From: Shreyas B Prabhu <shreyas@linux.vnet.ibm.com>
To: Michael Neuling <mikey@neuling.org>
Cc: mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] powerpc: Make doorbell check preemption safe
Date: Thu, 04 Jun 2015 12:15:12 +0530 [thread overview]
Message-ID: <556FF3F8.1070507@linux.vnet.ibm.com> (raw)
In-Reply-To: <1432083608.20823.19.camel@neuling.org>
On Wednesday 20 May 2015 06:30 AM, Michael Neuling wrote:
> On Wed, 2015-05-20 at 00:30 +0530, Shreyas B. Prabhu wrote:
>> Doorbell can be used to cause ipi on cpus which are sibling threads on
>> the same core. So icp_native_cause_ipi checks if the destination cpu
>> is a sibling thread of the current cpu and uses doorbell in such cases.
>>
>> But while running with CONFIG_PREEMPT=y, since this section is
>> preemtible, we can run into issues if after we check if the destination
>> cpu is a sibling cpu, the task gets migrated from a sibling cpu to a
>> cpu on another core.
>>
>> Fix this by using get_cpu()/ put_cpu()
>
> Thanks. Looks good and it's boots for me.
>
> Signed-off-by: Michael Neuling <mikey@neuling.org>
>
mikey, Thanks!
mpe, if this looks ok, can you please pick it up?
prev parent reply other threads:[~2015-06-04 6:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-19 19:00 [PATCH] powerpc: Make doorbell check preemption safe Shreyas B. Prabhu
2015-05-20 1:00 ` Michael Neuling
2015-06-04 6:45 ` Shreyas B Prabhu [this message]
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