Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761533AbXIMCFx (ORCPT ); Wed, 12 Sep 2007 22:05:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751276AbXIMCFq (ORCPT ); Wed, 12 Sep 2007 22:05:46 -0400 Received: from ozlabs.org ([203.10.76.45]:33013 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750922AbXIMCFp (ORCPT ); Wed, 12 Sep 2007 22:05:45 -0400 Subject: Re: [PATCH 15/15] Add DEFINE_SPUFS_ATTRIBUTE() From: Michael Ellerman Reply-To: michael@ellerman.id.au To: Arnd Bergmann Cc: linuxppc-dev@ozlabs.org, Jeremy Kerr , linux-kernel@vger.kernel.org In-Reply-To: <200709121047.05471.arnd@arndb.de> References: <2900ea4dbfd6e98e71ff400cbd25d1283a278972.1189583010.git.michael@ellerman.id.au> <1189583353.17835.22.camel@concordia.ozlabs.ibm.com> <200709121047.05471.arnd@arndb.de> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-oYh9g2k3bx1l2wvBffuN" Date: Thu, 13 Sep 2007 12:05:41 +1000 Message-Id: <1189649141.19087.13.camel@concordia.ozlabs.ibm.com> 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: 2693 Lines: 80 --=-oYh9g2k3bx1l2wvBffuN Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Wed, 2007-09-12 at 10:47 +0200, Arnd Bergmann wrote: > On Wednesday 12 September 2007, Michael Ellerman wrote: > > On Wed, 2007-09-12 at 17:43 +1000, Michael Ellerman wrote: > > > This patch adds DEFINE_SPUFS_ATTRIBUTE(), a wraper around > > > DEFINE_SIMPLE_ATTRIBUTE which does the specified locking for the get > > > routine for us. > > >=20 > > > Unfortunately we need two get routines (a locked and unlocked version= ) to > > > support the coredump code. This patch hides one of those (the locked = version) > > > inside the macro foo. >=20 > >=20 > > jk said: > > > "Good god man!" > >=20 > > Yeah, I'm a bit lukewarm on this one. But the diffstat is nice, 50% cod= e > > reduction ain't bad :) >=20 > Have you looked at the change in object code size? I would expect the > object code to actually become bigger. I also think that it hurts > readability rather than help it. Yeah I did, it's smaller actually: text data bss dec hex filename 44898 17804 120 62822 f566 spufs-before.o 44886 17804 120 62810 f55a spufs-after.o > Maybe a better solution is to change the core dump code to not > require the mutex to be held in the first place. By the time > we get to call the get functions, it should already be in > saved state and no longer be able to get scheduled, so we might > not actually need all the extra tricks with avoiding the > mutex to be taken again. Well that'd be nice, but I don't see anywhere that that happens. AFAICT the acquire we do in the first coredump callback is the first the SPU contexts know about their PPE process dying. And spufs is still live, so I think we definitely need to grab the mutex, or we might race with userspace accessing spufs files. cheers --=20 Michael Ellerman OzLabs, IBM Australia Development Lab wwweb: http://michael.ellerman.id.au phone: +61 2 6212 1183 (tie line 70 21183) We do not inherit the earth from our ancestors, we borrow it from our children. - S.M.A.R.T Person --=-oYh9g2k3bx1l2wvBffuN 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) iD8DBQBG6Jr1dSjSd0sB4dIRAmdjAKCI23oMOPJddZy9CBS8dLfeLMmH7QCgnpLf AGfWajn6wu1RqSSRhoAvRRs= =W2xN -----END PGP SIGNATURE----- --=-oYh9g2k3bx1l2wvBffuN-- - 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/