svn commit: r216421 - head/sys/sys

[Kirk McKusick]

Author: mckusick
Date: Mon Dec 13 23:53:55 2010
New Revision: 216421
URL: http://svn.freebsd.org/changeset/base/216421

Log:
  Tighten up some of the comments describing turnstiles and sleepqueues.
  No code changes.
  
  Reviewed by: John Baldwin

Modified:
  head/sys/sys/sleepqueue.h
  head/sys/sys/turnstile.h

Modified: head/sys/sys/sleepqueue.h
==============================================================================
--- head/sys/sys/sleepqueue.h	Mon Dec 13 23:30:56 2010	(r216420)
+++ head/sys/sys/sleepqueue.h	Mon Dec 13 23:53:55 2010	(r216421)
@@ -49,7 +49,7 @@
  * 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 to the sleep to be interruptible by signals, it can
+ * 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
@@ -68,7 +68,7 @@
  * 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 queeu chain lock.
+ * 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

Modified: head/sys/sys/turnstile.h
==============================================================================
--- head/sys/sys/turnstile.h	Mon Dec 13 23:30:56 2010	(r216420)
+++ head/sys/sys/turnstile.h	Mon Dec 13 23:53:55 2010	(r216421)
@@ -39,13 +39,14 @@
  * shared, or eread, lock, and one for threads waiting for an
  * exclusive, or write, lock.
  *
- * A thread calls turnstile_lock() to lock the turnstile chain associated
- * with a given lock.  A thread calls turnstile_wait() when the lock is
- * contested to be put on the queue and block.  If a thread needs to retry
- * a lock operation instead of blocking, it should call turnstile_release()
- * to unlock the associated turnstile chain lock.
+ * A thread calls turnstile_chain_lock() to lock the turnstile chain
+ * associated with a given lock.  A thread calls turnstile_wait() when
+ * the lock is contested to be put on the queue and block.  If a thread
+ * calls turnstile_trywait() and decides to retry a lock operation instead
+ * of blocking, it should call turnstile_cancel() to unlock the associated
+ * turnstile chain lock.
  *
- * When a lock is released, the thread calls turnstile_lookup() to loop
+ * When a lock is released, the thread calls turnstile_lookup() to look
  * up the turnstile associated with the given lock in the hash table.  Then
  * it calls either turnstile_signal() or turnstile_broadcast() to mark
  * blocked threads for a pending wakeup.  turnstile_signal() marks the
@@ -55,7 +56,7 @@
  * releasing the lock, turnstile_unpend() must be called to wake up the
  * pending thread(s) and give up ownership of the turnstile.
  *
- * Alternatively, if a thread wishes to relinquish ownership of a thread
+ * Alternatively, if a thread wishes to relinquish ownership of a lock
  * without waking up any waiters, it may call turnstile_disown().
  *
  * When a lock is acquired that already has at least one thread contested