From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 839B846E01E; Thu, 10 Sep 2026 11:14:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789038892; cv=none; b=qot6M1FnojMAdr3Wf6o+uPa2sf+5uIHuJsnEZM+rwD+pVJWp/Cp+XZRojOCKQ0pOIhimAbPIw5mh+OSVw1rS7cCp8UepDZIBuhftxnV3IBa9sfDYogNceK11xPgrpMW5d0e1u4kk+cwKJu38Z8VTQud9Xjru26gOCDVE3WjcKDY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789038892; c=relaxed/simple; bh=+iNltnroMtmCrjYqPz4G3jfFuqZCi0WBjE1SxKe6NZs=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=q3qD2JH0XtjcTu+KTTv1cmcJ5s0c7BKPIWAGSLCu557O211U3854OoEmrJ0NMTyZSo6hMVDhCJpW/B8UkuT0KTtVuPV2Xv/7LtfGLjbPPwFiYfF6/8Fi+yTosooglDdwrRa7fyuIh10NiSofSammV7sChU++KEH4R+vYLApK3bA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ohxqqE/h; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ohxqqE/h" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4AB881F000FF; Thu, 10 Sep 2026 11:14:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789038890; bh=PTk08ghQEYuYo89c0VG6xsdyLB9DUgU/FUr7ab35PKM=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=ohxqqE/h8/pErTUSk94yiONeiZNIo5OYZZfvgXM/isBkATQx22xTOFjqP5ws1BX0r O/zuLixBlzlJMHNnTACJ5rau/3/pmfku0CYHOYwr341hc958uhJFPQJzmQGlvmcJVK HYHi9WSHCL5dBDzixrjyPXW18twNc27UbTCDvuQbM6VLjdGGpOm2mwdddVhpj1/AQ9 N1vl4sxz7shcP8PQTxuztAszZk/x3NV1rLZ10aCpyGyNvgb3l1FJu2SqeliCsTtd7Y h9tz8KscbXjxI0bjVYTG764s6Oj34cer8zl4Glja/WzCDcwN50uGP7cZ3bR0ttfFU6 JDNUXhSywWWOQ== Message-ID: Date: Thu, 10 Sep 2026 13:14:42 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 3/3] kselftest: mm: introduce alloc_isolated_mem() To: Yeoreum Yun Cc: Andrew Morton , Lorenzo Stoakes , Zi Yan , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Kevin Brodsky , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260907-fix_split-v5-0-822b810458bc@arm.com> <20260907-fix_split-v5-3-822b810458bc@arm.com> <5c05b620-7a2f-453d-9725-fed4f536a019@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/10/26 13:02, Yeoreum Yun wrote: >>> diff --git a/tools/testing/selftests/mm/soft-dirty.c b/tools/testing/selftests/mm/soft-dirty.c >>> index 5f278913c4d7..b6fad38c8bee 100644 >>> --- a/tools/testing/selftests/mm/soft-dirty.c >>> +++ b/tools/testing/selftests/mm/soft-dirty.c >>> @@ -92,9 +92,9 @@ static void test_hugepage(int pagemap_fd, int pagesize) >>> if (!hpage_len) >>> ksft_exit_fail_msg("Reading PMD pagesize failed"); >>> >>> - map = memalign(hpage_len, hpage_len); >>> + map = alloc_isolated_mem(hpage_len, hpage_len); >>> if (!map) >>> - ksft_exit_fail_msg("memalign failed\n"); >>> + ksft_exit_fail_msg("alloc_isolated_mem failed\n"); >>> >>> ret = madvise(map, hpage_len, MADV_HUGEPAGE); >>> if (ret) >>> @@ -130,7 +130,7 @@ static void test_hugepage(int pagemap_fd, int pagesize) >>> ksft_test_result_skip("Test %s huge page allocation\n", __func__); >>> ksft_test_result_skip("Test %s huge page dirty bit\n", __func__); >>> } >>> - free(map); >>> + free_isolated_mem(map, hpage_len); >>> } >> >> smaps is really only problematic with merged VMAs when relying on exact page >> statistics. For other properties (vm flags, MMUPageSize) it's not a problem as >> long as our smap search just finds the VMA that covers an address. >> >> Assuming we fixed check_huge_anon() to not use smaps, why is this change here >> required? > > Since there is no interface to get vm_flags not via /proc/self/smaps, > It might be good to have it for preventing unwanted VMA merge. > > And might be useful for future to prevent unwated VMA merge. See my reply on why vm flags are generally not a problem. Just like other properties that are not changed during VMA merging. Let's not perform random code changes without a clear picture. And just to emphasize again: VMA merging could already be a problem before memalign() internal changes. (also observe here how we do a MADV_HUGEPAGE, so this is all rather arbitrary, which is not good) -- Cheers, David