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 84388477E4B; Wed, 8 Jul 2026 14:11:22 +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=1783519883; cv=none; b=grZUfuI0C5Yg679Wq3d0oZ+9IpRhw+Bwp3/Yxnl9QsVuHc2W+2PZfvmfXMEMzzXnKJqTG+uaXi/qZA3W/+kv4lWeOMeoK+lmxPo73FhXiHQBzrusgklRI9eE1lbrLHYEWfDDmNYDQ6SzcWm5ew7JB1a4R1RK+njzCN14oOzQZPE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783519883; c=relaxed/simple; bh=R6RRxAe6UnpB4HUgVrDT8mxjhDhatyd6BNWiNfIDF2k=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=EHKrxfxzQobuzixkfGKVsC4A9C3nRHKAZRvpZLpt37Crt3CApJEyLpf2Zf6rlGz+h4ixnWcZmPRLNJ69INua3FbNwxW71Ao6rh55noqxsicz5ewTX6NuCu54IGBffUTJNw86A1/T+WR12JMcYml54bjvDbKcgrJDjfS94mPg2vg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ckeOtBFV; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ckeOtBFV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E4A861F00A3A; Wed, 8 Jul 2026 14:11:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783519882; bh=tFyxPJ20nGKU5oJlQlEyooEUxC7eruHMjD4D5VqWTN4=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=ckeOtBFVWD1BusC3wMJcCqaTHmmEoHVgbLMGflu6kKlHozSqdtjnGzjb+7zJJ6VW9 VXatpfZhH7LW8uxrhnywjtXc9clRoKAbB0EVZrK1HS/SY+c0KemZnwjlTeEsFH84jR EHlR2ZitN+nlpIq7ZuM6mQyNUKLWaTNi2N7sKIQ7R0RseEEv7tUp0Fa8Z6LH97lhs8 +vvd80Nsy3C83H6H/PjuIHWfxiug6bK3hh/G9GT+ml8eB++m4oxmamKJwmHM0XPzTq 2e2oCRenybfCBPgg0qnZfUCpbQasLxBDNtCd/WKsHmfAQGoowgExk56GdvNe3nmnNe V5JUngawtF9kg== From: "David Hildenbrand (Arm)" Date: Wed, 08 Jul 2026 16:10:57 +0200 Subject: [PATCH 02/10] mm: provide free_reserved_pages(), removing x86 variant Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260708-bootmem_info_part2-v1-2-156ce4986598@kernel.org> References: <20260708-bootmem_info_part2-v1-0-156ce4986598@kernel.org> In-Reply-To: <20260708-bootmem_info_part2-v1-0-156ce4986598@kernel.org> To: Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , Muchun Song , Oscar Salvador Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-s390@vger.kernel.org, "David Hildenbrand (Arm)" X-Mailer: b4 0.15.2 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(). Add some kerneldoc. Use a single adjust_managed_page_count() call. Signed-off-by: David Hildenbrand (Arm) --- arch/x86/mm/init_64.c | 8 +------- include/linux/mm.h | 8 ++++++-- mm/page_alloc.c | 33 ++++++++++++++++++++++++++------- 3 files changed, 33 insertions(+), 16 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 69e36f02a663a..320e742b0bb3f 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -1000,12 +1000,6 @@ int arch_add_memory(int nid, u64 start, u64 size, 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(struct page *page, unsigned int order, while (nr_pages--) put_page_bootmem(page++); } else { - free_reserved_pages(page, nr_pages); + free_reserved_pages(page, order); } } else { __free_pages(page, order); diff --git a/include/linux/mm.h b/include/linux/mm.h index 113e1752548c2..62b261cccf16f 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3993,8 +3993,12 @@ extern unsigned long free_reserved_area(void *start, void *end, 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) { diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a63733dac659e..9311d1f3793ad 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6381,15 +6381,34 @@ void adjust_managed_page_count(struct page *page, long count) } 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); + ClearPageReserved(page + i); + set_page_count(page + i, 0); + } + 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) { -- 2.43.0