From: David Vrabel <david.vrabel@citrix.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: <linux-kernel@vger.kernel.org>, <xen-devel@lists.xensource.com>,
Keir Fraser <keir.fraser@citrix.com>
Subject: Re: [Xen-devel] [PATCH] xen/evtchn: Handle VIRQ_TIMER before any other hardirq in event loop.
Date: Tue, 2 Apr 2013 15:53:13 +0100 [thread overview]
Message-ID: <515AF0D9.80805@citrix.com> (raw)
In-Reply-To: <1364825261-25324-1-git-send-email-konrad.wilk@oracle.com>
On 01/04/13 15:07, Konrad Rzeszutek Wilk wrote:
> From: Keir Fraser <keir.fraser@citrix.com>
>
> This avoids any other hardirq handler seeing a very stale jiffies
> value immediately after wakeup from a long idle period. The one
> observable symptom of this was a USB keyboard, with software keyboard
> repeat, which would always repeat a key immediately that it was
> pressed. This is due to the key press waking the guest, the key
> handler immediately runs, sees an old jiffies value, and then that
> jiffies value significantly updated, before the key is unpressed.
It's a bit of hack but what else can you do when there is no generic
mechanism to have different event priorities.
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
The subject should be prefixed with: "xen/events" as this isn't a patch
to the evtchn driver.
David
WARNING: multiple messages have this Message-ID (diff)
From: David Vrabel <david.vrabel@citrix.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com,
Keir Fraser <keir.fraser@citrix.com>
Subject: Re: [Xen-devel] [PATCH] xen/evtchn: Handle VIRQ_TIMER before any other hardirq in event loop.
Date: Tue, 2 Apr 2013 15:53:13 +0100 [thread overview]
Message-ID: <515AF0D9.80805@citrix.com> (raw)
In-Reply-To: <1364825261-25324-1-git-send-email-konrad.wilk@oracle.com>
On 01/04/13 15:07, Konrad Rzeszutek Wilk wrote:
> From: Keir Fraser <keir.fraser@citrix.com>
>
> This avoids any other hardirq handler seeing a very stale jiffies
> value immediately after wakeup from a long idle period. The one
> observable symptom of this was a USB keyboard, with software keyboard
> repeat, which would always repeat a key immediately that it was
> pressed. This is due to the key press waking the guest, the key
> handler immediately runs, sees an old jiffies value, and then that
> jiffies value significantly updated, before the key is unpressed.
It's a bit of hack but what else can you do when there is no generic
mechanism to have different event priorities.
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
The subject should be prefixed with: "xen/events" as this isn't a patch
to the evtchn driver.
David
next prev parent reply other threads:[~2013-04-02 14:53 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-01 14:07 [PATCH] xen/evtchn: Handle VIRQ_TIMER before any other hardirq in event loop Konrad Rzeszutek Wilk
2013-04-02 14:53 ` David Vrabel [this message]
2013-04-02 14:53 ` [Xen-devel] " David Vrabel
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