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| author | Paolo Bonzini <pbonzini@redhat.com> | 2017-02-13 14:52:19 +0100 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2017-02-21 11:14:07 +0000 |
| commit | 0c330a734b51c177ab8488932ac3b0c4d63a718a (patch) | |
| tree | 1251fc380ca5313495d9a9c541460b3ac2ffb7e0 /util/trace-events | |
| parent | c2b38b277a7882a592f4f2ec955084b2b756daaa (diff) | |
| download | qemu-0c330a734b51c177ab8488932ac3b0c4d63a718a.zip qemu-0c330a734b51c177ab8488932ac3b0c4d63a718a.tar.gz qemu-0c330a734b51c177ab8488932ac3b0c4d63a718a.tar.bz2 | |
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 <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20170213135235.12274-3-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'util/trace-events')
| -rw-r--r-- | util/trace-events | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/util/trace-events b/util/trace-events index 1fa12f0..53bd70c 100644 --- a/util/trace-events +++ b/util/trace-events @@ -6,6 +6,10 @@ run_poll_handlers_end(void *ctx, bool progress) "ctx %p progress %d" poll_shrink(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64 poll_grow(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64 +# util/async.c +aio_co_schedule(void *ctx, void *co) "ctx %p co %p" +aio_co_schedule_bh_cb(void *ctx, void *co) "ctx %p co %p" + # util/thread-pool.c thread_pool_submit(void *pool, void *req, void *opaque) "pool %p req %p opaque %p" thread_pool_complete(void *pool, void *req, void *opaque, int ret) "pool %p req %p opaque %p ret %d" |