tracing: Rewrite filter logic to be simpler and faster
Al Viro reviewed the filter logic of ftrace trace events and found it to be very troubling. It creates a binary tree based on the logic operators and walks it during tracing. He sent myself and Tom Zanussi a long explanation (and formal proof) of how to do the string parsing better and end up with a program array that can be simply iterated to come up with the correct results. I took his ideas and his pseudo code and rewrote the filter logic based on them. In doing so, I was able to remove a lot of code, and have a much more condensed filter logic in the process. I wrote a very long comment describing the methadology that Al proposed in my own words. For more info on how this works, read the comment above predicate_parse(). Suggested-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
parent
478325f188
commit
80765597bc
|
@ -1216,12 +1216,11 @@ struct ftrace_event_field {
|
|||
int is_signed;
|
||||
};
|
||||
|
||||
struct prog_entry;
|
||||
|
||||
struct event_filter {
|
||||
int n_preds; /* Number assigned */
|
||||
int a_preds; /* allocated */
|
||||
struct filter_pred __rcu *preds;
|
||||
struct filter_pred __rcu *root;
|
||||
char *filter_string;
|
||||
struct prog_entry __rcu *prog;
|
||||
char *filter_string;
|
||||
};
|
||||
|
||||
struct event_subsystem {
|
||||
|
@ -1413,12 +1412,8 @@ struct filter_pred {
|
|||
unsigned short *ops;
|
||||
struct ftrace_event_field *field;
|
||||
int offset;
|
||||
int not;
|
||||
int not;
|
||||
int op;
|
||||
unsigned short index;
|
||||
unsigned short parent;
|
||||
unsigned short left;
|
||||
unsigned short right;
|
||||
};
|
||||
|
||||
static inline bool is_string_field(struct ftrace_event_field *field)
|
||||
|
|
File diff suppressed because it is too large
Load diff
Loading…
Reference in a new issue