RedHat 9 shipped glibc 2.3. Modern versions of glibc do not have the aio thread
exit issue that the comment references. This patch adjusts the check to only
limit aio_init on glibc versions < 2.4.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5304 c046a42c-6fe2-441c-8c8c-71466251a162
This patch refactors the AIO layer to allow multiple AIO implementations. It's
only possible because of the recent signalfd() patch.
Right now, the AIO infrastructure is pretty specific to the block raw backend.
For other block devices to implement AIO, the qemu_aio_wait function must
support registration. This patch introduces a new function,
qemu_aio_set_fd_handler, which can be used to register a file descriptor to be
called back. qemu_aio_wait() now polls a set of file descriptors registered
with this function until one becomes readable or writable.
This patch should allow the implementation of alternative AIO backends (via a
thread pool or linux-aio) and AIO backends in non-traditional block devices
(like NBD).
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5297 c046a42c-6fe2-441c-8c8c-71466251a162
This prevents two signalfd() threads from being spawned. This problem was
originally spotted by Blue Swirl.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5289 c046a42c-6fe2-441c-8c8c-71466251a162
The protocol_name "file" was added to the block driver when async IO was
introduced. This can be used to select that a file is treated as a raw
device instead of probing for the type. However, protocols are not subject
to path interpretation which cases qcow2 images with raw base images to not
function is the path was specified relatively.
The fix is simply to remove the protocol_name from the raw block driver. The
proper way to force the use of a raw block format is to use the format= option
with -drive.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5233 c046a42c-6fe2-441c-8c8c-71466251a162
My previous commit broke the build. This was spotted by C.W. Betts.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5231 c046a42c-6fe2-441c-8c8c-71466251a162
Right now, we sprinkle #if defined(QEMU_IMG) && defined(QEMU_NBD) all over the
code. It's ugly and causes us to have to build multiple object files for
linking against qemu and the tools.
This patch introduces a new file, qemu-tool.c which contains enough for
qemu-img, qemu-nbd, and QEMU to all share the same objects.
This also required getting qemu-nbd to be a bit more Windows friendly. I also
changed the Windows block-raw to use normal IO instead of overlapping IO since
we don't actually do AIO yet on Windows. I changed the various #if 0's to
#if WIN32_AIO to make it easier for someone to eventually fix AIO on Windows.
After this patch, there are no longer any #ifdef's related to qemu-img and
qemu-nbd.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5226 c046a42c-6fe2-441c-8c8c-71466251a162
OpenBSD doesn't use AIO so don't try to build compatfd when not using AIO.
Also make sure to call qemu_aio_init() from bdrv_init. Everything that uses
bdrv calls bdrv_init so it makes sense to init aio from there instead of
in every single tool.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5197 c046a42c-6fe2-441c-8c8c-71466251a162
This patch introduces signalfd() to work around the signal/select race in
checking for AIO completions. For platforms that don't support signalfd(), we
emulate it with threads.
There was a long discussion about this approach. I don't believe there are any
fundamental problems with this approach and I believe eliminating the use of
signals is a good thing.
I've tested Windows and Linux using Windows and Linux guests. I've also checked
for disk IO performance regressions.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5187 c046a42c-6fe2-441c-8c8c-71466251a162
aliguori