From: David Hildenbrand <david@redhat.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Joel Savitz <jsavitz@redhat.com>,
linux-kernel@vger.kernel.org
Cc: Valentin Schneider <valentin.schneider@arm.com>,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <frederic@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Yuan ZhaoXiong <yuanzhaoxiong@baidu.com>,
Baokun Li <libaokun1@huawei.com>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
YueHaibing <yuehaibing@huawei.com>,
Randy Dunlap <rdunlap@infradead.org>,
David Hildenbrand <dhildenb@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>
Subject: Re: [RFC PATCH] kernel/cpu: restart cpu_up when hotplug is disabled
Date: Thu, 21 Apr 2022 16:34:05 +0200 [thread overview]
Message-ID: <d0bf78a2-8bba-825e-89de-d41568ae2793@redhat.com> (raw)
In-Reply-To: <ca667dd9-f228-c6a8-390b-7e3abde391c4@redhat.com>
On 21.04.22 16:31, David Hildenbrand wrote:
>>> It's far from perfect I would say, but we really wanted to avoid
>>> letting user space having to deal with retry logic.
>>
>> What's so hard with retry logic in user space?
>>
>> If you can come up with a reasonable argument why user space cannot be
>> fixed, then there is certainly a better solution than slapping a
>> msleep(5) at some random place into the code.
> Most probably you're right and we should just retry in udev. Staring at
> the history, it looks like the -EBUSY might have been returned forever,
> so user space just never really triggered it on actual CPU hotplug
> because it doesn't usually happen that cpu hotplug is disabled.
The last part was confusing: "on actual CPU hotplug because it doesn't
usually happen that cpu hotplug is disabled when onlining a CPU that was
just hotplugged."
--
Thanks,
David / dhildenb
prev parent reply other threads:[~2022-04-21 14:34 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-18 19:54 Joel Savitz
2022-04-19 12:34 ` David Hildenbrand
2022-04-21 14:23 ` Thomas Gleixner
2022-04-21 14:31 ` David Hildenbrand
2022-04-21 14:34 ` David Hildenbrand [this message]
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