i386: Update new x86_apicid parsing rules with die_offset support

[mirror_qemu.git] / util / qemu-coroutine-lock.c

diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
index b44b5d55ebad8b8b6c4b8d7e41030ae527308c45..5da5234155a66e648f7615e1eeeb9083ff568237 100644 (file)
--- a/util/qemu-coroutine-lock.c
+++ b/util/qemu-coroutine-lock.c
@@ -27,7 +27,6 @@
  */
 
 #include "qemu/osdep.h"
-#include "qemu-common.h"
 #include "qemu/coroutine.h"
 #include "qemu/coroutine_int.h"
 #include "qemu/processor.h"
@@ -40,13 +39,13 @@ void qemu_co_queue_init(CoQueue *queue)
     QSIMPLEQ_INIT(&queue->entries);
 }
 
-void coroutine_fn qemu_co_queue_wait(CoQueue *queue, CoMutex *mutex)
+void coroutine_fn qemu_co_queue_wait_impl(CoQueue *queue, QemuLockable *lock)
 {
     Coroutine *self = qemu_coroutine_self();
     QSIMPLEQ_INSERT_TAIL(&queue->entries, self, co_queue_next);
 
-    if (mutex) {
-        qemu_co_mutex_unlock(mutex);
+    if (lock) {
+        qemu_lockable_unlock(lock);
     }
 
     /* There is no race condition here.  Other threads will call
@@ -60,43 +59,11 @@ void coroutine_fn qemu_co_queue_wait(CoQueue *queue, CoMutex *mutex)
     /* TODO: OSv implements wait morphing here, where the wakeup
      * primitive automatically places the woken coroutine on the
      * mutex's queue.  This avoids the thundering herd effect.
+     * This could be implemented for CoMutexes, but not really for
+     * other cases of QemuLockable.
      */
-    if (mutex) {
-        qemu_co_mutex_lock(mutex);
-    }
-}
-
-/**
- * qemu_co_queue_run_restart:
- *
- * Enter each coroutine that was previously marked for restart by
- * qemu_co_queue_next() or qemu_co_queue_restart_all().  This function is
- * invoked by the core coroutine code when the current coroutine yields or
- * terminates.
- */
-void qemu_co_queue_run_restart(Coroutine *co)
-{
-    Coroutine *next;
-    QSIMPLEQ_HEAD(, Coroutine) tmp_queue_wakeup =
-        QSIMPLEQ_HEAD_INITIALIZER(tmp_queue_wakeup);
-
-    trace_qemu_co_queue_run_restart(co);
-
-    /* Because "co" has yielded, any coroutine that we wakeup can resume it.
-     * If this happens and "co" terminates, co->co_queue_wakeup becomes
-     * invalid memory.  Therefore, use a temporary queue and do not touch
-     * the "co" coroutine as soon as you enter another one.
-     *
-     * In its turn resumed "co" can pupulate "co_queue_wakeup" queue with
-     * new coroutines to be woken up.  The caller, who has resumed "co",
-     * will be responsible for traversing the same queue, which may cause
-     * a different wakeup order but not any missing wakeups.
-     */
-    QSIMPLEQ_CONCAT(&tmp_queue_wakeup, &co->co_queue_wakeup);
-
-    while ((next = QSIMPLEQ_FIRST(&tmp_queue_wakeup))) {
-        QSIMPLEQ_REMOVE_HEAD(&tmp_queue_wakeup, co_queue_next);
-        qemu_coroutine_enter(next);
+    if (lock) {
+        qemu_lockable_lock(lock);
     }
 }
 
@@ -130,7 +97,7 @@ void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue)
     qemu_co_queue_do_restart(queue, false);
 }
 
-bool qemu_co_enter_next(CoQueue *queue)
+bool qemu_co_enter_next_impl(CoQueue *queue, QemuLockable *lock)
 {
     Coroutine *next;
 
@@ -140,7 +107,13 @@ bool qemu_co_enter_next(CoQueue *queue)
     }
 
     QSIMPLEQ_REMOVE_HEAD(&queue->entries, co_queue_next);
-    qemu_coroutine_enter(next);
+    if (lock) {
+        qemu_lockable_unlock(lock);
+    }
+    aio_co_wake(next);
+    if (lock) {
+        qemu_lockable_lock(lock);
+    }
     return true;
 }
 
@@ -402,6 +375,21 @@ void qemu_co_rwlock_unlock(CoRwlock *lock)
     qemu_co_mutex_unlock(&lock->mutex);
 }
 
+void qemu_co_rwlock_downgrade(CoRwlock *lock)
+{
+    Coroutine *self = qemu_coroutine_self();
+
+    /* lock->mutex critical section started in qemu_co_rwlock_wrlock or
+     * qemu_co_rwlock_upgrade.
+     */
+    assert(lock->reader == 0);
+    lock->reader++;
+    qemu_co_mutex_unlock(&lock->mutex);
+
+    /* The rest of the read-side critical section is run without the mutex.  */
+    self->locks_held++;
+}
+
 void qemu_co_rwlock_wrlock(CoRwlock *lock)
 {
     qemu_co_mutex_lock(&lock->mutex);
@@ -416,3 +404,23 @@ void qemu_co_rwlock_wrlock(CoRwlock *lock)
      * There is no need to update self->locks_held.
      */
 }
+
+void qemu_co_rwlock_upgrade(CoRwlock *lock)
+{
+    Coroutine *self = qemu_coroutine_self();
+
+    qemu_co_mutex_lock(&lock->mutex);
+    assert(lock->reader > 0);
+    lock->reader--;
+    lock->pending_writer++;
+    while (lock->reader) {
+        qemu_co_queue_wait(&lock->queue, &lock->mutex);
+    }
+    lock->pending_writer--;
+
+    /* The rest of the write-side critical section is run with
+     * the mutex taken, similar to qemu_co_rwlock_wrlock.  Do
+     * not account for the lock twice in self->locks_held.
+     */
+    self->locks_held--;
+}