From: David Vrabel <david.vrabel@citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
xen-devel@lists.xen.org,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Subject: Re: [PATCH 3/3] xen/events: schedule if the interrupted task is in a preemptible hypercall
Date: Wed, 12 Feb 2014 12:54:40 +0000 [thread overview]
Message-ID: <52FB6F10.8040307@citrix.com> (raw)
In-Reply-To: <52FB7042020000780011BAD0@nat28.tlf.novell.com>
On 12/02/14 11:59, Jan Beulich wrote:
>>>> On 11.02.14 at 20:19, David Vrabel <david.vrabel@citrix.com> wrote:
>> --- a/drivers/xen/events/events_base.c
>> +++ b/drivers/xen/events/events_base.c
>> @@ -1254,6 +1254,12 @@ void xen_evtchn_do_upcall(struct pt_regs *regs)
>>
>> irq_exit();
>> set_irq_regs(old_regs);
>> +
>> +#ifndef CONFIG_PREEMPT
>> + if ( __this_cpu_read(xed_nesting_count) == 0
>> + && is_preemptible_hypercall(regs) )
>> + _cond_resched();
>> +#endif
>
> I don't think this can be done here - a 64-bit x86 kernel would
> generally be on the IRQ stack, and I don't think scheduling
> should be done in this state.
_cond_resched() doesn't look that different from preempt_schedule_irq()
which is explicitly callable from irq context.
David
next prev parent reply other threads:[~2014-02-12 12:54 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-11 19:19 [PATCHv1 0/3]: xen: voluntary preemption for privcmd hypercalls David Vrabel
2014-02-11 19:19 ` [PATCH 1/3] x86/xen: allow for privcmd hypercalls to be preempted David Vrabel
2014-02-12 9:38 ` Ian Campbell
2014-02-12 10:10 ` Andrew Cooper
2014-02-12 10:18 ` Ian Campbell
2014-02-11 19:19 ` [PATCH 2/3] arm/xen: add stub is_preemptible_hypercall() David Vrabel
2014-02-11 19:19 ` [PATCH 3/3] xen/events: schedule if the interrupted task is in a preemptible hypercall David Vrabel
2014-02-12 11:59 ` Jan Beulich
2014-02-12 12:54 ` David Vrabel [this message]
2014-02-12 13:56 ` Jan Beulich
2014-02-12 16:35 ` David Vrabel
2014-02-12 16:47 ` Jan Beulich
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