Index: locking.9
===================================================================
RCS file: /home/ncvs/src/share/man/man9/locking.9,v
retrieving revision 1.4
diff -u -r1.4 locking.9
--- locking.9	14 Mar 2007 17:33:16 -0000	1.4
+++ locking.9	18 Mar 2007 11:18:49 -0000
@@ -37,7 +37,7 @@
 The 
 .Em FreeBSD
 kernel is written to run across multiple CPUs and as such requires
-several different sychronization primatives to allow the developers 
+several different synchronization primitives to allow the developers 
 to safely access and manipulate the many data types required.
 .Pp
 These include:
@@ -53,7 +53,7 @@
 .It
 Reader-Writer locks
 .It
-Turnstyles
+Turnstiles
 .It
 Semaphores
 .It
@@ -66,27 +66,31 @@
 Lockmanager locks
 .El
 .Pp
-The primnatives interact and have a number of rules regarding how
-they can and can not be combined. Ther eare too many for the average humanmind and they
-keep changing. (if you disagree, please write replacement text)  :-)
+The primitives interact and have a number of rules regarding how
+they can and can not be combined. There are too many for the average
+human mind and they keep changing. (if you disagree, please write
+replacement text)  :-)
 .Pp
-Some of these primatives may be used at the low (interrupt) level and some may not.
+Some of these primitives may be used at the low (interrupt) level
+and some may not.
 .Pp
-There are strict ordering requirements and for some of the types this
-is checked using the 
+There are strict ordering requirements and for some of the types
+this is checked using the
 .Xr witness 4
 code.
 .Pp
 .Ss SPIN Mutexes
-Mutexes are the basic primative.
+Mutexes are the basic primitive.
 You either hold it or you don't.
-If you don't own it then you just spin, waiting for the holder (on another CPU)
-to release it. Hopefully they are doing something fast. You can not do anythign that 
-deschedules the thread while you are holding a SPIN mutex.
-.Ss Sleep Mutexes
-Basically sleep (regular) mutexes will deschedule the thread if
-the mutex can not be acquired. As in spin mutexes, you either get it or you don't.
-You may call the
+If you don't own it then you just spin, waiting for the holder (on
+another CPU) to release it.
+Hopefully they are doing something fast.
+You can not do anything that deschedules the thread while you are
+holding a SPIN mutex.
+.Ss Sleep Mutexe
+Basically sleep (regular) mutexes will deschedule the thread if the
+mutex can not be acquired. As in spin mutexes, you either get it or
+you don't.  You may call the
 .Xr sleep 9
 call
 .Fn msleep
@@ -95,12 +99,13 @@
 variant. These will atomically drop the mutex and reacquire it
 as part of waking up.
 .Ss Pool Mutexes
-A variant of SLEEP mutexes where the allocation of the mutex is handled more by the system.
+A variant of SLEEP mutexes where the allocation of the mutex is
+handled more by the system.
 .Ss Sx_locks
-Shared/exclusive locks are used to protect data that are read far more often
-than they are written.
-Mutexes are inherently more efficient than shared/exclusive locks, so
-shared/exclusive locks should be used prudently.
+Shared/exclusive locks are used to protect data that are read far
+more often than they are written.
+Mutexes are inherently more efficient than shared/exclusive locks,
+so shared/exclusive locks should be used prudently.
 A thread may hold a shared or exclusive lock on an
 .Em sx_lock
 lock while sleeping.
@@ -146,23 +151,24 @@
 .Em rw_lock
 can recurse,
 but exclusive locks are not allowed to recurse.
-.Ss Turnstyless
+.Ss Turnstiles
 Turnstiles are used to hold a queue of threads blocked on
-non-sleepable locks.  Sleepable locks use condition variables to
-implement their queues.  Turnstiles differ from a sleep queue in that
-turnstile queue's are assigned to a lock held by an owning thread.  Thus,
-when one thread is enqueued onto a turnstile, it can lend its priority
-to the owning thread.
+non-sleepable locks.
+Sleepable locks use condition variables to implement their queues.
+Turnstiles differ from a sleep queue in that turnstile queue's are
+assigned to a lock held by an owning thread.
+Thus, when one thread is enqueued onto a turnstile, it can lend its
+priority to the owning thread.
 .Ss Semaphores
 .Ss Condition variables
-Condition variables are used in conjunction with mutexes to wait for conditions
-to occur.
