RLIST(9)               386BSD Kernel Programmer's Manual              RLIST(9)

NAME
     rlist - resource list

SYNOPSIS
     #include "rlist.h"

     void
     rlistfree(struct rlist **rlp, unsigned start, unsigned end)

     int
     rlistalloc(struct rlist **rlp, unsigned size, unsigned *loc)

     void
     rlistdestroy(struct rlist **rlp)

DESCRIPTION
     Resource lists are a sparse data abstraction used to record the use of
     real and abstract resources employed by the kernel program. Resource
     lists rely on dynamic memory (see malloc(9) ) to avoid compile-time
     scaling of space to hold fragmentation. Since resources may need to be
     allocated during interrupt level, or during times when memory can't be
     allocated (like when reclaiming memory pages), resource lists must be
     allocated without blocking (however, they may block on the free of
     resource).

     Each resource list is denoted by a head pointer, which initially points
     to a null list, and filled with resource by "freeing" space into it that
     can be allocated subsequently. If the resource list itself must be
     reclaimed, it must be destroyed by the service employing the resource.

     The rlistalloc() function allocates a segment of resource of a requested
     size if available.  The rlistfree() function assigns resource for use in
     the list, possibly blocking.  The rlistdestroy() function is used to
     reclaim the storage used in implementing the resource list itself.

RETURN VALUES
     The rlistalloc() function returns a success or failure indication on
     return.

SEE ALSO
     malloc(9)

386BSD Release 1.0              August 29, 1994                              1