From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F1DF6C433F5 for ; Tue, 9 Nov 2021 21:21:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D1BD7610A2 for ; Tue, 9 Nov 2021 21:21:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245039AbhKIVYZ (ORCPT ); Tue, 9 Nov 2021 16:24:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37938 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239453AbhKIVYY (ORCPT ); Tue, 9 Nov 2021 16:24:24 -0500 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AFCAEC061764; Tue, 9 Nov 2021 13:21:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=WjjHKRQzAPClRG+YAWkb8c4biTijnDdG5vi8nhBZI38=; b=hbvIdNjM1G/p7mGCbtWMFU9nIx ewsSWakSjhYXPcdz3Hue0OcATuuvrIbE/bcwyBqvR+BtdziTWzUP49qeA//9p+7lpyat49Sho2T2A uBy1IDkPwrJkddMJhSshNlGBDynSJMfI2EAp5gS5ra8SnkCHyN+WtbT3sqt8/zInFuRbbxbtrf9mg y9ICYkVcce1yCPqQ2ibFnTPnDeC/WqPpmuRJhqC+qQuGkisASbeAu9V4IevAV1BZo6HE4uWshhUSO PEo1GbhP0ed99g8hpceaTu23CKGVLPxg6JWy6uev01VoqzOTb4ExXjWvjHZEC39EuTKEN+pCynb4S 4qlrdLxA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mkYYP-00F8gf-Jm; Tue, 09 Nov 2021 21:21:18 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 9EA0A985A2A; Tue, 9 Nov 2021 22:21:16 +0100 (CET) Date: Tue, 9 Nov 2021 22:21:16 +0100 From: Peter Zijlstra To: Bill Wendling Cc: Nick Desaulniers , Josh Poimboeuf , x86@kernel.org, linux-kernel@vger.kernel.org, mark.rutland@arm.com, dvyukov@google.com, seanjc@google.com, pbonzini@redhat.com, mbenes@suse.cz, llvm@lists.linux.dev, linux-toolchains@vger.kernel.org Subject: Re: [PATCH 20/22] x86,word-at-a-time: Remove .fixup usage Message-ID: <20211109212116.GW174703@worktop.programming.kicks-ass.net> References: <20211105171023.989862879@infradead.org> <20211105171821.654356149@infradead.org> <20211108164711.mr2cqdcvedin2lvx@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 09, 2021 at 12:59:12PM -0800, Bill Wendling wrote: > > Adding attributes to labels shouldn't be difficult, as you mention. In > the case of cold/hot, it's adjusting some of the metadata that already > exists on some basic blocks. It might be enough to allow the normal > block placement algorithms to move the hot and cold blocks around for > us. The question becomes how many attributes does GCC allow on labels? I'm aware of 3: unused, hot, cold. Also: https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html