spice/gl: Enable dmabuf only for spice >= 0.13.1

[qemu.git] / async.c

diff --git a/async.c b/async.c
index 2be88cc9e9a28093937423fc7e39474c0cd825bb..d4dd2cc799283ecbbcad2ddd3a271e77685863dc 100644 (file)
--- a/async.c
+++ b/async.c
@@ -22,6 +22,7 @@
  * THE SOFTWARE.
  */
 
  * THE SOFTWARE.
  */
 

+#include "qemu/osdep.h"

 #include "qemu-common.h"
 #include "block/aio.h"
 #include "block/thread-pool.h"
 #include "qemu-common.h"
 #include "block/aio.h"
 #include "block/thread-pool.h"


@@ -59,6 +60,11 @@ QEMUBH *aio_bh_new(AioContext *ctx, QEMUBHFunc *cb, void *opaque)
     return bh;
 }
 
     return bh;
 }
 

+void aio_bh_call(QEMUBH *bh)
+{
+    bh->cb(bh->opaque);
+}
+

 /* Multiple occurrences of aio_bh_poll cannot be called concurrently */
 int aio_bh_poll(AioContext *ctx)
 {
 /* Multiple occurrences of aio_bh_poll cannot be called concurrently */
 int aio_bh_poll(AioContext *ctx)
 {


@@ -72,16 +78,19 @@ int aio_bh_poll(AioContext *ctx)
         /* Make sure that fetching bh happens before accessing its members */
         smp_read_barrier_depends();
         next = bh->next;
         /* Make sure that fetching bh happens before accessing its members */
         smp_read_barrier_depends();
         next = bh->next;

-        if (!bh->deleted && bh->scheduled) {
-            bh->scheduled = 0;
-            /* Paired with write barrier in bh schedule to ensure reading for
-             * idle & callbacks coming after bh's scheduling.
-             */
-            smp_rmb();
-            if (!bh->idle)
+        /* The atomic_xchg is paired with the one in qemu_bh_schedule.  The
+         * implicit memory barrier ensures that the callback sees all writes
+         * done by the scheduling thread.  It also ensures that the scheduling
+         * thread sees the zero before bh->cb has run, and thus will call
+         * aio_notify again if necessary.
+         */
+        if (!bh->deleted && atomic_xchg(&bh->scheduled, 0)) {
+            /* Idle BHs and the notify BH don't count as progress */
+            if (!bh->idle && bh != ctx->notify_dummy_bh) {

                 ret = 1;
                 ret = 1;

+            }

             bh->idle = 0;
             bh->idle = 0;

-            bh->cb(bh->opaque);
+            aio_bh_call(bh);

         }
     }
 
         }
     }
 


@@ -108,33 +117,28 @@ int aio_bh_poll(AioContext *ctx)
 
 void qemu_bh_schedule_idle(QEMUBH *bh)
 {
 
 void qemu_bh_schedule_idle(QEMUBH *bh)
 {

-    if (bh->scheduled)
-        return;

     bh->idle = 1;
     /* Make sure that idle & any writes needed by the callback are done
      * before the locations are read in the aio_bh_poll.
      */
     bh->idle = 1;
     /* Make sure that idle & any writes needed by the callback are done
      * before the locations are read in the aio_bh_poll.
      */

-    smp_wmb();
-    bh->scheduled = 1;
+    atomic_mb_set(&bh->scheduled, 1);

 }
 
 void qemu_bh_schedule(QEMUBH *bh)
 {
     AioContext *ctx;
 
 }
 
 void qemu_bh_schedule(QEMUBH *bh)
 {
     AioContext *ctx;
 

-    if (bh->scheduled)
-        return;

     ctx = bh->ctx;
     bh->idle = 0;
     ctx = bh->ctx;
     bh->idle = 0;

-    /* Make sure that:
+    /* The memory barrier implicit in atomic_xchg makes sure that:

      * 1. idle & any writes needed by the callback are done before the
      *    locations are read in the aio_bh_poll.
      * 2. ctx is loaded before scheduled is set and the callback has a chance
      *    to execute.
      */
      * 1. idle & any writes needed by the callback are done before the
      *    locations are read in the aio_bh_poll.
      * 2. ctx is loaded before scheduled is set and the callback has a chance
      *    to execute.
      */

-    smp_mb();
-    bh->scheduled = 1;
-    aio_notify(ctx);
+    if (atomic_xchg(&bh->scheduled, 1) == 0) {
+        aio_notify(ctx);
+    }

 }
 
 
 }
 
 


@@ -188,6 +192,8 @@ aio_ctx_prepare(GSource *source, gint    *timeout)
 {
     AioContext *ctx = (AioContext *) source;
 
 {
     AioContext *ctx = (AioContext *) source;
 

+    atomic_or(&ctx->notify_me, 1);
+

     /* We assume there is no timeout already supplied */
     *timeout = qemu_timeout_ns_to_ms(aio_compute_timeout(ctx));
 
     /* We assume there is no timeout already supplied */
     *timeout = qemu_timeout_ns_to_ms(aio_compute_timeout(ctx));
 


@@ -204,6 +210,9 @@ aio_ctx_check(GSource *source)
     AioContext *ctx = (AioContext *) source;
     QEMUBH *bh;
 
     AioContext *ctx = (AioContext *) source;
     QEMUBH *bh;
 

+    atomic_and(&ctx->notify_me, ~1);
+    aio_notify_accept(ctx);
+

     for (bh = ctx->first_bh; bh; bh = bh->next) {
         if (!bh->deleted && bh->scheduled) {
             return true;
     for (bh = ctx->first_bh; bh; bh = bh->next) {
         if (!bh->deleted && bh->scheduled) {
             return true;


