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ftrace: add not to regex on filtering functions

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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>
This commit is contained in:
Steven Rostedt 2008-12-17 15:05:36 -05:00 committed by Ingo Molnar
parent e05a43b744
commit ea3a6d6d60
1 changed files with 13 additions and 2 deletions
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15
kernel/trace/ftrace.c
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@ -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] == '*') {
@ -1100,8 +1107,12 @@ ftrace_match(unsigned char *buff, int len, int enable)
matched = 1;
break;
}
if (matched)
rec->flags |= flag;
if (matched) {
if (not)
rec->flags &= ~flag;
else
rec->flags |= flag;
}
}
pg = pg->next;
}