From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Zi Yan <ziy@nvidia.com>, Kiryl Shutsemau <kirill@shutemov.name>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Lorenzo Stoakes <ljs@kernel.org>, Mike Rapoport <rppt@kernel.org>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
Shuah Khan <shuah@kernel.org>,
"Kiryl Shutsemau (Meta)" <kas@kernel.org>,
Barry Song <baohua@kernel.org>, Dev Jain <dev.jain@arm.com>,
Lance Yang <lance.yang@linux.dev>,
"Liam R . Howlett" <liam@infradead.org>,
Michal Hocko <mhocko@suse.com>, Nico Pache <nico.pache@linux.dev>,
Ryan Roberts <ryan.roberts@arm.com>,
Suren Baghdasaryan <surenb@google.com>,
Usama Arif <usama.arif@linux.dev>,
Vlastimil Babka <vbabka@kernel.org>,
Yeoreum Yun <yeoreum.yun@arm.com>,
linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
linux-kernel@vger.kernel.org, kernel-team@meta.com
Subject: Re: [PATCH 1/4] selftests/mm: open pagemap and kpageflags once for check_huge()
Date: Thu, 1 Oct 2026 13:41:03 +0200 [thread overview]
Message-ID: <afbebeed-42cf-465d-89ce-3000fe361f11@kernel.org> (raw)
In-Reply-To: <C1FB2DE7-D93D-4CE0-A6D1-624CC0B9C8F8@nvidia.com>
On 9/29/26 17:28, Zi Yan wrote:
> On 29 Sep 2026, at 9:15, Kiryl Shutsemau wrote:
>
>> From: "Kiryl Shutsemau (Meta)" <kas@kernel.org>
>>
>> check_huge_anon() and check_huge_file() open /proc/self/pagemap and
>> /proc/kpageflags on every call and read the PMD size from sysfs on top.
>> The khugepaged test calls them hundreds of times.
>>
>> Open both once and keep the descriptors. A pagemap descriptor is tied
>> to the mm of the process that opened it, and the khugepaged fork() cases
>> call check_huge() from the child, so reopen it when getpid() changes.
>>
>> Cache the PMD size in read_pmd_pagesize() as well.
>
> This part might be overlapping with Yeoreum’s another series[1].
>
> [1] https://lore.kernel.org/all/20260921-fix_hpage_macro-v4-2-cdea4fc6ce3f@arm.com/
Yes, let's provide feedback there instead.
--
Cheers,
David
next prev parent reply other threads:[~2026-10-01 11:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-29 13:15 [PATCH 0/4] selftests/mm: check large folio results through check_huge() only Kiryl Shutsemau
2026-09-29 13:15 ` [PATCH 1/4] selftests/mm: open pagemap and kpageflags once for check_huge() Kiryl Shutsemau
2026-09-29 15:28 ` Zi Yan
2026-10-01 11:41 ` David Hildenbrand (Arm) [this message]
2026-09-29 13:15 ` [PATCH 2/4] selftests/mm: check sub-PMD ranges window by window in check_huge() Kiryl Shutsemau
2026-09-29 13:15 ` [PATCH 3/4] selftests/mm: check collapse results through check_huge() only Kiryl Shutsemau
2026-09-29 13:15 ` [PATCH 4/4] selftests/mm: check split results by position, drop gather_folio_orders() Kiryl Shutsemau
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