#ifndef QEMU_COROUTINE_H
#define QEMU_COROUTINE_H
+#include "qemu/coroutine-core.h"
#include "qemu/queue.h"
#include "qemu/timer.h"
* waiting for events to complete.
*
* These functions are re-entrant and may be used outside the global mutex.
- */
-
-/**
- * Mark a function that executes in coroutine context
*
- * Functions that execute in coroutine context cannot be called directly from
- * normal functions. In the future it would be nice to enable compiler or
- * static checker support for catching such errors. This annotation might make
- * it possible and in the meantime it serves as documentation.
- *
- * For example:
+ * Functions that execute in coroutine context cannot be called
+ * directly from normal functions. Use @coroutine_fn to mark such
+ * functions. For example:
*
* static void coroutine_fn foo(void) {
* ....
* }
- */
-#define coroutine_fn
-
-typedef struct Coroutine Coroutine;
-
-/**
- * Coroutine entry point
*
- * When the coroutine is entered for the first time, opaque is passed in as an
- * argument.
- *
- * When this function returns, the coroutine is destroyed automatically and
- * execution continues in the caller who last entered the coroutine.
- */
-typedef void coroutine_fn CoroutineEntry(void *opaque);
-
-/**
- * Create a new coroutine
- *
- * Use qemu_coroutine_enter() to actually transfer control to the coroutine.
- * The opaque argument is passed as the argument to the entry point.
- */
-Coroutine *qemu_coroutine_create(CoroutineEntry *entry, void *opaque);
-
-/**
- * Transfer control to a coroutine
- */
-void qemu_coroutine_enter(Coroutine *coroutine);
-
-/**
- * Transfer control to a coroutine if it's not active (i.e. part of the call
- * stack of the running coroutine). Otherwise, do nothing.
- */
-void qemu_coroutine_enter_if_inactive(Coroutine *co);
-
-/**
- * Transfer control to a coroutine and associate it with ctx
- */
-void qemu_aio_coroutine_enter(AioContext *ctx, Coroutine *co);
-
-/**
- * Transfer control back to a coroutine's caller
- *
- * This function does not return until the coroutine is re-entered using
- * qemu_coroutine_enter().
- */
-void coroutine_fn qemu_coroutine_yield(void);
-
-/**
- * Get the currently executing coroutine
- */
-Coroutine *coroutine_fn qemu_coroutine_self(void);
-
-/**
- * Return whether or not currently inside a coroutine
- *
- * This can be used to write functions that work both when in coroutine context
- * and when not in coroutine context. Note that such functions cannot use the
- * coroutine_fn annotation since they work outside coroutine context.
- */
-bool qemu_in_coroutine(void);
-
-/**
- * Return true if the coroutine is currently entered
- *
- * A coroutine is "entered" if it has not yielded from the current
- * qemu_coroutine_enter() call used to run it. This does not mean that the
- * coroutine is currently executing code since it may have transferred control
- * to another coroutine using qemu_coroutine_enter().
- *
- * When several coroutines enter each other there may be no way to know which
- * ones have already been entered. In such situations this function can be
- * used to avoid recursively entering coroutines.
+ * In the future it would be nice to have the compiler or a static
+ * checker catch misuse of such functions. This annotation might make
+ * it possible and in the meantime it serves as documentation.
*/
-bool qemu_coroutine_entered(Coroutine *co);
/**
* Provides a mutex that can be used to synchronise coroutines
*/
struct CoWaitRecord;
-typedef struct CoMutex {
+struct CoMutex {
/* Count of pending lockers; 0 for a free mutex, 1 for an
* uncontended mutex.
*/
unsigned handoff, sequence;
Coroutine *holder;
-} CoMutex;
-
-/**
- * Initialises a CoMutex. This must be called before any other operation is used
- * on the CoMutex.
- */
-void qemu_co_mutex_init(CoMutex *mutex);
-
-/**
- * Locks the mutex. If the lock cannot be taken immediately, control is
- * transferred to the caller of the current coroutine.
- */
-void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex);
+};
/**
- * Unlocks the mutex and schedules the next coroutine that was waiting for this
- * lock to be run.
+ * Assert that the current coroutine holds @mutex.
*/
-void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex);
-
+static inline coroutine_fn void qemu_co_mutex_assert_locked(CoMutex *mutex)
+{
+ /*
+ * mutex->holder doesn't need any synchronisation if the assertion holds
+ * true because the mutex protects it. If it doesn't hold true, we still
+ * don't mind if another thread takes or releases mutex behind our back,
+ * because the condition will be false no matter whether we read NULL or
+ * the pointer for any other coroutine.
+ */
+ assert(qatomic_read(&mutex->locked) &&
+ mutex->holder == qemu_coroutine_self());
+}
/**
* CoQueues are a mechanism to queue coroutines in order to continue executing
*/
void qemu_co_queue_init(CoQueue *queue);
+typedef enum {
+ /*
+ * Enqueue at front instead of back. Use this to re-queue a request when
+ * its wait condition is not satisfied after being woken up.
