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authorLinus Torvalds <torvalds@linux-foundation.org>2017-05-04 04:41:21 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-05-04 04:41:21 +0300
commit4c174688ee92805aa5df6e06e5b625a3286e415c (patch)
tree78e18b242b31a3a50eda41bfdd4705e07f13647a /arch
parent9c35baf6cee9a5745d55de6f9995916dde642517 (diff)
parent73a757e63114dfd765f1c5d1ff7e994f123d0234 (diff)
downloadlinux-4c174688ee92805aa5df6e06e5b625a3286e415c.tar.xz
Merge tag 'trace-v4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt: "New features for this release: - Pretty much a full rewrite of the processing of function plugins. i.e. echo do_IRQ:stacktrace > set_ftrace_filter - The rewrite was needed to add plugins to be unique to tracing instances. i.e. mkdir instance/foo; cd instances/foo; echo do_IRQ:stacktrace > set_ftrace_filter The old way was written very hacky. This removes a lot of those hacks. - New "function-fork" tracing option. When set, pids in the set_ftrace_pid will have their children added when the processes with their pids listed in the set_ftrace_pid file forks. - Exposure of "maxactive" for kretprobe in kprobe_events - Allow for builtin init functions to be traced by the function tracer (via the kernel command line). Module init function tracing will come in the next release. - Added more selftests, and have selftests also test in an instance" * tag 'trace-v4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (60 commits) ring-buffer: Return reader page back into existing ring buffer selftests: ftrace: Allow some event trigger tests to run in an instance selftests: ftrace: Have some basic tests run in a tracing instance too selftests: ftrace: Have event tests also run in an tracing instance selftests: ftrace: Make func_event_triggers and func_traceonoff_triggers tests do instances selftests: ftrace: Allow some tests to be run in a tracing instance tracing/ftrace: Allow for instances to trigger their own stacktrace probes tracing/ftrace: Allow for the traceonoff probe be unique to instances tracing/ftrace: Enable snapshot function trigger to work with instances tracing/ftrace: Allow instances to have their own function probes tracing/ftrace: Add a better way to pass data via the probe functions ftrace: Dynamically create the probe ftrace_ops for the trace_array tracing: Pass the trace_array into ftrace_probe_ops functions tracing: Have the trace_array hold the list of registered func probes ftrace: If the hash for a probe fails to update then free what was initialized ftrace: Have the function probes call their own function ftrace: Have each function probe use its own ftrace_ops ftrace: Have unregister_ftrace_function_probe_func() return a value ftrace: Add helper function ftrace_hash_move_and_update_ops() ftrace: Remove data field from ftrace_func_probe structure ...
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/ftrace.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 5b7153540727..8ee76dce9140 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -533,7 +533,13 @@ static void do_sync_core(void *data)
static void run_sync(void)
{
- int enable_irqs = irqs_disabled();
+ int enable_irqs;
+
+ /* No need to sync if there's only one CPU */
+ if (num_online_cpus() == 1)
+ return;
+
+ enable_irqs = irqs_disabled();
/* We may be called with interrupts disabled (on bootup). */
if (enable_irqs)