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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4AF96C433EF for ; Wed, 11 May 2022 07:45:20 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 85A756B0073; Wed, 11 May 2022 03:45:19 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 809006B0075; Wed, 11 May 2022 03:45:19 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6F8566B0078; Wed, 11 May 2022 03:45:19 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 5CDCE6B0073 for ; Wed, 11 May 2022 03:45:19 -0400 (EDT) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 2A76A62091 for ; Wed, 11 May 2022 07:45:19 +0000 (UTC) X-FDA: 79452676758.14.E91A3FB Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf22.hostedemail.com (Postfix) with ESMTP id 160ABC00A7 for ; Wed, 11 May 2022 07:45:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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=zQStQvqHTMn/lq4ztBBoUMAZrkzuwgeyV+t4snpAvM8=; b=UWiv7NTPus3l28tAO0e8eiSK9I RT06/y3Q8GxqTVOEDoMwVswZAx+Mirl+fY3OBWVaCPpHbCpf1ZxdMiL2ZF60fdSWtFtyrT0cDwL7c ts6ahlMXeNOSk6Pm2j1wajMVAa97+TiASz8nZRr6Fq1pxyAyn4YAf+5D7Hw7XHSrpdAKFrgT6yAV8 mDnM62iKyYMB+Q/hCKuZnvUzTUnPjA4nwCF9fYDCsi8Eu3hmegNKq+kkefuSswzZlvRf5IW/HxSw1 jXbKRSTi3j0atnx1m8lGCnq8QO2sM5mVKLK8sSTQ9B/iY72iprnW7PdDTTV2rFBHUHieP5S11LCWr 08ypHoYA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1noh1u-005F9n-QA; Wed, 11 May 2022 07:45:07 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 646FD980E3A; Wed, 11 May 2022 09:45:06 +0200 (CEST) Date: Wed, 11 May 2022 09:45:06 +0200 From: Peter Zijlstra To: "Kirill A. Shutemov" Cc: Dave Hansen , Andy Lutomirski , x86@kernel.org, Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , "H . J . Lu" , Andi Kleen , Rick Edgecombe , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFCv2 05/10] x86/mm: Provide untagged_addr() helper Message-ID: <20220511074506.GB100765@worktop.programming.kicks-ass.net> References: <20220511022751.65540-1-kirill.shutemov@linux.intel.com> <20220511022751.65540-7-kirill.shutemov@linux.intel.com> <20220511072116.GT76023@worktop.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220511072116.GT76023@worktop.programming.kicks-ass.net> X-Rspamd-Queue-Id: 160ABC00A7 X-Stat-Signature: 37886ide71q44d4ezccfgq6r6i33fgh3 X-Rspam-User: Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=UWiv7NTP; spf=none (imf22.hostedemail.com: domain of peterz@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=peterz@infradead.org; dmarc=none X-Rspamd-Server: rspam09 X-HE-Tag: 1652255116-619579 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, May 11, 2022 at 09:21:16AM +0200, Peter Zijlstra wrote: > On Wed, May 11, 2022 at 05:27:46AM +0300, Kirill A. Shutemov wrote: > > +#define __untagged_addr(addr, n) \ > > + ((__force __typeof__(addr))sign_extend64((__force u64)(addr), n)) > > + > > +#define untagged_addr(addr) ({ \ > > + u64 __addr = (__force u64)(addr); \ > > + if (__addr >> 63 == 0) { \ > > + if (current->thread.features & X86_THREAD_LAM_U57) \ > > + __addr &= __untagged_addr(__addr, 56); \ > > + else if (current->thread.features & X86_THREAD_LAM_U48) \ > > + __addr &= __untagged_addr(__addr, 47); \ > > + } \ > > + (__force __typeof__(addr))__addr; \ > > +}) > > Assuming you got your bits in hardware order: > > u64 __addr = addr; > if ((s64)__addr >= 0) { > int lam = (current->thread.features >> X86_THREAD_LAM_U57) & 3; That needs a _BIT suffix or something, same in the previous reply. > if (lam) > __addr &= sign_extend64(__addr, 65 - 9*lam); > } > __addr; > > has less branches on and should definitely result in better code (or I > need more morning juice). I definitely needs more morning juice :-)