linux/kernel/trace
Tero Kristo 08697bca9b trace/hwlat: Do not start per-cpu thread if it is already running
The hwlatd tracer will end up starting multiple per-cpu threads with
the following script:

    #!/bin/sh
    cd /sys/kernel/debug/tracing
    echo 0 > tracing_on
    echo hwlat > current_tracer
    echo per-cpu > hwlat_detector/mode
    echo 100000 > hwlat_detector/width
    echo 200000 > hwlat_detector/window
    echo 1 > tracing_on

To fix the issue, check if the hwlatd thread for the cpu is already
running, before starting a new one. Along with the previous patch, this
avoids running multiple instances of the same CPU thread on the system.

Link: https://lore.kernel.org/all/20230302113654.2984709-1-tero.kristo@linux.intel.com/
Link: https://lkml.kernel.org/r/20230310100451.3948583-3-tero.kristo@linux.intel.com

Cc: stable@vger.kernel.org
Fixes: f46b16520a ("trace/hwlat: Implement the per-cpu mode")
Signed-off-by: Tero Kristo <tero.kristo@linux.intel.com>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-03-19 12:20:49 -04:00
..
rv rv: remove redundant initialization of pointer ptr 2023-01-25 10:31:02 -05:00
blktrace.c blktrace: Fix output non-blktrace event when blk_classic option enabled 2022-12-08 09:26:11 -07:00
bpf_trace.c bpf: Skip task with pid=1 in send_signal_common() 2023-01-06 22:48:58 +01:00
bpf_trace.h
error_report-traces.c tracing: add error_report_end trace point 2021-02-26 09:41:02 -08:00
fgraph.c arm64 fixes for 5.19-rc1: 2022-06-03 14:05:34 -07:00
fprobe.c tracing/fprobe: Fix to check whether fprobe is registered correctly 2022-11-04 08:50:07 +09:00
ftrace_internal.h
ftrace.c ftrace: Fix invalid address access in lookup_rec() when index is 0 2023-03-09 22:17:06 -05:00
Kconfig tracing: Always use canonical ftrace path 2023-02-18 14:34:09 -05:00
kprobe_event_gen_test.c tracing: Fix wrong return in kprobe_event_gen_test.c 2023-03-19 12:20:48 -04:00
Makefile rv: Add Runtime Verification (RV) interface 2022-07-30 14:01:28 -04:00
pid_list.c tracing: Cleanup double word in comment 2022-04-26 17:58:50 -04:00
pid_list.h tracing: Create a sparse bitmask for pid filtering 2021-10-05 17:38:45 -04:00
power-traces.c
preemptirq_delay_test.c kernel: trace: preemptirq_delay_test: add cpu affinity 2021-02-02 17:02:07 -05:00
rethook.c rethook: fix a potential memleak in rethook_alloc() 2022-11-18 10:15:34 +09:00
ring_buffer_benchmark.c ring_buffer: Remove unused "event" parameter 2022-11-23 19:08:30 -05:00
ring_buffer.c tracing: Always use canonical ftrace path 2023-02-18 14:34:09 -05:00
rpm-traces.c
synth_event_gen_test.c tracing: Always use canonical ftrace path 2023-02-18 14:34:09 -05:00
trace_benchmark.c tracing: Add numeric delta time to the trace event benchmark 2022-09-26 13:01:09 -04:00
trace_benchmark.h tracing: Add numeric delta time to the trace event benchmark 2022-09-26 13:01:09 -04:00
trace_boot.c tracing: Initialize integer variable to prevent garbage return value 2022-05-26 21:13:00 -04:00
trace_branch.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_clock.c tracing: Do no increment trace_clock_global() by one 2021-06-18 09:10:00 -04:00
trace_dynevent.c tracing: Free buffers when a used dynamic event is removed 2022-11-23 19:07:12 -05:00
trace_dynevent.h tracing: Add DYNAMIC flag for dynamic events 2021-08-18 18:10:32 -04:00
trace_entries.h trace: Add timerlat tracer 2021-06-25 19:57:24 -04:00
trace_eprobe.c tracing: Fix race where eprobes can be called before the event 2022-11-24 00:42:18 +09:00
