Messages in this thread | | | Date | Tue, 3 Feb 2015 19:03:34 +0100 | From | "Luis R. Rodriguez" <> | Subject | Re: [Xen-devel] [PATCH v5 1/2] xen: add xen_is_preemptible_hypercall() |
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On Tue, Feb 03, 2015 at 11:05:15AM +0000, David Vrabel wrote: > On 27/01/15 01:51, Luis R. Rodriguez wrote: > > > > +#ifndef CONFIG_PREEMPT > > +extern struct { char _entry[32]; } preemptible_hypercall_page[]; > > + > > +static inline bool xen_is_preemptible_hypercall(struct pt_regs *regs) > > +{ > > + return !user_mode_vm(regs) && > > + regs->ip >= (unsigned long)preemptible_hypercall_page && > > + regs->ip < (unsigned long)preemptible_hypercall_page + PAGE_SIZE; > > I asked for this test to be optimized. > > return (regs->ip >> PAGE_SHIFT) > == ((unsigned long)preemptible_hypercall_page >> PAGE_SHIFT) > && !user_mode_vm(regs);
It didn't seem you were so sure about it and I asked some clarifications about it but you had not replied:
http://www.gossamer-threads.com/lists/xen/devel/363565?page=last
Luis
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