+Condition variables are used in conjunction with mutexes to wait for
+conditions to occur.
 A thread must hold the mutex before calling the
 .Fn cv_wait* ,
 functions.
-When a thread waits on a condition, the mutex
-is atomically released before the thread is blocked, then reacquired
-before the function call returns.
+When a thread waits on a condition, the mutex is atomically released
+before the thread is blocked, then reacquired before the function
+call returns.
 .Ss Giant
 Giant is a special instance of a sleep lock.
 it has several special characteristics.
@@ -176,14 +182,14 @@
 and
 .Fn wakeup_one
 handle event-based thread blocking.
-If a thread must wait for an
-external event, it is put to sleep by
+If a thread must wait for an external event, it is put to sleep by
 .Fn tsleep ,
 .Fn msleep ,
 .Fn msleep_spin ,
 or
 .Fn pause .
-Threads may also wait using one of the locking primitive sleep routines
+Threads may also wait using one of the locking primitive sleep
+routines
 .Xr mtx_sleep 9 ,
 .Xr rw_sleep 9 ,
 or
@@ -205,17 +211,16 @@
 .Fn msleep_spin ,
 and the locking primitive sleep routines specify an additional lock
 parameter.
-The lock will be released before sleeping and reacquired
-before the sleep routine returns.
+The lock will be released before sleeping and reacquired before the
+sleep routine returns.
 If
 .Fa priority
 includes the
 .Dv PDROP
-flag, then
-the lock will not be reacquired before returning.
-The lock is used to ensure that a condition can be checked atomically,
-and that the current thread can be suspended without missing a
-change to the condition, or an associated wakeup.
+flag, then the lock will not be reacquired before returning.
+The lock is used to ensure that a condition can be checked
+atomically, and that the current thread can be suspended without
+missing a change to the condition, or an associated wakeup.
 In addition, all of the sleep routines will fully drop the
 .Va Giant
 mutex
@@ -228,12 +233,12 @@
 Largly deprecated. See the 
 .Xr lock 9
 page for more information.
-I don't know what the downsides are but I'm sure someone will fill in this part.
+I don't know what the downsides are but I'm sure someone will fill
+in this part.
 .Sh Usage tables.
 .Ss Interaction table.
 The following table shows what you can and can not do if you hold
-one of the synchronisation primatives discussed here:
-(someone who knows what they are talking about should write this table)
+one of the synchronization primitives discussed here:
 .Bl -column ".Ic xxxxxxxxxxxxxxxxxxxx" ".Xr XXXXXXXXX" ".Xr XXXXXXX" ".Xr XXXXXXX" ".Xr XXXXXXX" ".Xr XXXXX" -offset indent
 .It Xo
 .Em "You have:  You want:" Ta Spin_mtx Ta Slp_mtx Ta sx_lock Ta rw_lock Ta sleep
@@ -245,14 +250,14 @@
 .El
 .Pp
 .Em *1
-Recursion is defined per lock. lock order is important.
+Recursion is defined per lock. Lock order is important.
 .Pp
 .Em *2
-readers can recurse tough writers can not. lock order is important.
+readers can recurse tough writers can not. Lock order is important.
 .Pp
 .Em *3
-There are calls atomically release this primative when going to sleep
-and reacquire it on wakeup (e.g. 
+There are calls atomically release this primitive when going to
+sleep and reacquire it on wakeup (e.g. 
 .Fn mtx_sleep ,
 .Fn rw_sleep
 and 
@@ -261,10 +266,11 @@
 .Em *4
 Though one can sleep holding an sx lock, one can also use 
 .Fn sx_sleep
-which atomically release this primative when going to sleep and reacquire it on wakeup.
+which atomically release this primitive when going to sleep and
+reacquire it on wakeup.
 .Ss Context mode table.
-The next table shows what can be used in differnt contexts. at this time this is a 
-rather easy to remember table.
+The next table shows what can be used in different contexts. At this
+time this is a rather easy to remember table.
 .Bl -column ".Ic Xxxxxxxxxxxxxxxxxxxx" ".Xr XXXXXXXXX" ".Xr XXXXXXX" ".Xr XXXXXXX" ".Xr XXXXXXX" ".Xr XXXXX" -offset indent
 .It Xo
 .Em "Context:" Ta Spin_mtx Ta Slp_mtx Ta sx_lock Ta rw_lock Ta sleep