From: Eric Dumazet <eduma...@google.com> Date: Sat, 31 Mar 2018 12:58:41 -0700
> IP defrag processing is one of the remaining problematic layer in linux. > > It uses static hash tables of 1024 buckets, and up to 128 items per bucket. > > A work queue is supposed to garbage collect items when host is under memory > pressure, and doing a hash rebuild, changing seed used in hash computations. > > This work queue blocks softirqs for up to 25 ms when doing a hash rebuild, > occurring every 5 seconds if host is under fire. > > Then there is the problem of sharing this hash table for all netns. > > It is time to switch to rhashtables, and allocate one of them per netns > to speedup netns dismantle, since this is a critical metric these days. > > Lookup is now using RCU, and 64bit hosts can now provision whatever amount > of memory needed to handle the expected workloads. ... Series applied, thanks Eric.
