Re: [PATCH v5 8/8] mm: huge_memory: enable debugfs to split huge pages to any order.

From: Zi Yan <ziy@nvidia.com>
To: Aishwarya TCV <aishwarya.tcv@arm.com>
Cc: "\"Pankaj Raghav (Samsung)\"" <kernel@pankajraghav.com>,
	linux-mm@kvack.org,
	"\"Matthew Wilcox (Oracle)\"" <willy@infradead.org>,
	"David Hildenbrand" <david@redhat.com>,
	"Yang Shi" <shy828301@gmail.com>, "Yu Zhao" <yuzhao@google.com>,
	"\"Kirill A . Shutemov\"" <kirill.shutemov@linux.intel.com>,
	"Ryan Roberts" <ryan.roberts@arm.com>,
	"\"Michal Koutný\"" <mkoutny@suse.com>,
	"Roman Gushchin" <roman.gushchin@linux.dev>,
	"\"Zach O'Keefe\"" <zokeefe@google.com>,
	"Hugh Dickins" <hughd@google.com>,
	"Luis Chamberlain" <mcgrof@kernel.org>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	"Mark Brown" <broonie@kernel.org>
Subject: Re: [PATCH v5 8/8] mm: huge_memory: enable debugfs to split huge pages to any order.
Date: Mon, 04 Mar 2024 09:58:26 -0500	[thread overview]
Message-ID: <1829EABB-7966-4686-A5E0-F6B6D26C510E@nvidia.com> (raw)
In-Reply-To: <0be630f0-ce8e-4a80-b42f-697ea603cfc6@arm.com>

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On 4 Mar 2024, at 4:50, Aishwarya TCV wrote:

> On 01/03/2024 21:10, Zi Yan wrote:
>> On 1 Mar 2024, at 15:02, Zi Yan wrote:
>>
>>> On 1 Mar 2024, at 14:37, Zi Yan wrote:
>>>
>>>> On 1 Mar 2024, at 4:51, Aishwarya TCV wrote:
>>>>
>>>>> On 26/02/2024 20:55, Zi Yan wrote:
>>>>>> From: Zi Yan <ziy@nvidia.com>
>>>>>>
>>>>>> It is used to test split_huge_page_to_list_to_order for pagecache THPs.
>>>>>> Also add test cases for split_huge_page_to_list_to_order via both
>>>>>> debugfs.
>>>>>>
>>>>>> Signed-off-by: Zi Yan <ziy@nvidia.com>
>>>>>> ---
>>>>>>  mm/huge_memory.c                              |  34 ++++--
>>>>>>  .../selftests/mm/split_huge_page_test.c       | 115 +++++++++++++++++-
>>>>>>  2 files changed, 131 insertions(+), 18 deletions(-)
>>>>>>
>>>>>
>>>>> Hi Zi,
>>>>>
>>>>> When booting the kernel against next-master(20240228)with Arm64 on
>>>>> Marvell Thunder X2 (TX2), the kselftest-mm test 'split_huge_page_test'
>>>>> is failing in our CI (with rootfs over NFS). I can send the full logs if
>>>>> required.
>>>>>
>>>>> A bisect (full log below) identified this patch as introducing the
>>>>> failure. Bisected it on the tag "next-20240228" at repo
>>>>> "https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git".
>>>>>
>>>>> This works fine on  Linux version 6.8.0-rc6
>>>>
>>>> Hi Aishwarya,
>>>>
>>>> Can you try the attached patch and see if it fixes the failure? I changed
>>>> the test to accept XFS dev as input, mount XFS on a temp folder under /tmp,
>>>> and skip if no XFS is mounted.
>>>
>>> Please try this updated one. It allows you to specify a XFS device path
>>> in SPLIT_HUGE_PAGE_TEST_XFS_PATH env variable, which is passed to
>>> split_huge_page_test in run_vmtests.sh. It at least allow CI/CD to run
>>> the test without too much change.
>>
>> OK. This hopefully will be my last churn. Now split_huge_page_test accepts
>> a path that is backed by XFS and run_vmtest.sh creates a XFS image in /tmp,
>> mounts it in /tmp, and gives the path to split_huge_page_test. I tested
>> it locally and it works. Let me know if you have any issue. Thanks.
>>
>> --
>> Best Regards,
>> Yan, Zi
>
> Hi Zi,
>
> Tested the patch by applying it on next-20240304. Logs from our CI with
> rootfs over nfs is attached below. "Bail out! cannot remove tmp dir:
> Directory not empty" is still observed.

