NAME

       io_uring_register_reg_wait - Registers fixed wait regions

SYNOPSIS

       #include <liburing.h>

       int io_uring_register_reg_wait(struct io_uring *ring,
                                      struct io_uring_reg_wait *reg,
                                      int nr);

DESCRIPTION

       The  io_uring_register_reg_wait(3)  registers a fixed wait region starting at reg and of nentries entries
       with the ring indicated by ring.

       This function works like io_uring_setup_reg_wait(3), except it doesn't allocate any memory on  behalf  of
       the  application.  The  application must pass in previously allocated memory in reg, which must be of the
       right size to hold nr entries and suitably aligned on a page boundary.

       The memory registered should not be freed until the ring for which it is registered is closed.

       Once a wait region has been setup, it persists for the  life  time  of  the  ring.   It's  currently  not
       possible  to  unregister  or  resize a wait region.  Additionally, a wait region may currently only use a
       single page of memory.  On a 4k page size system, this  means  an  application  is  limited  to  64  wait
       regions.  That  should  be enough, as each wait index may be modified as needed. With at least 64 indices
       available, hopefully applications can just use the appropriately setup wait region for each specific type
       of wait, with different indices having different wait settings.

       Available since kernel 6.13.

RETURN VALUE

       On success io_uring_register_reg_wait(3) returns 0 .  On failure, it returns a -errno value.

SEE ALSO

       io_uring_submit_and_wait_reg(3), io_uring_setup_reg_wait(3)

liburing-2.9                                    November 2, 2024                   io_uring_register_reg_wait(3)