Mark Tomlinson <mark.tomlinson@xxxxxxxxxxxxxxxxxxx> wrote: > When a new table value was assigned, it was followed by a write memory > barrier. This ensured that all writes before this point would complete > before any writes after this point. However, to determine whether the > rules are unused, the sequence counter is read. To ensure that all > writes have been done before these reads, a full memory barrier is > needed, not just a write memory barrier. The same argument applies when > incrementing the counter, before the rules are read. > > Changing to using smp_mb() instead of smp_wmb() fixes the kernel panic > reported in cc00bcaa5899 (which is still present), while still > maintaining the same speed of replacing tables. > > The smb_mb() barriers potentially slow the packet path, however testing > has shown no measurable change in performance on a 4-core MIPS64 > platform. Okay, thanks for testing. I have no further feedback.
