libceph: use kernel_sendpage() for sending zeroes (31739139) · Commits · 戴 / test

If a message queued for send gets revoked, zeroes are sent over the wire instead of any unsent data. This is done by constructing a message and passing it to kernel_sendmsg() via ceph_tcp_sendmsg(). Since we are already working with a page in this case we can use the sendpage interface instead. Create a new ceph_tcp_sendpage() helper that sets up flags to match the way ceph_tcp_sendmsg() does now. Signed-off-by:

Alex Elder <elder@dreamhost.com> Reviewed-by:

Sage Weil <sage@newdream.net>

net/ceph/messenger.c

+15 −5

Original line number	Diff line number	Diff line
		@@ -321,6 +321,19 @@ static int ceph_tcp_sendmsg(struct socket sock, struct kvec iov,
		return r;
		}

		static int ceph_tcp_sendpage(struct socket sock, struct page page,
		int offset, size_t size, int more)
		{
		int flags = MSG_DONTWAIT \| MSG_NOSIGNAL \| (more ? MSG_MORE : MSG_EOR);
		int ret;

		ret = kernel_sendpage(sock, page, offset, size, flags);
		if (ret == -EAGAIN)
		ret = 0;

		return ret;
		}


		/*
		* Shutdown/close the socket for the given connection.
		@@ -944,12 +957,9 @@ static int write_partial_skip(struct ceph_connection *con)
		int ret;

		while (con->out_skip > 0) {
		struct kvec iov = {
		.iov_base = zero_page_address,
		.iov_len = min(con->out_skip, (int)PAGE_CACHE_SIZE)
		};
		size_t size = min(con->out_skip, (int) PAGE_CACHE_SIZE);

		ret = ceph_tcp_sendmsg(con->sock, &iov, 1, iov.iov_len, 1);
		ret = ceph_tcp_sendpage(con->sock, zero_page, 0, size, 1);
		if (ret <= 0)
		goto out;
		con->out_skip -= ret;

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