Re: [Xen-devel] [PATCH] x86: also use tzcnt instead of bsf in __scanbit()

2015-01-26 Thread Andrew Cooper
On 26/01/15 12:03, Jan Beulich wrote: > ... when available, i.e. by runtime patching. This saves the > conditional move, having a back-to-back dependency on BSF's (EFLAGS) > result. > > The need to include asm/cpufeatures.h from asm/bitops.h requires a > workaround for an otherwise resulting circul

[Xen-devel] [PATCH] x86: also use tzcnt instead of bsf in __scanbit()

2015-01-26 Thread Jan Beulich
... when available, i.e. by runtime patching. This saves the conditional move, having a back-to-back dependency on BSF's (EFLAGS) result. The need to include asm/cpufeatures.h from asm/bitops.h requires a workaround for an otherwise resulting circular header file dependency: Provide a mode by whic