From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757223AbZJ3NRH (ORCPT ); Fri, 30 Oct 2009 09:17:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757202AbZJ3NRG (ORCPT ); Fri, 30 Oct 2009 09:17:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45625 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756397AbZJ3NRF (ORCPT ); Fri, 30 Oct 2009 09:17:05 -0400 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <4AE7ECC2.8050202@orcon.net.nz> References: <4AE7ECC2.8050202@orcon.net.nz> To: Michael Cree Cc: dhowells@redhat.com, linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, rth@twiddle.net, ink@jurassic.park.msu.ru Subject: Re: Alpha: suspicious compiler warning in entry.S Date: Fri, 30 Oct 2009 13:16:59 +0000 Message-ID: <5962.1256908619@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Michael Cree wrote: > On the assumption that it is important to include the TIF_NOTIFY_RESUME bit > one might be tempted to modify the code to: > > lda $2, _TIF_WORK_MASK > and $5, $2, $2 > > but this is time critical code. I am wondering whether it might be better > to rearrange the bits in the thread information flags so that _TIF_WORK_MASK > has a value less than 255 and the single instruction to perform an and > operation can be maintained. Unless the LDA can be interleaved around some memory accesses, then yes, compressing _TIF_WORK_MASK would be good. David