[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-devel] [Patch] x86: enforce strict memory order for x2apic
>From: Keir Fraser [mailto:keir.fraser@xxxxxxxxxxxxx] >Sent: 2008年9月25日 16:36 > >On 25/9/08 09:29, "Tian, Kevin" <kevin.tian@xxxxxxxxx> wrote: > >>> On the other hand you're penalizing LAPIC systems with >this, too. I'm >>> not certain that's better than fixing the (incorrect) >>> assumptions just in >>> the x2APIC case. >> >> I agree. I'll revise the patch to add a 'mb()' in x2APIC instead, >> though that may bring a bit overhead to cases when fencing >> is not required, like event check IPI. > >To be precise, mb() at top of send_IPI_mask_x2apic(), and >wmb() may as well >go from on_selected_cpus() as we can assume send_IPI_mask() is >a barrier. > >I'll do the patch for this myself. > Yes, and thanks. Also please add a wmb() in flush_area_mask, though it's a nop but semanticly desired like for on_selected_cpus. Thanks, Kevin _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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