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authorStefan Metzmacher <metze@samba.org>2022-10-27 21:34:45 +0300
committerJens Axboe <axboe@kernel.dk>2022-11-21 17:38:31 +0300
commite307e6698165ca6508ed42c69cb1be76c8eb6a3c (patch)
treeb64446ab77a5a0245f03be100af3ba00095cbcde /io_uring/notif.c
parenteb7081409f94a9a8608593d0fb63a1aa3d6f95d8 (diff)
downloadlinux-e307e6698165ca6508ed42c69cb1be76c8eb6a3c.tar.xz
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.c12
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;
}