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authorMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>2013-05-09 14:44:29 +0900
committerSteven Rostedt <rostedt@goodmis.org>2013-05-09 20:14:25 -0400
commit1cf4c0732db3cd3c49cadbc60ff6bda08604e6fa (patch)
tree74133737a3ecea18847788c10fae7bb474f1aaa8 /include
parent30052170dcc256c18a43fb3e76577a67394543f8 (diff)
downloadlinux-1cf4c0732db3cd3c49cadbc60ff6bda08604e6fa.tar.bz2
tracing: Modify soft-mode only if there's no other referrer
Modify soft-mode flag only if no other soft-mode referrer (currently only the ftrace triggers) by using a reference counter in each ftrace_event_file. Without this fix, adding and removing several different enable/disable_event triggers on the same event clear soft-mode bit from the ftrace_event_file. This also happens with a typo of glob on setting triggers. e.g. # echo vfs_symlink:enable_event:net:netif_rx > set_ftrace_filter # cat events/net/netif_rx/enable 0* # echo typo_func:enable_event:net:netif_rx > set_ftrace_filter # cat events/net/netif_rx/enable 0 # cat set_ftrace_filter #### all functions enabled #### vfs_symlink:enable_event:net:netif_rx:unlimited As above, we still have a trigger, but soft-mode is gone. Link: http://lkml.kernel.org/r/20130509054429.30398.7464.stgit@mhiramat-M0-7522 Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: David Sharp <dhsharp@google.com> Cc: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com> Cc: Tom Zanussi <tom.zanussi@intel.com> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/ftrace_event.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 34e00fb49bec..4372658c73ae 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -293,6 +293,7 @@ struct ftrace_event_file {
* caching and such. Which is mostly OK ;-)
*/
unsigned long flags;
+ atomic_t sm_ref; /* soft-mode reference counter */
};
#define __TRACE_EVENT_FLAGS(name, value) \