Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937099AbWLFSid (ORCPT ); Wed, 6 Dec 2006 13:38:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S937097AbWLFSid (ORCPT ); Wed, 6 Dec 2006 13:38:33 -0500 Received: from smtp.osdl.org ([65.172.181.25]:55807 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S937089AbWLFSib (ORCPT ); Wed, 6 Dec 2006 13:38:31 -0500 Date: Wed, 6 Dec 2006 10:37:23 -0800 (PST) From: Linus Torvalds To: David Howells cc: Andrew Morton , "Maciej W. Rozycki" , Roland Dreier , Andy Fleming , Ben Collins , Linux Kernel Mailing List , Jeff Garzik , linux-arch@vger.kernel.org Subject: Re: [PATCH] Export current_is_keventd() for libphy In-Reply-To: Message-ID: References: <1165125055.5320.14.camel@gullible> <20061203011625.60268114.akpm@osdl.org> <20061205123958.497a7bd6.akpm@osdl.org> <6FD5FD7A-4CC2-481A-BC87-B869F045B347@freescale.com> <20061205132643.d16db23b.akpm@osdl.org> <20061205135753.9c3844f8.akpm@osdl.org> <20061206075729.b2b6aa52.akpm@osdl.org> <21690.1165426993@redhat.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1346 Lines: 35 On Wed, 6 Dec 2006, Linus Torvalds wrote: > > and remove the "volatile" from all the bitop accessor functions. It might also be interesting to see if this would change code-size at all. There's a number of things that check different bits in the same word right now, and they just reload the word unnecessarily and do multiple tests. Some of the page flags functions obviously already work around this by doing horrible things by hand instead, eg: (page->flags & ( 1 << PG_lru | 1 << PG_private | 1 << PG_locked | 1 << PG_active | 1 << PG_reclaim | 1 << PG_slab | 1 << PG_swapcache | 1 << PG_writeback | 1 << PG_reserved | 1 << PG_buddy )) in the free_pages_check() thing. It may make sense there, but we really _should_ allow gcc to just do things like this for us, and just use the proper functions to test bits. Linus - 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/