From owner-svn-src-all@freebsd.org Sun Dec 15 02:02:27 2019 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 BD92D1DE34D; Sun, 15 Dec 2019 02:02:27 +0000 (UTC) (envelope-from jeff@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 47b72W4jG6z41Fp; Sun, 15 Dec 2019 02:02:27 +0000 (UTC) (envelope-from jeff@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 9CB746011; Sun, 15 Dec 2019 02:02:27 +0000 (UTC) (envelope-from jeff@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id xBF22RNF052433; Sun, 15 Dec 2019 02:02:27 GMT (envelope-from jeff@FreeBSD.org) Received: (from jeff@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id xBF22R6d052432; Sun, 15 Dec 2019 02:02:27 GMT (envelope-from jeff@FreeBSD.org) Message-Id: <201912150202.xBF22R6d052432@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: jeff set sender to jeff@FreeBSD.org using -f From: Jeff Roberson Date: Sun, 15 Dec 2019 02:02:27 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r355764 - head/sys/vm X-SVN-Group: head X-SVN-Commit-Author: jeff X-SVN-Commit-Paths: head/sys/vm X-SVN-Commit-Revision: 355764 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: Sun, 15 Dec 2019 02:02:27 -0000 Author: jeff Date: Sun Dec 15 02:02:27 2019 New Revision: 355764 URL: https://svnweb.freebsd.org/changeset/base/355764 Log: Slightly optimize locking in vm_map_copy_swap_entry(). Anonymous objects require the object lock to synchronize collapse. Other swap objects such as tmpfs do not. Reported by: mjg Reviewed by: kib, markj Differential Revision: https://reviews.freebsd.org/D22747 Modified: head/sys/vm/vm_map.c Modified: head/sys/vm/vm_map.c ============================================================================== --- head/sys/vm/vm_map.c Sun Dec 15 02:00:32 2019 (r355763) +++ head/sys/vm/vm_map.c Sun Dec 15 02:02:27 2019 (r355764) @@ -3870,15 +3870,19 @@ vm_map_copy_swap_object(vm_map_entry_t src_entry, vm_m int charged; src_object = src_entry->object.vm_object; - VM_OBJECT_WLOCK(src_object); charged = ENTRY_CHARGED(src_entry); - vm_object_collapse(src_object); - if ((src_object->flags & OBJ_ONEMAPPING) != 0) { - vm_object_split(src_entry); - src_object = src_entry->object.vm_object; - } - vm_object_reference_locked(src_object); - vm_object_clear_flag(src_object, OBJ_ONEMAPPING); + if ((src_object->flags & OBJ_ANON) != 0) { + VM_OBJECT_WLOCK(src_object); + vm_object_collapse(src_object); + if ((src_object->flags & OBJ_ONEMAPPING) != 0) { + vm_object_split(src_entry); + src_object = src_entry->object.vm_object; + } + vm_object_reference_locked(src_object); + vm_object_clear_flag(src_object, OBJ_ONEMAPPING); + VM_OBJECT_WUNLOCK(src_object); + } else + vm_object_reference(src_object); if (src_entry->cred != NULL && !(src_entry->eflags & MAP_ENTRY_NEEDS_COPY)) { KASSERT(src_object->cred == NULL, @@ -3887,7 +3891,6 @@ vm_map_copy_swap_object(vm_map_entry_t src_entry, vm_m src_object->cred = src_entry->cred; src_object->charge = size; } - VM_OBJECT_WUNLOCK(src_object); dst_entry->object.vm_object = src_object; if (charged) { cred = curthread->td_ucred;