From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1NfLy7-0006hu-Dt for qemu-devel@nongnu.org; Wed, 10 Feb 2010 18:27:39 -0500 Received: from [199.232.76.173] (port=58723 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NfLy7-0006hj-18 for qemu-devel@nongnu.org; Wed, 10 Feb 2010 18:27:39 -0500 Received: from Debian-exim by monty-python.gnu.org with spam-scanned (Exim 4.60) (envelope-from ) id 1NfLy5-0004Ds-Qj for qemu-devel@nongnu.org; Wed, 10 Feb 2010 18:27:38 -0500 Received: from mail-fx0-f223.google.com ([209.85.220.223]:40352) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1NfLy5-0004Dm-GJ for qemu-devel@nongnu.org; Wed, 10 Feb 2010 18:27:37 -0500 Received: by fxm23 with SMTP id 23so605565fxm.2 for ; Wed, 10 Feb 2010 15:27:36 -0800 (PST) Sender: Paolo Bonzini From: Paolo Bonzini Date: Thu, 11 Feb 2010 00:23:46 +0100 Message-Id: <1265844226-29613-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH] [uq/master] use eventfd for iothread List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kvm@vger.kernel.org Signed-off-by: Paolo Bonzini --- osdep.c | 32 ++++++++++++++++++++++++++++++++ qemu-common.h | 1 + vl.c | 9 +++++---- 3 files changed, 38 insertions(+), 4 deletions(-) diff --git a/osdep.c b/osdep.c index 9059f01..9e4b17b 100644 --- a/osdep.c +++ b/osdep.c @@ -37,6 +37,10 @@ #include #endif +#ifdef CONFIG_EVENTFD +#include +#endif + #ifdef _WIN32 #include #elif defined(CONFIG_BSD) @@ -281,6 +285,34 @@ ssize_t qemu_write_full(int fd, const void *buf, size_t count) #ifndef _WIN32 /* + * Creates an eventfd that looks like a pipe and has EFD_CLOEXEC set. + */ +int qemu_eventfd(int fds[2]) +{ + int ret; + +#ifdef CONFIG_EVENTFD + ret = eventfd(0, 0); + if (ret >= 0) { + fds[0] = ret; + qemu_set_cloexec(ret); + if ((fds[1] = dup(ret)) == -1) { + close(ret); + return -1; + } + qemu_set_cloexec(fds[1]); + return 0; + } + + if (errno != ENOSYS) { + return -1; + } +#endif + + return qemu_pipe(fds); +} + +/* * Creates a pipe with FD_CLOEXEC set on both file descriptors */ int qemu_pipe(int pipefd[2]) diff --git a/qemu-common.h b/qemu-common.h index b09f717..c941006 100644 --- a/qemu-common.h +++ b/qemu-common.h @@ -170,6 +170,7 @@ ssize_t qemu_write_full(int fd, const void *buf, size_t count) void qemu_set_cloexec(int fd); #ifndef _WIN32 +int qemu_eventfd(int pipefd[2]); int qemu_pipe(int pipefd[2]); #endif diff --git a/vl.c b/vl.c index 98918ac..1957018 100644 --- a/vl.c +++ b/vl.c @@ -3211,14 +3211,15 @@ static int io_thread_fd = -1; static void qemu_event_increment(void) { - static const char byte = 0; + /* Write 8 bytes to be compatible with eventfd. */ + static uint64_t val = 1; ssize_t ret; if (io_thread_fd == -1) return; do { - ret = write(io_thread_fd, &byte, sizeof(byte)); + ret = write(io_thread_fd, &val, sizeof(val)); } while (ret < 0 && errno == EINTR); /* EAGAIN is fine, a read must be pending. */ @@ -3235,7 +3236,7 @@ static void qemu_event_read(void *opaque) ssize_t len; char buffer[512]; - /* Drain the notify pipe */ + /* Drain the notify pipe. For eventfd, only 8 bytes will be read. */ do { len = read(fd, buffer, sizeof(buffer)); } while ((len == -1 && errno == EINTR) || len == sizeof(buffer)); @@ -3246,7 +3247,7 @@ static int qemu_event_init(void) int err; int fds[2]; - err = qemu_pipe(fds); + err = qemu_eventfd(fds); if (err == -1) return -errno; -- 1.6.6