[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 <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 80222de..a5a0420 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -68,6 +68,41 @@
}
#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 @@
* @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 @@
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 @@
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 @@
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 @@
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);