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Thu, 3 Jul 2025 14:30:54 GMT Received: from smtpav06.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id ABE3E58059; Thu, 3 Jul 2025 14:30:53 +0000 (GMT) Received: from smtpav06.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2A05358043; Thu, 3 Jul 2025 14:30:48 +0000 (GMT) Received: from [9.109.245.113] (unknown [9.109.245.113]) by smtpav06.dal12v.mail.ibm.com (Postfix) with ESMTP; Thu, 3 Jul 2025 14:30:47 +0000 (GMT) Message-ID: <3a99961c-6eda-434a-8721-58eaf8b989db@linux.ibm.com> Date: Thu, 3 Jul 2025 20:00:46 +0530 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 v2 4/7] mm/selftests: Fix split_huge_page_test failure on systems with 64KB page size To: Zi Yan Cc: David Hildenbrand , Aboorva Devarajan , akpm@linux-foundation.org, Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, shuah@kernel.org, pfalcato@suse.de, baolin.wang@linux.alibaba.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, ritesh.list@gmail.com References: <20250703060656.54345-1-aboorvad@linux.ibm.com> <20250703060656.54345-5-aboorvad@linux.ibm.com> <0e099baa-0a36-4ffd-821f-a7a4856fd52f@linux.ibm.com> <788EBC0F-67CB-4EE2-883F-A55CD394EE21@nvidia.com> Content-Language: en-US From: Donet Tom In-Reply-To: <788EBC0F-67CB-4EE2-883F-A55CD394EE21@nvidia.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: D03t7_6MGrbGXyfRp8-xBxLsF9Hy2eMx X-Authority-Analysis: v=2.4 cv=UtNjN/wB c=1 sm=1 tr=0 ts=68669420 cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=IkcTkHD0fZMA:10 a=Wb1JkmetP80A:10 a=VnNF1IyMAAAA:8 a=21Bkwq0YnMq5brnyCR8A:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-ORIG-GUID: tx_YuQD7yBpKDIN9Awfn9GQgTG13oirr X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNzAzMDEyMCBTYWx0ZWRfX4LOloxo/QbpE m9fQ2n14dHw8TGAcX+ZIf1i/sgX35PqrUrt7u+lSA5Z2F+wL47PrqM3z2lCChz27O1ZmdB18RlT UgV9mEwPbYk1sGRwyVGZGUFlvEDF09CTCeqYaAdnM2niNeFOqLEGqRNkjfbVyxP79OLTtO9cjCl c8hR5xdYlVCLoREElt8CFyeu7C73qv5Y4ZZLh7lHZHY37CfK4ozNkJuW3tUSknXDk3ingpa6NR9 S+woPxVVnWeCG2cpSAuYy6HMqALQ/xUEtvjtSLnGe0dBtjzsTeWiTPyzkhNJ/g1WqtYcESmVeFj x/rSm+E/1vhvA2kqOdc3G0+BKxz/a/jE4wxZBRLsFBFaB5cd4/jxslLo56XXG3+zqdSujlbj2se y5BDwcghSqI55qCbaUjHwzMLJFkbfYFOwHQnJbd4PU6CWBd6j64mP2nROOe4t59jee+YzAsC X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.1.7,FMLib:17.12.80.40 definitions=2025-07-03_04,2025-07-02_04,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 priorityscore=1501 phishscore=0 mlxscore=0 spamscore=0 mlxlogscore=999 adultscore=0 clxscore=1015 lowpriorityscore=0 bulkscore=0 impostorscore=0 malwarescore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2505280000 definitions=main-2507030120 On 7/3/25 7:51 PM, Zi Yan wrote: > On 3 Jul 2025, at 4:58, Donet Tom wrote: > >> On 7/3/25 1:52 PM, David Hildenbrand wrote: >>> On 03.07.25 08:06, Aboorva Devarajan wrote: >>>> From: Donet Tom >>>> >>>> The split_huge_page_test fails on systems with a 64KB base page size. >>>> This is because the order of a 2MB huge page is different: >>>> >>>> On 64KB systems, the order is 5. >>>> >>>> On 4KB systems, it's 9. >>>> >>>> The test currently assumes a maximum huge page order of 9, which is only >>>> valid for 4KB base page systems. On systems with 64KB pages, attempting >>>> to split huge pages beyond their actual order (5) causes the test to fail. >>>> >>>> In this patch, we calculate the huge page order based on the system's base >>>> page size. With this change, the tests now run successfully on both 64KB >>>> and 4KB page size systems. >>>> >>>> Fixes: fa6c02315f745 ("mm: huge_memory: a new debugfs interface for splitting THP tests") >>>> Signed-off-by: Donet Tom >>>> Signed-off-by: Aboorva Devarajan >>>> --- >>>>   .../selftests/mm/split_huge_page_test.c       | 23 ++++++++++++++----- >>>>   1 file changed, 17 insertions(+), 6 deletions(-) >>>> >>>> diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c >>>> index aa7400ed0e99..38296a758330 100644 >>>> --- a/tools/testing/selftests/mm/split_huge_page_test.c >>>> +++ b/tools/testing/selftests/mm/split_huge_page_test.c >>>> @@ -514,6 +514,15 @@ void split_thp_in_pagecache_to_order_at(size_t fd_size, const char *fs_loc, >>>>       } >>>>   } >>>>   +static unsigned int get_order(unsigned int pages) >>>> +{ >>>> +    unsigned int order = 0; >>>> + >>>> +    while ((1U << order) < pages) >>>> +        order++; >>>> +    return order; >>>> +} >>> I think this can simply be >>> >>> return 32 - __builtin_clz(pages - 1); >>> >>> That mimics what get_order() in the kernel does for BITS_PER_LONG == 32 >>> >>> or simpler >>> >>> return 31 - __builtin_clz(pages); >>> >>> E.g., if pages=512, you get 31-22=9 >> >> Sure David, We will  change it. >> >> >>>> + >>>>   int main(int argc, char **argv) >>>>   { >>>>       int i; >>>> @@ -523,6 +532,7 @@ int main(int argc, char **argv) >>>>       const char *fs_loc; >>>>       bool created_tmp; >>>>       int offset; >>>> +    unsigned int max_order; >>>>         ksft_print_header(); >>>>   @@ -534,32 +544,33 @@ int main(int argc, char **argv) >>>>       if (argc > 1) >>>>           optional_xfs_path = argv[1]; >>>>   -    ksft_set_plan(1+8+1+9+9+8*4+2); >>>> - >>>>       pagesize = getpagesize(); >>>>       pageshift = ffs(pagesize) - 1; >>>>       pmd_pagesize = read_pmd_pagesize(); >>>>       if (!pmd_pagesize) >>>>           ksft_exit_fail_msg("Reading PMD pagesize failed\n"); >>>>   +    max_order = get_order(pmd_pagesize/pagesize); >>>> + ksft_set_plan(1+(max_order-1)+1+max_order+max_order+(max_order-1)*4+2); >>> Wow. Can we simplify that in any sane way? >> >> It is counting test by test. Let me try to simplify it and send the next version. > Yeah, I did that (ksft_set_plan(1+8+1+9+9+8*4+2);) to count different tests > separately and in the same order as the following tests, so that I could > get ksft_set_plan number right when adding or removing tests. Maybe it is > fine to just sum them up now. Sure. Thank you > > Best Regards, > Yan, Zi >