> Yes, this came up before. Currently, if you add the if statement in the > trcacepoint, you just wasted space. But if we can add a discard_entry, > or better yet, I can add a TRACE_EVENT_CONDITION() that adds an if > statement to check. Something like: > > TRACE_EVENT_CONDITION(name, > [...] > TP_condition( > if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC | > I_DIRTY_PAGES)) > return 1; > else > return 0; > ), I love this idea. :) For MM, struct page has a lot of union hack. then, page tracer strongly need conditional trace point. > > Have this run on the parameters and not the entry fields (because the > entry fields are from the ring buffer, and to use them, we must first > write to the ring buffer (something we want to avoid). > > We could also make this code work with "pre-filters". That is, filters > on the tracepoints that access the parameters and not the final entries. > This would let us circumvent allocating ring buffer space when the > filter states to skip the entry. > > -- Steve > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
