On 2/8/19 6:34 PM, Jens Axboe wrote:
We normally have to fget/fput for each IO we do on a file. Even with
the batching we do, the cost of the atomic inc/dec of the file usage
count adds up.
This adds IORING_REGISTER_FILES, and IORING_UNREGISTER_FILES opcodes
for the io_uring_register(2) system call. The arguments passed in must
be an array of __s32 holding file descriptors, and nr_args should hold
the number of file descriptors the application wishes to pin for the
duration of the io_uring instance (or until IORING_UNREGISTER_FILES is
called).
When used, the application must set IOSQE_FIXED_FILE in the sqe->flags
member. Then, instead of setting sqe->fd to the real fd, it sets sqe->fd
to the index in the array passed in to IORING_REGISTER_FILES.
Files are automatically unregistered when the io_uring instance is torn
down. An application need only unregister if it wishes to register a new
set of fds.
Signed-off-by: Jens Axboe <[email protected]>
---
fs/io_uring.c | 256 ++++++++++++++++++++++++++++++----
include/uapi/linux/io_uring.h | 9 +-
2 files changed, 235 insertions(+), 30 deletions(-)
Reviewed-by: Hannes Reinecke <[email protected]>
Cheers,
Hannes
