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[Xen-devel] code question?

To: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] code question?
From: Jerone Young <jyoung5@xxxxxxxxxx>
Date: Thu, 11 Aug 2005 10:55:16 -0500
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Doing some janitorial (you cleaning the flooded toilets and such) work
today. I have come across this line of code that really I'm not sure
what the intent was..in xen/include/sched.h

#define hypercall_preempt_check() (unlikely(            \
        softirq_pending(smp_processor_id()) |           \
        (!!current->vcpu_info->evtchn_upcall_pending &  \
          !current->vcpu_info->evtchn_upcall_mask)      \

the part where we have !!current->vcpu_info_evtchen_upcall pending
should this be..should the "!! just be "!"?

And if so shouldn't this just be changed to 

#define hypercall_preempt_check() (unlikely( \
        softirq_pending(smp_processor_id()) |           \
        (!(current->vcpu_info->evtchn_upcall_pending & \
          current->vcpu_info->evtchn_upcall_mask)) \

In a lot of the code in Xen we are using the "!" operator with bitwise
operations..this is one of those examples.

Jerone Young
IBM Linux Technology Center
512-838-1157 (T/L: 678-1157)

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