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-rw-r--r--contrib/qemu/qemu-coroutine.c135
1 files changed, 135 insertions, 0 deletions
diff --git a/contrib/qemu/qemu-coroutine.c b/contrib/qemu/qemu-coroutine.c
new file mode 100644
index 00000000..423430d3
--- /dev/null
+++ b/contrib/qemu/qemu-coroutine.c
@@ -0,0 +1,135 @@
+/*
+ * QEMU coroutines
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
+ * Kevin Wolf <kwolf@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include "trace.h"
+#include "qemu-common.h"
+#include "qemu/thread.h"
+#include "block/coroutine.h"
+#include "block/coroutine_int.h"
+
+enum {
+ /* Maximum free pool size prevents holding too many freed coroutines */
+ POOL_MAX_SIZE = 64,
+};
+
+/** Free list to speed up creation */
+static QemuMutex pool_lock;
+static QSLIST_HEAD(, Coroutine) pool = QSLIST_HEAD_INITIALIZER(pool);
+static unsigned int pool_size;
+
+Coroutine *qemu_coroutine_create(CoroutineEntry *entry)
+{
+ Coroutine *co;
+
+ qemu_mutex_lock(&pool_lock);
+ co = QSLIST_FIRST(&pool);
+ if (co) {
+ QSLIST_REMOVE_HEAD(&pool, pool_next);
+ pool_size--;
+ }
+ qemu_mutex_unlock(&pool_lock);
+
+ if (!co) {
+ co = qemu_coroutine_new();
+ }
+
+ co->entry = entry;
+ QTAILQ_INIT(&co->co_queue_wakeup);
+ return co;
+}
+
+static void coroutine_delete(Coroutine *co)
+{
+ qemu_mutex_lock(&pool_lock);
+ if (pool_size < POOL_MAX_SIZE) {
+ QSLIST_INSERT_HEAD(&pool, co, pool_next);
+ co->caller = NULL;
+ pool_size++;
+ qemu_mutex_unlock(&pool_lock);
+ return;
+ }
+ qemu_mutex_unlock(&pool_lock);
+
+ qemu_coroutine_delete(co);
+}
+
+static void __attribute__((constructor)) coroutine_pool_init(void)
+{
+ qemu_mutex_init(&pool_lock);
+}
+
+static void __attribute__((destructor)) coroutine_pool_cleanup(void)
+{
+ Coroutine *co;
+ Coroutine *tmp;
+
+ QSLIST_FOREACH_SAFE(co, &pool, pool_next, tmp) {
+ QSLIST_REMOVE_HEAD(&pool, pool_next);
+ qemu_coroutine_delete(co);
+ }
+
+ qemu_mutex_destroy(&pool_lock);
+}
+
+static void coroutine_swap(Coroutine *from, Coroutine *to)
+{
+ CoroutineAction ret;
+
+ ret = qemu_coroutine_switch(from, to, COROUTINE_YIELD);
+
+ qemu_co_queue_run_restart(to);
+
+ switch (ret) {
+ case COROUTINE_YIELD:
+ return;
+ case COROUTINE_TERMINATE:
+ trace_qemu_coroutine_terminate(to);
+ coroutine_delete(to);
+ return;
+ default:
+ abort();
+ }
+}
+
+void qemu_coroutine_enter(Coroutine *co, void *opaque)
+{
+ Coroutine *self = qemu_coroutine_self();
+
+ trace_qemu_coroutine_enter(self, co, opaque);
+
+ if (co->caller) {
+ fprintf(stderr, "Co-routine re-entered recursively\n");
+ abort();
+ }
+
+ co->caller = self;
+ co->entry_arg = opaque;
+ coroutine_swap(self, co);
+}
+
+void coroutine_fn qemu_coroutine_yield(void)
+{
+ Coroutine *self = qemu_coroutine_self();
+ Coroutine *to = self->caller;
+
+ trace_qemu_coroutine_yield(self, to);
+
+ if (!to) {
+ fprintf(stderr, "Co-routine is yielding to no one\n");
+ abort();
+ }
+
+ self->caller = NULL;
+ coroutine_swap(self, to);
+}