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aio: add aio_notify

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With this change async.c does not rely anymore on any service from
main-loop.c, i.e. it is completely self-contained.

Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2012-09-24 18:44:14 +02:00
parent e3713e001f
commit 2f4dc3c1b2
2 changed files with 44 additions and 4 deletions
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30
async.c
View File

@ -30,6 +30,7 @@
/* bottom halves (can be seen as timers which expire ASAP) */
struct QEMUBH {
AioContext *ctx;
QEMUBHFunc *cb;
void *opaque;
QEMUBH *next;
@ -42,6 +43,7 @@ QEMUBH *aio_bh_new(AioContext *ctx, QEMUBHFunc *cb, void *opaque)
{
QEMUBH *bh;
bh = g_malloc0(sizeof(QEMUBH));
bh->ctx = ctx;
bh->cb = cb;
bh->opaque = opaque;
bh->next = ctx->first_bh;
@ -101,8 +103,7 @@ void qemu_bh_schedule(QEMUBH *bh)
return;
bh->scheduled = 1;
bh->idle = 0;
/* stop the currently executing CPU to execute the BH ASAP */
qemu_notify_event();
aio_notify(bh->ctx);
}
void qemu_bh_cancel(QEMUBH *bh)
@ -177,11 +178,20 @@ aio_ctx_dispatch(GSource *source,
return true;
}
static void
aio_ctx_finalize(GSource *source)
{
AioContext *ctx = (AioContext *) source;
aio_set_event_notifier(ctx, &ctx->notifier, NULL, NULL);
event_notifier_cleanup(&ctx->notifier);
}
static GSourceFuncs aio_source_funcs = {
aio_ctx_prepare,
aio_ctx_check,
aio_ctx_dispatch,
NULL
aio_ctx_finalize
};
GSource *aio_get_g_source(AioContext *ctx)
@ -190,9 +200,21 @@ GSource *aio_get_g_source(AioContext *ctx)
return &ctx->source;
}
void aio_notify(AioContext *ctx)
{
event_notifier_set(&ctx->notifier);
}
AioContext *aio_context_new(void)
{
return (AioContext *) g_source_new(&aio_source_funcs, sizeof(AioContext));
AioContext *ctx;
ctx = (AioContext *) g_source_new(&aio_source_funcs, sizeof(AioContext));
event_notifier_init(&ctx->notifier, false);
aio_set_event_notifier(ctx, &ctx->notifier,
(EventNotifierHandler *)
event_notifier_test_and_clear, NULL);
return ctx;
}
void aio_context_ref(AioContext *ctx)

18
qemu-aio.h
View File

@ -62,6 +62,9 @@ typedef struct AioContext {
* no callbacks are removed while we're walking and dispatching callbacks.
*/
int walking_bh;
/* Used for aio_notify. */
EventNotifier notifier;
} AioContext;
/* Returns 1 if there are still outstanding AIO requests; 0 otherwise */
@ -101,6 +104,21 @@ void aio_context_unref(AioContext *ctx);
*/
QEMUBH *aio_bh_new(AioContext *ctx, QEMUBHFunc *cb, void *opaque);
/**
* aio_notify: Force processing of pending events.
*
* Similar to signaling a condition variable, aio_notify forces
* aio_wait to exit, so that the next call will re-examine pending events.
* The caller of aio_notify will usually call aio_wait again very soon,
* or go through another iteration of the GLib main loop. Hence, aio_notify
* also has the side effect of recalculating the sets of file descriptors
* that the main loop waits for.
*
* Calling aio_notify is rarely necessary, because for example scheduling
* a bottom half calls it already.
*/
void aio_notify(AioContext *ctx);
/**
* aio_bh_poll: Poll bottom halves for an AioContext.
*