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authorPaolo Bonzini <pbonzini@redhat.com>2016-10-27 12:49:06 +0200
committerFam Zheng <famz@redhat.com>2016-10-28 21:50:18 +0800
commit65c1b5b622d09044af3f872240d65e7343f6f83e (patch)
tree6677708ea342fd5e2b6418a75777c699164bbda2 /async.c
parentc9d1a56174339b0afdef63b7d151b38f4bb6dae5 (diff)
downloadqemu-arm-65c1b5b622d09044af3f872240d65e7343f6f83e.tar.gz
iothread: release AioContext around aio_poll
This is the first step towards having fine-grained critical sections in dataplane threads, which will resolve lock ordering problems between address_space_* functions (which need the BQL when doing MMIO, even after we complete RCU-based dispatch) and the AioContext. Because AioContext does not use contention callbacks anymore, the unit test has to be changed. Previously applied as a0710f7995f914e3044e5899bd8ff6c43c62f916 and then reverted. Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <1477565348-5458-19-git-send-email-pbonzini@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
Diffstat (limited to 'async.c')
-rw-r--r--async.c22
1 files changed, 3 insertions, 19 deletions
diff --git a/async.c b/async.c
index fb37b031cb..27db7726e1 100644
--- a/async.c
+++ b/async.c
@@ -107,8 +107,8 @@ int aio_bh_poll(AioContext *ctx)
* aio_notify again if necessary.
*/
if (atomic_xchg(&bh->scheduled, 0)) {
- /* Idle BHs and the notify BH don't count as progress */
- if (!bh->idle && bh != ctx->notify_dummy_bh) {
+ /* Idle BHs don't count as progress */
+ if (!bh->idle) {
ret = 1;
}
bh->idle = 0;
@@ -260,7 +260,6 @@ aio_ctx_finalize(GSource *source)
{
AioContext *ctx = (AioContext *) source;
- qemu_bh_delete(ctx->notify_dummy_bh);
thread_pool_free(ctx->thread_pool);
#ifdef CONFIG_LINUX_AIO
@@ -346,19 +345,6 @@ static void aio_timerlist_notify(void *opaque)
aio_notify(opaque);
}
-static void aio_rfifolock_cb(void *opaque)
-{
- AioContext *ctx = opaque;
-
- /* Kick owner thread in case they are blocked in aio_poll() */
- qemu_bh_schedule(ctx->notify_dummy_bh);
-}
-
-static void notify_dummy_bh(void *opaque)
-{
- /* Do nothing, we were invoked just to force the event loop to iterate */
-}
-
static void event_notifier_dummy_cb(EventNotifier *e)
{
}
@@ -386,11 +372,9 @@ AioContext *aio_context_new(Error **errp)
#endif
ctx->thread_pool = NULL;
qemu_mutex_init(&ctx->bh_lock);
- rfifolock_init(&ctx->lock, aio_rfifolock_cb, ctx);
+ rfifolock_init(&ctx->lock, NULL, NULL);
timerlistgroup_init(&ctx->tlg, aio_timerlist_notify, ctx);
- ctx->notify_dummy_bh = aio_bh_new(ctx, notify_dummy_bh, NULL);
-
return ctx;
fail:
g_source_destroy(&ctx->source);