On Thu, Mar 07, 2013 at 01:41:43PM +0100, Stefan Hajnoczi wrote: > This patch series changes the global thread pool to a one ThreadPool per > AioContext model. We still only use the main loop AioContext so in practice > there is just one ThreadPool. But this opens the door to refactoring the > block > layer (which depends on ThreadPool) so block devices can be accessed outside > the global mutex in the future. > > ThreadPool is tightly bound to an AioContext because it uses an EventNotifier > to signal work completion. Completed work items are reaped and their callback > functions are invoked from the EventNotifier read handler (executing under > AioContext). > > It might be possible to record the AioContext for the completion callback on a > per-request basis and continuing to use a global pool of worker threads. > After > discussing thread pool models with Paolo I have been convinced that it is > simpler and more scalable to have one ThreadPool per AioContext instead. > Therefore this series implements the 1:1 approach. For details on previous > thread pool model discussion, see: > http://lists.gnu.org/archive/html/qemu-devel/2013-02/msg03987.html > > The final patch was previously separate but I have included it because it > depends on qemu_get_aio_context(). It is unrelated to ThreadPool but the > patch > reviewers are the same in both instances, so I combined the series. > > At the end of this series block/raw-posix.c and block/raw-win32.c are aware of > the ThreadPool they submit work to. The next step after this series is to > associate BlockDriverState with an AioContext so that the block layer can run > outside the global main loop. > > v2: > * Always find AioContext, don't split if (ctx) cases [Paolo] > * Introduce bdrv_get_aio_context() [Paolo] > * Add CoQueue AioContext patch since it depends on qemu_get_aio_context() > > Stefan Hajnoczi (7): > main-loop: add qemu_get_aio_context() > threadpool: move globals into struct ThreadPool > threadpool: add thread_pool_new() and thread_pool_free() > aio: add a ThreadPool instance to AioContext > block: add bdrv_get_aio_context() > threadpool: drop global thread pool > coroutine: use AioContext for CoQueue BH > > async.c | 11 ++ > block.c | 6 ++ > block/raw-posix.c | 8 +- > block/raw-win32.c | 4 +- > include/block/aio.h | 6 ++ > include/block/block_int.h | 7 ++ > include/block/coroutine.h | 1 + > include/block/thread-pool.h | 15 ++- > include/qemu/main-loop.h | 5 + > main-loop.c | 5 + > qemu-coroutine-lock.c | 55 ++++++---- > tests/test-thread-pool.c | 44 ++++---- > thread-pool.c | 243 > ++++++++++++++++++++++++++++---------------- > trace-events | 4 +- > 14 files changed, 276 insertions(+), 138 deletions(-) > > -- > 1.8.1.4 > >
Applied to my block tree: https://github.com/stefanha/qemu/commits/block Stefan
