io_uring/net: move mm accounting to a slower path

We can also move mm accounting to the extended callbacks. It removes a
few cycles from the hot path including skipping one function call and
setting io_req_task_complete as a callback directly. For user backed I/O
it shouldn't make any difference taking into considering atomic mm
accounting and page pinning.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1062f270273ad11c1b7b45ec59a6a317533d5e64.1667557923.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/net.c b/io_uring/net.c
index 9e3da84..966019f 100644 (file)
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -1097,6 +1097,7 @@ int io_send_zc(struct io_kiocb *req, unsigned int issue_flags)
                        return ret;
                msg.sg_from_iter = io_sg_from_iter;
        } else {
+               io_notif_set_extended(zc->notif);
                ret = import_single_range(WRITE, zc->buf, zc->len, &iov,
                                          &msg.msg_iter);
                if (unlikely(ret))
@@ -1158,6 +1159,8 @@ int io_sendmsg_zc(struct io_kiocb *req, unsigned int issue_flags)
        unsigned flags;
        int ret, min_ret = 0;
 
+       io_notif_set_extended(sr->notif);
+
        sock = sock_from_file(req->file);
        if (unlikely(!sock))
                return -ENOTSOCK;

diff --git a/io_uring/notif.c b/io_uring/notif.c
index 9864bde..c4bb793 100644 (file)
--- a/io_uring/notif.c
+++ b/io_uring/notif.c
@@ -9,11 +9,14 @@
 #include "notif.h"
 #include "rsrc.h"
 
-static void __io_notif_complete_tw(struct io_kiocb *notif, bool *locked)
+static void io_notif_complete_tw_ext(struct io_kiocb *notif, bool *locked)
 {
        struct io_notif_data *nd = io_notif_to_data(notif);
        struct io_ring_ctx *ctx = notif->ctx;
 
+       if (nd->zc_report && (nd->zc_copied || !nd->zc_used))
+               notif->cqe.res |= IORING_NOTIF_USAGE_ZC_COPIED;
+
        if (nd->account_pages && ctx->user) {
                __io_unaccount_mem(ctx->user, nd->account_pages);
                nd->account_pages = 0;
@@ -21,16 +24,6 @@ static void __io_notif_complete_tw(struct io_kiocb *notif, bool *locked)
        io_req_task_complete(notif, locked);
 }
 
-static void io_notif_complete_tw_ext(struct io_kiocb *notif, bool *locked)
-{
-       struct io_notif_data *nd = io_notif_to_data(notif);
-
-       if (nd->zc_report && (nd->zc_copied || !nd->zc_used))
-               notif->cqe.res |= IORING_NOTIF_USAGE_ZC_COPIED;
-
-       __io_notif_complete_tw(notif, locked);
-}
-
 static void io_tx_ubuf_callback(struct sk_buff *skb, struct ubuf_info *uarg,
                                bool success)
 {
@@ -59,11 +52,14 @@ void io_notif_set_extended(struct io_kiocb *notif)
 {
        struct io_notif_data *nd = io_notif_to_data(notif);
 
-       nd->zc_report = false;
-       nd->zc_used = false;
-       nd->zc_copied = false;
-       notif->io_task_work.func = io_notif_complete_tw_ext;
-       io_notif_to_data(notif)->uarg.callback = io_tx_ubuf_callback_ext;
+       if (nd->uarg.callback != io_tx_ubuf_callback_ext) {
+               nd->account_pages = 0;
+               nd->zc_report = false;
+               nd->zc_used = false;
+               nd->zc_copied = false;
+               nd->uarg.callback = io_tx_ubuf_callback_ext;
+               notif->io_task_work.func = io_notif_complete_tw_ext;
+       }
 }
 
 struct io_kiocb *io_alloc_notif(struct io_ring_ctx *ctx)
@@ -81,10 +77,9 @@ struct io_kiocb *io_alloc_notif(struct io_ring_ctx *ctx)
        notif->task = current;
        io_get_task_refs(1);
        notif->rsrc_node = NULL;
-       notif->io_task_work.func = __io_notif_complete_tw;
+       notif->io_task_work.func = io_req_task_complete;
 
        nd = io_notif_to_data(notif);
-       nd->account_pages = 0;
        nd->uarg.flags = SKBFL_ZEROCOPY_FRAG | SKBFL_DONT_ORPHAN;
        nd->uarg.callback = io_tx_ubuf_callback;
        refcount_set(&nd->uarg.refcnt, 1);