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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>
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1 parent f7311cc commit 9b34277d23a6fb15eb9513006c96d8026beeea1f Stefan Hajnoczi committed Mar 7, 2013
Showing with 17 additions and 0 deletions.
  1. +11 −0 async.c
  2. +6 −0 include/block/aio.h
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11 async.c
@@ -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 *)
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@@ -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);

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