details: http://hg.nginx.org/nginx/rev/31dd63dcb9ea
branches:
changeset: 5707:31dd63dcb9ea
user: Ruslan Ermilov <ru@nginx.com>
date: Fri May 23 16:37:05 2014 +0400
description:
Events: use eventfd() instead of syscall(SYS_eventfd) if possible.

This fixes --with-file-aio support on systems that lack eventfd()
syscall, notably aarch64 Linux.

The syscall(SYS_eventfd) may still be necessary on systems that
have eventfd() syscall in the kernel but lack it in glibc, e.g.
as seen in the current CentOS 5 release.

diffstat:

auto/unix | 33 +++++++++++++++++++++++++++------
src/event/modules/ngx_epoll_module.c | 8 ++++----
src/os/unix/ngx_linux_config.h | 3 +++
3 files changed, 34 insertions(+), 10 deletions(-)

diffs (103 lines):

diff -r a2bf26774cd3 -r 31dd63dcb9ea auto/unix
--- a/auto/unix Fri May 23 13:47:05 2014 +0400
+++ b/auto/unix Fri May 23 16:37:05 2014 +0400
@@ -398,16 +398,36 @@ if [ $NGX_FILE_AIO = YES ]; then

if [ $ngx_found = yes ]; then
CORE_SRCS="$CORE_SRCS $FILE_AIO_SRCS"
+ fi

- elif [ $ngx_found = no ]; then
+ if [ $ngx_found = no ]; then

ngx_feature="Linux AIO support"
ngx_feature_name="NGX_HAVE_FILE_AIO"
ngx_feature_run=no
ngx_feature_incs="#include <linux/aio_abi.h>
- #include <sys/syscall.h>"
+ #include <sys/eventfd.h>"
ngx_feature_path=
ngx_feature_libs=
+ ngx_feature_test="struct iocb iocb;
+ iocb.aio_lio_opcode = IOCB_CMD_PREAD;
+ iocb.aio_flags = IOCB_FLAG_RESFD;
+ iocb.aio_resfd = -1;
+ (void) eventfd(0, 0)"
+ . auto/feature
+
+ if [ $ngx_found = yes ]; then
+ have=NGX_HAVE_EVENTFD . auto/have
+ have=NGX_HAVE_SYS_EVENTFD_H . auto/have
+ CORE_SRCS="$CORE_SRCS $LINUX_AIO_SRCS"
+ fi
+ fi
+
+ if [ $ngx_found = no ]; then
+
+ ngx_feature="Linux AIO support (SYS_eventfd)"
+ ngx_feature_incs="#include <linux/aio_abi.h>
+ #include <sys/syscall.h>"
ngx_feature_test="int n = SYS_eventfd;
struct iocb iocb;
iocb.aio_lio_opcode = IOCB_CMD_PREAD;
@@ -418,16 +438,17 @@ if [ $NGX_FILE_AIO = YES ]; then
if [ $ngx_found = yes ]; then
have=NGX_HAVE_EVENTFD . auto/have
CORE_SRCS="$CORE_SRCS $LINUX_AIO_SRCS"
+ fi
+ fi

- else
- cat << END
+ if [ $ngx_found = no ]; then
+ cat << END

$0: no supported file AIO was found
Currently file AIO is supported on FreeBSD 4.3+ and Linux 2.6.22+ only

END
- exit 1
- fi
+ exit 1
fi
fi

diff -r a2bf26774cd3 -r 31dd63dcb9ea src/event/modules/ngx_epoll_module.c
--- a/src/event/modules/ngx_epoll_module.c Fri May 23 13:47:05 2014 +0400
+++ b/src/event/modules/ngx_epoll_module.c Fri May 23 16:37:05 2014 +0400
@@ -193,10 +193,6 @@ ngx_module_t ngx_epoll_module = {
* We call io_setup(), io_destroy() io_submit(), and io_getevents() directly
* as syscalls instead of libaio usage, because the library header file
* supports eventfd() since 0.3.107 version only.
- *
- * Also we do not use eventfd() in glibc, because glibc supports it
- * since 2.8 version and glibc maps two syscalls eventfd() and eventfd2()
- * into single eventfd() function with different number of parameters.
*/

static int
@@ -227,7 +223,11 @@ ngx_epoll_aio_init(ngx_cycle_t *cycle, n
int n;
struct epoll_event ee;

+#if (NGX_HAVE_SYS_EVENTFD_H)
+ ngx_eventfd = eventfd(0, 0);
+#else
ngx_eventfd = syscall(SYS_eventfd, 0);
+#endif

if (ngx_eventfd == -1) {
ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
diff -r a2bf26774cd3 -r 31dd63dcb9ea src/os/unix/ngx_linux_config.h
--- a/src/os/unix/ngx_linux_config.h Fri May 23 13:47:05 2014 +0400
+++ b/src/os/unix/ngx_linux_config.h Fri May 23 16:37:05 2014 +0400
@@ -94,6 +94,9 @@ extern ssize_t sendfile(int s, int fd, i


#if (NGX_HAVE_FILE_AIO)
+#if (NGX_HAVE_SYS_EVENTFD_H)
+#include <sys/eventfd.h>
+#endif
#include <sys/syscall.h>
#include <linux/aio_abi.h>
typedef struct iocb ngx_aiocb_t;

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