On Tue, Nov 07, 2023 at 10:23:16PM +0100, Mateusz Guzik wrote: > If the patch which dodges second lookup still somehow appears slower a > flamegraph or other profile would be nice. I can volunteer to take a > look at what's going on provided above measurements will be done and > show funkyness. When I looked at this last, it seemed like all the work done in do_filp_open() (my patch, which moved the lookup earlier) was heavier than the duplicate filename_lookup(). What I didn't test was moving the sched_exec() before the mm creation, which Peter confirmed shouldn't be a problem, but I think that might be only a tiny benefit, if at all. If you can do some comparisons, that would be great; it always takes me a fair bit of time to get set up for flame graph generation, etc. :) -Kees -- Kees Cook
