aio: add a ThreadPool instance to AioContext

This patch adds a ThreadPool to AioContext.  It's possible that some
AioContext instances will never use the ThreadPool, so defer creation
until aio_get_thread_pool().

The reason why AioContext should have the ThreadPool is because the
ThreadPool is bound to a AioContext instance where the work item's
callback function is invoked.  It doesn't make sense to keep the
ThreadPool pointer anywhere other than AioContext.  For example,
block/raw-posix.c can get its AioContext's ThreadPool and submit work.

Special note about headers: I used struct ThreadPool in aio.h because
there is a circular dependency if aio.h includes thread-pool.h.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2013-03-07 13:41:47 +01:00
parent f7311ccc63
commit 9b34277d23
2 changed files with 17 additions and 0 deletions

11
async.c
View file

@ -24,6 +24,7 @@
#include "qemu-common.h"
#include "block/aio.h"
#include "block/thread-pool.h"
#include "qemu/main-loop.h"
/***********************************************************/
@ -172,6 +173,7 @@ aio_ctx_finalize(GSource *source)
{
AioContext *ctx = (AioContext *) source;
thread_pool_free(ctx->thread_pool);
aio_set_event_notifier(ctx, &ctx->notifier, NULL, NULL);
event_notifier_cleanup(&ctx->notifier);
g_array_free(ctx->pollfds, TRUE);
@ -190,6 +192,14 @@ GSource *aio_get_g_source(AioContext *ctx)
return &ctx->source;
}
ThreadPool *aio_get_thread_pool(AioContext *ctx)
{
if (!ctx->thread_pool) {
ctx->thread_pool = thread_pool_new(ctx);
}
return ctx->thread_pool;
}
void aio_notify(AioContext *ctx)
{
event_notifier_set(&ctx->notifier);
@ -200,6 +210,7 @@ AioContext *aio_context_new(void)
AioContext *ctx;
ctx = (AioContext *) g_source_new(&aio_source_funcs, sizeof(AioContext));
ctx->pollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
ctx->thread_pool = NULL;
event_notifier_init(&ctx->notifier, false);
aio_set_event_notifier(ctx, &ctx->notifier,
(EventNotifierHandler *)

View file

@ -66,6 +66,9 @@ typedef struct AioContext {
/* GPollFDs for aio_poll() */
GArray *pollfds;
/* Thread pool for performing work and receiving completion callbacks */
struct ThreadPool *thread_pool;
} AioContext;
/* Returns 1 if there are still outstanding AIO requests; 0 otherwise */
@ -223,6 +226,9 @@ void aio_set_event_notifier(AioContext *ctx,
*/
GSource *aio_get_g_source(AioContext *ctx);
/* Return the ThreadPool bound to this AioContext */
struct ThreadPool *aio_get_thread_pool(AioContext *ctx);
/* Functions to operate on the main QEMU AioContext. */
bool qemu_aio_wait(void);