Konrad Rzeszutek Wilk wrote: > On Wed, Feb 22, 2012 at 05:02:59PM +0000, Liu, Jinsong wrote: >> Konrad Rzeszutek Wilk wrote: >>> On Tue, Feb 21, 2012 at 05:49:58AM +0000, Liu, Jinsong wrote: >>>> Konrad Rzeszutek Wilk wrote: >>>>>>>>> +struct pv_pad_ops { >>>>>>>>> + int (*acpi_pad_init)(void); >>>>>>>>> + void (*acpi_pad_exit)(void); >>>>>>>>> +}; >>>>>>>>> + >>>>>>> >>>>>>> Looking at this a bit closer I am not sure why you choose the >>>>>>> paravirt interface for this? There is another one - the x86 that >>>>>>> could have been choosen. Or introduce a new one that is >>>>>>> specific to ACPI. >>>>>>> >>>>>>> I am curious - what was the reason for using the paravirt >>>>>>> interface? I understand it does get the job done, but it seems a >>>>>>> bit overkill when something simple could have been used? >>>>>>> >>>>>> >>>>>> It uses paravirt interface to avoid some code like 'xen_...' in >>>>>> native code path (acpi_pad.c). >>>>>> I'm not quite sure what does 'x86' here mean? Adding 2 fields >>>>>> (acpi_pad_init/exit) in arch/x86/xen/enlighten.c --> xen_cpu_ops? >>>>>> seems it's much simpler. >>>>> >>>>> arch/x86/include/asm/x86_init.h >>>>> >>>>> But before you go that way let me ask you another question - can >>>>> ACPI PAD be used on ARM or IA64? If so, wouldn't this fail >>>>> compilation as this pvops structure is not defined on IA64? >>>> >>>> Ideally ACPI PAD is not bound to some arch, so IMO it could be used >>>> at least on IA64 (through currently no real PAD on IA64 platform as >>>> far as I know). However, in native acpi_pad implementation, it >>>> indeed depends on X86 for reason like mwait. >>>> So for xen acpi_pad, I think it's OK to choose x86, defining an >>>> acpi_pad_ops at x86_init.c which would be overwritten when xen >>>> init. >>> >>> OK, or in osl.c. We need Len to chime in here as I can see this >>> expanding in the future. >>>> >>>> Another choice is to define config ACPI_PROCESSOR_AGGREGATOR as >>>> 'bool', which would disable native acpi_pad module. >>> >>> Ewww. No. >> >> I'm OK with x86_init approach, but advantage of 'config >> ACPI_PROCESSOR_AGGREGATOR as bool' would get rid of X86/IA64/... >> arch issue for xen (at least from coding view), through it need >> disable native acpi_pad module (IMO acpi_pad module has not strong >> reason to must be so). Have a re-consider of this approach? :-) > > But it is a compile option right? We wantone kernel that can do both > baremetal and Xen. Sorry, I didn't speak clear my approach. The approach can enable kernel run both baremetal and Xen platform, and not bind acpi pad logic to x86. Send 2 patches as RFC. Thanks Jinsong-- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html