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 D5F90C433EF for ; Wed, 20 Apr 2022 08:26:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245432AbiDTI2t (ORCPT ); Wed, 20 Apr 2022 04:28:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50272 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376691AbiDTI2s (ORCPT ); Wed, 20 Apr 2022 04:28:48 -0400 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AD79535267; Wed, 20 Apr 2022 01:26:02 -0700 (PDT) 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 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org 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