From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 E619BCA5A for ; Fri, 17 Jul 2026 00:02:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784246578; cv=none; b=Q0x1RDwaTHPoN7J0WjfMDelvS60nHvyV8Vl+2ZHa0J1b+E26Gd7dSIu6159Kjkr2vha7UbVIBwuzQTTgX9SgCJpUSGpEQN20J9d5KHkI1q9902hji7pe+dFhNVZ7f79EnFdiLzIKZnYvZGx2MRsA2oA9rb94e1C2CGxsYIGjjbo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784246578; c=relaxed/simple; bh=VE3wCRoG8bjq3ZeVcI9a1XWpd/MdgG13joeYu0+lEK0=; h=Date:To:From:Subject:Message-Id; b=DGhYrZpxwG7Xyu9EfMXjLPWrfS5XJyof1Y3PhpjSslhnW/vIr44knGmJ82ddydYAy9JmG1cEhz4DEXiGFyEf+/MmZ4H2Q0V0OPY4DDy0i9K7Ar3AX70O3LxnBRyQEkElqO2L6E+f1lkJeNEYnIM2MiSPzk3VzrO8juoDFLCq1SU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=FzFw7LSg; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="FzFw7LSg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BA6831F000E9; Fri, 17 Jul 2026 00:02:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1784246576; bh=YJZB6R2ZMzrh6RfBd6E5+OmvTXmnDztk2D7RIizFNGE=; h=Date:To:From:Subject; b=FzFw7LSghOBRbjq8jyN/bGNYicaX4t+x96PaHE7G/+C7SsAzdqkisOz62RTyZL3GS WTOc6r0gZb5cK0H3BjxT2cMjZhT+43Ngvq+wKAx3Je1dI6MZGgMDP1sIheH/oOofBE 5YiwhTGgN75754WSLsxnfsALG3d/SfpNEERozDI4= Date: Thu, 16 Jul 2026 17:02:56 -0700 To: mm-commits@vger.kernel.org,david@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-provide-free_reserved_pages-removing-x86-variant.patch added to mm-unstable branch Message-Id: <20260717000256.BA6831F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm: provide free_reserved_pages(), removing x86 variant has been added to the -mm mm-unstable branch. Its filename is mm-provide-free_reserved_pages-removing-x86-variant.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-provide-free_reserved_pages-removing-x86-variant.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: "David Hildenbrand (Arm)" Subject: mm: provide free_reserved_pages(), removing x86 variant Date: Thu, 16 Jul 2026 16:51:01 +0200 Let's extend free_reserved_page() in page_alloc.c to free_reserved_pages(), dropping the custom x86 variant. The common-code variant will consume an order, so adjust the x86 callers accordingly. Make free_reserved_pages() assume that we are freeing ordinary high-order pages, just with the special "reserved" flavor. The target use case for now is freeing vmemmap PMD pages. Set the refcount directly to 0 (instead of 1) and call __free_frozen_pages(). Set the page count to 0 before clearing PG_reserved, so someone checking PG_reserved (and not finding it set) to then try grabbing a ref would not suddenly have that ref be dropped. That is arguably cleaner and safer than the old way of doing it. Add some kerneldoc. Use a single adjust_managed_page_count() call. Link: https://lore.kernel.org/20260716-bootmem_info_part2-v2-2-4afc76c73d61@kernel.org Signed-off-by: David Hildenbrand (Arm) Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Muchun Song Reviewed-by: Zi Yan Reviewed-by: Dave Hansen Cc: Alexander Gordeev Cc: Andy Lutomirski Cc: "Borislav Petkov (AMD)" Cc: Brendan Jackman Cc: Christian Borntraeger Cc: Gerald Schaefer Cc: Heiko Carstens Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Johannes Weiner Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Oscar Salvador Cc: Peter Zijlstra Cc: Suren Baghdasaryan Cc: Sven Schnelle Cc: Vasily Gorbik Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- arch/x86/mm/init_64.c | 8 +------- include/linux/mm.h | 8 ++++++-- mm/page_alloc.c | 33 ++++++++++++++++++++++++++------- 