From: "Jan Beulich" <JBeulich@suse.com>
To: Feng Wu <feng.wu@intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>, "keir@xen.org" <keir@xen.org>,
"george.dunlap@eu.citrix.com" <george.dunlap@eu.citrix.com>,
"andrew.cooper3@citrix.com" <andrew.cooper3@citrix.com>,
"dario.faggioli@citrix.com" <dario.faggioli@citrix.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: [PATCH 3/3] VMX: Remove the vcpu from the per-cpu blocking list after domain termination
Date: Mon, 23 May 2016 03:08:25 -0600 [thread overview]
Message-ID: <5742E4A902000078000EDAD7@prv-mh.provo.novell.com> (raw)
In-Reply-To: <E959C4978C3B6342920538CF579893F0196EB0C4@SHSMSX103.ccr.corp.intel.com>
>>> On 23.05.16 at 07:48, <feng.wu@intel.com> wrote:
>> From: Tian, Kevin
>> Sent: Monday, May 23, 2016 1:19 PM
>> > From: Wu, Feng
>> > Sent: Friday, May 20, 2016 4:54 PM
>> > --- a/xen/arch/x86/hvm/vmx/vmx.c
>> > +++ b/xen/arch/x86/hvm/vmx/vmx.c
>> > @@ -248,6 +248,36 @@ void vmx_pi_hooks_deassign(struct domain *d)
>> > d->arch.hvm_domain.vmx.pi_switch_to = NULL;
>> > }
>> >
>> > +static void vmx_pi_blocking_list_cleanup(struct domain *d)
>>
>> Is it more natural to move such cleanup under vcpu destroy?
>
> Yes, indeed it is more natural to add this function when vcpu is destroyed,
> however, the reason I add it here is I still have some concerns about the
> timing.
> When the VM is destroyed, here is the calling path:
>
> - vmx_pi_hooks_deassign() -->
> ......
> - vmx_vcpu_destroy() -->
> ......
> - vmx_domain_destroy()
> ......
>
> As I replied in the previous mail, when we remove the vcpus from the
> blocking
> list, there might be some _in-flight_ call to the hooks, so I put the cleanup
> code in the vmx_domain_destroy(), which is a bit more far from
> vmx_pi_hooks_deassign,
> and hence safer. If you have any other good ideas, I am all ears!:)
Well, either there is a possible race (then moving the addition
later just reduces the chances, but doesn't eliminate it), or there
isn't (in which case Kevin's suggestion should probably be followed).
Jan
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next prev parent reply other threads:[~2016-05-23 9:08 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-20 8:53 [PATCH 0/3] VMX: Properly handle pi descriptor and per-cpu blocking list Feng Wu
2016-05-20 8:53 ` [PATCH 1/3] VMX: Properly adjuest the status of pi descriptor Feng Wu
2016-05-23 5:15 ` Tian, Kevin
2016-05-23 5:27 ` Wu, Feng
2016-05-23 6:52 ` Tian, Kevin
2016-05-23 7:16 ` Wu, Feng
2016-05-23 9:03 ` Jan Beulich
2016-05-23 9:21 ` Wu, Feng
2016-05-23 11:04 ` Jan Beulich
2016-05-23 12:30 ` Jan Beulich
2016-05-20 8:53 ` [PATCH 2/3] VMX: Make hook pi_do_resume always available Feng Wu
2016-05-23 12:32 ` Jan Beulich
2016-05-23 12:51 ` Dario Faggioli
2016-05-20 8:53 ` [PATCH 3/3] VMX: Remove the vcpu from the per-cpu blocking list after domain termination Feng Wu
2016-05-23 5:19 ` Tian, Kevin
2016-05-23 5:48 ` Wu, Feng
2016-05-23 6:54 ` Tian, Kevin
2016-05-23 9:08 ` Jan Beulich [this message]
2016-05-23 9:17 ` Wu, Feng
2016-05-23 10:35 ` Wu, Feng
2016-05-23 11:11 ` Jan Beulich
2016-05-23 12:24 ` Wu, Feng
2016-05-23 12:46 ` Jan Beulich
2016-05-23 13:41 ` Wu, Feng
2016-05-23 12:30 ` Dario Faggioli
2016-05-23 13:32 ` Wu, Feng
2016-05-23 14:45 ` Dario Faggioli
2016-05-23 12:35 ` Jan Beulich
2016-05-23 13:33 ` Wu, Feng
2016-05-20 10:27 ` [PATCH 0/3] VMX: Properly handle pi descriptor and per-cpu blocking list Jan Beulich
2016-05-20 10:46 ` Wu, Feng
2016-05-23 8:08 ` Jan Beulich
2016-05-23 8:44 ` Wu, Feng
2016-05-23 8:51 ` Jan Beulich
2016-05-23 12:39 ` Dario Faggioli
2016-05-24 10:07 ` Wu, Feng
2016-05-24 13:33 ` Wu, Feng
2016-05-24 14:46 ` Dario Faggioli
2016-05-25 13:28 ` Wu, Feng
2016-05-24 14:02 ` Dario Faggioli
2016-05-25 12:39 ` Wu, Feng
2016-06-23 12:33 ` Wu, Feng
2016-06-23 15:11 ` Dario Faggioli
2016-06-24 6:11 ` Wu, Feng
2016-06-24 7:22 ` Dario Faggioli
2016-06-24 7:59 ` Wu, Feng
2016-06-24 10:27 ` Dario Faggioli
2016-06-24 13:25 ` Wu, Feng
2016-06-24 23:43 ` Dario Faggioli
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