diff options
| author | Stefan Metzmacher <metze@samba.org> | 2022-10-27 20:34:45 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2022-11-21 07:38:31 -0700 |
| commit | e307e6698165ca6508ed42c69cb1be76c8eb6a3c (patch) | |
| tree | b64446ab77a5a0245f03be100af3ba00095cbcde /io_uring/notif.c | |
| parent | eb7081409f94a9a8608593d0fb63a1aa3d6f95d8 (diff) | |
io_uring/net: introduce IORING_SEND_ZC_REPORT_USAGE flag
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>
Diffstat (limited to 'io_uring/notif.c')
| -rw-r--r-- | io_uring/notif.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/io_uring/notif.c b/io_uring/notif.c index e37c6569d82e..4bfef10161fa 100644 --- a/io_uring/notif.c +++ b/io_uring/notif.c @@ -18,6 +18,10 @@ static void __io_notif_complete_tw(struct io_kiocb *notif, bool *locked) __io_unaccount_mem(ctx->user, nd->account_pages); nd->account_pages = 0; } + + if (nd->zc_report && (nd->zc_copied || !nd->zc_used)) + notif->cqe.res |= IORING_NOTIF_USAGE_ZC_COPIED; + io_req_task_complete(notif, locked); } @@ -28,6 +32,13 @@ static void io_uring_tx_zerocopy_callback(struct sk_buff *skb, struct io_notif_data *nd = container_of(uarg, struct io_notif_data, uarg); struct io_kiocb *notif = cmd_to_io_kiocb(nd); + if (nd->zc_report) { + if (success && !nd->zc_used && skb) + WRITE_ONCE(nd->zc_used, true); + else if (!success && !nd->zc_copied) + WRITE_ONCE(nd->zc_copied, true); + } + if (refcount_dec_and_test(&uarg->refcnt)) { notif->io_task_work.func = __io_notif_complete_tw; io_req_task_work_add(notif); @@ -55,6 +66,7 @@ struct io_kiocb *io_alloc_notif(struct io_ring_ctx *ctx) nd->account_pages = 0; nd->uarg.flags = SKBFL_ZEROCOPY_FRAG | SKBFL_DONT_ORPHAN; nd->uarg.callback = io_uring_tx_zerocopy_callback; + nd->zc_report = nd->zc_used = nd->zc_copied = false; refcount_set(&nd->uarg.refcnt, 1); return notif; } |