> > Index: uvm_bio.c
> > ===================================================================
> > --- uvm_bio.c	(revision 641)
> > +++ uvm_bio.c	(working copy)
> > @@ -208,7 +208,11 @@ ubc_init(void)
> >  		    ubc_nwins << ubc_winshift, &ubc_object.uobj, 0, (vsize_t)va,
> >  		    UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_NONE,
> >  				UVM_ADV_RANDOM, UVM_FLAG_NOMERGE)) != 0) {
> > -		panic("ubc_init: failed to map ubc_object");
> > +		if (uvm_map(kernel_map, (vaddr_t *)&ubc_object.kva,
> > +		    ubc_nwins << ubc_winshift, &ubc_object.uobj, 0, 0,
> > +		    UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_NONE,
> > +				UVM_ADV_RANDOM, UVM_FLAG_NOMERGE)) != 0)
> > +			panic("ubc_init: failed to map ubc_object");
> >  	}
> >  	UVMHIST_INIT(ubchist, 300);
> >  }
> 
> va was set explicitly to 1. Why this change is needed?

it might not be 1, if you have PMAP_PREFER.

YAMAMOTO Takashi