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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 00255C7EE29 for ; Thu, 8 Jun 2023 09:02:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234107AbjFHJCA (ORCPT ); Thu, 8 Jun 2023 05:02:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51638 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235466AbjFHJB3 (ORCPT ); Thu, 8 Jun 2023 05:01:29 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5BE0D2738 for ; Thu, 8 Jun 2023 02:01:22 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E25DD64B10 for ; Thu, 8 Jun 2023 09:01:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 21BC0C4339B; Thu, 8 Jun 2023 09:01:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686214881; bh=ENY+GBR80KU6FtfZoQp38Y0wG9dMpgJdlLMVkzCZzJE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Wjo0r9oqO32DtHsSgog4dZlLy2/yDQdDAw64BfeonhYX4lVHGZbVXbsyIO3Md4aga h3kaE7NvslJinmYlrUPegQ6ZDM82vnE32bczkZKoDJFwPHpai+q+bVidl7Kv5ww6Y8 Yz3iS+Cq4gGpECGWacXSF/BYmOSMe1o6Xl4K5EO2M7zzrXeZBiH5/JJ1xYZUhZNygI A2XzXx71LFnXiSzSJJHdQBM9p+R6Trqhtz03VkKdOSrunFKjWF0doUX9zig0W3kXDq jCpyYraSmQ3/cmqI3nYYOZHLv4T3si8alVdJZ6HVyJG7eyY4LZsbQW23NGtYIT6vYb /Eg/cPuwvTteA== Date: Thu, 8 Jun 2023 12:00:56 +0300 From: Mike Rapoport To: Linus Walleij Cc: Matthew Wilcox , Andrew Morton , Jonathan Corbet , linux-mm@kvack.org, linux-doc@vger.kernel.org Subject: Re: [PATCH] Documentation/mm: Initial page table documentation Message-ID: <20230608090056.GH52412@kernel.org> References: <20230605221035.3681812-1-linus.walleij@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Thu, Jun 08, 2023 at 10:13:49AM +0200, Linus Walleij wrote: > Hi Matthew, > > I fixes up most of the comments. > > On Tue, Jun 6, 2023 at 5:57 AM Matthew Wilcox wrote: > > On Tue, Jun 06, 2023 at 12:10:35AM +0200, Linus Walleij wrote: > > > > +- **pte**, `pte_t`, `pteval_t` = **Page Table Entry** - mentioned earlier. > > > + The name is a bit confusing because while in Linux 1.0 this did refer to a > > > + single page table entry in the top level page table, it was retrofitted > > > + to be "what the level above points to". So when two-level page tables were > > > + introduced, the *pte* became a list of pointers, which is why > > > + `PTRS_PER_PTE` exists. This oxymoronic term can be mildly confusing. > > > > I don't think this is right. PTRS_PER_PTE is how many pointers are in > > the PMD page table, > > I don't get this. What does PTRS_PER_PMD mean then (and > then all the way up to PTRS_PER_PGD...) PTRS_PER_PTE is how many pointers in the lowest level (pte) page table and pte_t is a "pointer" to an actual physical page mapped by the page tables. > Yours, > Linus Walleij -- Sincerely yours, Mike.