ibv_fork_init(3) [debian man page]

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  allo-
       cated 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)

Check Out this Related Man Page

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

NAME

       ibv_get_device_list, ibv_free_device_list - get and release list of available RDMA devices

SYNOPSIS

       #include <infiniband/verbs.h>

       struct ibv_device **ibv_get_device_list(int *num_devices);

       void ibv_free_device_list(struct ibv_device **list);

DESCRIPTION

       ibv_get_device_list()  returns  a  NULL-terminated array of RDMA devices currently available.  The argument num_devices is optional; if not
       NULL, it is set to the number of devices returned in the array.

       ibv_free_device_list() frees the array of devices list returned by ibv_get_device_list().

RETURN VALUE

       ibv_get_device_list() returns the array of available RDMA devices, or sets errno and returns NULL if the request fails. If no  devices  are
       found then num_devices is set to 0, and non-NULL is returned.

       ibv_free_device_list() returns no value.

ERRORS

       EPERM  Permission denied.

       ENOSYS No kernel support for RDMA.

       ENOMEM Insufficient memory to complete the operation.

NOTES

       Client  code should open all the devices it intends to use with ibv_open_device() before calling ibv_free_device_list().  Once it frees the
       array with ibv_free_device_list(), it will be able to use only the open devices; pointers to unopened devices will no longer be valid.

SEE ALSO

       ibv_fork_init(3), ibv_get_device_name(3), ibv_get_device_guid(3), ibv_open_device(3)

AUTHORS

       Dotan Barak <dotanba@gmail.com>

libibverbs							    2006-10-31						    IBV_GET_DEVICE_LIST(3)

Linux and UNIX Man Pages

ibv_fork_init(3) [debian man page]

Check Out this Related Man Page