From: Geert Uytterhoeven Subject: Re: [BUG] SLOB breaks Crypto Date: Wed, 19 May 2010 13:50:52 +0200 Message-ID: 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: Herbert Xu , David Miller , penberg@cs.helsinki.fi, mpm@selenic.com, ken@codelabs.ch, michael-dev@fami-braun.de, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, anemo@mba.ocn.ne.jp To: David Woodhouse Return-path: Received: from mail-wy0-f174.google.com ([74.125.82.174]:55899 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754021Ab0ESLuz convert rfc822-to-8bit (ORCPT ); Wed, 19 May 2010 07:50:55 -0400 In-Reply-To: <1274269236.6930.9930.camel@macbook.infradead.org> Sender: linux-crypto-owner@vger.kernel.org List-ID: On Wed, May 19, 2010 at 13:40, David Woodhouse wr= ote: > On Wed, 2010-05-19 at 13:32 +0200, Geert Uytterhoeven wrote: >> Instead of having (different) defaults in sl[aou]b, perhaps we shoul= d >> just remove the defaults completely, to ensure all architectures set >> ARCH_SLAB_MINALIGN to the correct value? > > What is 'correct'? The architecture sets it to the minimum value that= it > can cope with, according to its own alignment constraints (and DMA/ca= che > constraints, in the case of ARCH_KMALLOC_MINALIGN). > > Some architectures don't _have_ any minimum required alignment, so th= ey > have no need to set it. If the architecture _does_ specify a minimum, > the allocators must honour it. Otherwise, they're free to do their ow= n > thing. And slob chooses to use a smaller alignment than slab and slub > do, in accordance with its design and its raison d'=C3=AAtre. Currently 7 out of 20+ architectures set it. Any bets on how many are missing, but should set it? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-= m68k.org In personal conversations with technical people, I call myself a hacker= =2E But when I'm talking to journalists I just say "programmer" or something li= ke that. -- Linus Torvalds