From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 F1AAE364924 for ; Wed, 8 Apr 2026 21:56:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775685367; cv=none; b=B6NCfycDJRB9Tso3XJXIZ5l8YcI9G18P1CUlvGpaFzlCHTQEAh5TVQ+xR5sHS9C8R9tQmZW5I80Gu08VE/iu0HzWna5fVghJ9VlO+M7FnpJOoO4Kv/f59zxTG+iQsUkD21YQ1SlBS+0hpMoaHI8egqcuPMe1lrD/8SSGzIFFXV8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775685367; c=relaxed/simple; bh=4Cmwdyn4KBE9B5STg5nSgoTldKL37xXx1HY1SITF3jQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=n7iNut5V32a+DQ9mUZTSjjgkmHoblA5wwP2ODLV9LzgzVg9QAWZ4FFsTC8PuzyzsTUM1H2Tdej/wTKhuBbRvUhJy13Jd0qVgL3SmEh6kJr2KJPDUeWzZ+SCMEljq+T7vS4NIVj0RFuSzFpb+17XRpoXQknFY/SKlXN/E2h8kjMo= 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=TGEQZz4k; arc=none smtp.client-ip=170.10.133.124 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="TGEQZz4k" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1775685365; 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=Hq35SUBjwxqd9KLJl2OrltCPEV7I2pvAcKQjuEe3wRk=; b=TGEQZz4kKV+XV2M41sxH5oYfqcu4b45iyX+gPk4TTSNI9aSn6Se3yHdBPGbSsgLPHZNv6c 9J4lSQDc7DOHng4a0XwOVOYxJHjwR4FdNOqBLj7twZ7ZPv0maHBK7P+C5Thu4YskFZzUf1 6GNGIjvP64Cm2Yo/MBbC/DzS41pVLZA= 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-683-pPCBymwrMiOTTKtZJl09dA-1; Wed, 08 Apr 2026 16:23:18 -0400 X-MC-Unique: pPCBymwrMiOTTKtZJl09dA-1 X-Mimecast-MFC-AGG-ID: pPCBymwrMiOTTKtZJl09dA_1775679795 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 0F34D1800617; Wed, 8 Apr 2026 20:23:15 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.22.88.140]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 6DDF71800671; Wed, 8 Apr 2026 20:23:13 +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 v3 00/10] mm: thp: always enable mTHP support Date: Wed, 8 Apr 2026 16:22:55 -0400 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 Linus tree bfe62a454542 ("Merge tag 'soc-fixes-7.0-2' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc"). v3 -- - Rebased on top of latest Linus tree - Removed i915 patch as driver dropped has_transparent_hugepage() usage - Moved init_arch_has_pmd_leaves() call in start_kernel() to avoid conflict with early_param handlers clearing CPU feature flags - Fixed build error with CONFIG_MMU=n (kernel test robot) - Fixed huge_anon_orders_inherit default setting when !pgtable_pmd_leaves() (Baolin) - Small commit changelog improvements 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 (10): docs: tmpfs: remove implementation detail reference mm: introduce pgtable_has_pmd_leaves() drivers: dax: 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 +- drivers/nvdimm/pfn_devs.c | 6 ++++-- include/linux/huge_mm.h | 7 ------- include/linux/pgtable.h | 19 ++++++++++++++++-- init/main.c | 1 + mm/debug_vm_pgtable.c | 20 +++++++++---------- mm/huge_memory.c | 15 +++++++------- mm/memory.c | 10 +++++++++- mm/shmem.c | 11 +++++----- 20 files changed, 80 insertions(+), 60 deletions(-) -- 2.53.0