trace_event_perf.c tracing/perf: Use strndup_user instead of kzalloc/strncpy_from_user 2022-11-23 19:08:31 -05:00
trace_events_filter_test.h
trace_events_filter.c tracing: Add a way to filter function addresses to function names 2023-01-25 10:31:11 -05:00
trace_events_hist.c tracing: Check field value in hist_field_name() 2023-03-09 22:17:06 -05:00
trace_events_inject.c tracing: Support __rel_loc relative dynamic data location attribute 2021-12-06 15:37:21 -05:00
trace_events_synth.c tracing/histogram: Don't use strlen to find length of stacktrace variables 2023-02-15 19:59:09 -05:00
trace_events_trigger.c tracing: Do not synchronize freeing of trigger filter on boot up 2022-12-14 08:50:56 -05:00
trace_events_user.c Tracing updates for 6.2: 2022-12-15 18:01:16 -08:00
trace_events.c tracing: Remove unnecessary NULL assignment 2023-02-18 14:34:36 -05:00
trace_export.c
trace_functions_graph.c tracing: in_irq() cleanup 2021-10-13 18:19:41 -04:00
trace_functions.c ftrace: disable preemption when recursion locked 2021-10-27 11:21:49 -04:00
trace_hwlat.c trace/hwlat: Do not start per-cpu thread if it is already running 2023-03-19 12:20:49 -04:00
trace_irqsoff.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_kdb.c kdb: Rename members of struct kdbtab_t 2021-07-27 17:05:06 +01:00
trace_kprobe_selftest.c
trace_kprobe_selftest.h
trace_kprobe.c trace/kprobe: remove duplicated calls of ring_buffer_event_data 2022-12-09 23:48:05 -05:00
trace_mmiotrace.c tracing: Remove definition of DEBUG in trace_mmiotrace.c 2021-02-02 17:02:07 -05:00
trace_nop.c
trace_osnoise.c tracing/osnoise: set several trace_osnoise.c variables storage-class-specifier to static 2023-03-19 12:20:48 -04:00
trace_output.c tracing: Make sure trace_printk() can output as soon as it can be used 2023-01-24 11:27:29 -05:00
trace_output.h
trace_preemptirq.c tracing: hold caller_addr to hardirq_{enable,disable}_ip 2022-09-06 22:26:00 -04:00
trace_printk.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace_probe_kernel.h tracing: Add "(fault)" name injection to kernel probes 2022-10-12 13:50:20 -04:00
trace_probe_tmpl.h tracing/probes: Add symstr type for dynamic events 2022-12-15 08:48:57 +09:00
trace_probe.c Trace probes updates for 6.2: 2022-12-21 18:57:24 -08:00
trace_probe.h tracing/probes: Reject symbol/symstr type for uprobe 2022-12-15 09:00:20 +09:00
trace_recursion_record.c tracing: Use trace_create_file() to simplify creation of tracefs entries 2022-05-26 21:12:52 -04:00
trace_sched_switch.c sched/tracing: Append prev_state to tp args instead 2022-05-12 00:37:11 +02:00
trace_sched_wakeup.c sched/tracing: Append prev_state to tp args instead 2022-05-12 00:37:11 +02:00
trace_selftest_dynamic.c
trace_selftest.c x86/ftrace: Make it call depth tracking aware 2022-10-17 16:41:19 +02:00
trace_seq.c tracing: Acquire buffer from temparary trace sequence 2023-02-07 12:42:54 -05:00
trace_stack.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace_stat.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace_stat.h
trace_synth.h tracing: Allow synthetic events to pass around stacktraces 2023-01-25 10:31:24 -05:00
trace_syscalls.c tracing: Remove unused __bad_type_size() method 2022-11-17 20:21:06 -05:00
trace_uprobe.c tracing/probes: Reject symbol/symstr type for uprobe 2022-12-15 09:00:20 +09:00
trace.c tracing: Always use canonical ftrace path 2023-02-18 14:34:09 -05:00
trace.h tracing: Add enabling of events to boot instances 2023-02-07 12:49:56 -05:00
tracing_map.c tracing: Remove unused variable 'dups' 2022-10-03 12:20:31 -04:00
tracing_map.h