| Message ID | 1333631135.18626.606.camel@edumazet-glaptop |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Eric Dumazet <eric.dumazet@gmail.com> Date: Thu, 05 Apr 2012 15:05:35 +0200 > Hmm, thinking again about this, I did more tests and it appears we need > to differentiate the SPLICE_F_MORE flag (user request) and the internal > marker provided by splice logic (handling a batch of pages) > > A program doing splice(... SPLICE_F_MORE) should really call tcp_push() > at the end of its work. This is the kind of problem I was hoping we weren't introducing when I asked about sendfile() et al. the other day :-) > [PATCH] tcp: tcp_sendpages() should call tcp_push() once > > commit 2f533844242 (tcp: allow splice() to build full TSO packets) added > a regression for splice() calls using SPLICE_F_MORE. > > We need to call tcp_flush() at the end of the last page processed in > tcp_sendpages(), or else transmits can be deferred and future sends > stall. > > Add a new internal flag, MSG_SENDPAGE_NOTLAST, acting like MSG_MORE, but > with different semantic. > > For all sendpage() providers, its a transparent change. Only > sock_sendpage() and tcp_sendpages() can differentiate the two different > flags provided by pipe_to_sendpage() > > Reported-by: Tom Herbert <therbert@google.com> > Cc: Nandita Dukkipati <nanditad@google.com> > Cc: Neal Cardwell <ncardwell@google.com> > Cc: Tom Herbert <therbert@google.com> > Cc: Yuchung Cheng <ycheng@google.com> > Cc: H.K. Jerry Chu <hkchu@google.com> > Cc: Maciej Żenczykowski <maze@google.com> > Cc: Mahesh Bandewar <maheshb@google.com> > Cc: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> > Signed-off-by: Eric Dumazet <eric.dumazet@gmail>com> Applied, thanks Eric. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 2012-04-05 at 19:05 -0400, David Miller wrote: > From: Eric Dumazet <eric.dumazet@gmail.com> > Date: Thu, 05 Apr 2012 15:05:35 +0200 > > > Hmm, thinking again about this, I did more tests and it appears we need > > to differentiate the SPLICE_F_MORE flag (user request) and the internal > > marker provided by splice logic (handling a batch of pages) > > > > A program doing splice(... SPLICE_F_MORE) should really call tcp_push() > > at the end of its work. > > This is the kind of problem I was hoping we weren't introducing > when I asked about sendfile() et al. the other day :-) Yes, sorry for this. Yet sendfile() did not have this problem (or so I believe), only the splice(SPLICE_F_MORE) did. Thanks -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/splice.c b/fs/splice.c index 5f883de..f847684 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -30,6 +30,7 @@ #include <linux/uio.h> #include <linux/security.h> #include <linux/gfp.h> +#include <linux/socket.h> /* * Attempt to steal a page from a pipe buffer. This should perhaps go into @@ -690,7 +691,9 @@ static int pipe_to_sendpage(struct pipe_inode_info *pipe, if (!likely(file->f_op && file->f_op->sendpage)) return -EINVAL; - more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; + more = (sd->flags & SPLICE_F_MORE) ? MSG_MORE : 0; + if (sd->len < sd->total_len) + more |= MSG_SENDPAGE_NOTLAST; return file->f_op->sendpage(file, buf->page, buf->offset, sd->len, &pos, more); } diff --git a/include/linux/socket.h b/include/linux/socket.h index da2d3e2..b84bbd4 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -265,7 +265,7 @@ struct ucred { #define MSG_NOSIGNAL 0x4000 /* Do not generate SIGPIPE */ #define MSG_MORE 0x8000 /* Sender will send more */ #define MSG_WAITFORONE 0x10000 /* recvmmsg(): block until 1+ packets avail */ - +#define MSG_SENDPAGE_NOTLAST 0x20000 /* sendpage() internal : not the last page */ #define MSG_EOF MSG_FIN #define MSG_CMSG_CLOEXEC 0x40000000 /* Set close_on_exit for file diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 2ff6f45..5d54ed3 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -860,7 +860,7 @@ wait_for_memory: } out: - if (copied && !(flags & MSG_MORE)) + if (copied && !(flags & MSG_SENDPAGE_NOTLAST)) tcp_push(sk, flags, mss_now, tp->nonagle); return copied; diff --git a/net/socket.c b/net/socket.c index 484cc69..851edcd 100644 --- a/net/socket.c +++ b/net/socket.c @@ -811,9 +811,9 @@ static ssize_t sock_sendpage(struct file *file, struct page *page, sock = file->private_data; - flags = !(file->f_flags & O_NONBLOCK) ? 0 : MSG_DONTWAIT; - if (more) - flags |= MSG_MORE; + flags = (file->f_flags & O_NONBLOCK) ? MSG_DONTWAIT : 0; + /* more is a combination of MSG_MORE and MSG_SENDPAGE_NOTLAST */ + flags |= more; return kernel_sendpage(sock, page, offset, size, flags); }