On Wed, Apr 6, 2016 at 9:45 PM, Andi Kleen <[email protected]> wrote: > [email protected] writes: > >> From: Zhaoxiu Zeng <[email protected]> >> >> Use alternatives, lifted from arch_hweight > > Is there actually anything performance critical in the kernel that uses > parity? > > FWIW the arch hweight custom calling convention is a problem for LTO > because it needs different special flags, so I usually have to disable > it. Likely other reasonable usages, such as automatic source code > analysis, and other tool chain based usages have similar problems. > > As far as I can tell both for hweight and likely for parity it is > badly overengineering and normal calling conventions would work as well, > and cause much less problems. > > So if parity is really worth adding here (which I find doubtful, > but you may have numbers), please add it without these magic > calling hacks.
Hweight custom calling convention caused crashes with KCOV coverage. We had to disable instrumentation of the file.
