oliveira1-31/+595
The timerlat tracer aims to help the preemptive kernel developers to found souces of wakeup latencies of real-time threads. Like cyclictest, the tracer sets a periodic timer that wakes up a thread. The thread then computes a *wakeup latency* value as the difference between the *current time* and the *absolute time* that the timer was set to expire. The main goal of timerlat is tracing in such a way to help kernel developers. Usage Write the ASCII text "timerlat" into the current_tracer file of the tracing system (generally mounted at /sys/kernel/tracing). For example: [root@f32 ~]# cd /sys/kernel/tracing/ [root@f32 tracing]# echo timerlat > current_tracer It is possible to follow the trace by reading the trace trace file: [root@f32 tracing]# cat trace # tracer: timerlat # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # || / # |||| ACTIVATION # TASK-PID CPU# |||| TIMESTAMP ID CONTEXT LATENCY # | | | |||| | | | | <idle>-0 [000] d.h1 54.029328: #1 context irq timer_latency 932 ns <...>-867 [000] .... 54.029339: #1 context thread timer_latency 11700 ns <idle>-0 [001] dNh1 54.029346: #1 context irq timer_latency 2833 ns <...>-868 [001] .... 54.029353: #1 context thread timer_latency 9820 ns <idle>-0 [000] d.h1 54.030328: #2 context irq timer_latency 769 ns <...>-867 [000] .... 54.030330: #2 context thread timer_latency 3070 ns <idle>-0 [001] d.h1 54.030344: #2 context irq timer_latency 935 ns <...>-868 [001] .... 54.030347: #2 context thread timer_latency 4351 ns The tracer creates a per-cpu kernel thread with real-time priority that prints two lines at every activation. The first is the *timer latency* observed at the *hardirq* context before the activation of the thread. The second is the *timer latency* observed by the thread, which is the same level that cyclictest reports. The ACTIVATION ID field serves to relate the *irq* execution to its respective *thread* execution. The irq/thread splitting is important to clarify at which context the unexpected high value is coming from. The *irq* context can be delayed by hardware related actions, such as SMIs, NMIs, IRQs or by a thread masking interrupts. Once the timer happens, the delay can also be influenced by blocking caused by threads. For example, by postponing the scheduler execution via preempt_disable(), by the scheduler execution, or by masking interrupts. Threads can also be delayed by the interference from other threads and IRQs. The timerlat can also take advantage of the osnoise: traceevents. For example: [root@f32 ~]# cd /sys/kernel/