From: Suzuki.Poulose@arm.com (Suzuki K. Poulose)
To: linux-arm-kernel@lists.infradead.org
Subject: ARM64: CPU Hotplug: can't enable more cpus than maxcpus value (kernel 4.5)
Date: Thu, 3 Mar 2016 15:01:00 +0000 [thread overview]
Message-ID: <56D851AC.7040908@arm.com> (raw)
In-Reply-To: <56D85151.9050607@arm.com>
On 03/03/16 14:59, Suzuki K. Poulose wrote:
> On 03/03/16 14:42, Mark Rutland wrote:
>
>>> However for arm64 it is implemented that cpu_present_mask is
>>> explicetely set accordingly to 'maxcpus' value. Is it design intent ?
>>
>> To some extent, yes.
>>
>> Due to the possibility of a heterogeneous system, we must bring all CPUs
>> online at boot time, and cannot defer this.
>>
>> This is necessary to detect the common subset of supported features, and
>> also to detect the full set of CPUs in the system to correctly apply
>> errata workarounds which require kernel text patching.
>
> We don't have this limitation anymore, as we can check if the booting CPU
s/we can/we do/
for the hotplugged CPUs.
Cheers
Suzuki
next prev parent reply other threads:[~2016-03-03 15:01 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-03 14:17 ARM64: CPU Hotplug: can't enable more cpus than maxcpus value (kernel 4.5) Vadim Lomovtsev
2016-03-03 14:42 ` Mark Rutland
2016-03-03 14:59 ` Suzuki K. Poulose
2016-03-03 15:01 ` Suzuki K. Poulose [this message]
2016-03-03 15:12 ` Mark Rutland
2016-03-03 15:41 ` Suzuki K. Poulose
2016-03-07 17:22 ` Suzuki K. Poulose
2016-03-07 17:18 ` Catalin Marinas
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