SLEEPQUEUE(9): Import from FreeBSD

freebsd/sys/sys/sleepqueue.h

@@ -0,0 +1,117 @@
+/*-
+ * Copyright (c) 2004 John Baldwin <jhb@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _SYS_SLEEPQUEUE_H_
+#define _SYS_SLEEPQUEUE_H_
+
+/*
+ * Sleep queue interface.  Sleep/wakeup, condition variables, and sx
+ * locks use a sleep queue for the queue of threads blocked on a sleep
+ * channel.
+ *
+ * A thread calls sleepq_lock() to lock the sleep queue chain associated
+ * with a given wait channel.  A thread can then call call sleepq_add() to
+ * add themself onto a sleep queue and call one of the sleepq_wait()
+ * functions to actually go to sleep.  If a thread needs to abort a sleep
+ * operation it should call sleepq_release() to unlock the associated sleep
+ * queue chain lock.  If the thread also needs to remove itself from a queue
+ * it just enqueued itself on, it can use sleepq_remove() instead.
+ *
+ * If the thread only wishes to sleep for a limited amount of time, it can
+ * call sleepq_set_timeout() after sleepq_add() to setup a timeout.  It
+ * should then use one of the sleepq_timedwait() functions to block.
+ *
+ * If the thread wants the sleep to be interruptible by signals, it can
+ * call sleepq_catch_signals() after sleepq_add().  It should then use
+ * one of the sleepq_wait_sig() functions to block.  After the thread has
+ * been resumed, it should call sleepq_calc_signal_retval() to determine
+ * if it should return EINTR or ERESTART passing in the value returned from
+ * the earlier call to sleepq_catch_signals().
+ *
+ * A thread is normally resumed from a sleep queue by either the
+ * sleepq_signal() or sleepq_broadcast() functions.  Sleepq_signal() wakes
+ * the thread with the highest priority that is sleeping on the specified
+ * wait channel.  Sleepq_broadcast() wakes all threads that are sleeping
+ * on the specified wait channel.  A thread sleeping in an interruptible
+ * sleep can be interrupted by calling sleepq_abort().  A thread can also
+ * be removed from a specified sleep queue using the sleepq_remove()
+ * function.  Note that the sleep queue chain must first be locked via
+ * sleepq_lock() before calling sleepq_abort(), sleepq_broadcast(), or
+ * sleepq_signal().  These routines each return a boolean that will be true
+ * if at least one swapped-out thread was resumed.  In that case, the caller
+ * is responsible for waking up the swapper by calling kick_proc0() after
+ * releasing the sleep queue chain lock.
+ *
+ * Each thread allocates a sleep queue at thread creation via sleepq_alloc()
+ * and releases it at thread destruction via sleepq_free().  Note that
+ * a sleep queue is not tied to a specific thread and that the sleep queue
+ * released at thread destruction may not be the same sleep queue that the
+ * thread allocated when it was created.
+ *
+ * XXX: Some other parts of the kernel such as ithread sleeping may end up
+ * using this interface as well (death to TDI_IWAIT!)
+ */
+
+struct lock_object;
+struct sleepqueue;
+struct thread;
+
+#ifdef _KERNEL
+
+#define	SLEEPQ_TYPE		0x0ff		/* Mask of sleep queue types. */
+#define	SLEEPQ_SLEEP		0x00		/* Used by sleep/wakeup. */
+#define	SLEEPQ_CONDVAR		0x01		/* Used for a cv. */
+#define	SLEEPQ_PAUSE		0x02		/* Used by pause. */
+#define	SLEEPQ_SX		0x03		/* Used by an sx lock. */
+#define	SLEEPQ_LK		0x04		/* Used by a lockmgr. */
+#define	SLEEPQ_INTERRUPTIBLE	0x100		/* Sleep is interruptible. */
+#define	SLEEPQ_STOP_ON_BDRY	0x200		/* Stop sleeping thread on
+						   user mode boundary */
+
+void	init_sleepqueues(void);
+int	sleepq_abort(struct thread *td, int intrval);
+void	sleepq_add(void *wchan, struct lock_object *lock, const char *wmesg,
+	    int flags, int queue);
+struct sleepqueue *sleepq_alloc(void);
+int	sleepq_broadcast(void *wchan, int flags, int pri, int queue);
+void	sleepq_free(struct sleepqueue *sq);
+void	sleepq_lock(void *wchan);
+struct sleepqueue *sleepq_lookup(void *wchan);
+void	sleepq_release(void *wchan);
+void	sleepq_remove(struct thread *td, void *wchan);
+int	sleepq_signal(void *wchan, int flags, int pri, int queue);
+void	sleepq_set_timeout(void *wchan, int timo);
+u_int	sleepq_sleepcnt(void *wchan, int queue);
+int	sleepq_timedwait(void *wchan, int pri);
+int	sleepq_timedwait_sig(void *wchan, int pri);
+int	sleepq_type(void *wchan);
+void	sleepq_wait(void *wchan, int pri);
+int	sleepq_wait_sig(void *wchan, int pri);
+
+#endif	/* _KERNEL */
+#endif	/* !_SYS_SLEEPQUEUE_H_ */