@@ -229,12 +238,25 @@ aio_ctx_finalize(GSource     *source)
 {
     AioContext *ctx = (AioContext *) source;
 
 {
     AioContext *ctx = (AioContext *) source;
 

+    qemu_bh_delete(ctx->notify_dummy_bh);

     thread_pool_free(ctx->thread_pool);
     thread_pool_free(ctx->thread_pool);

-    aio_set_event_notifier(ctx, &ctx->notifier, NULL);
+
+    qemu_mutex_lock(&ctx->bh_lock);
+    while (ctx->first_bh) {
+        QEMUBH *next = ctx->first_bh->next;
+
+        /* qemu_bh_delete() must have been called on BHs in this AioContext */
+        assert(ctx->first_bh->deleted);
+
+        g_free(ctx->first_bh);
+        ctx->first_bh = next;
+    }
+    qemu_mutex_unlock(&ctx->bh_lock);
+
+    aio_set_event_notifier(ctx, &ctx->notifier, false, NULL);

     event_notifier_cleanup(&ctx->notifier);
     rfifolock_destroy(&ctx->lock);
     qemu_mutex_destroy(&ctx->bh_lock);
     event_notifier_cleanup(&ctx->notifier);
     rfifolock_destroy(&ctx->lock);
     qemu_mutex_destroy(&ctx->bh_lock);

-    g_array_free(ctx->pollfds, TRUE);

     timerlistgroup_deinit(&ctx->tlg);
 }
 
     timerlistgroup_deinit(&ctx->tlg);
 }
 


@@ -259,24 +281,22 @@ ThreadPool *aio_get_thread_pool(AioContext *ctx)
     return ctx->thread_pool;
 }
 
     return ctx->thread_pool;
 }
 

-void aio_set_dispatching(AioContext *ctx, bool dispatching)
+void aio_notify(AioContext *ctx)

 {
 {

-    ctx->dispatching = dispatching;
-    if (!dispatching) {
-        /* Write ctx->dispatching before reading e.g. bh->scheduled.
-         * Optimization: this is only needed when we're entering the "unsafe"
-         * phase where other threads must call event_notifier_set.
-         */
-        smp_mb();
+    /* Write e.g. bh->scheduled before reading ctx->notify_me.  Pairs
+     * with atomic_or in aio_ctx_prepare or atomic_add in aio_poll.
+     */
+    smp_mb();
+    if (ctx->notify_me) {
+        event_notifier_set(&ctx->notifier);
+        atomic_mb_set(&ctx->notified, true);

     }
 }
 
     }
 }
 

-void aio_notify(AioContext *ctx)
+void aio_notify_accept(AioContext *ctx)

 {
 {

-    /* Write e.g. bh->scheduled before reading ctx->dispatching.  */
-    smp_mb();
-    if (!ctx->dispatching) {
-        event_notifier_set(&ctx->notifier);
+    if (atomic_xchg(&ctx->notified, false)) {
+        event_notifier_test_and_clear(&ctx->notifier);

     }
 }
 
     }
 }
 


@@ -287,32 +307,54 @@ static void aio_timerlist_notify(void *opaque)
 
 static void aio_rfifolock_cb(void *opaque)
 {
 
 static void aio_rfifolock_cb(void *opaque)
 {

+    AioContext *ctx = opaque;
+

     /* Kick owner thread in case they are blocked in aio_poll() */
     /* Kick owner thread in case they are blocked in aio_poll() */

-    aio_notify(opaque);
+    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)
+{

 }
 
 AioContext *aio_context_new(Error **errp)
 {
     int ret;
     AioContext *ctx;
 }
 
 AioContext *aio_context_new(Error **errp)
 {
     int ret;
     AioContext *ctx;

+    Error *local_err = NULL;
+

     ctx = (AioContext *) g_source_new(&aio_source_funcs, sizeof(AioContext));
     ctx = (AioContext *) g_source_new(&aio_source_funcs, sizeof(AioContext));

+    aio_context_setup(ctx, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        goto fail;
+    }

     ret = event_notifier_init(&ctx->notifier, false);
     if (ret < 0) {
     ret = event_notifier_init(&ctx->notifier, false);
     if (ret < 0) {

-        g_source_destroy(&ctx->source);

         error_setg_errno(errp, -ret, "Failed to initialize event notifier");
         error_setg_errno(errp, -ret, "Failed to initialize event notifier");

-        return NULL;
+        goto fail;

     }
     g_source_set_can_recurse(&ctx->source, true);
     aio_set_event_notifier(ctx, &ctx->notifier,
     }
     g_source_set_can_recurse(&ctx->source, true);
     aio_set_event_notifier(ctx, &ctx->notifier,

+                           false,

                            (EventNotifierHandler *)
                            (EventNotifierHandler *)

-                           event_notifier_test_and_clear);
-    ctx->pollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
+                           event_notifier_dummy_cb);

     ctx->thread_pool = NULL;
     qemu_mutex_init(&ctx->bh_lock);
     rfifolock_init(&ctx->lock, aio_rfifolock_cb, ctx);
     timerlistgroup_init(&ctx->tlg, aio_timerlist_notify, ctx);
 
     ctx->thread_pool = NULL;
     qemu_mutex_init(&ctx->bh_lock);
     rfifolock_init(&ctx->lock, aio_rfifolock_cb, ctx);
     timerlistgroup_init(&ctx->tlg, aio_timerlist_notify, ctx);
 

+    ctx->notify_dummy_bh = aio_bh_new(ctx, notify_dummy_bh, NULL);
+

     return ctx;
     return ctx;

+fail:
+    g_source_destroy(&ctx->source);
+    return NULL;

 }
 
 void aio_context_ref(AioContext *ctx)
 }
 
 void aio_context_ref(AioContext *ctx)