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 F13C5C04E69 for ; Wed, 16 Aug 2023 11:30:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244443AbjHPLaH (ORCPT ); Wed, 16 Aug 2023 07:30:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52482 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244622AbjHPL3r (ORCPT ); Wed, 16 Aug 2023 07:29:47 -0400 Received: from madras.collabora.co.uk (madras.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e5ab]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 59D881B4; Wed, 16 Aug 2023 04:29:46 -0700 (PDT) Received: from [192.168.100.7] (unknown [59.103.216.185]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: usama.anjum) by madras.collabora.co.uk (Postfix) with ESMTPSA id 6B23A66071DF; Wed, 16 Aug 2023 12:29:38 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1692185383; bh=jzdDeX6pUFEUXGNfKX/EwXm6M3rdWUmKoZ0lN9Hznw4=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=Dt8B2jZbp7t6JaXUWr+dIqQM9RjQq2p/RnIdZ7kiF6zOcLSro8jgoV7XUdcMc1Oit LRpKHs3AGqiYDS0sD2De3J020Bpt9SOeJ2KYtIfKLsSTQXfXh1eXWSvgux/FypoVoh uDT5bj7M1rdgnPp92pQpljqC4mx10HCV9jLjzPJdSMX1nAm1QP6LaPa580+5aH2QQ6 KGRBk0B8KPf6RRK4DvtGuBN+VnROAGEAed2E/cqkkHdbn94+1AzLpTkw4RZqCi43IZ 1+wfOIvDjh92S1UnnqihPgYK7/K2CaMMdJbKyGKV663ah8AkBHAKERhHuxY1wYbkxt kUXWM+tOZCd7w== Message-ID: Date: Wed, 16 Aug 2023 16:29:34 +0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.1 Cc: Muhammad Usama Anjum , Peter Xu , Andrew Morton , =?UTF-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= , Andrei Vagin , Paul Gofman , Alexander Viro , Shuah Khan , Christian Brauner , Yang Shi , Vlastimil Babka , "Liam R . Howlett" , Yun Zhou , Suren Baghdasaryan , Alex Sierra , Matthew Wilcox , Pasha Tatashin , Axel Rasmussen , "Gustavo A . R . Silva" , Dan Williams , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, Greg KH , kernel@collabora.com, Cyrill Gorcunov , Mike Rapoport , Nadav Amit , David Hildenbrand Subject: Re: [PATCH v31 2/6] fs/proc/task_mmu: Implement IOCTL to get and optionally clear info about PTEs Content-Language: en-US To: =?UTF-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= References: <20230816103814.1522393-1-usama.anjum@collabora.com> <20230816103814.1522393-3-usama.anjum@collabora.com> From: Muhammad Usama Anjum In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/16/23 4:17 PM, Michał Mirosław wrote: > On Wed, Aug 16, 2023 at 03:38:10PM +0500, Muhammad Usama Anjum wrote: >> The PAGEMAP_SCAN IOCTL on the pagemap file can be used to get or optionally >> clear the info about page table entries. > [...] >> --- a/fs/proc/task_mmu.c >> +++ b/fs/proc/task_mmu.c > [...] >> +static long do_pagemap_scan(struct mm_struct *mm, unsigned long uarg) >> +{ > [...] >> + for (walk_start = p.arg.start; walk_start < p.arg.end; >> + walk_start = p.arg.walk_end) { > [...] >> + /* The walk_end isn't set when ret is zero */ >> + if (!p.arg.walk_end) >> + p.arg.walk_end = p.arg.end; > > This is now redundant with the `if` after the loop. [1] > >> + if (ret != -ENOSPC) >> + break; >> + >> + if (p.arg.vec_len == 0 || p.found_pages == p.arg.max_pages) >> + break; >> + } >> + >> + /* ENOSPC signifies early stop (buffer full) from the walk. */ >> + if (!ret || ret == -ENOSPC) >> + ret = n_ranges_out; >> + >> + if (!p.arg.walk_end) >> + p.arg.walk_end = p.arg.end; > > [1] The one above. Thank you for noting it down. Let me remove it. > > Best Regards > Michał Mirosław -- BR, Muhammad Usama Anjum