Right now, iothreads are relying on a "contention callback" to release the AioContext (e.g. for block device operations or to do bdrv_drain_all). This is necessary because aio_poll needs to be called within an aio_context_acquire.
This series drops this requirement for aio_poll, with two effects: 1) it makes it possible to remove the "contention callback" in RFifoLock (and possibly to convert it to a normal GRecMutex, which is why I am not including a patch to remove callbacks from RFifoLock). 2) it makes it possible to start work around making critical sections for the block layer fine-grained. In order to do this, some data is moved from AioContext to local storage. Stack allocation has size limitations, so thread-local storage is used instead. There are no reentrancy problems because the data is only live throughout a small part of aio_poll, and in particular not during the invocation of callbacks. Comments? Paolo Paolo Bonzini (3): aio-posix: move pollfds to thread-local storage AioContext: acquire/release AioContext during aio_poll iothread: release iothread around aio_poll aio-posix.c | 86 ++++++++++++++++++++++++++++++++++++++++------------- aio-win32.c | 8 +++++ async.c | 10 +------ include/block/aio.h | 18 +++++------ iothread.c | 11 ++----- tests/test-aio.c | 21 +++++++------ 6 files changed, 96 insertions(+), 58 deletions(-) -- 2.3.0
