From: Steven Rostedt Date: Fri, 28 Jan 2011 04:12:05 +0000 (-0500) Subject: tracing/filter: Optimize short ciruit check X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=55719274188f13cff9e3bd11fdd4c0e7617cd03d;p=linux-beck.git 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 Signed-off-by: Steven Rostedt --- diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 10390491b6d0..0a3e0502b507 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -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,