From owner-svn-src-all@freebsd.org Thu Jan 23 16:45:11 2020 Return-Path: Delivered-To: svn-src-all@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 0967F1F71C8; Thu, 23 Jan 2020 16:45:11 +0000 (UTC) (envelope-from markj@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 483Sn26WLmz3MQY; Thu, 23 Jan 2020 16:45:10 +0000 (UTC) (envelope-from markj@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 mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id D642719B38; Thu, 23 Jan 2020 16:45:10 +0000 (UTC) (envelope-from markj@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id 00NGjADv086144; Thu, 23 Jan 2020 16:45:10 GMT (envelope-from markj@FreeBSD.org) Received: (from markj@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 00NGjArH086143; Thu, 23 Jan 2020 16:45:10 GMT (envelope-from markj@FreeBSD.org) Message-Id: <202001231645.00NGjArH086143@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: markj set sender to markj@FreeBSD.org using -f From: Mark Johnston Date: Thu, 23 Jan 2020 16:45:10 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r357052 - head/sys/vm X-SVN-Group: head X-SVN-Commit-Author: markj X-SVN-Commit-Paths: head/sys/vm X-SVN-Commit-Revision: 357052 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 23 Jan 2020 16:45:11 -0000 Author: markj Date: Thu Jan 23 16:45:10 2020 New Revision: 357052 URL: https://svnweb.freebsd.org/changeset/base/357052 Log: vm_map_submap(): Avoid unnecessary clipping. A submap can only be created from an entry spanning the entire request range. In particular, if vm_map_lookup_entry() returns false or the returned entry contains "end". Since the only use of submaps in FreeBSD is for the static pipe and execve argument KVA maps, this has no functional effect. Github PR: https://github.com/freebsd/freebsd/pull/420 Submitted by: Wuyang Chung (original) Reviewed by: dougm, kib MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D23299 Modified: head/sys/vm/vm_map.c Modified: head/sys/vm/vm_map.c ============================================================================== --- head/sys/vm/vm_map.c Thu Jan 23 16:36:58 2020 (r357051) +++ head/sys/vm/vm_map.c Thu Jan 23 16:45:10 2020 (r357052) @@ -2477,19 +2477,12 @@ vm_map_submap( vm_map_unlock(submap); vm_map_lock(map); - VM_MAP_RANGE_CHECK(map, start, end); - - if (vm_map_lookup_entry(map, start, &entry)) { + if (vm_map_lookup_entry(map, start, &entry) && entry->end >= end && + (entry->eflags & MAP_ENTRY_COW) == 0 && + entry->object.vm_object == NULL) { vm_map_clip_start(map, entry, start); - } else - entry = vm_map_entry_succ(entry); - - vm_map_clip_end(map, entry, end); - - if ((entry->start == start) && (entry->end == end) && - ((entry->eflags & MAP_ENTRY_COW) == 0) && - (entry->object.vm_object == NULL)) { + vm_map_clip_end(map, entry, end); entry->object.sub_map = submap; entry->eflags |= MAP_ENTRY_IS_SUB_MAP; result = KERN_SUCCESS;