aboutsummaryrefslogtreecommitdiff
path: root/block/raw-posix-aio.h
AgeCommit message (Collapse)Author
2009-10-30Remove aio_ctx from paio_* interfaceKevin Wolf
The context parameter in paio_submit isn't used anyway, so there is no reason why block drivers should need to remember it. This also avoids passing a Linux AIO context to paio_submit (which doesn't do any harm as long as the parameter is unused, but it is highly confusing). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-09-11block: add aio_flush operationChristoph Hellwig
Instead stalling the VCPU while serving a cache flush try to do it asynchronously. Use our good old helper thread pool to issue an asynchronous fdatasync for raw-posix. Note that while Linux AIO implements a fdatasync operation it is not useful for us because it isn't actually implement in asynchronous fashion. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-08-27raw-posix: add Linux native AIO supportChristoph Hellwig
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>
2009-08-27raw-posix: refactor AIO supportChristoph Hellwig
Currently the raw-posix.c code contains a lot of knowledge about the asynchronous I/O scheme that is mostly implemented in posix-aio-compat.c. All this code does not really belong here and is getting a bit in the way of implementing native AIO on Linux. So instead move all the guts of the AIO implementation into posix-aio-compat.c (which might need a better name, btw). There's now a very small interface between the AIO providers and raw-posix.c: - an init routine is called from raw_open_common to return an AIO context for this drive. An AIO implementation may either re-use one context for all drives, or use a different one for each as the Linux native AIO support will do. - an submit routine is called from the aio_reav/writev methods to submit an AIO request There are no indirect calls involved in this interface as we need to decide which one to call manually. We will only call the Linux AIO native init function if we were requested to by vl.c, and we will only call the native submit function if we are asked to and the request is properly aligned. That's also the reason why the alignment check actually does the inverse move and now goes into raw-posix.c. The old posix-aio-compat.h headers is removed now that most of it's content is private to posix-aio-compat.c, and instead we add a new block/raw-posix-aio.h headers is created containing only the tiny interface between raw-posix.c and the AIO implementation. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>