From 9dd4ccf16994ff6228ab9afb33f2df4556212a28 Mon Sep 17 00:00:00 2001 From: normal Date: Fri, 29 May 2015 02:24:18 +0000 Subject: socket: avoid redundant fcntl on Linux * ext/socket/ancdata.c (bsock_sendmsg_internal, bsock_recvmsg_internal): avoid redundant fcntl on Linux [ruby-core:69154] [Feature #11145] * ext/socket/init.c (rsock_s_recvfrom_nonblock): ditto * ext/socket/rubysocket.h (MSG_DONTWAIT_RELIABLE): new macro MSG_DONTWAIT is enough to force non-blocking I/O under Linux, so avoid changing the state of a socket. This will allow certain threads to do a non-destructive non-blocking "peek" while others block (without relying on an extra ppoll syscall). We shall be conservative about enabling this feature since some OSes may have incomplete support for MSG_DONTWAIT. I shall defer to a FreeBSD expert to enable that for FreeBSD. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@50666 b2dd03c8-39d4-4d8f-98ff-823fe69b080e --- ext/socket/ancdata.c | 4 ++-- ext/socket/init.c | 5 ++++- ext/socket/rubysocket.h | 11 +++++++++++ 3 files changed, 17 insertions(+), 3 deletions(-) (limited to 'ext') diff --git a/ext/socket/ancdata.c b/ext/socket/ancdata.c index 3eaed1cb49..0a94149b08 100644 --- a/ext/socket/ancdata.c +++ b/ext/socket/ancdata.c @@ -1277,7 +1277,7 @@ bsock_sendmsg_internal(int argc, VALUE *argv, VALUE sock, int nonblock) #endif rb_io_check_closed(fptr); - if (nonblock) + if (nonblock && !MSG_DONTWAIT_RELIABLE) rb_io_set_nonblock(fptr); ss = rb_sendmsg(fptr->fd, &mh, flags); @@ -1595,7 +1595,7 @@ bsock_recvmsg_internal(int argc, VALUE *argv, VALUE sock, int nonblock) flags |= MSG_PEEK; rb_io_check_closed(fptr); - if (nonblock) + if (nonblock && !MSG_DONTWAIT_RELIABLE) rb_io_set_nonblock(fptr); ss = rb_recvmsg(fptr->fd, &mh, flags); diff --git a/ext/socket/init.c b/ext/socket/init.c index 317dd67479..455652d082 100644 --- a/ext/socket/init.c +++ b/ext/socket/init.c @@ -211,7 +211,10 @@ rsock_s_recvfrom_nonblock(VALUE sock, int argc, VALUE *argv, enum sock_recv_type str = rb_tainted_str_new(0, buflen); rb_io_check_closed(fptr); - rb_io_set_nonblock(fptr); + + if (!MSG_DONTWAIT_RELIABLE) + rb_io_set_nonblock(fptr); + len0 = alen; slen = recvfrom(fd, RSTRING_PTR(str), buflen, flags, &buf.addr, &alen); if (slen != -1 && len0 < alen) diff --git a/ext/socket/rubysocket.h b/ext/socket/rubysocket.h index 689a7a8219..359d28ea3d 100644 --- a/ext/socket/rubysocket.h +++ b/ext/socket/rubysocket.h @@ -407,9 +407,20 @@ NORETURN(void rsock_sys_fail_raddrinfo_or_sockaddr(const char *, VALUE addr, VAL #if defined(__linux__) static inline int rsock_maybe_fd_writable(int fd) { return 1; } static inline void rsock_maybe_wait_fd(int fd) { } +# ifdef MSG_DONTWAIT +# define MSG_DONTWAIT_RELIABLE 1 +# endif #else /* some systems (mswin/mingw) need these. ref: r36946 */ # define rsock_maybe_fd_writable(fd) rb_thread_fd_writable((fd)) # define rsock_maybe_wait_fd(fd) rb_thread_wait_fd((fd)) #endif +/* + * some OSes may support MSG_DONTWAIT inconsistently depending on socket + * type, we only expect Linux to support it consistently for all socket types. + */ +#ifndef MSG_DONTWAIT_RELIABLE +# define MSG_DONTWAIT_RELIABLE 0 +#endif + #endif -- cgit v1.2.3