From b4b5cc85ed4ecbe4adbfbc4df028850de67a9f09 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Thu, 11 Aug 2005 16:25:29 -0400 Subject: [PATCH] [PATCH] RPC: Reduce stack utilization in xs_sendpages Reduce stack utilization of the RPC socket transport's send path. A couple of unlikely()s are added to ensure the compiler places the tail processing at the end of the csect. Test-plan: Millions of fsx operations. Performance characterization such as "sio" or "iozone". Version: Thu, 11 Aug 2005 16:04:30 -0400 Signed-off-by: Chuck Lever Signed-off-by: Trond Myklebust --- net/sunrpc/xprtsock.c | 73 +++++++++++++++++++++++++------------------ 1 file changed, 43 insertions(+), 30 deletions(-) diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 80222de3af..a5a04203a6 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -68,6 +68,41 @@ static inline void xs_pktdump(char *msg, u32 *packet, unsigned int count) } #endif +#define XS_SENDMSG_FLAGS (MSG_DONTWAIT | MSG_NOSIGNAL) + +static inline int xs_send_head(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base, unsigned int len) +{ + struct kvec iov = { + .iov_base = xdr->head[0].iov_base + base, + .iov_len = len - base, + }; + struct msghdr msg = { + .msg_name = addr, + .msg_namelen = addrlen, + .msg_flags = XS_SENDMSG_FLAGS, + }; + + if (xdr->len > len) + msg.msg_flags |= MSG_MORE; + + if (likely(iov.iov_len)) + return kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len); + return kernel_sendmsg(sock, &msg, NULL, 0, 0); +} + +static int xs_send_tail(struct socket *sock, struct xdr_buf *xdr, unsigned int base, unsigned int len) +{ + struct kvec iov = { + .iov_base = xdr->tail[0].iov_base + base, + .iov_len = len - base, + }; + struct msghdr msg = { + .msg_flags = XS_SENDMSG_FLAGS, + }; + + return kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len); +} + /** * xs_sendpages - write pages directly to a socket * @sock: socket to send on @@ -77,7 +112,7 @@ static inline void xs_pktdump(char *msg, u32 *packet, unsigned int count) * @base: starting position in the buffer * */ -static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base, int msgflags) +static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base) { struct page **ppage = xdr->pages; unsigned int len, pglen = xdr->page_len; @@ -86,35 +121,20 @@ static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, len = xdr->head[0].iov_len; if (base < len || (addr != NULL && base == 0)) { - struct kvec iov = { - .iov_base = xdr->head[0].iov_base + base, - .iov_len = len - base, - }; - struct msghdr msg = { - .msg_name = addr, - .msg_namelen = addrlen, - .msg_flags = msgflags, - }; - if (xdr->len > len) - msg.msg_flags |= MSG_MORE; - - if (iov.iov_len != 0) - err = kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len); - else - err = kernel_sendmsg(sock, &msg, NULL, 0, 0); + err = xs_send_head(sock, addr, addrlen, xdr, base, len); if (ret == 0) ret = err; else if (err > 0) ret += err; - if (err != iov.iov_len) + if (err != (len - base)) goto out; base = 0; } else base -= len; - if (pglen == 0) + if (unlikely(pglen == 0)) goto copy_tail; - if (base >= pglen) { + if (unlikely(base >= pglen)) { base -= pglen; goto copy_tail; } @@ -127,7 +147,7 @@ static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, sendpage = sock->ops->sendpage ? : sock_no_sendpage; do { - int flags = msgflags; + int flags = XS_SENDMSG_FLAGS; len = PAGE_CACHE_SIZE; if (base) @@ -154,14 +174,7 @@ static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, copy_tail: len = xdr->tail[0].iov_len; if (base < len) { - struct kvec iov = { - .iov_base = xdr->tail[0].iov_base + base, - .iov_len = len - base, - }; - struct msghdr msg = { - .msg_flags = msgflags, - }; - err = kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len); + err = xs_send_tail(sock, xdr, base, len); if (ret == 0) ret = err; else if (err > 0) @@ -202,7 +215,7 @@ static int xs_sendmsg(struct rpc_xprt *xprt, struct rpc_rqst *req) skip = req->rq_bytes_sent; clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags); - result = xs_sendpages(sock, addr, addrlen, xdr, skip, MSG_DONTWAIT); + result = xs_sendpages(sock, addr, addrlen, xdr, skip); dprintk("RPC: xs_sendmsg(%d) = %d\n", xdr->len - skip, result); -- 2.39.5