Hi Namhyung, On Fri, 2014-04-04 at 16:36 +0900, Namhyung Kim wrote: > Hi Tom, > > On Wed, 02 Apr 2014 09:51:54 -0500, Tom Zanussi wrote: > > Hi Namhyung, > > > > On Wed, 2014-04-02 at 08:31 +0000, Namhyung Kim wrote: > >> One thing I noticed in the main logic is that it seems there's no > >> limit checking when adding/creating new entry. In > >> hash_trigger_entry_create(), there's a check against max_entries but > >> if it goes beyond the max, it'd just access a NULL pointer AFAICS. Am > >> I missing something? Also I don't know what the difference between > >> ->n_entries and ->total_entries (in hash_data). > >> > >> I guess you wanted to set ->drops in that case, but I cannot find > > > > Yes, the code is missing a very important snippet, which I realized > > after hitting the problem. My current code has this: > > > > if (hash_data->drops) > > return NULL; > > I think this part can be omitted since it's already checked earlier. > But it's a minor issue. >
Right, exactly, it's completely redundant. > > > else if (hash_data->n_entries == hash_data->max_entries) { > > hash_data->drops = 1; > > return NULL; > > } > > > > n_entries is the current number of entries used up, and max_entries is > > the total number of available entries (a cached value to avoid > > calculating it every time). > > But there's "total_entries" - increased in hash_trigger_entry_insert() - > too and I think it's just same as n_entries. > And this is too - in a previous version they could be different, but you're right, n_entries is sufficient now - I'll consolidate in the next version. Thanks, Tom > > > >> where it gets set. And I'm not sure it's good to check ->drop first, > >> since entry can find an existing entry and merged to it even if it > >> reached the max already. > >> > > > > The assumption is that if you have any drops at all, you probably want > > to redo the test with a bigger table, but regardless the data reflects > > the situation up to the point the drops started happening. Letting > > events that already have a entry merge while rejecting those that don't > > would invalidate the data you already have. > > Okay, I won't insist on it. > > Thanks, > Namhyung -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/