[RFC PATCH v1 2/3] liburing: add documentation for new napi busy polling

[Stefan Roesch <shr@devkernel.io>]

This adds two man pages for the two new functions:
- io_uring_register_busy_poll_timeout
- io_uring_unregister_busy_poll_timeout

Signed-off-by: Stefan Roesch <shr@devkernel.io>
---
 man/io_uring_register_napi.3   | 35 ++++++++++++++++++++++++++++++++++
 man/io_uring_unregister_napi.3 | 26 +++++++++++++++++++++++++
 2 files changed, 61 insertions(+)
 create mode 100644 man/io_uring_register_napi.3
 create mode 100644 man/io_uring_unregister_napi.3

diff --git a/man/io_uring_register_napi.3 b/man/io_uring_register_napi.3
new file mode 100644
index 0000000..2063b5c
--- /dev/null
+++ b/man/io_uring_register_napi.3
@@ -0,0 +1,35 @@
+.\" Copyright (C) 2022 Stefan Roesch <shr@devkernel.io>
+.\"
+.\" SPDX-License-Identifier: LGPL-2.0-or-later
+.\"
+.TH io_uring_register_busy_poll_timeout 3 "November 1, 2022" "liburing-2.3" "liburing Manual"
+.SH NAME
+io_uring_register_busy_poll_timeout \- register NAPI busy poll timeout
+.SH SYNOPSIS
+.nf
+.B #include <liburing.h>
+.PP
+.BI "int io_uring_register_busy_poll_timeout(struct io_uring *" ring ","
+.BI "                                        unsigned int " timeout)
+.PP
+.fi
+.SH DESCRIPTION
+.PP
+The
+.BR io_uring_register_busy_poll_timeout (3)
+function registers the NAPI busy poll
+.I timeout
+for subsequent operations.
+
+Registering a NAPI busy poll timeout is a requirement to be able to use
+NAPI busy polling. The other way to enable NAPI busy polling is to set the
+proc setting /proc/sys/net/core/busy_poll.
+
+NAPI busy poll can reduce the network roundtrip time.
+
+
+.SH RETURN VALUE
+On success
+.BR io_uring_register_busy_poll_timeout (3)
+return 0. On failure they return
+.BR -errno .
diff --git a/man/io_uring_unregister_napi.3 b/man/io_uring_unregister_napi.3
new file mode 100644
index 0000000..f294ab3
--- /dev/null
+++ b/man/io_uring_unregister_napi.3
@@ -0,0 +1,26 @@
+.\" Copyright (C) 2022 Stefan Roesch <shr@devkernel.io>
+.\"
+.\" SPDX-License-Identifier: LGPL-2.0-or-later
+.\"
+.TH io_uring_unregister_busy_poll_timeout 3 "November 1, 2022" "liburing-2.3" "liburing Manual"
+.SH NAME
+io_uring_unregister_busy_poll_timeout \- register NAPI busy poll timeout
+.SH SYNOPSIS
+.nf
+.B #include <liburing.h>
+.PP
+.BI "int io_uring_register_busy_poll_timeout(struct io_uring *" ring ")
+.PP
+.fi
+.SH DESCRIPTION
+.PP
+The
+.BR io_uring_unregister_busy_poll_timeout (3)
+function unregisters the NAPI busy poll
+for subsequent operations.
+
+.SH RETURN VALUE
+On success
+.BR io_uring_unregister_busy_poll_timeout (3)
+return 0. On failure they return
+.BR -errno .
-- 
2.30.2