From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jerone Young Subject: code question? Date: Thu, 11 Aug 2005 10:55:16 -0500 Message-ID: <1123775716.3043.15.camel@thinkpad> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel List-Id: xen-devel@lists.xenproject.org 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 jyoung5@us.ibm.com 512-838-1157 (T/L: 678-1157)