From: Matt Mackall Subject: Re: [BUG] SLOB breaks Crypto Date: Wed, 19 May 2010 09:11:47 -0500 Message-ID: <1274278307.11603.1264.camel@calx> References: <1274211235.11603.1205.camel@calx> <20100518.135945.180391159.davem@davemloft.net> <20100518.142021.135951273.davem@davemloft.net> <1274224834.6930.8361.camel@macbook.infradead.org> <20100519010524.GB18813@gondor.apana.org.au> <1274253269.6930.9325.camel@macbook.infradead.org> <1274269236.6930.9930.camel@macbook.infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: David Woodhouse , Herbert Xu , David Miller , penberg@cs.helsinki.fi, ken@codelabs.ch, michael-dev@fami-braun.de, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, anemo@mba.ocn.ne.jp To: Geert Uytterhoeven Return-path: Received: from waste.org ([173.11.57.241]:50954 "EHLO waste.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751873Ab0ESOLv (ORCPT ); Wed, 19 May 2010 10:11:51 -0400 In-Reply-To: Sender: linux-crypto-owner@vger.kernel.org List-ID: On Wed, 2010-05-19 at 13:50 +0200, Geert Uytterhoeven wrote: > On Wed, May 19, 2010 at 13:40, David Woodhouse = wrote: > > On Wed, 2010-05-19 at 13:32 +0200, Geert Uytterhoeven wrote: > >> Instead of having (different) defaults in sl[aou]b, perhaps we sho= uld > >> just remove the defaults completely, to ensure all architectures s= et > >> ARCH_SLAB_MINALIGN to the correct value? > > > > What is 'correct'? The architecture sets it to the minimum value th= at it > > can cope with, according to its own alignment constraints (and DMA/= cache > > constraints, in the case of ARCH_KMALLOC_MINALIGN). > > > > Some architectures don't _have_ any minimum required alignment, so = they > > have no need to set it. If the architecture _does_ specify a minimu= m, > > the allocators must honour it. Otherwise, they're free to do their = own > > thing. And slob chooses to use a smaller alignment than slab and sl= ub > > do, in accordance with its design and its raison d'=C3=AAtre. >=20 > Currently 7 out of 20+ architectures set it. > Any bets on how many are missing, but should set it? I still think we should add it to all of them as positive documentation that this issue has been considered. And then make the kernel not compile without it so new arch implementors can't miss it. --=20 Mathematics is the supreme nostalgia of our time.