IBV_FORK_INIT(3)        Libibverbs Programmer's Manual        IBV_FORK_INIT(3)

NAME
       ibv_fork_init - initialize libibverbs to support fork()

SYNOPSIS
       #include <infiniband/verbs.h>

       int ibv_fork_init(void);

DESCRIPTION
       ibv_fork_init() initializes libibverbs's data structures to handle
       fork() function calls correctly and avoid data corruption, whether
       fork() is called explicitly or implicitly (such as in system()).

       It is not necessary to use this function if all parent process threads
       are always blocked until all child processes end or change address
       spaces via an exec() operation.

RETURN VALUE
       ibv_fork_init() returns 0 on success, or the value of errno on failure
       (which indicates the failure reason).

NOTES
       ibv_fork_init() works on Linux kernels supporting the MADV_DONTFORK
       flag for madvise() (2.6.17 and higher).

       Setting the environment variable RDMAV_FORK_SAFE or IBV_FORK_SAFE has
       the same effect as calling ibv_fork_init().

       Setting the environment variable RDMAV_HUGEPAGES_SAFE tells the library
       to check the underlying page size used by the kernel for memory
       regions.  This is required if an application uses huge pages either
       directly or indirectly via a library such as libhugetlbfs.

       Calling ibv_fork_init() will reduce performance due to an extra system
       call for every memory registration, and the additional memory allocated
       to track memory regions.  The precise performance impact depends on the
       workload and usually will not be significant.

       Setting RDMAV_HUGEPAGES_SAFE adds further overhead to all memory
       registrations.

SEE ALSO
       fork(2), wait(2), system(3), exec(3), ibv_get_device_list(3)

AUTHORS
       Dotan Barak <dotanba@gmail.com>

libibverbs                        2006-10-31                  IBV_FORK_INIT(3)