Add some clarifications to address question from "Kevin Hart"

<kevin.hart@hp.com>.

diff --git a/doc/threads.texi b/doc/threads.texi
index f538d8382b2f1554f4457e0241325f3e95ecae62..2f42e3dc5979b8f8ab33fd79db7af020a285c932 100644 (file)
--- a/doc/threads.texi
+++ b/doc/threads.texi
@@ -462,8 +462,8 @@ holds, then both @var{M} and @var{L} should be boosted to @var{H}'s
 priority.
 
 You must implement priority donation for locks.  You need not
-implement priority donation for semaphores or condition variables,
-but you are welcome to do so.  You do need to implement
+implement priority donation for semaphores or condition variables
+(but you are welcome to do so).  You do need to implement
 priority scheduling in all cases.
 
 Finally, implement the following functions that allow a thread to
@@ -480,6 +480,9 @@ Returns the current thread's priority.  In the presence of priority
 donation, returns the higher (donated) priority.
 @end deftypefun
 
+You need not provide any interface to allow a thread to directly modify
+other threads' priorities.
+
 The priority scheduler is not used in any later project.
 
 @node Advanced Scheduler
@@ -626,7 +629,7 @@ list.
 Yes.  As long as there is a single highest-priority thread, it continues
 running until it blocks or finishes, even if it calls
 @func{thread_yield}.
-If there are multiple threads have the same highest priority,
+If multiple threads have the same highest priority,
 @func{thread_yield} should switch among them in ``round robin'' order.
 
 @item What happens to the priority of a donating thread?
@@ -652,6 +655,12 @@ processor.  It is not acceptable to wait for the next timer interrupt.
 The highest priority thread should run as soon as it is runnable,
 preempting whatever thread is currently running.
 
+@item How does @func{thread_set_priority} affect a thread receiving donations?
+
+It should do something sensible, but no particular behavior is
+required.  None of the test cases call @func{thread_set_priority} from a
+thread while it is receiving a priority donation.
+
 @item Calling @func{printf} in @func{sema_up} or @func{sema_down} reboots!
 
 @anchor{printf Reboots}