raw-posix: add Linux native AIO support
Now that do have a nicer interface to work against we can add Linux native
AIO support. It's an extremly thing layer just setting up an iocb for
the io_submit system call in the submission path, and registering an
eventfd with the qemu poll handler to do complete the iocbs directly
from there.
This started out based on Anthony's earlier AIO patch, but after
estimated 42,000 rewrites and just as many build system changes
there's not much left of it.
To enable native kernel aio use the aio=native sub-command on the
drive command line. I have also added an option to qemu-io to
test the aio support without needing a guest.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/configure b/configure
index b993b65..81272fa 100755
--- a/configure
+++ b/configure
@@ -191,6 +191,7 @@
vnc_tls=""
vnc_sasl=""
xen=""
+linux_aio=""
gprof="no"
debug_tcg="no"
@@ -523,6 +524,10 @@
;;
--enable-mixemu) mixemu="yes"
;;
+ --disable-linux-aio) linux_aio="no"
+ ;;
+ --enable-linux-aio) linux_aio="yes"
+ ;;
--enable-io-thread) io_thread="yes"
;;
--disable-blobs) blobs="no"
@@ -674,6 +679,8 @@
echo " --sparc_cpu=V Build qemu for Sparc architecture v7, v8, v8plus, v8plusa, v9"
echo " --disable-vde disable support for vde network"
echo " --enable-vde enable support for vde network"
+echo " --disable-linux-aio disable Linux AIO support"
+echo " --enable-linux-aio enable Linux AIO support"
echo " --enable-io-thread enable IO thread"
echo " --disable-blobs disable installing provided firmware blobs"
echo " --kerneldir=PATH look for kernel includes in PATH"
@@ -1304,6 +1311,26 @@
fi
##########################################
+# linux-aio probe
+AIOLIBS=""
+
+if test "$linux_aio" != "no" ; then
+ cat > $TMPC <<EOF
+#include <libaio.h>
+#include <sys/eventfd.h>
+int main(void) { io_setup(0, NULL); io_set_eventfd(NULL, 0); eventfd(0, 0); return 0; }
+EOF
+ if compile_prog "" "-laio" ; then
+ linux_aio=yes
+ LIBS="$LIBS -laio"
+ else
+ if test "$linux_aio" = "yes" ; then
+ feature_not_found "linux AIO"
+ fi
+ fi
+fi
+
+##########################################
# iovec probe
cat > $TMPC <<EOF
#include <sys/types.h>
@@ -1638,6 +1665,7 @@
echo "GUEST_BASE $guest_base"
echo "vde support $vde"
echo "IO thread $io_thread"
+echo "Linux AIO support $linux_aio"
echo "Install blobs $blobs"
echo "KVM support $kvm"
echo "fdt support $fdt"
@@ -1811,6 +1839,9 @@
if test "$io_thread" = "yes" ; then
echo "CONFIG_IOTHREAD=y" >> $config_host_mak
fi
+if test "$linux_aio" = "yes" ; then
+ echo "CONFIG_LINUX_AIO=y" >> $config_host_mak
+fi
if test "$blobs" = "yes" ; then
echo "INSTALL_BLOBS=yes" >> $config_host_mak
fi