+ */
+ CO_QUEUE_WAIT_FRONT = 0x1,
+} CoQueueWaitFlags;
+
/**
* Adds the current coroutine to the CoQueue and transfers control to the
* caller of the coroutine. The mutex is unlocked during the wait and
* locked again afterwards.
*/
-void coroutine_fn qemu_co_queue_wait(CoQueue *queue, CoMutex *mutex);
+#define qemu_co_queue_wait(queue, lock) \
+ qemu_co_queue_wait_impl(queue, QEMU_MAKE_LOCKABLE(lock), 0)
+#define qemu_co_queue_wait_flags(queue, lock, flags) \
+ qemu_co_queue_wait_impl(queue, QEMU_MAKE_LOCKABLE(lock), (flags))
+void coroutine_fn qemu_co_queue_wait_impl(CoQueue *queue, QemuLockable *lock,
+ CoQueueWaitFlags flags);
/**
- * Restarts the next coroutine in the CoQueue and removes it from the queue.
- *
- * Returns true if a coroutine was restarted, false if the queue is empty.
+ * Removes the next coroutine from the CoQueue, and queue it to run after
+ * the currently-running coroutine yields.
+ * Returns true if a coroutine was removed, false if the queue is empty.
+ * Used from coroutine context, use qemu_co_enter_next outside.
*/
bool coroutine_fn qemu_co_queue_next(CoQueue *queue);
/**
- * Restarts all coroutines in the CoQueue and leaves the queue empty.
+ * Empties the CoQueue and queues the coroutine to run after
+ * the currently-running coroutine yields.
+ * Used from coroutine context, use qemu_co_enter_all outside.
*/
void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue);
/**
- * Enter the next coroutine in the queue
+ * Removes the next coroutine from the CoQueue, and wake it up. Unlike
+ * qemu_co_queue_next, this function releases the lock during aio_co_wake
+ * because it is meant to be used outside coroutine context; in that case, the
+ * coroutine is entered immediately, before qemu_co_enter_next returns.
+ *
+ * If used in coroutine context, qemu_co_enter_next is equivalent to
+ * qemu_co_queue_next.
*/
-bool qemu_co_enter_next(CoQueue *queue);
+#define qemu_co_enter_next(queue, lock) \
+ qemu_co_enter_next_impl(queue, QEMU_MAKE_LOCKABLE(lock))
+bool qemu_co_enter_next_impl(CoQueue *queue, QemuLockable *lock);
+
+/**
+ * Empties the CoQueue, waking the waiting coroutine one at a time. Unlike
+ * qemu_co_queue_all, this function releases the lock during aio_co_wake
+ * because it is meant to be used outside coroutine context; in that case, the
+ * coroutine is entered immediately, before qemu_co_enter_all returns.
+ *
+ * If used in coroutine context, qemu_co_enter_all is equivalent to
+ * qemu_co_queue_all.
+ */
+#define qemu_co_enter_all(queue, lock) \
+ qemu_co_enter_all_impl(queue, QEMU_MAKE_LOCKABLE(lock))
+void qemu_co_enter_all_impl(CoQueue *queue, QemuLockable *lock);
/**
* Checks if the CoQueue is empty.
bool qemu_co_queue_empty(CoQueue *queue);
+typedef struct CoRwTicket CoRwTicket;
typedef struct CoRwlock {
- int pending_writer;
- int reader;
CoMutex mutex;
- CoQueue queue;
+
+ /* Number of readers, or -1 if owned for writing. */
+ int owners;
+
+ /* Waiting coroutines. */
+ QSIMPLEQ_HEAD(, CoRwTicket) tickets;
} CoRwlock;
/**
* of a parallel writer, control is transferred to the caller of the current
* coroutine.
*/
-void qemu_co_rwlock_rdlock(CoRwlock *lock);
+void coroutine_fn qemu_co_rwlock_rdlock(CoRwlock *lock);
/**
* Write Locks the CoRwlock from a reader. This is a bit more efficient than
* @qemu_co_rwlock_unlock followed by a separate @qemu_co_rwlock_wrlock.
- * However, if the lock cannot be upgraded immediately, control is transferred
- * to the caller of the current coroutine. Also, @qemu_co_rwlock_upgrade
- * only overrides CoRwlock fairness if there are no concurrent readers, so
- * another writer might run while @qemu_co_rwlock_upgrade blocks.
+ * Note that if the lock cannot be upgraded immediately, control is transferred
+ * to the caller of the current coroutine; another writer might run while
+ * @qemu_co_rwlock_upgrade blocks.
*/
-void qemu_co_rwlock_upgrade(CoRwlock *lock);
+void coroutine_fn qemu_co_rwlock_upgrade(CoRwlock *lock);
/**
* Downgrades a write-side critical section to a reader. Downgrading with
* followed by @qemu_co_rwlock_rdlock. This makes it more efficient, but
* may also sometimes be necessary for correctness.
