From: Paolo Bonzini <pbonzini@redhat.com> To: qemu-devel@nongnu.org Cc: kvm@vger.kernel.org Subject: [PATCH] [uq/master] use eventfd for iothread Date: Thu, 11 Feb 2010 00:23:46 +0100 [thread overview] Message-ID: <1265844226-29613-1-git-send-email-pbonzini@redhat.com> (raw) Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- 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 <sys/statvfs.h> #endif +#ifdef CONFIG_EVENTFD +#include <sys/eventfd.h> +#endif + #ifdef _WIN32 #include <windows.h> #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
WARNING: multiple messages have this Message-ID (diff)
From: Paolo Bonzini <pbonzini@redhat.com> To: qemu-devel@nongnu.org Cc: kvm@vger.kernel.org Subject: [Qemu-devel] [PATCH] [uq/master] use eventfd for iothread Date: Thu, 11 Feb 2010 00:23:46 +0100 [thread overview] Message-ID: <1265844226-29613-1-git-send-email-pbonzini@redhat.com> (raw) Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- 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 <sys/statvfs.h> #endif +#ifdef CONFIG_EVENTFD +#include <sys/eventfd.h> +#endif + #ifdef _WIN32 #include <windows.h> #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
next reply other threads:[~2010-02-10 23:27 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-02-10 23:23 Paolo Bonzini [this message] 2010-02-10 23:23 ` [Qemu-devel] [PATCH] [uq/master] use eventfd for iothread Paolo Bonzini 2010-02-17 12:59 ` Avi Kivity 2010-02-17 12:59 ` [Qemu-devel] " Avi Kivity
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