NAME

       io_uring_register_iowq_max_workers - modify the maximum allowed async workers

SYNOPSIS

       #include <liburing.h>

       int io_uring_register_iowq_max_workers(struct io_uring *ring,
                                              unsigned int *values);

DESCRIPTION

       io_uring async workers are split into two types:

       Bounded
              These workers have a bounded execution time. Examples of that are filesystem reads,
              which normally complete in a relatively short amount  of  time.  In  case  of  disk
              failures,  they  are  still  bounded by a timeout operation that will abort them if
              exceeded.

       Unbounded
              Work items here may take an indefinite amount of time to complete. Examples include
              doing IO to sockets, pipes, or any other non-regular type of file.

       By  default,  the  amount of bounded IO workers is limited to how many SQ entries the ring
       was setup with, or 4 times the number of online CPUs in the system, whichever is  smaller.
       Unbounded  workers  are only limited by the process task limit, as indicated by the rlimit
       RLIMIT_NPROC limit.

       This can be modified by calling io_uring_register_iowq_max_workers with ring  set  to  the
       ring  in question, and values pointing to an array of two values. The first element should
       contain the number of desired bounded workers, and the second element should  contain  the
       number  of  desired  unbounded  workers.  These are both maximum values, io_uring will not
       maintain a high count of idle workers,  they  are  reaped  when  they  are  not  necessary
       anymore.

       If called with both values set to 0, the existing values are returned.

RETURN VALUE

       Returns  0  on  success,  with  values containing the previous values for the settings. On
       error, any of the following may be returned.

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

       -EINVAL
              values was NULL or the new values exceeded the maximum allowed value.

SEE ALSO

       io_uring_queue_init(3), io_uring_register(2)