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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-12-06 08:34:16 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-12-06 08:34:16 -0800 |
| commit | 843f4f4bb1a2c4c196a1af1d18bb6477a580ac78 (patch) | |
| tree | 53b795cb810b7430e46fe485d081bab675792ddb | |
| parent | c537aba00e3f1df8ce6c7c9fcb98b82c0c2d1d2c (diff) | |
| parent | 3ccb01239201af06a07482ec686b14cd148102a5 (diff) | |
| download | linux-843f4f4bb1a2c4c196a1af1d18bb6477a580ac78.tar.bz2 | |
Merge tag 'trace-fixes-3.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fix from Steven Rostedt:
"A regression showed up that there's a large delay when enabling all
events. This was prevalent when FTRACE_SELFTEST was enabled which
enables all events several times, and caused the system bootup to
pause for over a minute.
This was tracked down to an addition of a synchronize_sched()
performed when system call tracepoints are unregistered.
The synchronize_sched() is needed between the unregistering of the
system call tracepoint and a deletion of a tracing instance buffer.
But placing the synchronize_sched() in the unreg of *every* system
call tracepoint is a bit overboard. A single synchronize_sched()
before the deletion of the instance is sufficient"
* tag 'trace-fixes-3.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Only run synchronize_sched() at instance deletion time
| -rw-r--r-- | kernel/trace/trace_events.c | 3 | ||||
| -rw-r--r-- | kernel/trace/trace_syscalls.c | 10 |
2 files changed, 3 insertions, 10 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index f919a2e21bf3..a11800ae96de 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -2314,6 +2314,9 @@ int event_trace_del_tracer(struct trace_array *tr) /* Disable any running events */ __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0); + /* Access to events are within rcu_read_lock_sched() */ + synchronize_sched(); + down_write(&trace_event_sem); __trace_remove_event_dirs(tr); debugfs_remove_recursive(tr->event_dir); diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index e4b6d11bdf78..ea90eb5f6f17 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -431,11 +431,6 @@ static void unreg_event_syscall_enter(struct ftrace_event_file *file, if (!tr->sys_refcount_enter) unregister_trace_sys_enter(ftrace_syscall_enter, tr); mutex_unlock(&syscall_trace_lock); - /* - * Callers expect the event to be completely disabled on - * return, so wait for current handlers to finish. - */ - synchronize_sched(); } static int reg_event_syscall_exit(struct ftrace_event_file *file, @@ -474,11 +469,6 @@ static void unreg_event_syscall_exit(struct ftrace_event_file *file, if (!tr->sys_refcount_exit) unregister_trace_sys_exit(ftrace_syscall_exit, tr); mutex_unlock(&syscall_trace_lock); - /* - * Callers expect the event to be completely disabled on - * return, so wait for current handlers to finish. - */ - synchronize_sched(); } static int __init init_syscall_trace(struct ftrace_event_call *call) |