Commit ea3a6d6d authored Dec 17, 2008 by Steven Rostedt Committed by Ingo Molnar Dec 18, 2008

ftrace: add not to regex on filtering functions



Impact: enhancement

Ingo Molnar has asked about a way to remove items from the filter
lists. Currently, you can only add or replace items. The way
items are added to the list is through opening one of the list
files (set_ftrace_filter or set_ftrace_notrace) via append.
If the file is opened for truncate, the list is cleared.

  echo spin_lock > /debug/tracing/set_ftrace_filter

The above will replace the list with only spin_lock

  echo spin_lock >> /debug/tracing/set_ftrace_filter

The above will add spin_lock to the list.

Now this patch adds:

  echo '!spin_lock' >> /debug/tracing/set_ftrace_filter

This will remove spin_lock from the list.

The limited glob features of these lists also can be notted.

  echo '!spin_*' >> /debug/tracing/set_ftrace_filter

This will remove all functions that start with 'spin_'

Note:

  echo '!spin_*' > /debug/tracing/set_ftrace_filter

will simply clear out the list (notice the '>' instead of '>>')

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent e05a43b7

kernel/trace/ftrace.c

+13 −2

Original line number	Diff line number	Diff line
		@@ -1047,6 +1047,13 @@ ftrace_match(unsigned char *buff, int len, int enable)
		int type = MATCH_FULL;
		unsigned long flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
		unsigned i, match = 0, search_len = 0;
		int not = 0;

		if (buff[0] == '!') {
		not = 1;
		buff++;
		len--;
		}

		for (i = 0; i < len; i++) {
		if (buff[i] == '*') {
		@@ -1100,9 +1107,13 @@ ftrace_match(unsigned char *buff, int len, int enable)
		matched = 1;
		break;
		}
		if (matched)
		if (matched) {
		if (not)
		rec->flags &= ~flag;
		else
		rec->flags \|= flag;
		}
		}
		pg = pg->next;
		}
		spin_unlock(&ftrace_lock);

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