Allocating large chunks of memory

Drivers that need to allocate large chunks of memory need to make special arrangements, especially if that memory must be physically contiguous. The memory must be allocated very early in the system start-up process or it is unlikely that large chunks of physically contiguous memory will be available.

DDI drivers that allocate large chunks of memory should be statically configured, or split into two drivers:

• a small driver that allocates the memory and is statically configured

• the larger driver that is dynamically loaded and configured to $depend on the statically linked driver. This driver could be hot pluggable as well as dynamically loadable.

All ODDI drivers are statically configured, so can allocate large chunks of physically contiguous memory in their init(D2oddi) or start(D2oddi) routines.

For information about supporting large driver mappings, see ``Memory-mapped I/O''.