From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4253AE541; Wed, 24 Jan 2024 05:46:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706075196; cv=none; b=nVb1TsBRXtOrClXGGgQ7sxRuxP5Icy/c24//KJFRt7kvjmvlYb4h0cZnogWW22wwxUp9IN5r6QSl9+sn6qBS6iHDerpNXpHXaiestEsCWAPk3ftYs5ulfqRf7JWeqciqqehjjpPJXxXr50GMZDTJ60sHjp6zwkqxztRpBv228g4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706075196; c=relaxed/simple; bh=LhesHwoZXRdX5jfbi0laKsTDlPHkqd2QNDhd5PA0n64=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=iJJISIS9oqk5MjaHfBm/s39voVfmMo35oSGarl05+nF6wwa00TUekmsaCp9+7p635HNdhg7vd/A+p7ZJ8DkYlVxjL4Qp40Gf4TQdYdaRIs5DXW1cNDRmS8yix/Bo3hrwz4bs1eKU3DbH+Gk1QVKE8WLQ4yLOfljTZ51FG5Uju6s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SgqZYUET; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="SgqZYUET" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75644C433F1; Wed, 24 Jan 2024 05:46:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1706075195; bh=LhesHwoZXRdX5jfbi0laKsTDlPHkqd2QNDhd5PA0n64=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=SgqZYUETYp0U/lExF64JKpfQ4QQzjrtotn/ONStmemo8UuEWx22RNGcCPysz/GGdH wF4/0iVnvQm3wM0s4Ag4Pkguroe5zo7K7nKVaDa3YhK1ow6WyrrQ0jGg/jh0nlfdU+ f9jiSYnPlhA+oQTs1xwIrXNokUtNwZ94UcVY9oqXd8lQQbttaFJlpF0H4Hptl0pH0W L6Si/Ez2ZPcSiKG/jTqZNA1RfHBeGdDrwVDOodIiOjh9BxNSAwCbUb8UnpBbsGqMmX Fry6owvnHK5HB/4QPvBt/16sEl5jOidoL18vHxJm0dea3fi94NjlvWmuxijOXq/zBL NkyRrt3sGxNQg== X-Mailer: emacs 29.1 (via feedmail 11-beta-1 I) From: Aneesh Kumar K.V To: David Hildenbrand , Christophe Leroy , Ryan Roberts , "linux-kernel@vger.kernel.org" Cc: "linux-mm@kvack.org" , Andrew Morton , Matthew Wilcox , Russell King , Catalin Marinas , Will Deacon , Dinh Nguyen , Michael Ellerman , Nicholas Piggin , "Naveen N. Rao" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , "David S. Miller" , "linux-arm-kernel@lists.infradead.org" , "linuxppc-dev@lists.ozlabs.org" , "linux-riscv@lists.infradead.org" , "linux-s390@vger.kernel.org" , "sparclinux@vger.kernel.org" Subject: Re: [PATCH v1 01/11] arm/pgtable: define PFN_PTE_SHIFT on arm and arm64 In-Reply-To: <3a970289-a72f-418e-b43c-89f67f0d5283@redhat.com> References: <20240122194200.381241-1-david@redhat.com> <20240122194200.381241-2-david@redhat.com> <46080ac1-7789-499b-b7f3-0231d7bd6de7@redhat.com> <6703b648-10ab-4fea-b7f1-75421319465b@arm.com> <3a970289-a72f-418e-b43c-89f67f0d5283@redhat.com> Date: Wed, 24 Jan 2024 11:16:23 +0530 Message-ID: <87zfwvp9lc.fsf@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain David Hildenbrand writes: >>> >>>> If high bits are used for >>>> something else, then we might produce a garbage PTE on overflow, but that >>>> shouldn't really matter I concluded for folio_pte_batch() purposes, we'd not >>>> detect "belongs to this folio batch" either way. >>> >>> Exactly. >>> >>>> >>>> Maybe it's likely cleaner to also have a custom pte_next_pfn() on ppc, I just >>>> hope that we don't lose any other arbitrary PTE bits by doing the pte_pgprot(). >>> >>> I don't see the need for ppc to implement pte_next_pfn(). >> >> Agreed. > > So likely we should then do on top for powerpc (whitespace damage): > > diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c > index a04ae4449a025..549a440ed7f65 100644 > --- a/arch/powerpc/mm/pgtable.c > +++ b/arch/powerpc/mm/pgtable.c > @@ -220,10 +220,7 @@ void set_ptes(struct mm_struct *mm, unsigned long addr, pte_t *ptep, > break; > ptep++; > addr += PAGE_SIZE; > - /* > - * increment the pfn. > - */ > - pte = pfn_pte(pte_pfn(pte) + 1, pte_pgprot((pte))); > + pte = pte_next_pfn(pte); > } > } Agreed. -aneesh