From owner-svn-src-head@freebsd.org Wed Jun 1 20:39:01 2016 Return-Path: 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 639CAB61B55; Wed, 1 Jun 2016 20:39:01 +0000 (UTC) (envelope-from kib@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 1753D11D8; Wed, 1 Jun 2016 20:39:01 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id u51Kd0ob023340; Wed, 1 Jun 2016 20:39:00 GMT (envelope-from kib@FreeBSD.org) Received: (from kib@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id u51Kd0Zs023339; Wed, 1 Jun 2016 20:39:00 GMT (envelope-from kib@FreeBSD.org) Message-Id: <201606012039.u51Kd0Zs023339@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: kib set sender to kib@FreeBSD.org using -f From: Konstantin Belousov Date: Wed, 1 Jun 2016 20:39:00 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r301165 - 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: 2.1.22 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: Wed, 01 Jun 2016 20:39:01 -0000 Author: kib Date: Wed Jun 1 20:39:00 2016 New Revision: 301165 URL: https://svnweb.freebsd.org/changeset/base/301165 Log: If the fast path unbusy in vm_page_replace() fails, slow path needs to acquire the page lock, which recurses. Avoid the recursion by reusing the code from vm_page_remove() in a new helper vm_page_xunbusy_maybelocked(). Reviewed by: alc Sponsored by: The FreeBSD Foundation Modified: head/sys/vm/vm_page.c Modified: head/sys/vm/vm_page.c ============================================================================== --- head/sys/vm/vm_page.c Wed Jun 1 20:30:31 2016 (r301164) +++ head/sys/vm/vm_page.c Wed Jun 1 20:39:00 2016 (r301165) @@ -759,6 +759,22 @@ vm_page_trysbusy(vm_page_t m) } } +static void +vm_page_xunbusy_maybelocked(vm_page_t m) +{ + bool lockacq; + + vm_page_assert_xbusied(m); + + lockacq = !mtx_owned(vm_page_lockptr(m)); + if (lockacq) + vm_page_lock(m); + vm_page_flash(m); + atomic_store_rel_int(&m->busy_lock, VPB_UNBUSIED); + if (lockacq) + vm_page_unlock(m); +} + /* * vm_page_xunbusy_hard: * @@ -1197,25 +1213,14 @@ void vm_page_remove(vm_page_t m) { vm_object_t object; - boolean_t lockacq; if ((m->oflags & VPO_UNMANAGED) == 0) - vm_page_lock_assert(m, MA_OWNED); + vm_page_assert_locked(m); if ((object = m->object) == NULL) return; VM_OBJECT_ASSERT_WLOCKED(object); - if (vm_page_xbusied(m)) { - lockacq = FALSE; - if ((m->oflags & VPO_UNMANAGED) != 0 && - !mtx_owned(vm_page_lockptr(m))) { - lockacq = TRUE; - vm_page_lock(m); - } - vm_page_flash(m); - atomic_store_rel_int(&m->busy_lock, VPB_UNBUSIED); - if (lockacq) - vm_page_unlock(m); - } + if (vm_page_xbusied(m)) + vm_page_xunbusy_maybelocked(m); /* * Now remove from the object's list of backed pages. @@ -1340,7 +1345,7 @@ vm_page_replace(vm_page_t mnew, vm_objec TAILQ_REMOVE(&object->memq, mold, listq); mold->object = NULL; - vm_page_xunbusy(mold); + vm_page_xunbusy_maybelocked(mold); /* * The object's resident_page_count does not change because we have