From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id D5A226FC5; Mon, 14 Sep 2026 16:46:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789404404; cv=none; b=GuNC2hkyvFaQKPmbdIA2D2DJbgnftt1WBdI3bJ3cjgHbg7lfWC52pMs6xJ5doiPdTYOO2yNUWWLiMmko+9guECZWh91M23f6YMkspIwKBYQAr4E5F45DkhHrRWHLoMuF2V72nTk1pb2dzFLlxjbsKfJYnpL34NG4NPjxMjpqvJM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789404404; c=relaxed/simple; bh=1r0rw5uXWXH7+bTv+MSPJvopnTN1PMSJsWeAueQ3OIw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=J6r/IRLjXzYoPJxtrmlnVwMgyJ29CAm2WBG0M2oQZ8NanT5sJF9FNiX7UQKMgT3kZceJWu+Kvk9asFwYU4QjjK9CVayJTCsgF4x6dpT1Jyer6IQ33PU9v3PKKPJaHjKIO21rM4G/VdDTYbTtQo3jQLg1FPT9PVlQu9YLD/qVxoo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=uQlLzw5h; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="uQlLzw5h" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 64B02153B; Mon, 14 Sep 2026 09:46:38 -0700 (PDT) Received: from e129823.arm.com (e129823.arm.com [10.2.213.3]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F2B093F86F; Mon, 14 Sep 2026 09:46:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1789404402; bh=1r0rw5uXWXH7+bTv+MSPJvopnTN1PMSJsWeAueQ3OIw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=uQlLzw5hH4+y/inqoVF5LI/F5v/0OKn3hBu6YiJiF5RclJSOU30kwx8YQiz+Vd6PF Kv7GPxXOdE5fNGfmy84Lk4zDUWKwNpomuiIOPLKBUe5upqoT8HCMnT9CQccy6wU2yp spL1qj8fM3HA59WNxLYe00SO/h32opTmY4jE0wkM= Date: Mon, 14 Sep 2026 17:46:36 +0100 From: Yeoreum Yun To: "David Hildenbrand (Arm)" Cc: Yeoreum Yun , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Kiryl Shutsemau , Peter Xu , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Andrew Morton , Shuah Khan , Jason Gunthorpe , Leon Romanovsky , Sarthak Sharma Subject: Re: [PATCH v3 2/3] kselftest: mm: remove HPAGE_SIZE and HPAGE_SHIFT macro Message-ID: References: <20260914-fix_hpage_macro-v3-0-c9a305a01d39@arm.com> <20260914-fix_hpage_macro-v3-2-c9a305a01d39@arm.com> <08d3313b-d891-4202-b460-c5cefa96bbce@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <08d3313b-d891-4202-b460-c5cefa96bbce@kernel.org> On Mon, Sep 14, 2026 at 04:08:03PM +0200, David Hildenbrand (Arm) wrote: > On 9/14/26 09:30, Yeoreum Yun wrote: > > HPAGE_SIZE and HPAGE_SHIFT macro is written based on the 4KB PAGE_SIZE. > > When this macro is used in some test, test result would be strange in > > the system where PAGE_SIZE is more then 4KB. > > > > Here is the example with transhuge-stress test with 16KB PAGE_SIZE: > > > > transhuge-stress: allocate 61073 transhuge pages, using 122146 MiB virtual memory and 1908 MiB of ram > > 3.292 s/loop, 0.054 ms/page, 37106.002 MiB/s 2566 succeed, 58507 failed, 2566 different pages > > 0.591 s/loop, 0.010 ms/page, 206850.792 MiB/s 0 succeed, 61073 failed, 0 different pages > > 0.527 s/loop, 0.009 ms/page, 231895.107 MiB/s 0 succeed, 61073 failed, 0 different pages > > 0.527 s/loop, 0.009 ms/page, 231839.704 MiB/s 0 succeed, 61073 failed, 0 different pages > > 0.528 s/loop, 0.009 ms/page, 231544.782 MiB/s 0 succeed, 61073 failed, 0 different pages > > 0.528 s/loop, 0.009 ms/page, 231462.074 MiB/s 0 succeed, 61073 failed, 0 different pages > > 0.527 s/loop, 0.009 ms/page, 231770.300 MiB/s 0 succeed, 61073 failed, 0 different pages > > ... > > ok 1 Completed > > > > Remove the HPAGE_SIZE and HPAGE_SHIFT macro and introduce pmd_pshift() > > helper to get the HPAGE_SHIFT properly. For HPAGE_SIZE, use pre-existing > > helper, pmd_psize(). > > > > Also, run the KSM_MERGE_TIME_HUGE_PAGES test with a size of 512 MiB, > > which is the least common multiple of the PMD sizes for 4 KiB, 16 KiB, > > and 64 KiB base pages. Since allocate_transhuge() allocates mappings in > > PMD-sized units, the test may fail with the previous size of 100 MiB, > > which is not a multiple of the PMD size when the base page size is > > 16 KiB or 64 KiB. > > > > After this patch, output of transhuge-stress: > > > > transhuge-stress: allocate 3817 transhuge pages, using 122146 MiB virtual memory and 119 MiB of ram > > 2.558 s/loop, 0.670 ms/page, 47755.759 MiB/s 2585 succeed, 1232 failed, 2585 different pages > > 2.640 s/loop, 0.692 ms/page, 46268.432 MiB/s 2585 succeed, 1232 failed, 2585 different pages > > 2.635 s/loop, 0.690 ms/page, 46360.298 MiB/s 2585 succeed, 1232 failed, 2585 different pages > > 2.782 s/loop, 0.729 ms/page, 43899.795 MiB/s 2616 succeed, 1201 failed, 2616 different pages > > 2.692 s/loop, 0.705 ms/page, 45380.876 MiB/s 2627 succeed, 1190 failed, 2627 different pages > > 2.612 s/loop, 0.684 ms/page, 46765.812 MiB/s 2628 succeed, 1189 failed, 2628 different pages > > 2.683 s/loop, 0.703 ms/page, 45520.990 MiB/s 2630 succeed, 1187 failed, 2630 different pages > > 2.727 s/loop, 0.714 ms/page, 44789.321 MiB/s 2631 succeed, 1186 failed, 2631 different pages > > ... > > ok 1 Completed > > > > Suggested-by: Lorenzo Stoakes (ARM) > > Signed-off-by: Yeoreum Yun > > --- > > [...] > > > index e712a980851c..fd1432dc6152 100644 > > --- a/tools/testing/selftests/mm/vm_util.c > > +++ b/tools/testing/selftests/mm/vm_util.c > > @@ -21,6 +21,8 @@ > > > > unsigned int __page_size; > > unsigned int __page_shift; > > +uint64_t __pmd_psize; > > +uint64_t __pmd_pshift; > > > > uint64_t pagemap_get_entry(int fd, char *start) > > { > > @@ -161,6 +163,9 @@ uint64_t pmd_psize(void) > > char buf[20]; > > ssize_t num_read; > > > > + if (__pmd_psize) > > + return __pmd_psize; > > The only suboptmial thing about these functions is that we keep querying > repeatedly in case of failure. > > If it failed once, it will fail always. > > You could either add a new variable for "queried" or encode it in the variables like > > uint64_t __pmd_psize = -1ull; > uint64_t __pmd_pshift = -1ull; > > To then set them to 0 or the actual value after we queried. Okay. I'll respin it with above. Thanks. -- Sincerely, Yeoreum Yun