From nobody Sun Feb 8 14:10:50 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 F10C824A07C; Sun, 11 Jan 2026 08:28:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768120093; cv=none; b=iAcndcZKSo2YkmQKke5T+hIK8yKnWdWFxiMO8zH2sAdMFnsbLJazwbv858l2bXK4uneRqIqYrRKnB7ty7cssXhTBQsmuAaInoiD/Ll+tPBCJSUBGd+r+aDFklciCUyjLx/dxAloC166G4LAfeDKt9Rkbxkzv5ig+J7P5A9mLyVA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768120093; c=relaxed/simple; bh=lDFvaekhrX06KnCNy1QGia/PQK3dVcgIHt/+LyovC/0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=I0zj+LIHCmTMKdeymB1chnIkUt69Vx/OvuYhUZgdR4+9Tsuwq0XHA5V6MgZzCAU1nt3tTehRgO+700dP7dBN20ullJSUTuEMOuhXTgMwjBBu7ejQJZz5x9vJOFFjPbmYOsJBKAZsnL5G/I3fzyMn+dJf/NZnldPOsKjmeX22YCs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LnogDuI5; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LnogDuI5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B4542C16AAE; Sun, 11 Jan 2026 08:27:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768120092; bh=lDFvaekhrX06KnCNy1QGia/PQK3dVcgIHt/+LyovC/0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LnogDuI51Wh2iQtykCPtXb+3ZwA/RPXF6d1W7I46ki/6Jc1Rs5UH2koUxvRoftjQ9 kXOWSFLp7adBLDzqOa/pwWvk/PIqml9Sq6hkU4gc6esawH2itJoGxAIp9gutgA72Xz n/8CF/RqtYuyJnZgA/H+k+QHWoNn5raVznfrAotcaeM9akWVlrrNirLC1JBdfff39x 11g3rsfxu/EBXGCJjrQRnhc7OSOhAyltyPOWjiaR5/zeOHvR5rvxFxWVfB0ubMURqp ALAhKkqK48XbijPQ/wwWYl53Jdov2zbf7D88umc2xuGS132UCsNvFQYFmWOTA3Mq5q tBPzXtppm7Q/Q== From: Mike Rapoport To: Andrew Morton Cc: Alex Shi , Alexander Gordeev , Andreas Larsson , Borislav Petkov , Brian Cain , "Christophe Leroy (CS GROUP)" , Catalin Marinas , "David S. Miller" , Dave Hansen , David Hildenbrand , Dinh Nguyen , Geert Uytterhoeven , Guo Ren , Heiko Carstens , Helge Deller , Huacai Chen , Ingo Molnar , Johannes Berg , John Paul Adrian Glaubitz , Jonathan Corbet , Klara Modin , "Liam R. Howlett" , Lorenzo Stoakes , Magnus Lindholm , Matt Turner , Max Filippov , Michael Ellerman , Michal Hocko , Michal Simek , Mike Rapoport , Muchun Song , Oscar Salvador , Palmer Dabbelt , Pratyush Yadav , Richard Weinberger , Ritesh Harjani , Russell King , Stafford Horne , Suren Baghdasaryan , Thomas Bogendoerfer , Thomas Gleixner , Vasily Gorbik , Vineet Gupta , Vlastimil Babka , Will Deacon , x86@kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-cxl@vger.kernel.org, linux-doc@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-openrisc@vger.kernel.org, linux-parisc@vger.kernel.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-um@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, loongarch@lists.linux.dev, sparclinux@vger.kernel.org Subject: [PATCH v3 27/29] mm, arch: consolidate hugetlb CMA reservation Date: Sun, 11 Jan 2026 10:21:01 +0200 Message-ID: <20260111082105.290734-28-rppt@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260111082105.290734-1-rppt@kernel.org> References: <20260111082105.290734-1-rppt@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: "Mike Rapoport (Microsoft)" Every architecture that supports hugetlb_cma command line parameter reserves CMA areas for hugetlb during setup_arch(). This obfuscates the ordering of hugetlb CMA initialization with respect to the rest initialization of the core MM. Introduce arch_hugetlb_cma_order() callback to allow architectures report the desired order-per-bit of CMA areas and provide a week implementation of arch_hugetlb_cma_order() for