From owner-svn-src-head@FreeBSD.ORG Mon Oct 4 16:49:41 2010 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 55B52106566B; Mon, 4 Oct 2010 16:49:41 +0000 (UTC) (envelope-from alc@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id 39A0B8FC14; Mon, 4 Oct 2010 16:49:41 +0000 (UTC) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id o94GnfET020350; Mon, 4 Oct 2010 16:49:41 GMT (envelope-from alc@svn.freebsd.org) Received: (from alc@localhost) by svn.freebsd.org (8.14.3/8.14.3/Submit) id o94Gnfa0020348; Mon, 4 Oct 2010 16:49:41 GMT (envelope-from alc@svn.freebsd.org) Message-Id: <201010041649.o94Gnfa0020348@svn.freebsd.org> From: Alan Cox Date: Mon, 4 Oct 2010 16:49:41 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Subject: svn commit: r213408 - head/sys/vm X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 04 Oct 2010 16:49:41 -0000 Author: alc Date: Mon Oct 4 16:49:40 2010 New Revision: 213408 URL: http://svn.freebsd.org/changeset/base/213408 Log: If vm_map_find() is asked to allocate a superpage-aligned region of virtual addresses that is greater than a superpage in size but not a multiple of the superpage size, then vm_map_find() is not always expanding the kernel pmap to support the last few small pages being allocated. These failures are not commonplace, so this was first noticed by someone porting FreeBSD to a new architecture. Previously, we grew the kernel page table in vm_map_findspace() when we found the first available virtual address. This works most of the time because we always grow the kernel pmap or page table by an amount that is a multiple of the superpage size. Now, instead, we defer the call to pmap_growkernel() until we are committed to a range of virtual addresses in vm_map_insert(). In general, there is another reason to prefer calling pmap_growkernel() in vm_map_insert(). It makes it possible for someone to do the equivalent of an mmap(MAP_FIXED) on the kernel map. Reported by: Svatopluk Kraus Reviewed by: kib@ MFC after: 3 weeks Modified: head/sys/vm/vm_map.c Modified: head/sys/vm/vm_map.c ============================================================================== --- head/sys/vm/vm_map.c Mon Oct 4 16:07:48 2010 (r213407) +++ head/sys/vm/vm_map.c Mon Oct 4 16:49:40 2010 (r213408) @@ -1163,6 +1163,9 @@ vm_map_insert(vm_map_t map, vm_object_t } charged: + /* Expand the kernel pmap, if necessary. */ + if (map == kernel_map && end > kernel_vm_end) + pmap_growkernel(end); if (object != NULL) { /* * OBJ_ONEMAPPING must be cleared unless this mapping @@ -1299,7 +1302,7 @@ vm_map_findspace(vm_map_t map, vm_offset vm_offset_t *addr) /* OUT */ { vm_map_entry_t entry; - vm_offset_t end, st; + vm_offset_t st; /* * Request must fit within min/max VM address and must avoid @@ -1313,7 +1316,7 @@ vm_map_findspace(vm_map_t map, vm_offset /* Empty tree means wide open address space. */ if (map->root == NULL) { *addr = start; - goto found; + return (0); } /* @@ -1323,7 +1326,7 @@ vm_map_findspace(vm_map_t map, vm_offset map->root = vm_map_entry_splay(start, map->root); if (start + length <= map->root->start) { *addr = start; - goto found; + return (0); } /* @@ -1334,7 +1337,7 @@ vm_map_findspace(vm_map_t map, vm_offset st = (start > map->root->end) ? start : map->root->end; if (length <= map->root->end + map->root->adj_free - st) { *addr = st; - goto found; + return (0); } /* With max_free, can immediately tell if no solution. */ @@ -1352,22 +1355,13 @@ vm_map_findspace(vm_map_t map, vm_offset entry = entry->left; else if (entry->adj_free >= length) { *addr = entry->end; - goto found; + return (0); } else entry = entry->right; } /* Can't get here, so panic if we do. */ panic("vm_map_findspace: max_free corrupt"); - -found: - /* Expand the kernel pmap, if necessary. */ - if (map == kernel_map) { - end = round_page(*addr + length); - if (end > kernel_vm_end) - pmap_growkernel(end); - } - return (0); } int