io_uring/net: introduce IORING_SEND_ZC_REPORT_USAGE flag
authorStefan Metzmacher <metze@samba.org>
Thu, 27 Oct 2022 18:34:45 +0000 (20:34 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 31 Dec 2022 12:33:11 +0000 (13:33 +0100)
commit3a6ee45e3ceb60818c5fa4acd3c258bb124452a8
tree7b758b7fb4ad7d1c75796df3f7aa660687225a2b
parent215f9437dda09531bcb80605298a24219f01cec5
io_uring/net: introduce IORING_SEND_ZC_REPORT_USAGE flag

commit e307e6698165ca6508ed42c69cb1be76c8eb6a3c upstream.

It might be useful for applications to detect if a zero copy transfer with
SEND[MSG]_ZC was actually possible or not. The application can fallback to
plain SEND[MSG] in order to avoid the overhead of two cqes per request. Or
it can generate a log message that could indicate to an administrator that
no zero copy was possible and could explain degraded performance.

Cc: stable@vger.kernel.org # 6.1
Link: https://lore.kernel.org/io-uring/fb6a7599-8a9b-15e5-9b64-6cd9d01c6ff4@gmail.com/T/#m2b0d9df94ce43b0e69e6c089bdff0ce6babbdfaa
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/8945b01756d902f5d5b0667f20b957ad3f742e5e.1666895626.git.metze@samba.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
include/uapi/linux/io_uring.h
io_uring/net.c
io_uring/notif.c
io_uring/notif.h