architectures that don't support hugetlb with CMA. Use this callback in hugetlb_cma_reserve() instead if passing the order as parameter and call hugetlb_cma_reserve() from mm_core_init_early() rather than have it spread over architecture specific code. Signed-off-by: Mike Rapoport (Microsoft) --- .../driver-api/cxl/linux/early-boot.rst | 2 +- arch/arm64/include/asm/hugetlb.h | 2 -- arch/arm64/mm/hugetlbpage.c | 10 +++------- arch/arm64/mm/init.c | 9 --------- arch/powerpc/include/asm/hugetlb.h | 5 ----- arch/powerpc/kernel/setup-common.c | 1 - arch/powerpc/mm/hugetlbpage.c | 11 ++++------- arch/riscv/mm/hugetlbpage.c | 8 ++++++++ arch/riscv/mm/init.c | 2 -- arch/s390/kernel/setup.c | 2 -- arch/s390/mm/hugetlbpage.c | 8 ++++++++ arch/x86/kernel/setup.c | 4 ---- arch/x86/mm/hugetlbpage.c | 8 ++++++++ include/linux/hugetlb.h | 6 ++++-- mm/hugetlb_cma.c | 19 ++++++++++++++----- mm/mm_init.c | 1 + 16 files changed, 51 insertions(+), 47 deletions(-) diff --git a/Documentation/driver-api/cxl/linux/early-boot.rst b/Documentat= ion/driver-api/cxl/linux/early-boot.rst index a7fc6fc85fbe..414481f33819 100644 --- a/Documentation/driver-api/cxl/linux/early-boot.rst +++ b/Documentation/driver-api/cxl/linux/early-boot.rst @@ -125,7 +125,7 @@ The contiguous memory allocator (CMA) enables reservati= on of contiguous memory regions on NUMA nodes during early boot. However, CMA cannot reserve memo= ry on NUMA nodes that are not online during early boot. :: =20 - void __init hugetlb_cma_reserve(int order) { + void __init hugetlb_cma_reserve(void) { if (!node_online(nid)) /* do not allow reservations */ } diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/huge= tlb.h index 44c1f757bfcf..e6f8ff3cc630 100644 --- a/arch/arm64/include/asm/hugetlb.h +++ b/arch/arm64/include/asm/hugetlb.h @@ -56,8 +56,6 @@ extern void huge_pte_clear(struct mm_struct *mm, unsigned= long addr, #define __HAVE_ARCH_HUGE_PTEP_GET extern pte_t huge_ptep_get(struct mm_struct *mm, unsigned long addr, pte_t= *ptep); =20 -void __init arm64_hugetlb_cma_reserve(void); - #define huge_ptep_modify_prot_start huge_ptep_modify_prot_start extern pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep); diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index 1d90a7e75333..f8dd58ab67a8 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -36,16 +36,12 @@ * huge pages could still be served from those areas. */ #ifdef CONFIG_CMA -void __init arm64_hugetlb_cma_reserve(void) +unsigned int arch_hugetlb_cma_order(void) { - int order; - if (pud_sect_supported()) - order =3D PUD_SHIFT - PAGE_SHIFT; - else - order =3D CONT_PMD_SHIFT - PAGE_SHIFT; + return PUD_SHIFT - PAGE_SHIFT; =20 - hugetlb_cma_reserve(order); + return CONT_PMD_SHIFT - PAGE_SHIFT; } #endif /* CONFIG_CMA */ =20 diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 9d271aff7652..96711b8578fd 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -311,15 +311,6 @@ void __init bootmem_init(void) =20 arch_numa_init(); =20 - /* - * must be done after arch_numa_init() which calls numa_init() to - * initialize node_online_map that gets used in hugetlb_cma_reserve() - * while allocating required CMA size across online nodes. - */ -#if defined(CONFIG_HUGETLB_PAGE) && defined(CONFIG_CMA) - arm64_hugetlb_cma_reserve(); -#endif - kvm_hyp_reserve(); dma_limits_init(); =20 diff --git a/arch/powerpc/include/asm/hugetlb.h b/arch/powerpc/include/asm/= hugetlb.h