Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263628AbTHZMNr (ORCPT ); Tue, 26 Aug 2003 08:13:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263633AbTHZMNr (ORCPT ); Tue, 26 Aug 2003 08:13:47 -0400 Received: from lmail.actcom.co.il ([192.114.47.13]:16351 "EHLO smtp1.actcom.net.il") by vger.kernel.org with ESMTP id S263628AbTHZMNp (ORCPT ); Tue, 26 Aug 2003 08:13:45 -0400 Date: Tue, 26 Aug 2003 12:02:48 +0300 From: Muli Ben-Yehuda To: Andrew Morton Cc: arjanv@redhat.com, mingo@redhat.com, rusty@rustcorp.com.au, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] Futex non-page-pinning fix Message-ID: <20030826090248.GB16407@actcom.co.il> References: <20030825231449.7de28ba6.akpm@osdl.org> <20030826000218.2ceaea1d.akpm@osdl.org> <1061884611.2982.4.camel@laptop.fenrus.com> <20030826080759.GK13390@actcom.co.il> <20030826012529.7be1955f.akpm@osdl.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="zx4FCpZtqtKETZ7O" Content-Disposition: inline In-Reply-To: <20030826012529.7be1955f.akpm@osdl.org> User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1504 Lines: 48 --zx4FCpZtqtKETZ7O Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Aug 26, 2003 at 01:25:29AM -0700, Andrew Morton wrote: > Muli Ben-Yehuda wrote: > > How about combining something that's shared to all of the threads that > > share a futex but not system wide (the mm?) with something simple that > > won't change, like the page offset? >=20 > The mm's could well be independent. I assumed all threads sharing a futex share an mm since you suggested hashing on mm + vaddr? =20 > Some userspace help would be needed to avoid defeating the hash. In the > case where a bunch of threads with a shared mm are waiting on the same > futex things should automatically be OK. Userspace help would be fine, but relying only on userspace could lead to an immediate DoS by forcing the hash to always hash to the same bucket. --=20 Muli Ben-Yehuda http://www.mulix.org --zx4FCpZtqtKETZ7O Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (GNU/Linux) iD8DBQE/SyI4KRs727/VN8sRAme4AJ0ZjVDbZZFCzkHkNd2MeLDwNReQ7ACdH2o5 M8Z+iSdiNm2H2pUm9D9sgIE= =1T0F -----END PGP SIGNATURE----- --zx4FCpZtqtKETZ7O-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/