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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3FB58C5518F for ; Tue, 4 Aug 2026 14:17:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4F5E56B00EF; Tue, 4 Aug 2026 10:17:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4A61A6B00F1; Tue, 4 Aug 2026 10:17:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 39A876B00EF; Tue, 4 Aug 2026 10:17:53 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 11B256B00EF for ; Tue, 4 Aug 2026 10:17:53 -0400 (EDT) Received: from smtpin14.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay02.hostedemail.com (Postfix) with ESMTP id C45C712013B for ; Tue, 4 Aug 2026 12:59:32 +0000 (UTC) X-FDA: 85063593384.14.1385404 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf18.hostedemail.com (Postfix) with ESMTP id 119D31C0006 for ; Tue, 4 Aug 2026 12:59:30 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=gVucjhvr; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf18.hostedemail.com: domain of ljs@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=ljs@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1785848371; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=rkEir9uFm1qRBCXp0zpCOeuLTQKL4glDCYZRatT+50Y=; b=kHqm1DaHlIqQu4OKI18Di9wVKvg40xEHpXk4Mu+hcDQb+reOPrLsRJ6qvbFulMuC+FNx7A vsFRmDJLW3o8PGcpjAuz6R43kqDH/5KK4v5MRbk/jjc4nqhcIvGBZlvWbr00Wd42Bo0Wel GTJZRFg9IBqhHpK4pe+kF+SEEb6qhw0= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=gVucjhvr; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf18.hostedemail.com: domain of ljs@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=ljs@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1785848371; b=xdDo/ly9pgMruKr4omMpps2nmh70kfzP6S612NoIisb+usRWIeoY/BAEM4nMw1evfbW+7X tlR8txjTLH4Pv5xJH7LUnWLyLS+4mCkUT/2ZxBdtxAd6tBv2ZVWGxFPjdVsQEVPG8OR6+a kZHqA707YrN6wcbrdyHoYHTRRG/+4H8= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 2551A41FC2; Tue, 4 Aug 2026 12:59:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A3B111F000E9; Tue, 4 Aug 2026 12:59:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785848370; bh=rkEir9uFm1qRBCXp0zpCOeuLTQKL4glDCYZRatT+50Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=gVucjhvrdbhER92eS5xBHqYeZpRRPk+DMQSNxJPje3bAw5/f6Is/Nlxg+QiKYxfyL pGQoOaMN++o0pL9N4wS88gUthxS0LEzYZKJZYvjbiDx/YUuiHmFTpl65FF4Q9xwM0s a3HI42iOihbi5kLSp3FDAlBecuXQkaSEbziibdWB2HI43ExYZ5VxAwgNzL8NLKy4/V BvJA7uaB+cbSx42oZRA6c8/ULe0tqE31ITKSKG8p1/ldAswRXodrmvS/+E0is3fQsS w6b9GFu80tahoLmlwJ3y8g26YTuFV2gojiLnnLp6U02LXioHwZLgPZzUCMN88kobJv U6M2c8qhm7r5g== Date: Tue, 4 Aug 2026 13:59:08 +0100 From: "Lorenzo Stoakes (ARM)" To: "Christophe Leroy (CS GROUP)" Cc: Pedro Falcato , David Hildenbrand , Andrew Morton , Catalin Marinas , Will Deacon , "James E.J. Bottomley" , Helge Deller , Madhavan Srinivasan , Michael Ellerman , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , "Matthew Wilcox (Oracle)" , Jan Kara , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Kevin Brodsky , Muhammad Usama Anjum , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v2 3/6] mm/powerpc/8xx: constify ptep_get() argument Message-ID: References: <20260803164400.531199-1-pfalcato@suse.de> <20260803164400.531199-4-pfalcato@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Stat-Signature: io75pub96f6t6qdqawiqw598eecgz1na X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 119D31C0006 X-HE-Tag: 1785848370-568262 X-HE-Meta: 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 1zFfFN2M hh2nwdol30CoK/1+uKdkrLHf1+Jemyt17yZWiexgNplNYNRNtwn6Y6bR+dgf7wYFWoIpm+nzr7Lct+wFIo8CUnWJp0Kvn5aEK5UcOkg/TwwWYrEwQiklVfaUT3dBRbxBOaAMQcMvqdaRHJGiEcs6Mfut29GmqiOdXUPlGizzUQK9yQXJZ/3P9jZPcXBmnoDTiIY+e/AUHLc3yZz6MGglLzAPAbaPDFXyYcVFH2hK7YuXXq991qDNMqsv/x8VJ/FyuVg8F5Ew623Jc1T7FNr9fPwG1B9X5ftYnDc6QKEsUSZSeRGiAsNy1b8Ttf5COTdePJ4sXgfQl8SE+i8hYqK/dhGV/EmTEJOieg1cx5f7kXhi8g0p/sx8BIjLFx5W1M3mnRLEvdhOGOXznwo1/aUbpZebDSz9PPXtI1vOXzlLQfuEANwk= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Aug 04, 2026 at 02:50:19PM +0200, Christophe Leroy (CS GROUP) wrote: > Hi Lorenzo, > > Le 04/08/2026 à 13:13, Lorenzo Stoakes (ARM) a écrit : > > On Mon, Aug 03, 2026 at 05:43:57PM +0100, Pedro Falcato wrote: > > > There is no need for write access to the PTE. > > > > > > Signed-off-by: Pedro Falcato > > > > With below addressed LGTM so: > > > > Reviewed-by: Lorenzo Stoakes (ARM) > > > > > --- > > > arch/powerpc/include/asm/nohash/32/pte-8xx.h | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/arch/powerpc/include/asm/nohash/32/pte-8xx.h b/arch/powerpc/include/asm/nohash/32/pte-8xx.h > > > index e2ea8ba9f8ca..f2bab31040c7 100644 > > > --- a/arch/powerpc/include/asm/nohash/32/pte-8xx.h > > > +++ b/arch/powerpc/include/asm/nohash/32/pte-8xx.h > > > @@ -226,7 +226,7 @@ static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, p > > > > > > #ifdef CONFIG_PPC_16K_PAGES > > > #define ptep_get ptep_get > > > -static inline pte_t ptep_get(pte_t *ptep) > > > +static inline pte_t ptep_get(const pte_t *ptep) > > > { > > > pte_basic_t val = READ_ONCE(ptep->pte); > > > pte_t pte = {val, val, val, val}; > > > > Worth making these const too (that {val, val, val, val} horrifies me btw :)? > > Any suggestion welcome. I'm being super nitty, all I mean is: - pte_basic_t val = READ_ONCE(ptep->pte); - pte_t pte = {val, val, val, val}; + const pte_basic_t val = READ_ONCE(ptep->pte); + const pte_t pte = {val, val, val, val}; :) > > powerpc 8xx page table is independant on page size. When you use 16k pages, > depending on the address you hit the page for the first time, the HW assist > page table walk will fetch one of four 4k cells in page table that need to > be identical as they all four define the same 16k page. Not sure I'm clear. No that's clear, thanks! (I say 'horrifying' because I am looking into RCU page table freeing which this may complicate, though perhaps not in practice, to be continued :) > > Christophe > -- Cheers, Lorenzo