3 files changed, 33 insertions(+), 16 deletions(-) --- a/arch/x86/mm/init_64.c~mm-provide-free_reserved_pages-removing-x86-variant +++ a/arch/x86/mm/init_64.c @@ -1000,12 +1000,6 @@ int arch_add_memory(int nid, u64 start, return add_pages(nid, start_pfn, nr_pages, params); } -static void free_reserved_pages(struct page *page, unsigned long nr_pages) -{ - while (nr_pages--) - free_reserved_page(page++); -} - static void __meminit free_pagetable(struct page *page) { /* bootmem page has reserved flag */ @@ -1038,7 +1032,7 @@ static void __meminit free_vmemmap_pages while (nr_pages--) put_page_bootmem(page++); } else { - free_reserved_pages(page, nr_pages); + free_reserved_pages(page, order); } } else { __free_pages(page, order); --- a/include/linux/mm.h~mm-provide-free_reserved_pages-removing-x86-variant +++ a/include/linux/mm.h @@ -3996,8 +3996,12 @@ extern unsigned long free_reserved_area( extern void adjust_managed_page_count(struct page *page, long count); -/* Free the reserved page into the buddy system, so it gets managed. */ -void free_reserved_page(struct page *page); +void free_reserved_pages(struct page *page, unsigned int order); + +static inline void free_reserved_page(struct page *page) +{ + free_reserved_pages(page, 0); +} static inline void mark_page_reserved(struct page *page) { --- a/mm/page_alloc.c~mm-provide-free_reserved_pages-removing-x86-variant +++ a/mm/page_alloc.c @@ -6389,15 +6389,34 @@ void adjust_managed_page_count(struct pa } EXPORT_SYMBOL(adjust_managed_page_count); -void free_reserved_page(struct page *page) +/** + * free_reserved_pages - free reserved pages + * @page: First page to free. + * @order: The page order to free. + * + * Free pages allocated through memblock during boot, letting the buddy + * manage them from now on. + * + * @page must be naturally aligned to the order and the order must not + * exceed MAX_PAGE_ORDER. All pages must be reserved. + */ +void free_reserved_pages(struct page *page, unsigned int order) { - clear_page_tag_ref(page); - ClearPageReserved(page); - init_page_count(page); - __free_page(page); - adjust_managed_page_count(page, 1); + const unsigned long nr_pages = 1UL << order; + int i; + + VM_WARN_ON_ONCE(!IS_ALIGNED(page_to_pfn(page), nr_pages)); + VM_WARN_ON_ONCE(order > MAX_PAGE_ORDER); + + for (i = 0; i < nr_pages; i++) { + clear_page_tag_ref(page + i); + set_page_count(page + i, 0); + ClearPageReserved(page + i); + } + adjust_managed_page_count(page, nr_pages); + __free_frozen_pages(page, order, FPI_NONE); } -EXPORT_SYMBOL(free_reserved_page); +EXPORT_SYMBOL(free_reserved_pages); static int page_alloc_cpu_dead(unsigned int cpu) { _ Patches currently in -mm which might be from david@kernel.org are sparc-mm-drop-custom-pte_clear_not_present_full.patch mm-drop-pte_clear_not_present_full.patch mm-cleanup-clear_not_present_full_ptes-and-rename-to-clear_non_present_ptes.patch x86-mm-drop-order-parameter-from-free_pagetable.patch mm-provide-free_reserved_pages-removing-x86-variant.patch s390-mm-use-free_reserved_pages-in-vmem_free_pages.patch mm-bootmem_info-allow-calling-free_bootmem_page-on-pages-without-a-bootmem_type.patch x86-mm-stop-marking-vmemmap-as-section_info.patch x86-mm-stop-marking-page-tables-as-mix_section_info.patch x86-mm-remove-config_have_bootmem_info_node.patch mm-hugetlb_vmemmap-remove-bootmem_info-leftovers.patch mm-sparse-remove-bootmem_infoh-include.patch mm-bootmem_info-remove-config_have_bootmem_info_node.patch mm-standardize-printing-for-pgtable-entries.patch