Messages in this thread | | | Date | Tue, 19 May 2020 20:42:10 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2] sched/cputime: make scale_stime() more precise |
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On Tue, May 19, 2020 at 11:33:34AM -0700, Linus Torvalds wrote: > On Tue, May 19, 2020 at 10:25 AM Peter Zijlstra <peterz@infradead.org> wrote: > > > > --- a/include/linux/math64.h > > +++ b/include/linux/math64.h > > @@ -263,6 +263,47 @@ static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor) > > } > > #endif /* mul_u64_u32_div */ > > > > +#ifndef mul_u64_u64_div_u64 > > +static inline u64 mul_u64_u64_div_u64(u64 a, u64 b, u64 c) > > Do we really want to inline this? Particularly if we expect this to be > the "architecture doesn't have a better version" case? > > It's not like we'd expect people to call it with constant values that > could be optimized by inlining, do we? If any of the values are > actually constants and it's performance-critical, the code is likely > better off using some special helper rather than this anyway. > > So I'd much rather see it as a weak function defined in > lib/math/div64.c, and then architectures don't even need to override > it at all. Just let them define their own (inline or not) function, > and we have this as a weak fallback.
I completely forgot we had a .c file to go with all this. Yes, I'll put it in there.
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