From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 75A25311587 for ; Mon, 9 Feb 2026 22:14:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770675291; cv=none; b=fG7aY0r6yKGJx1n6Y4OWR+CFx6wuMkxCqrw6OLg8iagxh9jgW6B4VDrzfUHPBjnEO9GlEPeGKJLSxnpRh2MzDzjSlWKT0uxf9HCYWQoY8clB5X97DOIxj5k6YzxeldLOklVfqQ3CFP6ZElldaYmbHbRFs/Bx5E8k1bCv1+BrFks= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770675291; c=relaxed/simple; bh=rz3I5CnefwjIa5RddYfW7y6/+1Fv+qZ7VjvV6KH6G9g=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=r33Ty7UmY9aqgVxHShrOYuX4Fr5TzfhDl36RB749hbs47UgriHiiXXVuwvelHmUpHLoWnVCRsPUkJ1/PBNChB5EiqU70mQLrROqXlQd86JmEOOm6P1KDNUUvOA3OST/P8+sfiE50o7yxozlY3Mj5UE8Nlr1a5v3vwlloV79Ixks= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=ilj+ME0v; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ilj+ME0v" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1770675289; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=NfzhOy6xg1VuRqICbaMNurwJEWL8Ja4JqB6dHNFVjfc=; b=ilj+ME0v/OnhhHNunehoKhryTTwIC9DMFNT3W2WHNuolUJFNQuTuwhcTJgh/vm0jLgKhQK 2kqRaa5u+qStpm4tzrxEdg8O613aOTj5uHSwWyYJ7tpC4AZGWsDXxlicpDpkK0eoQMksse FZWBxrqykJUjyDs0to1pfISBUu/EcZU= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-157-so6k0CXbN9qiupln15RHPw-1; Mon, 09 Feb 2026 17:14:46 -0500 X-MC-Unique: so6k0CXbN9qiupln15RHPw-1 X-Mimecast-MFC-AGG-ID: so6k0CXbN9qiupln15RHPw_1770675285 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A28A61800282; Mon, 9 Feb 2026 22:14:44 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.22.65.66]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 430AB1800464; Mon, 9 Feb 2026 22:14:43 +0000 (UTC) From: Luiz Capitulino To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, david@kernel.org, baolin.wang@linux.alibaba.com Cc: ryan.roberts@arm.com, akpm@linux-foundation.org, lorenzo.stoakes@oracle.com Subject: [PATCH v2 00/11] mm: thp: always enable mTHP support Date: Mon, 9 Feb 2026 17:14:22 -0500 Message-ID: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 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+. v2 -- - Added support for always enabling mTHPs for shmem (Baolin) - Improved commits changelog & added reviewed-by v1 -- - Call init_arch_has_pmd_leaves() from start_kernel() - Keep pgtable_has_pmd_leaves() calls tied to CONFIG_TRANSPARENT_HUGEPAGE (David) - Clear PUD_ORDER when clearing PMD_ORDER (David) - Small changelog improvements (David) - Rebased on top of latest mm-new Luiz Capitulino (11): docs: tmpfs: remove implementation detail reference mm: introduce pgtable_has_pmd_leaves() drivers: dax: use pgtable_has_pmd_leaves() drivers: i915 selftest: use pgtable_has_pmd_leaves() drivers: nvdimm: use pgtable_has_pmd_leaves() mm: debug_vm_pgtable: use pgtable_has_pmd_leaves() mm: shmem: drop has_transparent_hugepage() usage treewide: rename has_transparent_hugepage() to arch_has_pmd_leaves() mm: replace thp_disabled_by_hw() with pgtable_has_pmd_leaves() mm: thp: always enable mTHP support mm: thp: x86: cleanup PSE feature bit usage Documentation/filesystems/tmpfs.rst | 5 ++--- arch/mips/include/asm/pgtable.h | 4 ++-- arch/mips/mm/tlb-r4k.c | 4 ++-- arch/powerpc/include/asm/book3s/64/hash-4k.h | 2 +- arch/powerpc/include/asm/book3s/64/hash-64k.h | 2 +- arch/powerpc/include/asm/book3s/64/pgtable.h | 10 +++++----- arch/powerpc/include/asm/book3s/64/radix.h | 2 +- arch/powerpc/mm/book3s64/hash_pgtable.c | 4 ++-- arch/s390/include/asm/pgtable.h | 4 ++-- arch/x86/include/asm/pgtable.h | 6 ------ arch/x86/include/asm/pgtable_32.h | 6 ++++++ drivers/dax/dax-private.h | 2 +- .../gpu/drm/i915/gem/selftests/huge_pages.c | 4 +++- drivers/nvdimm/pfn_devs.c | 6 ++++-- include/linux/huge_mm.h | 7 ------- include/linux/pgtable.h | 11 ++++++++-- init/main.c | 1 + mm/debug_vm_pgtable.c | 20 +++++++++---------- mm/huge_memory.c | 13 ++++++------ mm/memory.c | 10 +++++++++- mm/shmem.c | 11 +++++----- 21 files changed, 74 insertions(+), 60 deletions(-) -- 2.53.0