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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 84CFCC48260 for ; Tue, 13 Feb 2024 16:54:06 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4TZ6qK1vw4z3dnN for ; Wed, 14 Feb 2024 03:54:05 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=arm.com (client-ip=217.140.110.172; helo=foss.arm.com; envelope-from=mark.rutland@arm.com; receiver=lists.ozlabs.org) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lists.ozlabs.org (Postfix) with ESMTP id 4TZ6pr2tqdz2y1Y for ; Wed, 14 Feb 2024 03:53:39 +1100 (AEDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CCA9CDA7; Tue, 13 Feb 2024 08:53:48 -0800 (PST) Received: from FVFF77S0Q05N.cambridge.arm.com (FVFF77S0Q05N.cambridge.arm.com [10.1.36.130]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CB5073F5A1; Tue, 13 Feb 2024 08:53:03 -0800 (PST) Date: Tue, 13 Feb 2024 16:53:01 +0000 From: Mark Rutland To: Ryan Roberts Subject: Re: [PATCH v5 21/25] arm64/mm: Implement new [get_and_]clear_full_ptes() batch APIs Message-ID: References: <20240202080756.1453939-1-ryan.roberts@arm.com> <20240202080756.1453939-22-ryan.roberts@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kefeng Wang , x86@kernel.org, David Hildenbrand , Catalin Marinas , Yang Shi , Dave Hansen , linux-mm@kvack.org, Andrey Ryabinin , "H. Peter Anvin" , Will Deacon , Ard Biesheuvel , Marc Zyngier , Alistair Popple , Barry Song <21cnbao@gmail.com>, Matthew Wilcox , "Aneesh Kumar K.V" , Ingo Molnar , Zi Yan , "Naveen N. Rao" , John Hubbard , Nicholas Piggin , Borislav Petkov , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, James Morse , Andrew Morton , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, Feb 13, 2024 at 04:48:50PM +0000, Ryan Roberts wrote: > On 13/02/2024 16:43, Mark Rutland wrote: > > On Fri, Feb 02, 2024 at 08:07:52AM +0000, Ryan Roberts wrote: > >> +static inline void __clear_full_ptes(struct mm_struct *mm, unsigned long addr, > >> + pte_t *ptep, unsigned int nr, int full) > >> +{ > >> + for (;;) { > >> + __ptep_get_and_clear(mm, addr, ptep); > >> + if (--nr == 0) > >> + break; > >> + ptep++; > >> + addr += PAGE_SIZE; > >> + } > >> +} > > > > The loop construct is a bit odd; can't this be: > > I found it a little odd at first, but its avoiding the ptep and addr increments > the last time through the loop. Its the preferred pattern for these functions in > core-mm. See default set_ptes(), wrprotect_ptes(), clear_full_ptes() in > include/linux/pgtable.h. > > So I'd prefer to leave it as is so that we match them. What do you think? That's fair enough; it I'm happy with it as-is. Mark.