Messages in this thread | | | From | Yury Norov <> | Date | Mon, 1 Feb 2021 23:10:02 -0800 | Subject | Re: [PATCH 5/8] bitsperlong.h: introduce SMALL_CONST() macro |
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On Mon, Feb 1, 2021 at 5:45 AM Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote: > > On Sat, Jan 30, 2021 at 11:17:16AM -0800, Yury Norov wrote: > > Many algorithms become simpler if they are passed with relatively small > > input values. One example is bitmap operations when the whole bitmap fits > > into one word. To implement such simplifications, linux/bitmap.h declares > > small_const_nbits() macro. > > > > Other subsystems may also benefit from optimizations of this sort, like > > find_bit API in the following patches. So it looks helpful to generalize > > the macro and extend it's visibility. > > Hmm... Are we really good to allow 0 as a parameter to it? I remember we had > a thread at some point where Rasmus explained why 0 is excluded.
Now we pass (nbits - 1) instead of nbits, which is ULONG_MAX in case of nbits == 0
> > --- a/tools/include/asm-generic/bitsperlong.h > > +++ b/tools/include/asm-generic/bitsperlong.h > > Tools part in a separate patch? > > -- > With Best Regards, > Andy Shevchenko > >
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