UMEM_SETMTBF(3MALLOC) Memory Allocation Library Functions

NAME

umem_setmtbf - set umem failure threshold

SYNOPSIS

Object-Caching Memory Allocation Library (libumem, -lumem
#include <umem.h>

void
umem_setmtbf(uint_t thresh);

DESCRIPTION

The umem_setmtbf() function can be used to modify the run-time behavior
of the libumem(3LIB) library to set a threshold to cause injected
memory allocation failures.

By default, no failures are injected. When a non-zero value is passed
in thresh then error injection is enabled, if the umem debugging
features described in umem_debug(3MALLOC) are enabled through the
UMEM_DEBUG environment variable. If a process has not enabled the
debugging functionality of libumem(3LIB) then no errors will be
injected, no matter what thresh is set to.

Passing the value 0 disables error injection. To cause every
allocation to fail, pass the value 1. The larger the value passed, the
more time that will pass between error injections. Currently, an error
is injected if the current time in nanoseconds since boot modulus the
mtbf is zero. Concretely:

if (gethrtime() % thresh) == 0) {
<inject error>
}

This mechanism is not guaranteed over time; however, the meanings of a
threshold of zero, one, and the general tendency of larger numbers to
indicate less errors is.

MT-LEVEL
Unsafe

INTERFACE STABILITY

Uncommitted

SEE ALSO

libumem(3LIB), umem_debug(3MALLOC)

illumos February 23, 2020 illumos