[PATCH v5 7/8] rtla: Unconditionally clean any pre-existing filters for user-provided events
From: Valentin Schneider <vschneid@redhat.com>
Date: 2026-09-02 12:40:50
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documentation, real-time linux analysis (rtla) tools, the rest · Maintainers:
Jonathan Corbet, Steven Rostedt, Tomas Glozar, Linus Torvalds
A later commit will apply a filter to events recorded to the trace output. To prevent any user confusion, remove pre-existing filters when enabling an event provided via the '-e' command line argument. Suggested-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Valentin Schneider <vschneid@redhat.com> --- Documentation/tools/rtla/common_options.txt | 9 ++++++++- tools/tracing/rtla/src/trace.c | 4 ++++ 2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/Documentation/tools/rtla/common_options.txt b/Documentation/tools/rtla/common_options.txt
index 38da1cf443a48..6bf0f86393333 100644
--- a/Documentation/tools/rtla/common_options.txt
+++ b/Documentation/tools/rtla/common_options.txt@@ -26,12 +26,19 @@ **--filter** *<filter>* - Filter the previous **-e** *sys:event* event with *<filter>*. For further information about event filtering see https://www.kernel.org/doc/html/latest/trace/events.html#event-filtering. + Filter the previous **-e** *sys:event* event with *<filter>*. + + If the same event is specified more than once but with different filters, the last specified filter will be the only one applied. + + For further information about event filtering see https://www.kernel.org/doc/html/latest/trace/events.html#event-filtering. This option cannot be unset. **--trigger** *<trigger>* Enable a trace event trigger to the previous **-e** *sys:event*. + + If the same event is specified more than once but with different triggers, the last specified trigger will be the only one applied. + If the *hist:* trigger is activated, the output histogram will be automatically saved to a file named *system_event_hist.txt*. For example, the command:
diff --git a/tools/tracing/rtla/src/trace.c b/tools/tracing/rtla/src/trace.c
index 17d148f7d5d6e..06204d339f967 100644
--- a/tools/tracing/rtla/src/trace.c
+++ b/tools/tracing/rtla/src/trace.c@@ -487,6 +487,10 @@ static int trace_event_enable_filter(struct trace_instance *instance, char filter[MAX_PATH]; int retval; + /* Unconditionally clean any pre-existing filters */ + tracefs_event_file_write(instance->inst, tevent->system, + tevent->event, "filter", "0"); + if (!tevent->filter) return 0;
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2.55.0