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ceph: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage 

Use sendmsg() and MSG_SPLICE_PAGES rather than sendpage in ceph when
transmitting data.  For the moment, this can only transmit one page at a
time because of the architecture of net/ceph/, but if
write_partial_message_data() can be given a bvec[] at a time by the
iteration code, this would allow pages to be sent in a batch.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Xiubo Li <xiubli@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
Link: https://lore.kernel.org/r/20230623225513.2732256-4-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
David Howells 2023-06-23 23:55:00 +01:00 committed by Jakub Kicinski
parent c729ed6f5b
commit 40a8c17aa7
1 changed files with 20 additions and 40 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

60
net/ceph/messenger_v1.c
View File

@ -74,37 +74,6 @@ static int ceph_tcp_sendmsg(struct socket *sock, struct kvec *iov,
return r;
}
/*
* @more: either or both of MSG_MORE and MSG_SENDPAGE_NOTLAST
*/
static int ceph_tcp_sendpage(struct socket *sock, struct page *page,
int offset, size_t size, int more)
{
ssize_t (*sendpage)(struct socket *sock, struct page *page,
int offset, size_t size, int flags);
int flags = MSG_DONTWAIT | MSG_NOSIGNAL | more;
int ret;
/*
* sendpage cannot properly handle pages with page_count == 0,
* we need to fall back to sendmsg if that's the case.
*
* Same goes for slab pages: skb_can_coalesce() allows
* coalescing neighboring slab objects into a single frag which
* triggers one of hardened usercopy checks.
*/
if (sendpage_ok(page))
sendpage = sock->ops->sendpage;
else
sendpage = sock_no_sendpage;
ret = sendpage(sock, page, offset, size, flags);
if (ret == -EAGAIN)
ret = 0;
return ret;
}
static void con_out_kvec_reset(struct ceph_connection *con)
{
BUG_ON(con->v1.out_skip);
@ -464,7 +433,6 @@ static int write_partial_message_data(struct ceph_connection *con)
struct ceph_msg *msg = con->out_msg;
struct ceph_msg_data_cursor *cursor = &msg->cursor;
bool do_datacrc = !ceph_test_opt(from_msgr(con->msgr), NOCRC);
int more = MSG_MORE | MSG_SENDPAGE_NOTLAST;
u32 crc;
dout("%s %p msg %p\n", __func__, con, msg);
@ -482,6 +450,10 @@ static int write_partial_message_data(struct ceph_connection *con)
*/
crc = do_datacrc ? le32_to_cpu(msg->footer.data_crc) : 0;
while (cursor->total_resid) {
struct bio_vec bvec;
struct msghdr msghdr = {
.msg_flags = MSG_SPLICE_PAGES,
};
struct page *page;
size_t page_offset;
size_t length;
@ -493,10 +465,13 @@ static int write_partial_message_data(struct ceph_connection *con)
}
page = ceph_msg_data_next(cursor, &page_offset, &length);
if (length == cursor->total_resid)
more = MSG_MORE;
ret = ceph_tcp_sendpage(con->sock, page, page_offset, length,
more);
if (length != cursor->total_resid)
msghdr.msg_flags |= MSG_MORE;
bvec_set_page(&bvec, page, length, page_offset);
iov_iter_bvec(&msghdr.msg_iter, ITER_SOURCE, &bvec, 1, length);
ret = sock_sendmsg(con->sock, &msghdr);
if (ret <= 0) {
if (do_datacrc)
msg->footer.data_crc = cpu_to_le32(crc);
@ -526,7 +501,10 @@ static int write_partial_message_data(struct ceph_connection *con)
*/
static int write_partial_skip(struct ceph_connection *con)
{
int more = MSG_MORE | MSG_SENDPAGE_NOTLAST;
struct bio_vec bvec;
struct msghdr msghdr = {
.msg_flags = MSG_SPLICE_PAGES | MSG_MORE,
};
int ret;
dout("%s %p %d left\n", __func__, con, con->v1.out_skip);
@ -534,9 +512,11 @@ static int write_partial_skip(struct ceph_connection *con)
size_t size = min(con->v1.out_skip, (int)PAGE_SIZE);
if (size == con->v1.out_skip)
more = MSG_MORE;
ret = ceph_tcp_sendpage(con->sock, ceph_zero_page, 0, size,
more);
msghdr.msg_flags &= ~MSG_MORE;
bvec_set_page(&bvec, ZERO_PAGE(0), size, 0);
iov_iter_bvec(&msghdr.msg_iter, ITER_SOURCE, &bvec, 1, size);
ret = sock_sendmsg(con->sock, &msghdr);
if (ret <= 0)
goto out;
con->v1.out_skip -= ret;