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SubjectRe: [PATCH v2 0/3] powernv/cpuidle: Fastsleep workaround and fixes


On Thursday 02 October 2014 02:16 AM, Rafael J. Wysocki wrote:
> On Wednesday, October 01, 2014 01:15:57 PM Shreyas B. Prabhu wrote:
>> Fast sleep is an idle state, where the core and the L1 and L2
>> caches are brought down to a threshold voltage. This also means that
>> the communication between L2 and L3 caches have to be fenced. However
>> the current P8 chips have a bug wherein this fencing between L2 and
>> L3 caches get delayed by a cpu cycle. This can delay L3 response to
>> the other cpus if they request for data during this time. Thus they
>> would fetch the same data from the memory which could lead to data
>> corruption if L3 cache is not flushed.
>>
>> This series overcomes above problem in kernel.
>>
>> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>> Cc: Paul Mackerras <paulus@samba.org>
>> Cc: Michael Ellerman <mpe@ellerman.id.au>
>> Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
>> Cc: linux-pm@vger.kernel.org
>> Cc: linuxppc-dev@lists.ozlabs.org
>> Cc: Srivatsa S. Bhat <srivatsa@mit.edu>
>> Cc: Preeti U. Murthy <preeti@linux.vnet.ibm.com>
>> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
>>
>> v2:
>> Rebased on 3.17-rc7
>> Split from 'powerpc/powernv: Support for fastsleep and winkle'
>>
>> v1:
>> https://lkml.org/lkml/2014/8/25/446
>>
>> Preeti U Murthy (1):
>> powerpc/powernv/cpuidle: Add workaround to enable fastsleep
>>
>> Shreyas B. Prabhu (1):
>> powerpc/kvm/book3s_hv: Enable CPUs to run guest after waking up from
>> fast-sleep
>>
>> Srivatsa S. Bhat (1):
>> powerpc/powernv: Enable Offline CPUs to enter deep idle states
>>
>> arch/powerpc/include/asm/machdep.h | 3 +
>> arch/powerpc/include/asm/opal.h | 7 ++
>> arch/powerpc/include/asm/processor.h | 4 +-
>> arch/powerpc/kernel/exceptions-64s.S | 35 ++++----
>> arch/powerpc/kernel/idle.c | 19 ++++
>> arch/powerpc/kernel/idle_power7.S | 2 +-
>> arch/powerpc/platforms/powernv/opal-wrappers.S | 1 +
>> arch/powerpc/platforms/powernv/powernv.h | 7 ++
>> arch/powerpc/platforms/powernv/setup.c | 118 +++++++++++++++++++++++++
>> arch/powerpc/platforms/powernv/smp.c | 11 ++-
>> drivers/cpuidle/cpuidle-powernv.c | 13 ++-
>> 11 files changed, 194 insertions(+), 26 deletions(-)
>
> [2/3] seems to be missig from the series.
>
> Also, since that mostly modifies arch/powerpc, I think it should go through
> that tree. I'm fine with the cpuidle-powernv changes in [1/3] and [3/3].
>
Hi Rafael,

Thanks for looking into this. The second patch is an independent fix in the
powerpc exception handler. To be safe I am ccing you and linux-pm list on that
patch now.


Thanks,
Shreyas



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