From owner-svn-src-user@freebsd.org Mon Aug 1 22:53:30 2016 Return-Path: Delivered-To: svn-src-user@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 0DEC1BACA45 for ; Mon, 1 Aug 2016 22:53:30 +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 CE0591254; Mon, 1 Aug 2016 22:53:29 +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 u71MrTfW029886; Mon, 1 Aug 2016 22:53:29 GMT (envelope-from alc@FreeBSD.org) Received: (from alc@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id u71MrT3q029885; Mon, 1 Aug 2016 22:53:29 GMT (envelope-from alc@FreeBSD.org) Message-Id: <201608012253.u71MrT3q029885@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: alc set sender to alc@FreeBSD.org using -f From: Alan Cox Date: Mon, 1 Aug 2016 22:53:29 +0000 (UTC) To: src-committers@freebsd.org, svn-src-user@freebsd.org Subject: svn commit: r303649 - user/alc/PQ_LAUNDRY/sys/vm X-SVN-Group: user MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-user@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: "SVN commit messages for the experimental " user" src tree" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 01 Aug 2016 22:53:30 -0000 Author: alc Date: Mon Aug 1 22:53:28 2016 New Revision: 303649 URL: https://svnweb.freebsd.org/changeset/base/303649 Log: Update a couple comments. In particular, explain why we dequeue the page early in vm_pageout_scan(). Modified: user/alc/PQ_LAUNDRY/sys/vm/vm_pageout.c Modified: user/alc/PQ_LAUNDRY/sys/vm/vm_pageout.c ============================================================================== --- user/alc/PQ_LAUNDRY/sys/vm/vm_pageout.c Mon Aug 1 22:41:50 2016 (r303648) +++ user/alc/PQ_LAUNDRY/sys/vm/vm_pageout.c Mon Aug 1 22:53:28 2016 (r303649) @@ -948,9 +948,8 @@ vm_pageout_launder(struct vm_domain *vmd } /* - * We unlock the laundry queue, invalidating the - * 'next' pointer. Use our marker to remember our - * place. + * Unlock the laundry queue, invalidating the 'next' pointer. + * Use a marker to remember our place in the laundry queue. */ TAILQ_INSERT_AFTER(&pq->pq_pl, m, &vmd->vmd_laundry_marker, plinks.q); @@ -1333,9 +1332,12 @@ unlock_page: KASSERT(m->hold_count == 0, ("Held page %p", m)); /* - * We unlock the inactive page queue, invalidating the - * 'next' pointer. Use our marker to remember our - * place. + * Dequeue the inactive page and unlock the inactive page + * queue, invalidating the 'next' pointer. Dequeueing the + * page here avoids a later reacquisition (and release) of + * the inactive page queue lock when vm_page_activate(), + * vm_page_free(), or vm_page_launder() is called. Use a + * marker to remember our place in the inactive queue. */ TAILQ_INSERT_AFTER(&pq->pq_pl, m, &vmd->vmd_marker, plinks.q); vm_page_dequeue_locked(m);