NAME

       io_uring_register_iowq_aff - register async worker CPU affinities

SYNOPSIS

       #include <sched.h>
       #include <liburing.h>

       int io_uring_register_iowq_aff(struct io_uring *ring,
                                      size_t cpusz,
                                      const cpu_set_t *mask);

       void io_uring_unregister_iowq_aff(struct io_uring *ring);

DESCRIPTION

       The  io_uring_prep_register_iowq_aff(3)  function  registers  a  set  of CPU affinities to be used by the
       io_uring async workers. By default, io_uring async workers are allowed to run on any CPU in  the  system.
       If this function is called with ring set to the ring in question and mask set to a pointer to a cpu_set_t
       value  and  cpusz  set  to the size of the CPU set, then async workers will only be allowed to run on the
       CPUs specified in the mask. Existing workers may need to hit a schedule point before they are migrated.

       For unregistration, io_uring_unregister_iowq_aff(3) may be  called  to  restore  CPU  affinities  to  the
       default.

       Applications  must  define  _GNU_SOURCE to obtain the definition of this helper, as cpu_set_t will not be
       defined without it.

RETURN VALUE

       Returns 0 on success, or any of the following values in case of error.

       -EFAULT
              The kernel was unable to copy the memory pointer to by mask as it was invalid.

       -ENOMEM
              The kernel was unable to allocate memory for the new CPU mask.

       -EINVAL
              cpusz or mask was NULL/0, or any other value specified was invalid.

SEE ALSO

       io_uring_queue_init(3), io_uring_register(2)

liburing-2.2                                     March 13, 2022                    io_uring_register_iowq_aff(3)