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Date: Fri, 30 Jan 2004 10:59:32 +0100 (CET)
From: Divacky Roman <xdivac02@stud.fit.vutbr.cz>
Reply-To: Divacky Roman <xdivac02@stud.fit.vutbr.cz>
To: FreeBSD-gnats-submit@freebsd.org
Cc:
Subject: obreak update
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>Number:         62102
>Category:       kern
>Synopsis:       obreak update
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    alc
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          update
>Submitter-Id:   current-users
>Arrival-Date:   Fri Jan 30 02:00:34 PST 2004
>Closed-Date:    
>Last-Modified:  Thu Feb 05 00:32:35 PST 2004
>Originator:     Divacky Roman
>Release:        FreeBSD 5.2-CURRENT i386
>Organization:
home
>Environment:
System: FreeBSD eva.fit.vutbr.cz 4.9-STABLE FreeBSD 4.9-STABLE #2: Thu Nov 20 11:20:53 CET 2003 root@tereza.fit.vutbr.cz:/home/src/sys/sys-49/compile/EVA i386


	
>Description:
 A small speed up of obreak()
 we needlessly lock and unlock vm_map if new==old in obreak() this removes it
 netbsd and linux does it the same way... not big imporovement but cannot hurt
 ;)
>How-To-Repeat:
 apply this patch
>Fix:
--- vm_unix.c	Wed Nov 12 20:45:35 2003
+++ vm_unix.c.new	Mon Jan 26 15:22:27 2004
@@ -83,10 +83,15 @@
 
 	do_map_wirefuture = FALSE;
 	new = round_page((vm_offset_t)uap->nsize);
-	vm_map_lock(&vm->vm_map);
 
 	base = round_page((vm_offset_t) vm->vm_daddr);
 	old = base + ctob(vm->vm_dsize);
+
+	if (new == old)
+	   return 0;
+
+	vm_map_lock(&vm->vm_map);
+
 	if (new > base) {
 		/*
 		 * Check the resource limit, but allow a process to reduce
>Release-Note:
>Audit-Trail:
Responsible-Changed-From-To: freebsd-bugs->alc 
Responsible-Changed-By: silby 
Responsible-Changed-When: Thu Feb 5 00:32:04 PST 2004 
Responsible-Changed-Why:  
Alc would know best whether this should be changed or not. 

http://www.freebsd.org/cgi/query-pr.cgi?pr=62102 
>Unformatted:
