From mboxrd@z Thu Jan  1 00:00:00 1970
From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: Re: [PATCHv5] x86/xen: allow privcmd hypercalls to be
	preempted
Date: Thu, 05 Feb 2015 11:16:47 -0500
Message-ID: <54D3976F.9070304@oracle.com>
References: <1423140077-32356-1-git-send-email-david.vrabel@citrix.com>
	<54D39628.4020508@oracle.com> <54D396C9.7070404@citrix.com>
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To: David Vrabel <david.vrabel@citrix.com>, xen-devel@lists.xenproject.org
Cc: "Luis R. Rodriguez" <mcgrof@suse.com>
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On 02/05/2015 11:14 AM, David Vrabel wrote:
> On 05/02/15 16:11, Boris Ostrovsky wrote:
>> On 02/05/2015 07:41 AM, David Vrabel wrote:
>>> +
>>> +void xen_maybe_preempt_hcall(void)
>>> +{
>>> +    if (__this_cpu_read(xen_in_preemptible_hcall)) {
>> Can you check should_resched() here?
> _cond_resched() already does this.
>

Right, you'd be checking it twice, but since in most cases you won't 
need to reschedule you will then avoid making unnecessary call (and 
per-cpu updates).

-boris