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From: Razvan Cojocaru <rcojocaru@bitdefender.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>,
	Xen-devel <xen-devel@lists.xenproject.org>
Cc: Petre Pircalabu <ppircalabu@bitdefender.com>,
	Tamas K Lengyel <tamas@tklengyel.com>
Subject: Re: [PATCH 4/5] xen/vm-event: Fix interactions with the vcpu list
Date: Mon, 3 Jun 2019 17:56:54 +0300	[thread overview]
Message-ID: <b9456f0c-af8c-a4de-73e0-db4a69240c3a@bitdefender.com> (raw)
In-Reply-To: <1559564728-17167-5-git-send-email-andrew.cooper3@citrix.com>

On 6/3/19 3:25 PM, Andrew Cooper wrote:
> vm_event_resume() should use domain_vcpu(), rather than opencoding it
> without its Spectre v1 safety.
> 
> vm_event_wake_blocked() can't ever be invoked in a case where d->vcpu is
> NULL, so drop the outer if() and reindent, fixing up style issues.
> 
> The comment, which is left alone, is false.  This algorithm still has
> starvation issues when there is an asymetric rate of generated events.
> 
> However, the existing logic is sufficiently complicated and fragile that
> I don't think I've followed it fully, and because we're trying to
> obsolete this interface, the safest course of action is to leave it
> alone, rather than to end up making things subtly different.
> 
> Therefore, no practical change that callers would notice.
> 
> Signed-off-by: Andrew Cooper<andrew.cooper3@citrix.com>

Acked-by: Razvan Cojocaru <rcojocaru@bitdefender.com>


Thanks,
Razvan

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

WARNING: multiple messages have this Message-ID (diff)
From: Razvan Cojocaru <rcojocaru@bitdefender.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>,
	Xen-devel <xen-devel@lists.xenproject.org>
Cc: Petre Pircalabu <ppircalabu@bitdefender.com>,
	Tamas K Lengyel <tamas@tklengyel.com>
Subject: Re: [Xen-devel] [PATCH 4/5] xen/vm-event: Fix interactions with the vcpu list
Date: Mon, 3 Jun 2019 17:56:54 +0300	[thread overview]
Message-ID: <b9456f0c-af8c-a4de-73e0-db4a69240c3a@bitdefender.com> (raw)
Message-ID: <20190603145654.khsLmt8ft-Cz9GOYktPaFCQS9OZCP6dARbWO6opV6HU@z> (raw)
In-Reply-To: <1559564728-17167-5-git-send-email-andrew.cooper3@citrix.com>

On 6/3/19 3:25 PM, Andrew Cooper wrote:
> vm_event_resume() should use domain_vcpu(), rather than opencoding it
> without its Spectre v1 safety.
> 
> vm_event_wake_blocked() can't ever be invoked in a case where d->vcpu is
> NULL, so drop the outer if() and reindent, fixing up style issues.
> 
> The comment, which is left alone, is false.  This algorithm still has
> starvation issues when there is an asymetric rate of generated events.
> 
> However, the existing logic is sufficiently complicated and fragile that
> I don't think I've followed it fully, and because we're trying to
> obsolete this interface, the safest course of action is to leave it
> alone, rather than to end up making things subtly different.
> 
> Therefore, no practical change that callers would notice.
> 
> Signed-off-by: Andrew Cooper<andrew.cooper3@citrix.com>

Acked-by: Razvan Cojocaru <rcojocaru@bitdefender.com>


Thanks,
Razvan

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

  reply	other threads:[~2019-06-03 14:57 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-03 12:25 [PATCH 0/5] xen/vm-event: Cleanup Andrew Cooper
2019-06-03 12:25 ` [Xen-devel] " Andrew Cooper
2019-06-03 12:25 ` [PATCH 1/5] xen/vm-event: Drop unused u_domctl parameter from vm_event_domctl() Andrew Cooper
2019-06-03 12:25   ` [Xen-devel] " Andrew Cooper
2019-06-03 13:52   ` Razvan Cojocaru
2019-06-03 13:52     ` [Xen-devel] " Razvan Cojocaru
2019-06-03 13:52   ` Jan Beulich
2019-06-03 13:52     ` [Xen-devel] " Jan Beulich
2019-06-03 12:25 ` [PATCH 2/5] xen/vm-event: Expand vm_event_* spinlock macros and rename the lock Andrew Cooper
2019-06-03 12:25   ` [Xen-devel] " Andrew Cooper
2019-06-03 14:02   ` Razvan Cojocaru
2019-06-03 14:02     ` [Xen-devel] " Razvan Cojocaru
2019-06-03 12:25 ` [PATCH 3/5] xen/vm-event: Remove unnecessary vm_event_domain indirection Andrew Cooper
2019-06-03 12:25   ` [Xen-devel] " Andrew Cooper
2019-06-03 14:31   ` Razvan Cojocaru
2019-06-03 14:31     ` [Xen-devel] " Razvan Cojocaru
2019-06-03 12:25 ` [PATCH 4/5] xen/vm-event: Fix interactions with the vcpu list Andrew Cooper
2019-06-03 12:25   ` [Xen-devel] " Andrew Cooper
2019-06-03 14:56   ` Razvan Cojocaru [this message]
2019-06-03 14:56     ` Razvan Cojocaru
2019-06-03 12:25 ` [PATCH 5/5] xen/vm-event: Misc fixups Andrew Cooper
2019-06-03 12:25   ` [Xen-devel] " Andrew Cooper
2019-06-03 14:16   ` Razvan Cojocaru
2019-06-03 14:16     ` [Xen-devel] " Razvan Cojocaru

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