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authorTom Zanussi <zanussi@kernel.org>2020-04-03 14:31:21 -0500
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2020-06-01 08:22:30 -0400
commit2d19bd79ae6509858582a9cade739c2e9a4fdca8 (patch)
tree7612f1c6d4821e70b8b69d91a0608ae68c4d3413 /kernel/trace/trace.h
parent16b585fe71924b3aebaef5548a291021efaf7c7f (diff)
downloadlinux-2d19bd79ae6509858582a9cade739c2e9a4fdca8.tar.bz2
tracing: Add hist_debug trace event files for histogram debugging
Add a new "hist_debug" file for each trace event, which when read will dump out a bunch of internal details about the hist triggers defined on that event. This is normally off but can be enabled by saying 'y' to the new CONFIG_HIST_TRIGGERS_DEBUG config option. This is in support of the new Documentation file describing histogram internals, Documentation/trace/histogram-design.rst, which was requested by developers trying to understand the internals when extending or making use of the hist triggers for higher-level tools. The histogram-design.rst documentation refers to the hist_debug files and demonstrates their use with output in the test examples. Link: http://lkml.kernel.org/r/77914c22b0ba493d9783c53bbfbc6087d6a7e1b1.1585941485.git.zanussi@kernel.org Signed-off-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace.h')
-rw-r--r--kernel/trace/trace.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 4eb1d004d5f2..def769df5bf1 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1661,6 +1661,7 @@ extern struct list_head ftrace_events;
extern const struct file_operations event_trigger_fops;
extern const struct file_operations event_hist_fops;
+extern const struct file_operations event_hist_debug_fops;
extern const struct file_operations event_inject_fops;
#ifdef CONFIG_HIST_TRIGGERS