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authorMiao Xie <miaox@cn.fujitsu.com>2013-12-16 15:20:01 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-01-08 09:42:10 -0800
commit09951c9b33f8cfdc0e8c4e03fe83bc66c9d908dc (patch)
tree4b5081c15d8231b7cb2adbb0d06a6e9f0d531150
parent58c2314ac41e8f24a2a594bd866915e38de9648e (diff)
downloadlinux-linaro-stable-09951c9b33f8cfdc0e8c4e03fe83bc66c9d908dc.tar.gz
ftrace: Initialize the ftrace profiler for each possible cpu
commit c4602c1c818bd6626178d6d3fcc152d9f2f48ac0 upstream. Ftrace currently initializes only the online CPUs. This implementation has two problems: - If we online a CPU after we enable the function profile, and then run the test, we will lose the trace information on that CPU. Steps to reproduce: # echo 0 > /sys/devices/system/cpu/cpu1/online # cd <debugfs>/tracing/ # echo <some function name> >> set_ftrace_filter # echo 1 > function_profile_enabled # echo 1 > /sys/devices/system/cpu/cpu1/online # run test - If we offline a CPU before we enable the function profile, we will not clear the trace information when we enable the function profile. It will trouble the users. Steps to reproduce: # cd <debugfs>/tracing/ # echo <some function name> >> set_ftrace_filter # echo 1 > function_profile_enabled # run test # cat trace_stat/function* # echo 0 > /sys/devices/system/cpu/cpu1/online # echo 0 > function_profile_enabled # echo 1 > function_profile_enabled # cat trace_stat/function* # run test # cat trace_stat/function* So it is better that we initialize the ftrace profiler for each possible cpu every time we enable the function profile instead of just the online ones. Link: http://lkml.kernel.org/r/1387178401-10619-1-git-send-email-miaox@cn.fujitsu.com Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--kernel/trace/ftrace.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 8c8169bf5020..f0e76e93aee5 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -688,7 +688,7 @@ static int ftrace_profile_init(void)
int cpu;
int ret = 0;
- for_each_online_cpu(cpu) {
+ for_each_possible_cpu(cpu) {
ret = ftrace_profile_init_cpu(cpu);
if (ret)
break;