From owner-svn-src-head@freebsd.org  Sat Jan 16 04:41:41 2016
Return-Path: <owner-svn-src-head@freebsd.org>
Delivered-To: svn-src-head@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id D9427A6D9E6;
 Sat, 16 Jan 2016 04:41:41 +0000 (UTC) (envelope-from alc@FreeBSD.org)
Received: from repo.freebsd.org (repo.freebsd.org
 [IPv6:2610:1c1:1:6068::e6a:0])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id AA8921EDD;
 Sat, 16 Jan 2016 04:41:41 +0000 (UTC) (envelope-from alc@FreeBSD.org)
Received: from repo.freebsd.org ([127.0.1.37])
 by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id u0G4fehR014131;
 Sat, 16 Jan 2016 04:41:40 GMT (envelope-from alc@FreeBSD.org)
Received: (from alc@localhost)
 by repo.freebsd.org (8.15.2/8.15.2/Submit) id u0G4fem1014130;
 Sat, 16 Jan 2016 04:41:40 GMT (envelope-from alc@FreeBSD.org)
Message-Id: <201601160441.u0G4fem1014130@repo.freebsd.org>
X-Authentication-Warning: repo.freebsd.org: alc set sender to alc@FreeBSD.org
 using -f
From: Alan Cox <alc@FreeBSD.org>
Date: Sat, 16 Jan 2016 04:41:40 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org
Subject: svn commit: r294130 - head/sys/vm
X-SVN-Group: head
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
X-BeenThere: svn-src-head@freebsd.org
X-Mailman-Version: 2.1.20
Precedence: list
List-Id: SVN commit messages for the src tree for head/-current
 <svn-src-head.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-head/>
List-Post: <mailto:svn-src-head@freebsd.org>
List-Help: <mailto:svn-src-head-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 16 Jan 2016 04:41:41 -0000

Author: alc
Date: Sat Jan 16 04:41:40 2016
New Revision: 294130
URL: https://svnweb.freebsd.org/changeset/base/294130

Log:
  A fix to r292469: Iterate over the physical segments in descending rather
  than ascending order in vm_phys_alloc_contig() so that, for example, a
  sequence of contigmalloc(low=0, high=4GB) calls doesn't exhaust the supply
  of low physical memory resulting in a later contigmalloc(low=0, high=1MB)
  failure.
  
  Reported by:	cy
  Tested by:	cy
  Sponsored by:	EMC / Isilon Storage Division

Modified:
  head/sys/vm/vm_phys.c

Modified: head/sys/vm/vm_phys.c
==============================================================================
--- head/sys/vm/vm_phys.c	Sat Jan 16 02:28:07 2016	(r294129)
+++ head/sys/vm/vm_phys.c	Sat Jan 16 04:41:40 2016	(r294130)
@@ -1372,12 +1372,12 @@ restartdom:
 		return (NULL);
 	}
 	m_run = NULL;
-	for (segind = 0; segind < vm_phys_nsegs; segind++) {
+	for (segind = vm_phys_nsegs - 1; segind >= 0; segind--) {
 		seg = &vm_phys_segs[segind];
-		if (seg->start >= high)
-			break;
-		if (low >= seg->end || seg->domain != domain)
+		if (seg->start >= high || seg->domain != domain)
 			continue;
+		if (low >= seg->end)
+			break;
 		if (low <= seg->start)
 			pa_start = seg->start;
 		else