From: Ben Pfaff <blp@cs.stanford.edu>
Date: Mon, 2 Apr 2007 07:23:22 +0000 (+0000)
Subject: Improve comment on thread_unblock().
X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=47ed78ddbcd6133d49b8ba11e7bbfcc2cf9f6ea4;p=pintos-anon

Improve comment on thread_unblock().
Suggested by Godmar Back.
---

diff --git a/src/threads/thread.c b/src/threads/thread.c
index f6768c0..92d1aa8 100644
--- a/src/threads/thread.c
+++ b/src/threads/thread.c
@@ -216,7 +216,12 @@ thread_block (void)
 
 /* Transitions a blocked thread T to the ready-to-run state.
    This is an error if T is not blocked.  (Use thread_yield() to
-   make the running thread ready.) */
+   make the running thread ready.)
+
+   This function does not preempt the running thread.  This can
+   be important: if the caller had disabled interrupts itself,
+   it may expect that it can atomically unblock a thread and
+   update other data. */
 void
 thread_unblock (struct thread *t) 
 {