Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262231AbTIMWS0 (ORCPT ); Sat, 13 Sep 2003 18:18:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262232AbTIMWS0 (ORCPT ); Sat, 13 Sep 2003 18:18:26 -0400 Received: from natsmtp00.webmailer.de ([192.67.198.74]:17300 "EHLO post.webmailer.de") by vger.kernel.org with ESMTP id S262231AbTIMWSZ (ORCPT ); Sat, 13 Sep 2003 18:18:25 -0400 Message-Id: <200309132218.h8DMIBHj007826@post.webmailer.de> From: Arnd Bergmann Subject: Re: [patch] Make slab allocator work with SLAB_MUST_HWCACHE_ALIGN To: Manfred Spraul , linux-kernel@vger.kernel.org, Martin Schwidefsky , Ravikiran G Thirumalai Date: Sun, 14 Sep 2003 00:18:02 +0200 References: User-Agent: KNode/0.7.2 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7Bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1197 Lines: 21 Manfred Spraul wrote: > But back to the patch that started this thread: Do you still need the > ability to set an explicit alignment for slab allocations? If yes, then > I'd polish my patch, double check all kmem_cache_create callers and then > send the patch to akpm. Otherwise I'd wait - the patch is not a bugfix. The explicit alignment would be my preferred way to fix slab debugging on s390. We still have the problem that practically all s390 device drivers need 64-bit alignment on slab allocations. Our current hack is to redefine BYTES_PER_WORD in slab.c to 8, but what I'd like to see is a per-architecture alignment in kmem_cache_init that would default to 8 on s390 and to sizeof(long) otherwise. Using the current SLAB_MUST_HWCACHE_ALIGN is not an option since it wastes a lot of memory with our 2048-bit L1 cache lines. I'd also like to avoid creating special slab caches for anything that needs 8-byte alignment. Arnd <>< - 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/