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From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Luiz Capitulino <luizcap@redhat.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	baolin.wang@linux.alibaba.com
Cc: ryan.roberts@arm.com, akpm@linux-foundation.org,
	lorenzo.stoakes@oracle.com
Subject: Re: [PATCH v2 00/11] mm: thp: always enable mTHP support
Date: Wed, 8 Apr 2026 16:14:37 +0200	[thread overview]
Message-ID: <3b7d20c2-a0c7-42c9-b303-1dfd6503cae1@kernel.org> (raw)
In-Reply-To: <8d03a508-5836-4001-8eb8-b216251dc29d@redhat.com>

On 4/2/26 13:56, Luiz Capitulino wrote:
> On 2026-04-02 04:25, David Hildenbrand (Arm) wrote:
>> On 2/9/26 23:14, Luiz Capitulino wrote:
>>> Today, if an architecture implements has_transparent_hugepage() and
>>> the CPU
>>> lacks support for PMD-sized pages, the THP code disables all THP,
>>> including
>>> mTHP. In addition, the kernel lacks a well defined API to check for
>>> PMD-sized page support. It currently relies on
>>> has_transparent_hugepage()
>>> and thp_disabled_by_hw(), but they are not well defined and are tied to
>>> THP support.
>>>
>>> This series addresses both issues by introducing a new well defined API
>>> to query PMD-sized page support: pgtable_has_pmd_leaves(). Using this
>>> new helper, we ensure that mTHP remains enabled even when the
>>> architecture or CPU doesn't support PMD-sized pages.
>>>
>>> Thanks to David Hildenbrand for suggesting this improvement and for
>>> providing guidance (all bugs and misconceptions are mine).
>>>
>>> This applies to v6.19, but I tested it on v6.19-rc8+.
>>
>> Apologies for the delay Luiz (as told you off-list :) ), I'll try going
>> through this soon so we can start queuing this after -rc1.
> 
> Oh, wow, thanks for the support!
> 
> I intended to get back to this series this week to address Baolin's
> comments, but I got busy with other things (which is something I may
> bring up on upstream but it's not related to this series at all).
> 

Okay, I'll wait for your next posting and prioritize that :)

-- 
Cheers,

David


      reply	other threads:[~2026-04-08 14:14 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-09 22:14 Luiz Capitulino
2026-02-09 22:14 ` [PATCH v2 01/11] docs: tmpfs: remove implementation detail reference Luiz Capitulino
2026-02-09 22:14 ` [PATCH v2 02/11] mm: introduce pgtable_has_pmd_leaves() Luiz Capitulino
2026-02-10  7:45   ` kernel test robot
2026-02-10  8:05   ` kernel test robot
2026-02-09 22:14 ` [PATCH v2 03/11] drivers: dax: use pgtable_has_pmd_leaves() Luiz Capitulino
2026-02-09 22:14 ` [PATCH v2 04/11] drivers: i915 selftest: " Luiz Capitulino
2026-02-09 22:14 ` [PATCH v2 05/11] drivers: nvdimm: " Luiz Capitulino
2026-02-09 22:14 ` [PATCH v2 06/11] mm: debug_vm_pgtable: " Luiz Capitulino
2026-02-09 22:14 ` [PATCH v2 07/11] mm: shmem: drop has_transparent_hugepage() usage Luiz Capitulino
2026-02-10  9:20   ` Baolin Wang
2026-04-08 20:32     ` Luiz Capitulino
2026-02-09 22:14 ` [PATCH v2 08/11] treewide: rename has_transparent_hugepage() to arch_has_pmd_leaves() Luiz Capitulino
2026-02-09 22:14 ` [PATCH v2 09/11] mm: replace thp_disabled_by_hw() with pgtable_has_pmd_leaves() Luiz Capitulino
2026-02-09 22:14 ` [PATCH v2 10/11] mm: thp: always enable mTHP support Luiz Capitulino
2026-02-10  9:56   ` Baolin Wang
2026-02-10 13:28     ` Luiz Capitulino
2026-02-11  1:12       ` Baolin Wang
2026-04-08 20:37     ` Luiz Capitulino
2026-02-09 22:14 ` [PATCH v2 11/11] mm: thp: x86: cleanup PSE feature bit usage Luiz Capitulino
2026-04-02  8:25 ` [PATCH v2 00/11] mm: thp: always enable mTHP support David Hildenbrand (Arm)
2026-04-02 11:56   ` Luiz Capitulino
2026-04-08 14:14     ` David Hildenbrand (Arm) [this message]

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