Hi Aishwarya,

Do you have the config file for the CI kernel? And /tmp is also on nfs?
Any detailed information about CI machine environment? I cannot reproduce
the error locally, either on bare metal or VM. Maybe because my /tmp is
not NFS mounted?

>
>
> Test run log:
> # # ------------------------------
> # # running ./split_huge_page_test
> # # ------------------------------
> # # TAP version 13
> # # 1..12
> # # ok 1 Split huge pages successful
> # # ok 2 Split PTE-mapped huge pages successful
> # # # Please enable pr_debug in split_huge_pages_in_file() for more info.
> # # # Please check dmesg for more information
> # # ok 3 File-backed THP split test done
> <6>[  639.821657] split_huge_page (111099): drop_caches: 3
> <6>[  639.821657] split_huge_page (111099): drop_caches: 3
> # # # No large pagecache folio generated, please provide a filesystem
> supporting large folio
> # # ok 4 # SKIP Pagecache folio split skipped
> <6>[  645.392184] split_huge_page (111099): drop_caches: 3
> <6>[  645.392184] split_huge_page (111099): drop_caches: 3
> # # # No large pagecache folio generated, please provide a filesystem
> supporting large folio
> # # ok 5 # SKIP Pagecache folio split skipped
> <6>[  650.938248] split_huge_page (111099): drop_caches: 3
> <6>[  650.938248] split_huge_page (111099): drop_caches: 3
> # # # No large pagecache folio generated, please provide a filesystem
> supporting large folio
> # # ok 6 # SKIP Pagecache folio split skipped
> <6>[  656.500149] split_huge_page (111099): drop_caches: 3
> <6>[  656.500149] split_huge_page (111099): drop_caches: 3
> # # # No large pagecache folio generated, please provide a filesystem
> supporting large folio
> # # ok 7 # SKIP Pagecache folio split skipped
> <6>[  662.044085] split_huge_page (111099): drop_caches: 3
> <6>[  662.044085] split_huge_page (111099): drop_caches: 3
> # # # No large pagecache folio generated, please provide a filesystem
> supporting large folio
> # # ok 8 # SKIP Pagecache folio split skipped
> <6>[  667.591841] split_huge_page (111099): drop_caches: 3
> <6>[  667.591841] split_huge_page (111099): drop_caches: 3
> # # # No large pagecache folio generated, please provide a filesystem
> supporting large folio
> # # ok 9 # SKIP Pagecache folio split skipped
> <6>[  673.172441] split_huge_page (111099): drop_caches: 3
> <6>[  673.172441] split_huge_page (111099): drop_caches: 3
> # # # No large pagecache folio generated, please provide a filesystem
> supporting large folio
> # # ok 10 # SKIP Pagecache folio split skipped
> <6>[  678.726263] split_huge_page (111099): drop_caches: 3
> <6>[  678.726263] split_huge_page (111099): drop_caches: 3
> # # # No large pagecache folio generated, please provide a filesystem
> supporting large folio
> # # ok 11 # SKIP Pagecache folio split skipped
> <6>[  684.272851] split_huge_page (111099): drop_caches: 3
> <6>[  684.272851] split_huge_page (111099): drop_caches: 3
> # # # No large pagecache folio generated, please provide a filesystem
> supporting large folio
> # # ok 12 # SKIP Pagecache folio split skipped
> # # Bail out! cannot remove tmp dir: Directory not empty
> # # # Totals: pass:3 fail:0 xfail:0 xpass:0 skip:9 error:0
> # # [FAIL]
> # not ok 51 split_huge_page_test # exit=1
> # # ------------------
>
> Thanks,
> Aishwarya

--
Best Regards,
Yan, Zi

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