Hi Andrew, David, David Miller <da...@davemloft.net> writes:
>>> +bool dsa_uses_tagged_protocol(struct dsa_switch_tree *dst) >>> +{ >>> + return !!dst->rcv; >>> +} >>> + >> >> You need to be careful here. This is in the hot path. Every frame >> received uses this code. And think about a distro kernel, which might >> have DSA enabled by default, yet is unlikely to have any switches. You >> are adding a function call which can be called millions of times per >> second.... > > Yeah, we really can't make this change. > > This isn't glibc where we're trying to hide the implementation of "FILE *" > behind accessor functions that caller can't see. We inline things when > performance dictates, and it does here. Thanks for the explanation, this wasn't obvious to me at all. So inline is mandatory here. Would a dereference like "!!dst->tag_ops->rcv" have an significant impact on performance? Thanks, Vivien