Installing Pager Backends

The kernel-extension data providers must provide appropriate routines to be called by the virtual memory manager. These routines move a page-sized block of data into or out of a specified page. These services are also referred to as pager backends.

For a local device, the device strategy routine is required. A call to the vm_mount service is used to identify the device (through a dev_t value) to the virtual memory manager.

For a remote data provider, the routine required is a strategy routine, which is specified in the vm_mount service. These strategy routines must run as interrupt-level routines. They must not page fault, and they cannot sleep waiting for locks.

When access to a remote data provider or a local device is removed, the vm_umount service must be called to remove the device entry from the virtual memory manager's paging device table.