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From: Eduardo Habkost <ehabkost@redhat.com>
To: Luiz Capitulino <lcapitulino@redhat.com>
Cc: qemu-devel@nongnu.org, armbru@redhat.com,
	mihajlov@linux.vnet.ibm.com, eblake@redhat.com,
	berrange@redhat.com
Subject: Re: [Qemu-devel] [PATCH v2] qmp: add query-cpus-fast
Date: Thu, 8 Feb 2018 18:33:42 -0200	[thread overview]
Message-ID: <20180208203342.GE13981@localhost.localdomain> (raw)
In-Reply-To: <20180208111732.09869f84@redhat.com>

On Thu, Feb 08, 2018 at 11:17:32AM -0500, Luiz Capitulino wrote:
[...]
> The "halted" field is somewhat controversial. On the one hand,
> it offers a convenient way to know if a guest CPU is idle or
> running. On the other hand, it's a field that can change many
> times a second. In fact, the halted state can change even
> before query-cpus-fast has returned. This makes one wonder if
> this field should be dropped all together. Having the "halted"
> field as optional gives a better option for dropping it in
> the future, since we can just stop returning it.

I'd just drop it, unless we find a use case where it's really
useful.

Also, the code that sets/clears cpu->halted is target-specific,
so I wouldn't be so sure that simply checking for
!kvm_irqchip_in_kernel() is enough on all targets.

-- 
Eduardo

  reply	other threads:[~2018-02-08 20:33 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-08 16:17 [Qemu-devel] [PATCH v2] qmp: add query-cpus-fast Luiz Capitulino
2018-02-08 20:33 ` Eduardo Habkost [this message]
2018-02-09  7:56   ` Viktor Mihajlovski
2018-02-09 13:49     ` Luiz Capitulino
2018-02-09 14:16       ` Viktor Mihajlovski
2018-02-09 14:27       ` Eduardo Habkost
2018-02-09 14:50         ` Viktor Mihajlovski
2018-02-09 18:35           ` Luiz Capitulino

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