On 05/05/2015 11:16 AM, Ingo Molnar wrote: > We could put the SDM name into a comment, next to the field > definition? Something like, if 'xfeatures' is too long: > > struct xstate_header { > u64 xfeat; /* xstate components, SDM: XSTATE_BV > */ > u64 xfeat_comp; /* compacted xstate components, SDM: XCOMP_BV */ > u64 reserved[6]; > } __attribute__((packed));
When you're in the depths of the SDM and the kernel code, the fewer context switches you have to make, the better. I say this from the perspective of someone who's had a copy of the SDM open to xsave* for about a month straight. In any case, having "xfeat" and "xfeat_comp" is a bad idea. They're not really related concepts other than their bits refer to the same states. They should not have such similar names. XSTATE_BV is the set of states written to the xsave area. XCOMP_BV is essentially always XCR0 (aka pcntxt_mask, aka xfeatures_mask) or'd with bit 63. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/