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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59161C433EF for ; Wed, 20 Apr 2022 08:26:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8006A6B0078; Wed, 20 Apr 2022 04:26:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7AF666B007B; Wed, 20 Apr 2022 04:26:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 69E266B007D; Wed, 20 Apr 2022 04:26:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.a.hostedemail.com [64.99.140.24]) by kanga.kvack.org (Postfix) with ESMTP id 59B876B0078 for ; Wed, 20 Apr 2022 04:26:02 -0400 (EDT) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay13.hostedemail.com (Postfix) with ESMTP id 217B16251F for ; Wed, 20 Apr 2022 08:26:02 +0000 (UTC) X-FDA: 79376574564.01.AB70A72 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [46.235.227.227]) by imf23.hostedemail.com (Postfix) with ESMTP id C769C140014 for ; Wed, 20 Apr 2022 08:25:59 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: usama.anjum) with ESMTPSA id 93F3F1F43067 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1650443159; bh=MgSbLWfAifI4DFaTIg3jOQ8OVtknhW15URbnIfz+19I=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=Xfm58R44mhuC4me/qgex0MH4rrK3lfxKTeqb0UeHrnT1HSbwI2wcEr5rFvjG2r/Jc tg/XPFZw5q+7z3O6gmwtVuflrSK1yDmtnRzZ6eTjA6j1krphZZMkQ8VIJG9MlDJHlq f87PqwpLPGgCMW57dmIbcDZyAoM47dkPXSuuuVz6dbBPb/DdiTvObtrB54cIIdTA8r SEaz+UPbOtITcFeJh+lgw1ot25/an7S6f5nFymxEhQfbDMFcKNSPOx7gydfas5bv2O eaNEIpnKNsam7AhnibAZ9eANbJePzCFUOEGvqhXOZjUZuw23kaQFjHM54zuXhtedxK oMzukw1st5zSA== Message-ID: <2d83eab4-3ba9-6947-690e-2b0fd7de0653@collabora.com> Date: Wed, 20 Apr 2022 13:25:53 +0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Cc: usama.anjum@collabora.com, Andrew Morton , Shuah Khan , kernel@collabora.com, david@redhat.com, Will Deacon , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH V5 2/2] selftests: vm: Add test for Soft-Dirty PTE bit Content-Language: en-US To: Gabriel Krisman Bertazi References: <20220317103323.94799-1-usama.anjum@collabora.com> <20220317103323.94799-2-usama.anjum@collabora.com> <87ilsbyshs.fsf@collabora.com> From: Muhammad Usama Anjum In-Reply-To: <87ilsbyshs.fsf@collabora.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: C769C140014 X-Rspam-User: Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=collabora.com header.s=mail header.b=Xfm58R44; spf=pass (imf23.hostedemail.com: domain of usama.anjum@collabora.com designates 46.235.227.227 as permitted sender) smtp.mailfrom=usama.anjum@collabora.com; dmarc=pass (policy=none) header.from=collabora.com X-Stat-Signature: 5erp9qcs9ijrsfwhcxie3d6ejunmaubh X-HE-Tag: 1650443159-181223 X-Bogosity: Ham, tests=bogofilter, spamicity=0.004647, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 3/19/22 12:23 AM, Gabriel Krisman Bertazi wrote: >> +static void test_vma_reuse(int pagemap_fd, int pagesize) >> +{ >> + char *map, *map2; >> + >> + map = mmap(NULL, pagesize, (PROT_READ | PROT_WRITE), (MAP_PRIVATE | MAP_ANON), -1, 0); >> + if (map == MAP_FAILED) >> + ksft_exit_fail_msg("mmap failed"); >> + >> + clear_softdirty(); >> + >> + /* Write to the page before unmapping and map the same size region again to check >> + * if same memory region is gotten next time and if dirty bit is preserved across >> + * this type of allocations. >> + */ > This reads weird. It should *not* be preserved across different > mappings. Also, we are not testing if the same region is reused, we are > depending on it to test the sd bit. > > /* Ensures the soft-dirty bit is reset accross different mappings on the > same address. */ Soft dirty bit is always set for new regions (reused or not). I'll correct the comment and improve this sub test. -- Muhammad Usama Anjum