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authorJens Axboe <axboe@kernel.dk>2022-02-13 16:09:32 -0700
committerJens Axboe <axboe@kernel.dk>2022-02-13 16:09:32 -0700
commit4095eaf5ff3dd08f2c8dd68b3368a6c50ff49d2d (patch)
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parentbd207310a1e93f08e522d0aa89ece33b33a71dee (diff)
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man/io_uring_register_buffers.3: mention why registered buffers are useful
There are no details in this man page, so mention why it is in fact beneficial to register buffers. This is specific to O_DIRECT file IO for now, but the kernel side use cases will be expanded in the future. Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'man/io_uring_register_buffers.3')
-rw-r--r--man/io_uring_register_buffers.39
1 files changed, 8 insertions, 1 deletions
diff --git a/man/io_uring_register_buffers.3 b/man/io_uring_register_buffers.3
index 48cc506..58cdec7 100644
--- a/man/io_uring_register_buffers.3
+++ b/man/io_uring_register_buffers.3
@@ -26,9 +26,16 @@ belonging to the
After the caller has registered the buffers, they can be used with one of the
fixed buffers functions.
+Registered buffers is an optimization that is useful in conjunction with
+.B O_DIRECT
+reads and writes, where maps the specified range into the kernel once when
+the buffer is registered, rather than doing a map and unmap for each IO
+every time IO is performed to that region. Additionally, it also avoids
+manipulating the page reference counts for each IO.
+
.SH RETURN VALUE
On success
.BR io_uring_register_buffers (3)
returns 0. On failure it returns -errno.
.SH SEE ALSO
-.BR io_uring_get_sqe (3), io_uring_unregister_buffers (3) \ No newline at end of file
+.BR io_uring_get_sqe (3), io_uring_unregister_buffers (3), io_uring_prep_read_fixed (3), io_uring_prep_write_fixed (3)