From: Kiryl Shutsemau <kirill@shutemov.name>
To: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Cc: akpm@linux-foundation.org, david@kernel.org,
nico.pache@linux.dev, baolin.wang@linux.alibaba.com,
baohua@kernel.org, dev.jain@arm.com, hughd@google.com,
lance.yang@linux.dev, liam@infradead.org, mhocko@suse.com,
rppt@kernel.org, ryan.roberts@arm.com, shuah@kernel.org,
surenb@google.com, usama.arif@linux.dev, vbabka@kernel.org,
ziy@nvidia.com, usama.anjum@arm.com, agordeev@linux.ibm.com,
linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 09/19] selftests/mm: add folio-order detection self-check
Date: Mon, 7 Sep 2026 14:11:15 +0100 [thread overview]
Message-ID: <ap63H6oZmka_oWpD@thinkstation> (raw)
In-Reply-To: <aoQzXhP0W0FVsvTp@lucifer>
On Tue, Aug 18, 2026 at 11:30:06AM +0100, Lorenzo Stoakes (ARM) wrote:
> On Sat, Aug 15, 2026 at 02:58:51AM +0100, Kiryl Shutsemau wrote:
> > From: "Kiryl Shutsemau (Meta)" <kas@kernel.org>
> >
> > The khugepaged mTHP tests detect collapse results with the vm_util
> > folio-order helpers rather than smaps AnonHugePages, which only sees PMD
> > mappings. If those helpers are wrong, every case built on them is wrong
> > the same way, and nothing says so.
> >
> > Check them directly. For every anon THP order the kernel supports, fault
> > memory in with only that order enabled. Require the helpers to classify
> > the backing as exactly that order: not a neighbouring order, and 4K-backed
> > memory as order 0.
> >
> > Run it in the thp category, ahead of ./khugepaged, so a broken helper is
> > reported as itself rather than as a collapse failure. Verified on x86-64
> > 4K (orders 0, 2-9) and arm64 64K (orders 0, 2-13).
> >
> > The test needs ALIGN(), which hmm-tests.c and migration.c each defined
> > privately. Move it to vm_util.h and drop both copies.
>
> Also:
>
> uffd-unit-tests defines ALIGN_UP()...
>
> And really you probably want to match the kernel convention of ALIGN()
> defaulting to align-up (for some reason) and name this ALIGN_DOWN() to be
> consistent and avoid confusion BUT...
Hm? It is align-up:
#define ALIGN(x, a) (((x) + (a) - 1) & ~((a) - 1))
It matches kernel definition.
pkey-helpers.h has ALIGN_UP(), ALIGN_DOWN() and two pointer variants of
its own. Folding those onto the vm_util.h one is worth doing, as a
follow-up rather than in this series.
