From: Joao Martins <joao.m.martins@oracle.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Sean Christopherson" <sean.j.christopherson@intel.com>,
"Vitaly Kuznetsov" <vkuznets@redhat.com>,
"Wanpeng Li" <wanpengli@tencent.com>,
"Jim Mattson" <jmattson@google.com>,
"Joerg Roedel" <joro@8bytes.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
"Daniel Lezcano" <daniel.lezcano@linaro.org>,
linux-pm@vger.kernel.org,
"Boris Ostrovsky" <boris.ostrovsky@oracle.com>
Subject: Re: [PATCH v2] cpuidle-haltpoll: vcpu hotplug support
Date: Mon, 2 Sep 2019 11:48:06 +0100 [thread overview]
Message-ID: <5df5b2b1-11ce-9b1a-dd4a-8fe32e491543@oracle.com> (raw)
In-Reply-To: <20190829152714.GA15616@amt.cnet>
On 8/29/19 4:27 PM, Marcelo Tosatti wrote:
> On Thu, Aug 29, 2019 at 04:10:27PM +0100, Joao Martins wrote:
>> When cpus != maxcpus cpuidle-haltpoll will fail to register all vcpus
>> past the online ones and thus fail to register the idle driver.
>> This is because cpuidle_add_sysfs() will return with -ENODEV as a
>> consequence from get_cpu_device() return no device for a non-existing
>> CPU.
>>
>> Instead switch to cpuidle_register_driver() and manually register each
>> of the present cpus through cpuhp_setup_state() callback and future
>> ones that get onlined. This mimmics similar logic that intel_idle does.
>>
>> Fixes: fa86ee90eb11 ("add cpuidle-haltpoll driver")
>> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
>> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>> ---
>> v2:
>> * move cpus_read_unlock() right after unregistering all cpuidle_devices;
>> (Marcello Tosatti)
>> * redundant usage of cpuidle_unregister() when only
>> cpuidle_unregister_driver() suffices; (Marcelo Tosatti)
>> * cpuhp_setup_state() returns a state (> 0) on success with CPUHP_AP_ONLINE_DYN
>> thus we set @ret to 0
[ ... ]
>
> Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
>
Thanks!
Meanwhile upon re-reading cpuhp_setup_state() I found out the teardown/offlining
and haltpoll_uninit() could be a bit simplified. So I sent out a new version[0],
but didn't add your Rb because there's was some very slight functional changes.
[0] https://lore.kernel.org/kvm/20190902104031.9296-1-joao.m.martins@oracle.com/
Joao
next prev parent reply other threads:[~2019-09-02 10:49 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-29 15:10 [PATCH v2] cpuidle-haltpoll: vcpu hotplug support Joao Martins
2019-08-29 15:27 ` Marcelo Tosatti
2019-09-02 10:48 ` Joao Martins [this message]
2019-08-29 17:16 ` Is: Default governor regardless of cpuidle driver Was: " Joao Martins
2019-08-29 17:23 ` Marcelo Tosatti
2019-09-02 21:55 ` Rafael J. Wysocki
2019-09-03 10:13 ` Joao Martins
2019-08-29 17:42 ` Daniel Lezcano
2019-08-29 18:07 ` Joao Martins
2019-08-29 18:28 ` Daniel Lezcano
2019-08-29 19:11 ` Default governor regardless of cpuidle driver Joao Martins
2019-08-29 20:22 ` Daniel Lezcano
2019-08-29 21:12 ` Joao Martins
2019-08-29 21:51 ` Daniel Lezcano
2019-08-30 11:07 ` Joao Martins
2019-09-02 21:58 ` Rafael J. Wysocki
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