Defines starting with `p' in vm

• PAGER_MAP_SIZE vm/vm_pager.c:116
• PAGE_SHIFT vm/vm_param.h:98
• PAGE_SIZE vm/vm_param.h:97
• PG_DEVICE vm/vm_pager.h:63
• PG_DFLT vm/vm_pager.h:60
• PG_SWAP vm/vm_pager.h:61
• PG_VNODE vm/vm_pager.h:62