--
Kiryl Shutsemau / Kirill A. Shutemov
next prev parent reply other threads:[~2026-09-07 13:11 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-15 1:58 [PATCH v4 00/19] selftests/mm: improve khugepaged coverage Kiryl Shutsemau
2026-08-15 1:58 ` [PATCH v4 01/19] selftests/mm: raise the khugepaged test-case cap Kiryl Shutsemau
2026-08-18 9:11 ` Lorenzo Stoakes (ARM)
2026-08-15 1:58 ` [PATCH v4 02/19] selftests/mm: skip collapse_compound_extreme() where the PMD is too large Kiryl Shutsemau
2026-08-18 9:22 ` Lorenzo Stoakes (ARM)
2026-08-15 1:58 ` [PATCH v4 03/19] selftests/mm: scale khugepaged's collapse wait with the PMD size Kiryl Shutsemau
2026-08-18 10:04 ` Lorenzo Stoakes (ARM)
2026-08-23 19:17 ` Kiryl Shutsemau
2026-08-15 1:58 ` [PATCH v4 04/19] selftests/mm: skip khugepaged page cache cases without a PMD folio Kiryl Shutsemau
2026-08-18 10:07 ` Lorenzo Stoakes (ARM)
2026-08-23 19:44 ` Kiryl Shutsemau
2026-08-20 8:40 ` Mike Rapoport
2026-08-15 1:58 ` [PATCH v4 05/19] selftests/mm: make the swap cases' swapout reliable Kiryl Shutsemau
2026-08-18 10:11 ` Lorenzo Stoakes (ARM)
2026-08-20 8:40 ` Mike Rapoport
2026-08-23 19:49 ` Kiryl Shutsemau
2026-08-15 1:58 ` [PATCH v4 06/19] selftests/mm: stop khugepaged during the MADV_COLLAPSE cases Kiryl Shutsemau
2026-08-18 10:12 ` Lorenzo Stoakes (ARM)
2026-08-20 8:40 ` Mike Rapoport
2026-08-15 1:58 ` [PATCH v4 07/19] selftests/mm: move is_backed_by_folio() into vm_util Kiryl Shutsemau
2026-08-18 10:14 ` Lorenzo Stoakes (ARM)
2026-08-15 1:58 ` [PATCH v4 08/19] selftests/mm: add folio-order check for address ranges Kiryl Shutsemau
2026-08-18 10:25 ` Lorenzo Stoakes (ARM)
2026-09-07 12:59 ` Kiryl Shutsemau
2026-08-20 8:40 ` Mike Rapoport
2026-08-15 1:58 ` [PATCH v4 09/19] selftests/mm: add folio-order detection self-check Kiryl Shutsemau
2026-08-18 10:30 ` Lorenzo Stoakes (ARM)
2026-09-07 13:11 ` Kiryl Shutsemau [this message]
2026-08-20 8:40 ` Mike Rapoport
2026-08-15 1:58 ` [PATCH v4 10/19] selftests/mm: add khugepaged completion barrier helper Kiryl Shutsemau
2026-08-18 10:34 ` Lorenzo Stoakes (ARM)
2026-08-20 8:40 ` Mike Rapoport
2026-08-15 1:58 ` [PATCH v4 11/19] selftests/mm: add order-parameterized khugepaged collapse cases Kiryl Shutsemau
2026-08-18 10:38 ` Lorenzo Stoakes (ARM)
2026-08-20 8:40 ` Mike Rapoport
2026-08-15 1:58 ` [PATCH v4 12/19] selftests/mm: parameterize the mixed-source collapse case by source order Kiryl Shutsemau
2026-08-18 10:47 ` Lorenzo Stoakes (ARM)
2026-08-20 8:40 ` Mike Rapoport
2026-09-07 13:40 ` Kiryl Shutsemau
2026-08-15 1:58 ` [PATCH v4 13/19] selftests/mm: cover a shared-source collapse write race Kiryl Shutsemau
2026-08-20 8:40 ` Mike Rapoport
2026-08-15 1:58 ` [PATCH v4 14/19] selftests/mm: run every supported collapse order by default Kiryl Shutsemau
2026-08-20 8:40 ` Mike Rapoport
2026-08-15 1:58 ` [PATCH v4 15/19] selftests/mm: check that one khugepaged pass collapses one window Kiryl Shutsemau
2026-08-15 1:58 ` [PATCH v4 16/19] selftests/mm: add khugepaged race harness Kiryl Shutsemau
2026-08-15 1:58 ` [PATCH v4 17/19] selftests/mm: race collapse of windows with holes Kiryl Shutsemau
2026-08-15 1:59 ` [PATCH v4 18/19] selftests/mm: add memory-pressure threads to the khugepaged race harness Kiryl Shutsemau
2026-08-15 1:59 ` [PATCH v4 19/19] selftests/mm: zap whole PTE tables in " Kiryl Shutsemau
2026-08-20 8:40 ` [PATCH v4 00/19] selftests/mm: improve khugepaged coverage Mike Rapoport
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