From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [GIT PULL] x86/atomic changes for v2.6.35 Date: Wed, 19 May 2010 07:24:00 -0700 Message-ID: <4BF3F480.3000902@zytor.com> References: <20100517224531.GA27400@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from terminus.zytor.com ([198.137.202.10]:36611 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752175Ab0ESOYd (ORCPT ); Wed, 19 May 2010 10:24:33 -0400 In-Reply-To: Sender: linux-arch-owner@vger.kernel.org List-ID: To: Geert Uytterhoeven Cc: Ingo Molnar , Luca Barbieri , Linus Torvalds , linux-kernel@vger.kernel.org, Thomas Gleixner , Andrew Morton , linux-arch@vger.kernel.org On 05/19/2010 04:46 AM, Geert Uytterhoeven wrote: > On Tue, May 18, 2010 at 00:45, Ingo Molnar wrote: >> Please pull the latest x86-atomic-for-linus git tree from: >> >> git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.gi= t x86-atomic-for-linus >> >> >> out-of-topic modifications in x86-atomic-for-linus: >> --------------------------------------------------- >> lib/Makefile # 86a8938: lib: Add self-test for= atomic64_t >> lib/atomic64.c # 9757789: lib: Fix atomic64_add_= unless retu >> lib/atomic64_test.c # a5c9161: x86, atomic64: In self= test, disti >> # 25a304f: lib: Fix atomic64_inc_n= ot_zero te >> # 9efbcd5: lib: Fix atomic64_add_u= nless test >> # d7f6de1: x86: Implement atomic[6= 4]_dec_if_ >> # 8f4f202: lib: Only test atomic64= _dec_if_po >> # 86a8938: lib: Add self-test for = atomic64_t >=20 > Is having atomic64_t mandatory now? >=20 > According to the allmodconfig build logs > (http://kisskb.ellerman.id.au/kisskb/matrix/), > several architectures (at least m68k and mips) don't have it. > Furthermore, the test fails to compile on a few architectures that do= have it > (parisc, s390, sh, ...). >=20 > > It's a pity this wasn't raised/resolved between its detection in linu= x-next and > before it entered mainline... > >=20 Is having atomic64_t mandatory? Not yet, I don't think, but it probabl= y will be soon -- which is why there is a generic implementation available. All those architectures just need to select CONFIG_GENERIC_ATOMIC64 and voil=C3=A0, problem solved. As far as your boilerplate is concerned, I think Linus made it clear at the Kernel Summit that is it not the obligation of x86/ARM/PowerPC to slow down to not break the smaller architectures; it's the responsibility of those architecture maintainers to keep up. Sorry. -hpa --=20 H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.