*/
-void qemu_co_rwlock_downgrade(CoRwlock *lock);
+void coroutine_fn qemu_co_rwlock_downgrade(CoRwlock *lock);
/**
* Write Locks the mutex. If the lock cannot be taken immediately because
* of a parallel reader, control is transferred to the caller of the current
* coroutine.
*/
-void qemu_co_rwlock_wrlock(CoRwlock *lock);
+void coroutine_fn qemu_co_rwlock_wrlock(CoRwlock *lock);
/**
* Unlocks the read/write lock and schedules the next coroutine that was
* waiting for this lock to be run.
*/
-void qemu_co_rwlock_unlock(CoRwlock *lock);
+void coroutine_fn qemu_co_rwlock_unlock(CoRwlock *lock);
+
+typedef struct QemuCoSleep {
+ Coroutine *to_wake;
+} QemuCoSleep;
+
+/**
+ * Yield the coroutine for a given duration. Initializes @w so that,
+ * during this yield, it can be passed to qemu_co_sleep_wake() to
+ * terminate the sleep.
+ */
+void coroutine_fn qemu_co_sleep_ns_wakeable(QemuCoSleep *w,
+ QEMUClockType type, int64_t ns);
/**
- * Yield the coroutine for a given duration
+ * Yield the coroutine until the next call to qemu_co_sleep_wake.
+ */
+void coroutine_fn qemu_co_sleep(QemuCoSleep *w);
+
+static inline void coroutine_fn qemu_co_sleep_ns(QEMUClockType type, int64_t ns)
+{
+ QemuCoSleep w = { 0 };
+ qemu_co_sleep_ns_wakeable(&w, type, ns);
+}
+
+typedef void CleanupFunc(void *opaque);
+/**
+ * Run entry in a coroutine and start timer. Wait for entry to finish or for
+ * timer to elapse, what happen first. If entry finished, return 0, if timer
+ * elapsed earlier, return -ETIMEDOUT.
*
- * Behaves similarly to co_sleep_ns(), but the sleeping coroutine will be
- * resumed when using aio_poll().
+ * Be careful, entry execution is not canceled, user should handle it somehow.
+ * If @clean is provided, it's called after coroutine finish if timeout
+ * happened.
+ */
+int coroutine_fn qemu_co_timeout(CoroutineEntry *entry, void *opaque,
+ uint64_t timeout_ns, CleanupFunc clean);
+
+/**
+ * Wake a coroutine if it is sleeping in qemu_co_sleep_ns. The timer will be
+ * deleted. @sleep_state must be the variable whose address was given to
+ * qemu_co_sleep_ns() and should be checked to be non-NULL before calling
+ * qemu_co_sleep_wake().
*/
-void coroutine_fn co_aio_sleep_ns(AioContext *ctx, QEMUClockType type,
- int64_t ns);
+void qemu_co_sleep_wake(QemuCoSleep *w);
/**
* Yield until a file descriptor becomes readable
*/
void coroutine_fn yield_until_fd_readable(int fd);
+/**
+ * Increase coroutine pool size
+ */
+void qemu_coroutine_inc_pool_size(unsigned int additional_pool_size);
+
+/**
+ * Decrease coroutine pool size
+ */
+void qemu_coroutine_dec_pool_size(unsigned int additional_pool_size);
+
+#include "qemu/lockable.h"
+
+/**
+ * Sends a (part of) iovec down a socket, yielding when the socket is full, or
+ * Receives data into a (part of) iovec from a socket,
+ * yielding when there is no data in the socket.
+ * The same interface as qemu_sendv_recvv(), with added yielding.
+ * XXX should mark these as coroutine_fn
+ */
+ssize_t coroutine_fn qemu_co_sendv_recvv(int sockfd, struct iovec *iov,
+ unsigned iov_cnt, size_t offset,
+ size_t bytes, bool do_send);
+#define qemu_co_recvv(sockfd, iov, iov_cnt, offset, bytes) \
+ qemu_co_sendv_recvv(sockfd, iov, iov_cnt, offset, bytes, false)
+#define qemu_co_sendv(sockfd, iov, iov_cnt, offset, bytes) \
+ qemu_co_sendv_recvv(sockfd, iov, iov_cnt, offset, bytes, true)
+
+/**
+ * The same as above, but with just a single buffer
+ */
+ssize_t coroutine_fn qemu_co_send_recv(int sockfd, void *buf, size_t bytes,
+ bool do_send);
+#define qemu_co_recv(sockfd, buf, bytes) \
+ qemu_co_send_recv(sockfd, buf, bytes, false)
+#define qemu_co_send(sockfd, buf, bytes) \
+ qemu_co_send_recv(sockfd, buf, bytes, true)
+
#endif /* QEMU_COROUTINE_H */
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