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 0E468C64ED8 for ; Mon, 20 Feb 2023 13:27:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232040AbjBTN1H (ORCPT ); Mon, 20 Feb 2023 08:27:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39852 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231749AbjBTN1G (ORCPT ); Mon, 20 Feb 2023 08:27:06 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D70101A66C; Mon, 20 Feb 2023 05:27:04 -0800 (PST) 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 ams.source.kernel.org (Postfix) with ESMTPS id 64BADB80B96; Mon, 20 Feb 2023 13:27:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4C6B3C433EF; Mon, 20 Feb 2023 13:26:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1676899622; bh=gABycNmDsaE8rStdHvaqVjETdB3UP1bj2wN6aXwFGQ4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UkLjZU/xmTq7YtlM2nRS961aOed/9VW/PzOscHWvnJF+9fL9OLHpz1uahozF0Culs d8ASa1roMSsa4yEEvcwtNAyQIcxKxTfi0dHgjHd/MHDmnkP7KsvLSvvqu1IVdPyjiB J8WphKgkLEFGTCxTD1Lh6sEdPMz+PiK6tycDIjJzTl9I6ZeVGKH3xlvpNMohSwh0F6 rd4FLUysaC1d6mr0vnuyr+6v5RgiQD7rMki64k3V9UK4sarN/1MpAgFkFrIcC+AdNY Qo3MKGc1EYFMS9hVjLnCz94LHRQvxBArNBrvr2uKJuFkf7Pa3rzHV9j3p9AtdIVNbT PUPxhGqs7wdcw== Date: Mon, 20 Feb 2023 15:26:42 +0200 From: Mike Rapoport To: Muhammad Usama Anjum Cc: Peter Xu , David Hildenbrand , Andrew Morton , =?utf-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= , Andrei Vagin , Danylo Mocherniuk , Paul Gofman , Cyrill Gorcunov , Alexander Viro , Shuah Khan , Christian Brauner , Yang Shi , Vlastimil Babka , "Liam R . Howlett" , Yun Zhou , Suren Baghdasaryan , Alex Sierra , Matthew Wilcox , Pasha Tatashin , Nadav Amit , 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 Subject: Re: [PATCH v10 3/6] fs/proc/task_mmu: Implement IOCTL to get and/or the clear info about PTEs Message-ID: References: <20230202112915.867409-1-usama.anjum@collabora.com> <20230202112915.867409-4-usama.anjum@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230202112915.867409-4-usama.anjum@collabora.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Thu, Feb 02, 2023 at 04:29:12PM +0500, Muhammad Usama Anjum wrote: > This IOCTL, PAGEMAP_SCAN on pagemap file can be used to get and/or clear > the info about page table entries. The following operations are supported > in this ioctl: > - Get the information if the pages have been written-to (PAGE_IS_WRITTEN), > file mapped (PAGE_IS_FILE), present (PAGE_IS_PRESENT) or swapped > (PAGE_IS_SWAPPED). > - Write-protect the pages (PAGEMAP_WP_ENGAGE) to start finding which > pages have been written-to. > - Find pages which have been written-to and write protect the pages > (atomic PAGE_IS_WRITTEN + PAGEMAP_WP_ENGAGE) > > +/* > + * struct pagemap_scan_arg - Pagemap ioctl argument > + * @start: Starting address of the region > + * @len: Length of the region (All the pages in this length are included) > + * @vec: Address of page_region struct array for output > + * @vec_len: Length of the page_region struct array > + * @max_pages: Optional max return pages > + * @flags: Flags for the IOCTL > + * @required_mask: Required mask - All of these bits have to be set in the PTE > + * @anyof_mask: Any mask - Any of these bits are set in the PTE > + * @excluded_mask: Exclude mask - None of these bits are set in the PTE > + * @return_mask: Bits that are to be reported in page_region > + */ > +struct pagemap_scan_arg { > + __u64 start; > + __u64 len; > + __u64 vec; > + __u64 vec_len; > + __u32 max_pages; > + __u32 flags; > + __u64 required_mask; > + __u64 anyof_mask; > + __u64 excluded_mask; > + __u64 return_mask; > +}; After Nadav's comment I've realized I missed the API part :) A few quick notes for now: * The arg struct is fixed, so it would be impossible to extend the API later. Following the clone3() example, I'd add 'size' field to the pagemam_scan_arg so that it would be possible to add new fields afterwards. * Please make flags __u64, just in case * Put size and flags at the beginning of the struct, e.g. strucr pagemap_scan_arg { size_t size; __u64 flags; /* all the rest */ }; > + > +/* Special flags */ > +#define PAGEMAP_WP_ENGAGE (1 << 0) > + > #endif /* _UAPI_LINUX_FS_H */ > -- > 2.30.2 > -- Sincerely yours, Mike.