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From: "Jan Beulich" <JBeulich@suse.com>
To: Daniel Kiper <daniel.kiper@oracle.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
	eric.devolder@oracle.com, wei.liu2@citrix.com,
	ian.jackson@eu.citrix.com, xen-devel@lists.xen.org
Subject: Re: [PATCH] kexec: Add spinlock for the whole hypercall
Date: Tue, 11 Apr 2017 06:31:36 -0600	[thread overview]
Message-ID: <58ECE8C8020000780014FE04@prv-mh.provo.novell.com> (raw)
In-Reply-To: <20170411112423.GC4372@olila.local.net-space.pl>

>>> On 11.04.17 at 13:24, <daniel.kiper@oracle.com> wrote:
> On Tue, Apr 11, 2017 at 01:46:37AM -0600, Jan Beulich wrote:
>> >>> On 10.04.17 at 21:44, <eric.devolder@oracle.com> wrote:
>> wouldn't it be better to handle this with a static state variable,
>> which gets checked/set atomically, and which if already set simply
>> leads to a continuation being arranged for?
> 
> Do you think about something like that:
> 
> if ( test_bit(KEXEC_FLAG_IN_PROGRESS, &kexec_flags) && hypercall_preempt_check() )
>     return hypercall_create_continuation(__HYPERVISOR_kexec_op, "h", uarg);

Well, minus the hypercall_preempt_check() call of course. And I'd
expect this to be a test_and_set_bit().

Jan


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  reply	other threads:[~2017-04-11 12:31 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-10 19:44 [PATCH] kexec: Add spinlock for the whole hypercall Eric DeVolder
2017-04-11  7:46 ` Jan Beulich
2017-04-11 11:24   ` Daniel Kiper
2017-04-11 12:31     ` Jan Beulich [this message]
2017-04-11 12:39       ` Daniel Kiper

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