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From: Robert Watson <rwatson@FreeBSD.org>
Subject: PERFORCE change 8055 for review
To: Perforce Change Reviews <perforce@freebsd.org>
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http://people.freebsd.org/~peter/p4db/chv.cgi?CH=8055

Change 8055 by rwatson@rwatson_tislabs on 2002/03/20 07:45:41

	Add a description of the kernel module locking.
	
	Submitted by:	arr

Affected files ...

... //depot/projects/smpng/sys/design/article.sgml#18 edit

Differences ...

==== //depot/projects/smpng/sys/design/article.sgml#18 (text+ko) ====

@@ -23,7 +23,7 @@
       </author>
     </authorgroup>
 
-    <pubdate>$SMPng: //depot/projects/smpng/sys/design/article.sgml#17 $</pubdate>
+    <pubdate>$SMPng: //depot/projects/smpng/sys/design/article.sgml#18 $</pubdate>
 
     <copyright>
       <year>2002</year>
@@ -486,6 +486,23 @@
     </sect2>
 
     <sect2>
+      <title>Modules</title>
+
+      <para>For the module subsystem there exists a single lock that is
+	used to protect the shared data.  This lock is a shared/exclusive
+	(SX) lock and has a good chance of needing to be acquired (shared
+	or exclusively), there fore there are a few macros that have been
+	added to make access to the lock more easy.  These macros can be
+	located in <filename>sys/module.h</filename> and are quite basic
+	in terms of usage.  The main structures protected under this lock
+	are the <structname>module_t</structname> structures (when shared)
+	and the global <structname>modulelist_t</structname> structure,
+	modules.  One should review the related source code in
+	<filename>kern/kern_module.c</filename> to further understand the
+	locking strategy.</para>
+    </sect2>
+
+    <sect2>
       <title>Newbus Device Tree</title>
 
       <para>The newbus system will have one sx lock.  Readers will

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