From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Ostrovsky Subject: Re: [PATCH] x86/xen: resume timer irqs early Date: Thu, 07 Aug 2014 13:29:59 -0400 Message-ID: <53E3B797.9060701@oracle.com> References: <1407431785-21394-1-git-send-email-david.vrabel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1XFRVu-0003xd-5Q for xen-devel@lists.xenproject.org; Thu, 07 Aug 2014 17:30:06 +0000 In-Reply-To: <1407431785-21394-1-git-send-email-david.vrabel@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: David Vrabel , xen-devel@lists.xenproject.org List-Id: xen-devel@lists.xenproject.org On 08/07/2014 01:16 PM, David Vrabel wrote: > If the timer irqs are resumed during device resume it is possible in > certain circumstances for the resume to hang early on, before device > interrupts are resumed. > > It is not entirely clear what is occuring the point of the hang but I > think a task necessary for the resume calls schedule_timeout(), > waiting for a timer interrupt (which never arrives). This failure may > require specific tasks to be running on the other VCPUs to trigger > (processes are not frozen during a suspend/resume if PREEMPT is > disabled). > > Add IRQF_EARLY_RESUME to the timer interrupts so they are resumed in > syscore_resume(). > > Also add IRQF_NO_SUSPEND as it is not necessary to suspend the timer > interrupts and IRQF_FORCE_RESUME was already set. IRQF_NO_SUSPEND is a component of IRQF_TIMER. -boris > > Signed-off-by: David Vrabel > --- > arch/x86/xen/time.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c > index 7b78f88..90dd311 100644 > --- a/arch/x86/xen/time.c > +++ b/arch/x86/xen/time.c > @@ -443,8 +443,10 @@ void xen_setup_timer(int cpu) > name = ""; > > irq = bind_virq_to_irqhandler(VIRQ_TIMER, cpu, xen_timer_interrupt, > - IRQF_PERCPU|IRQF_NOBALANCING|IRQF_TIMER| > - IRQF_FORCE_RESUME, > + IRQF_PERCPU | IRQF_NOBALANCING > + | IRQF_TIMER > + | IRQF_NO_SUSPEND | IRQF_FORCE_RESUME > + | IRQF_EARLY_RESUME, > name, NULL); > (void)xen_set_irq_priority(irq, XEN_IRQ_PRIORITY_MAX); >