https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=254333
--- Comment #19 from Richard Scheffenegger <rsch...@freebsd.org> --- (In reply to Michael Tuexen from comment #18) > Richard: Do you see a way how the counter could be off? Unfortunately not. I was thinking about adding KASSERTS when the counter is about to be decremented, but is already zero... Or simply reset all the counters to zero (hch_length, cache_count) when a purgeall is being performed, to return to a "known good" state. The only feasible way I can thing of right now, would be if the hostcache settings are changed dynamically, while the hostcache is already populated with some entries. That may leave the hc_bucket full, but the counters off... But all the normal processing of the accounting variables look good. > But tcp_hc_purge_internal() decrements the counter when it removes an > entry and frees it. I double checked the code and I think the counter > is handled correctly. I did look for an underflow, but I could not > find it... > I also looked at the 11.4 code, but I see no issue. The diff between 11.4 and HEAD is minuscle. None of the logic has changed (meaning this very same issue could potentially still be impacting HEAD). > If the hash buckets are used highly un-symmetric, I wouldn't suggest > to use larger buckets. That results in long processing time. In that > case I would suggest to use a better hash algorithm. But this is not > the issue right now. Correct. (A different salt during hashing may also help. Frequently used entries do percholate to the head of the TAILQ, though.) > For the counter having such a large value could happen when there is > an underflow. But I don't see how it can happen. For me it looks like > the global and the bucket counter are handled correctly. Still, a underflow is more likely than an overflow. > Since the statement is that this happens every 3 to 4 month, it must > be a rare event. Or some other code is writing in the memory location > where the counter is... KASSERTS for safety? (And an eventual core to potentially analyze) -- You are receiving this mail because: You are on the CC list for the bug. _______________________________________________ freebsd-net@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
