From 0c330a734b51c177ab8488932ac3b0c4d63a718a Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Mon, 13 Feb 2017 14:52:19 +0100 Subject: aio: introduce aio_co_schedule and aio_co_wake aio_co_wake provides the infrastructure to start a coroutine on a "home" AioContext. It will be used by CoMutex and CoQueue, so that coroutines don't jump from one context to another when they go to sleep on a mutex or waitqueue. However, it can also be used as a more efficient alternative to one-shot bottom halves, and saves the effort of tracking which AioContext a coroutine is running on. aio_co_schedule is the part of aio_co_wake that starts a coroutine on a remove AioContext, but it is also useful to implement e.g. bdrv_set_aio_context callbacks. The implementation of aio_co_schedule is based on a lock-free multiple-producer, single-consumer queue. The multiple producers use cmpxchg to add to a LIFO stack. The consumer (a per-AioContext bottom half) grabs all items added so far, inverts the list to make it FIFO, and goes through it one item at a time until it's empty. The data structure was inspired by OSv, which uses it in the very code we'll "port" to QEMU for the thread-safe CoMutex. Most of the new code is really tests. Signed-off-by: Paolo Bonzini Reviewed-by: Fam Zheng Message-id: 20170213135235.12274-3-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi --- tests/iothread.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 tests/iothread.h (limited to 'tests/iothread.h') diff --git a/tests/iothread.h b/tests/iothread.h new file mode 100644 index 0000000000..4877cea6a3 --- /dev/null +++ b/tests/iothread.h @@ -0,0 +1,25 @@ +/* + * Event loop thread implementation for unit tests + * + * Copyright Red Hat Inc., 2013, 2016 + * + * Authors: + * Stefan Hajnoczi + * Paolo Bonzini + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ +#ifndef TEST_IOTHREAD_H +#define TEST_IOTHREAD_H + +#include "block/aio.h" +#include "qemu/thread.h" + +typedef struct IOThread IOThread; + +IOThread *iothread_new(void); +void iothread_join(IOThread *iothread); +AioContext *iothread_get_aio_context(IOThread *iothread); + +#endif -- cgit 1.4.1