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2012-12-11aio: Get rid of qemu_aio_flush()Kevin Wolf1-7/+2
There are no remaining users, and new users should probably be using bdrv_drain_all() in the first place. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-11-14aio: rename AIOPool to AIOCBInfoStefan Hajnoczi1-4/+4
Now that AIOPool no longer keeps a freelist, it isn't really a "pool" anymore. Rename it to AIOCBInfo and make it const since it no longer needs to be modified. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-11-14aio: use g_slice_alloc() for AIOCB poolingStefan Hajnoczi1-2/+0
AIO control blocks are frequently acquired and released because each aio request involves at least one AIOCB. Therefore, we pool them to avoid heap allocation overhead. The problem with the freelist approach in AIOPool is thread-safety. If we want BlockDriverStates to associate with AioContexts that execute in multiple threads, then a global freelist becomes a problem. This patch drops the freelist and instead uses g_slice_alloc() which is tuned for per-thread fixed-size object pools. qemu_aio_get() and qemu_aio_release() are now thread-safe. Note that the change from g_malloc0() to g_slice_alloc() should be safe since the freelist reuse case doesn't zero the AIOCB either. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-11-14aio: switch aiocb_size type int -> size_tStefan Hajnoczi1-1/+1
Using appropriate types for variables is a good thing :). All users simply do sizeof(MyType) and the value is passed to a memory allocator, it should be size_t. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-10-30aio: clean up now-unused functionsPaolo Bonzini1-1/+0
Some cleanups can now be made, now that the main loop does not anymore need hooks into the bottom half code. Reviewed-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-10-30aio: add aio_notifyPaolo Bonzini1-0/+18
With this change async.c does not rely anymore on any service from main-loop.c, i.e. it is completely self-contained. Reviewed-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-10-30aio: make AioContexts GSourcesPaolo Bonzini1-0/+23
This lets AioContexts be used (optionally) with a glib main loop. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-10-30aio: prepare for introducing GSource-based dispatchPaolo Bonzini1-0/+7
This adds a GPollFD to each AioHandler. It will then be possible to attach these GPollFDs to a GSource, and from there to the main loop. aio_wait examines the GPollFDs and avoids calling select() if any is set (similar to what it does if bottom halves are available). Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-10-30aio: add non-blocking variant of aio_waitPaolo Bonzini1-6/+15
This will be used when polling the GSource attached to an AioContext. Reviewed-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-10-30aio: add I/O handlers to the AioContext interfacePaolo Bonzini1-7/+35
With this patch, I/O handlers (including event notifier handlers) can be attached to a single AioContext. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-10-30aio: introduce AioContext, move bottom halves therePaolo Bonzini1-1/+78
Start introducing AioContext, which will let us remove globals from aio.c/async.c, and introduce multiple I/O threads. The bottom half functions now take an additional AioContext argument. A bottom half is created with a specific AioContext that remains the same throughout the lifetime. qemu_bh_new is just a wrapper that uses a global context. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-10-30aio: provide platform-independent APIPaolo Bonzini1-1/+18
This adds to aio.c a platform-independent API based on EventNotifiers, that can be used by both POSIX and Win32. Reviewed-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-10-30aio: change qemu_aio_set_fd_handler to return voidPaolo Bonzini1-5/+5
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-04-19aio: return "AIO in progress" state from qemu_aio_waitPaolo Bonzini1-2/+4
The definition of when qemu_aio_flush should loop is much simpler than it looks. It just has to call qemu_aio_wait until it makes no progress and all flush callbacks return false. qemu_aio_wait is the logical place to tell the caller about this. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-19aio: remove process_queue callback and qemu_aio_process_queuePaolo Bonzini1-13/+0
Both unused after the previous patch. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-05aio: move BlockDriverAIOCB to qemu-aio.hPaolo Bonzini1-0/+21
And remove several block_int.h inclusions that should not be there. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2009-10-27Add qemu_aio_process_queue()Kevin Wolf1-0/+13
We'll leave some AIO completions unhandled when we can't call the callback. qemu_aio_process_queue() is used later to run any callbacks that are left and can be run then. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-06-15fix qemu_aio_flushAndrea Arcangeli1-3/+4
qemu_aio_wait by invoking the bh or one of the aio completion callbacks, could end up submitting new pending aio, breaking the invariant that qemu_aio_flush returns only when no pending aio is outstanding (possibly a problem for migration as such). Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Kevin Wolf <kwolf@redhat.com>
2008-09-22Refactor AIO to allow multiple AIO implementationsaliguori1-0/+45
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