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| author | Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> | 2013-05-09 14:44:29 +0900 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2013-05-09 20:14:25 -0400 |
| commit | 1cf4c0732db3cd3c49cadbc60ff6bda08604e6fa (patch) | |
| tree | 74133737a3ecea18847788c10fae7bb474f1aaa8 /include | |
| parent | 30052170dcc256c18a43fb3e76577a67394543f8 (diff) | |
| download | lwn-1cf4c0732db3cd3c49cadbc60ff6bda08604e6fa.tar.gz lwn-1cf4c0732db3cd3c49cadbc60ff6bda08604e6fa.zip | |
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.h | 1 |
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) \ |