Kees Cook <keescook@xxxxxxxxxxxx> writes: > On Fri, Aug 18, 2023 at 04:10:49PM -0400, Jeff Layton wrote: >> [...] >> extra checks (supposedly) compile down to nothing. It should be possible >> to build alternate refcount_t handling functions that are just wrappers >> around atomic_t with no extra checks, for folks who want to really run >> "fast and loose". > > No -- there's no benefit for this. We already did all this work years > ago with the fast vs full break-down. All that got tossed out since it > didn't matter. We did all the performance benchmarking and there was no > meaningful difference -- refcount _is_ atomic with an added check that > is branch-predicted away. Peter Zijlstra and Will Deacon spent a lot of > time making it run smoothly. :) Since you did all of the work should the text size of be growing by a kilobyte for this change? Is that expected? That is a valid concern with this change and it really should be justified in the change long as someone brought it up. Eric
