From owner-freebsd-current@FreeBSD.ORG Tue Jan 3 10:26:41 2012 Return-Path: Delivered-To: current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id AF48D1065670; Tue, 3 Jan 2012 10:26:41 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from mail.zoral.com.ua (mx0.zoral.com.ua [91.193.166.200]) by mx1.freebsd.org (Postfix) with ESMTP id 0F2EC8FC15; Tue, 3 Jan 2012 10:26:40 +0000 (UTC) Received: from alf.home (alf.kiev.zoral.com.ua [10.1.1.177]) by mail.zoral.com.ua (8.14.2/8.14.2) with ESMTP id q03AQ8jT040541 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 3 Jan 2012 12:26:08 +0200 (EET) (envelope-from kostikbel@gmail.com) Received: from alf.home (kostik@localhost [127.0.0.1]) by alf.home (8.14.5/8.14.5) with ESMTP id q03AQ7Km042092; Tue, 3 Jan 2012 12:26:07 +0200 (EET) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by alf.home (8.14.5/8.14.5/Submit) id q03AQ7GN042091; Tue, 3 Jan 2012 12:26:07 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: alf.home: kostik set sender to kostikbel@gmail.com using -f Date: Tue, 3 Jan 2012 12:26:07 +0200 From: Kostik Belousov To: Don Lewis Message-ID: <20120103102607.GO50300@deviant.kiev.zoral.com.ua> References: <20120103091819.GN50300@deviant.kiev.zoral.com.ua> <201201030945.q039jQ4j007027@gw.catspoiler.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="Kg9bXG3rqf9MxIZW" Content-Disposition: inline In-Reply-To: <201201030945.q039jQ4j007027@gw.catspoiler.org> User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: clamav-milter 0.95.2 at skuns.kiev.zoral.com.ua X-Virus-Status: Clean X-Spam-Status: No, score=-3.9 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on skuns.kiev.zoral.com.ua Cc: attilio@freebsd.org, flo@freebsd.org, current@freebsd.org, mckusick@mckusick.com, phk@phk.freebsd.dk, seanbru@yahoo-inc.com Subject: Re: dogfooding over in clusteradm land X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 03 Jan 2012 10:26:41 -0000 --Kg9bXG3rqf9MxIZW Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jan 03, 2012 at 01:45:26AM -0800, Don Lewis wrote: > On 3 Jan, Kostik Belousov wrote: >=20 > > This sounds very plausible. I think that there is no sense in restarting > > the scan if it is requested in async mode at all. See below. > >=20 > > Would be thrilled if this finally solves the svn2cvs issues. > >=20 > > commit 41aaafe5e3be5387949f303b8766da64ee4a521f > > Author: Kostik Belousov > > Date: Tue Jan 3 11:16:30 2012 +0200 > >=20 > > Do not restart the scan in vm_object_page_clean() if requested > > mode is async. > > =20 > > Proposed by: truckman > >=20 > > diff --git a/sys/vm/vm_object.c b/sys/vm/vm_object.c > > index 716916f..52fc08b 100644 > > --- a/sys/vm/vm_object.c > > +++ b/sys/vm/vm_object.c > > @@ -841,7 +841,8 @@ rescan: > > if (p->valid =3D=3D 0) > > continue; > > if (vm_page_sleep_if_busy(p, TRUE, "vpcwai")) { > > - if (object->generation !=3D curgeneration) > > + if ((flags & OBJPC_SYNC) !=3D 0 && > > + object->generation !=3D curgeneration) > > goto rescan; > > np =3D vm_page_find_least(object, pi); > > continue; >=20 > I wonder if it would make more sense to just skip the busy pages in > async mode instead of sleeping ... >=20 It would be too much weakening the guarantee of the vfs_msync(MNT_NOWAIT) to not write such pages, IMO. Busy state indeed means that the page most likely undergoing the i/o, but in case it is not, we would not write it at all. Lets see whether the change alone helps. Do you agree ? --Kg9bXG3rqf9MxIZW Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (FreeBSD) iEYEARECAAYFAk8C178ACgkQC3+MBN1Mb4hHgACdE/rxPa1jc/HtDf0e5lllCt1F 5oMAn0w8LJtV/gHa1ogbWvGypHTkxiAF =f+AK -----END PGP SIGNATURE----- --Kg9bXG3rqf9MxIZW--