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tracing/filter: Optimize short ciruit check 

The test if we should break out early for OR and AND operations
can be optimized by comparing the current result with
  (pred->op == OP_OR)

That is if the result is true and the op is an OP_OR, or
if the result is false and the op is not an OP_OR (thus an OP_AND)
we can break out early in either case. Otherwise we continue
processing.

Cc: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt 2011-01-27 23:12:05 -05:00 committed by Steven Rostedt
parent 61e9dea20e
commit 5571927418
1 changed files with 9 additions and 3 deletions
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12
kernel/trace/trace_events_filter.c
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@ -426,9 +426,15 @@ int filter_match_preds(struct event_filter *filter, void *rec)
pred->parent, &move);
continue;
case MOVE_UP_FROM_LEFT:
/* Check for short circuits */
if ((match && pred->op == OP_OR) ||
(!match && pred->op == OP_AND)) {
/*
* Check for short circuits.
*
* Optimization: !!match == (pred->op == OP_OR)
* is the same as:
* if ((match && pred->op == OP_OR) ||
* (!match && pred->op == OP_AND))
*/
if (!!match == (pred->op == OP_OR)) {
if (pred == root)
break;
pred = get_pred_parent(pred, preds,