FreeBSD Device Drivers

malloc_type Structures

The malloc, free, realloc, and reallocf functions include a type argument, which expects a pointer to a malloc_type structure; this structure describes the purpose of the allocated memory. The type argument has no impact on performance; it is used for memory profiling and for basic sanity checks.

Note

You can profile kernel dynamic memory usage, sorted by type, with the vmstat -m command.

MALLOC_DEFINE Macro

The MALLOC_DEFINE macro defines a new malloc_type structure. Here is its function prototype:

#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/kernel.h>

MALLOC_DEFINE(type, shortdesc, longdesc);

The type argument is the new malloc_type structure’s name. In general, type should begin with M_ and be in uppercase letters; ...