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    SubjectRe: [RFC][PATCH 6/8] sched,idle: Avoid spurious wakeup IPIs
    On Fri, May 09, 2014 at 03:57:45PM +0100, Catalin Marinas wrote:
    > On Fri, May 09, 2014 at 03:50:02PM +0100, Peter Zijlstra wrote:
    > > On Fri, May 09, 2014 at 03:40:34PM +0100, Catalin Marinas wrote:
    > >
    > > > I wonder why we still need TIF_POLLING_NRFLAG for arm64. It was on arm
    > > > until commit 16a8016372c42c7628eb (sanitize tsk_is_polling()). On arm64
    > > > we use wfi for idle or a firmware call but in both cases the assumption
    > > > is that we need an interrupt for waking up.
    > > >
    > > > So I think we should remove this macro for arm64.
    > >
    > > Does ARM64 support idle=poll? If so, you could keep it for that,
    > > otherwise it does indeed appear to be pointless.
    >
    > We don't support idle=poll either.
    >
    > > As to 32bit ARM, are there SMP chips which do not have WFI?
    >
    > No. WFI is even used for the secondary booting protocol (we need to send
    > an IPI to get them going).

    OK, so I'll queue a patch removing TIF_POLLING_NRFLAG for arm64.

    Thanks!
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