From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264385AbTDPOVu (for ); Wed, 16 Apr 2003 10:21:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264386AbTDPOVu (for ); Wed, 16 Apr 2003 10:21:50 -0400 Received: from pizda.ninka.net ([216.101.162.242]:32901 "EHLO pizda.ninka.net") by vger.kernel.org with ESMTP id S264385AbTDPOVu (for ); Wed, 16 Apr 2003 10:21:50 -0400 Date: Wed, 16 Apr 2003 07:26:38 -0700 (PDT) Message-Id: <20030416.072638.65480350.davem@redhat.com> To: ak@muc.de Cc: akpm@digeo.com, linux-kernel@vger.kernel.org, anton@samba.org, schwidefsky@de.ibm.com, davidm@hpl.hp.com, matthew@wil.cx, ralf@linux-mips.org, rth@redhat.com Subject: Re: Reduce struct page by 8 bytes on 64bit From: "David S. Miller" In-Reply-To: <20030416140715.GA2159@averell> References: <20030415112430.GA21072@averell> <20030416.054521.26525548.davem@redhat.com> <20030416140715.GA2159@averell> X-FalunGong: Information control. X-Mailer: Mew version 2.1 on Emacs 21.1 / Mule 5.0 (SAKAKI) 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 From: Andi Kleen Date: Wed, 16 Apr 2003 16:07:15 +0200 How so? Of course I could write an generic set_bit32, but the question is if these bit operations would be still atomic on SMP and not conflict with fields occuping the same 8 byte slot. I remember you flaming someone some time ago because he used set_bit in an atomic fashion on a type smaller than unsigned long for example. It's OK if you align the pointer to 8 bytes, and subsequently the bit offset as appropriate. :-)