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    SubjectRe: [patch 08/34] arm: Use generic idle loop
    On 04/25/13 14:01, Thomas Gleixner wrote:
    > On Thu, 25 Apr 2013, Stephen Boyd wrote:
    >> On 04/09/13 02:38, Russell King - ARM Linux wrote:
    >>> On Tue, Apr 09, 2013 at 11:20:31AM +0200, Thomas Gleixner wrote:
    >>>> On Mon, 8 Apr 2013, Russell King - ARM Linux wrote:
    >>>>> On Mon, Mar 25, 2013 at 03:02:39PM +0100, Thomas Gleixner wrote:
    >>>>> So, how can I review these changes when all there is is a git URL, and
    >>>>> I *do* not want to pull them into my tree without first looking at the
    >>>>> patches, possibly reviewing them and *replying* with the patch inline?
    >>>> the patches were CC'ed to LKML and linux-arch and I expected that you
    >>>> are at least having the latter. Find the relevant patch inlined below.
    >>> I've not been on linux-arch for a few years now, after it evolved into
    >>> yet another lkml-like list with high traffic rates, where mainly specific
    >>> x86 issues seemed to be discussed, rather than it being a way to contact
    >>> all arch maintainers.
    >>>
    >>>> It is a counter. I looked carefully at all the various slightly
    >>>> differently fcked up implementations and picked the counter based one
    >>>> as it fits all requirements.
    >>> Great, thanks. The attached patch looks fine to me.
    >> I'm pretty sure that we need to apply this patch now that
    >> rcu_idle_enter()/exit() is called lower down in the idle loop. Kevin,
    >> did you test hotplug?
    > If the patch is agreed on, I guess I should take it via my idle
    > consolidation branch, right ?

    Yes I think so. Hopefully Russell King or Paul McKenney can ack this patch.

    >
    >> ----8<-----
    >>
    >> From: Stephen Boyd <sboyd@codeaurora.org>
    >> Subject: [PATCH] ARM: smp: Drop RCU_NONIDLE usage in cpu_die()
    >>
    >> Before f7b861b (arm: Use generic idle loop, 2013-03-21) ARM would
    >> kill the CPU within the rcu idle section. Now that the
    >> rcu_idle_enter()/exit() pair have been pushed lower down in the
    >> idle loop this is no longer true and so using RCU_NONIDLE here is
    >> no longer necessary and also harmful because RCU is not actually
    >> idle at this point.
    >>
    >> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
    >> ---
    >> arch/arm/kernel/smp.c | 2 +-
    >> 1 file changed, 1 insertion(+), 1 deletion(-)
    >>
    >> diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
    >> index 4619177..78f1eb5 100644
    >> --- a/arch/arm/kernel/smp.c
    >> +++ b/arch/arm/kernel/smp.c
    >> @@ -233,7 +233,7 @@ void __ref cpu_die(void)
    >> mb();
    >>
    >> /* Tell __cpu_die() that this CPU is now safe to dispose of */
    >> - RCU_NONIDLE(complete(&cpu_died));
    >> + complete(&cpu_died);
    >>
    >> /*
    >> * actual CPU shutdown procedure is at least platform (if not
    >>
    >> --
    >> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
    >> hosted by The Linux Foundation
    >>
    >>


    --
    Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
    hosted by The Linux Foundation



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