Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759810AbXJLKhc (ORCPT ); Fri, 12 Oct 2007 06:37:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751002AbXJLKhY (ORCPT ); Fri, 12 Oct 2007 06:37:24 -0400 Received: from viefep18-int.chello.at ([213.46.255.22]:46244 "EHLO viefep20-int.chello.at" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750861AbXJLKhX (ORCPT ); Fri, 12 Oct 2007 06:37:23 -0400 Subject: Re: [PATCH] mm: avoid dirtying shared mappings on mlock From: Peter Zijlstra To: Nick Piggin Cc: Suleiman Souhlal , Andrew Morton , linux-kernel@vger.kernel.org, Suleiman Souhlal , linux-mm , hugh In-Reply-To: <200710120257.05960.nickpiggin@yahoo.com.au> References: <11854939641916-git-send-email-ssouhlal@FreeBSD.org> <69AF9B2A-6AA7-4078-B0A2-BE3D4914AEDC@FreeBSD.org> <1192179805.27435.6.camel@twins> <200710120257.05960.nickpiggin@yahoo.com.au> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-5U/g6opYOoJT2WQRDHyS" Date: Fri, 12 Oct 2007 12:37:19 +0200 Message-Id: <1192185439.27435.19.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.10.1 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1703 Lines: 51 --=-5U/g6opYOoJT2WQRDHyS Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Fri, 2007-10-12 at 02:57 +1000, Nick Piggin wrote: > On Friday 12 October 2007 19:03, Peter Zijlstra wrote: > > Subject: mm: avoid dirtying shared mappings on mlock > > > > Suleiman noticed that shared mappings get dirtied when mlocked. > > Avoid this by teaching make_pages_present about this case. > > > > Signed-off-by: Peter Zijlstra > > Acked-by: Suleiman Souhlal >=20 > Umm, I don't see the other piece of this thread, so I don't > know what the actual problem was. >=20 > But I would really rather not do this. If you do this, then you > now can get random SIGBUSes when you write into the memory if it > can't allocate blocks or ... (some other filesystem specific > condition). I'm not getting this, make_pages_present() only has to ensure all the pages are read from disk and in memory. How is this different from a read-scan? The pages will still be read-only due to dirty tracking, so the first write will still do page_mkwrite(). --=-5U/g6opYOoJT2WQRDHyS Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQBHD05fXA2jU0ANEf4RAu2gAJ9NtXDA2E6emN+/OJpCt9TPYCcHOgCgkLUz Nzg60UY4sfss94SPRiG2eYI= =UOp0 -----END PGP SIGNATURE----- --=-5U/g6opYOoJT2WQRDHyS-- - 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/