DTRACE_DTMALLOC(4)

NAME
dtrace_dtmalloc - a DTrace provider for tracing kernel memory allocations by type

SYNOPSIS
dtmalloc::function:malloc
dtmalloc::function:free

DESCRIPTION
The dtmalloc provider instruments malloc(9) and free(9) kernel functions to trace memory allocations by type. Refer to malloc(9) for more details about malloc types.

The dtmalloc::function:malloc probe fires upon a successful allocation. Its probe arguments are:
Probe Argument | Definition
args[0] | struct malloc_type *mtp
args[1] | struct malloc_type_internal *mtip
args[2] | struct malloc_type_stats *mtsp
args[3] | unsigned long size
args[4] | int zindx

The dtmalloc::function:free probe fires upon a free operation. Its probe arguments are:
free Probe Argument | Definition
args[0] | struct malloc_type *mtp
args[1] | struct malloc_type_internal *mtip
args[2] | struct malloc_type_stats *mtsp
args[3] | unsigned long size
args[4] | Always 0

The first three arguments for each probe (i.e., mtp, mtip, and mtsp) provide references to the malloc(9) type internals; size is the size of the allocation; zindx is the index into the kmemzones[] array used for the allocation. In practice, size is the most useful parameter to trace.

IMPLEMENTATION NOTES
The function part of the probe description in the dtmalloc provider is the malloc(9) type short description with all whitespace characters replaced with underscores. For example, a malloc type defined by

    MALLOC_DEFINE(M_FOO_BAR, "foo bar", "FooBar subsystem");

will have probes called

    dtmalloc::foo_bar:

FILES

<sys/malloc.h>
    The header where struct malloc_type is defined.

EXAMPLES

  Example 1 : Counting Successful Memory Allocations by Type

    # dtrace -n 'dtmalloc:::malloc {@[stringof args[0]->ks_shortdesc] = count()}'
    dtrace: description 'dtmalloc:::malloc ' matched 480 probes
    ^C
      80211node                                                         1
      CAM CCB                                                           1
      CAM periph                                                        1
      ioctlops                                                          1
      netlink                                                           1
      soname                                                            4
      sysctltmp                                                         4
      solaris                                                           5
      acpica                                                           16
      temp                                                             36
      lkpikmalloc                                                      44
      iov                                                             100
      selfd                                                           648

SEE ALSO
dtrace(1), tracing(7), malloc(9)

AUTHORS
-nosplit dtrace_dtmalloc was written by John Birrell <jb@FreeBSD.org>.

This manual page was written by Mateusz Piotrowski <0mp@FreeBSD.org>.

CAVEATS
The dtmalloc provider does not trace uma(9) allocations.