On Thu, 15 Dec 2011, tip-bot for Jan Beulich wrote: > x86: Fix and improve percpu_cmpxchg{8,16}b_double() Great. Thanks. I wish you would have been there when I had to put this together. Had a difficult time finding relevant docs etc on how to exactly do this. And the failure messages from the inline asm parser were not that helpful. Acked-by: Christoph Lameter <cl@xxxxxxxxx> > The __dummy variable was pointless (and needlessly initialized > in the 2x32-bit case), given that local copies of the inputs > already exist. Hmm... I had some failures if I did not specify that dummy in the inline asm. Does this work for all gcc versions? > The 2x64-bit variant forced the address of the first object into > %rsi, even though this is needed only for the call to the > emulation function. The real cmpxchg16b can operate on an > memory. Yup. Good idea to code the load into the alternative code path to avoid the cmpxchg of the primary code path to be restricted to %si register. You dropped the padding with NOPs. Are the instructions on both paths always the same length? -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html