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man pages section 9: DDI and DKI Kernel Functions

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Updated: July 2017



rmallocmap, rmallocmap_wait, rmfreemap - allocate and free resource maps


#include <sys/ddi.h>
#include <sys/sunddi.h>

struct map *rmallocmap(size_t mapsize);
struct map *rmallocmap_wait(size_t mapsize);
void rmfreemap(struct map *mp);

Interface Level

Architecture independent level 1 (DDI/DKI).



Number of entries for the map.


A pointer to the map structure to be deallocated.


rmallocmap() dynamically allocates a resource map structure. The argument mapsize defines the total number of entries in the map. In particular, it is the total number of allocations that can be outstanding at any one time.

rmallocmap() initializes the map but does not associate it with the actual resource. In order to associate the map with the actual resource, a call to rmfree(9F) is used to make the entirety of the actual resource available for allocation, starting from the first index into the resource. Typically, the call to rmallocmap() is followed by a call to rmfree(9F), passing the address of the map returned from rmallocmap(), the total size of the resource, and the first index into the actual resource.

The resource map allocated by rmallocmap() can be used to describe an arbitrary resource in whatever allocation units are appropriate, such as blocks, pages, or data structures. This resource can then be managed by the system by subsequent calls to rmalloc(9F), rmalloc_wait(9F), and rmfree(9F).

rmallocmap_wait() is similar to rmallocmap(), with the exception that it will wait for space to become available if necessary.

rmfreemap() deallocates a resource map structure previously allocated by rmallocmap() or rmallocmap_wait(). The argument mp is a pointer to the map structure to be deallocated.

Return Values

Upon successful completion, rmallocmap() and rmallocmap_wait() return a pointer to the newly allocated map structure. Upon failure, rmallocmap() returns a NULL pointer.


rmallocmap() and rmfreemap() can be called from user, kernel, or interrupt context.

rmallocmap_wait() can only be called from user or kernel context.

See Also

rmalloc(9F), rmalloc_wait(9F), rmfree(9F)

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