index 86326587e58d..6d32a4299445 100644 --- a/arch/powerpc/include/asm/hugetlb.h +++ b/arch/powerpc/include/asm/hugetlb.h @@ -68,7 +68,6 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, pte_t pte, int dirty); =20 -void gigantic_hugetlb_cma_reserve(void) __init; #include =20 #else /* ! CONFIG_HUGETLB_PAGE */ @@ -77,10 +76,6 @@ static inline void flush_hugetlb_page(struct vm_area_str= uct *vma, { } =20 -static inline void __init gigantic_hugetlb_cma_reserve(void) -{ -} - static inline void __init hugetlbpage_init_defaultsize(void) { } diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup= -common.c index c8c42b419742..cb5b73adc250 100644 --- a/arch/powerpc/kernel/setup-common.c +++ b/arch/powerpc/kernel/setup-common.c @@ -1003,7 +1003,6 @@ void __init setup_arch(char **cmdline_p) fadump_cma_init(); kdump_cma_reserve(); kvm_cma_reserve(); - gigantic_hugetlb_cma_reserve(); =20 early_memtest(min_low_pfn << PAGE_SHIFT, max_low_pfn << PAGE_SHIFT); =20 diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index d3c1b749dcfc..558fafb82b8a 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -200,18 +200,15 @@ static int __init hugetlbpage_init(void) =20 arch_initcall(hugetlbpage_init); =20 -void __init gigantic_hugetlb_cma_reserve(void) +unsigned int __init arch_hugetlb_cma_order(void) { - unsigned long order =3D 0; - if (radix_enabled()) - order =3D PUD_SHIFT - PAGE_SHIFT; + return PUD_SHIFT - PAGE_SHIFT; else if (!firmware_has_feature(FW_FEATURE_LPAR) && mmu_psize_defs[MMU_PAG= E_16G].shift) /* * For pseries we do use ibm,expected#pages for reserving 16G pages. */ - order =3D mmu_psize_to_shift(MMU_PAGE_16G) - PAGE_SHIFT; + return mmu_psize_to_shift(MMU_PAGE_16G) - PAGE_SHIFT; =20 - if (order) - hugetlb_cma_reserve(order); + return 0; } diff --git a/arch/riscv/mm/hugetlbpage.c b/arch/riscv/mm/hugetlbpage.c index 375dd96bb4a0..a6d217112cf4 100644 --- a/arch/riscv/mm/hugetlbpage.c +++ b/arch/riscv/mm/hugetlbpage.c @@ -447,3 +447,11 @@ static __init int gigantic_pages_init(void) } arch_initcall(gigantic_pages_init); #endif + +unsigned int __init arch_hugetlb_cma_order(void) +{ + if (IS_ENABLED(CONFIG_64BIT)) + return PUD_SHIFT - PAGE_SHIFT; + + return 0; +} diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index 11ac4041afc0..848efeb9e163 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -311,8 +311,6 @@ static void __init setup_bootmem(void) memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va)); =20 dma_contiguous_reserve(dma32_phys_limit); - if (IS_ENABLED(CONFIG_64BIT)) - hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT); } =20 #ifdef CONFIG_RELOCATABLE diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index c1fe0b53c5ac..b60284328fe3 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -963,8 +963,6 @@ void __init setup_arch(char **cmdline_p) setup_uv(); dma_contiguous_reserve(ident_map_size); vmcp_cma_reserve(); - if (cpu_has_edat2()) - hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT); =20 reserve_crashkernel(); #ifdef CONFIG_CRASH_DUMP diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c index d42e61c7594e..d93417d1e53c 100644 --- a/arch/s390/mm/hugetlbpage.c +++ b/arch/s390/mm/hugetlbpage.c @@ -255,3 +255,11 @@ bool __init arch_hugetlb_valid_size(unsigned long size) else return false; } + +unsigned int __init arch_hugetlb_cma_order(void) +{ + if (cpu_has_edat2()) + return PUD_SHIFT - PAGE_SHIFT; + + return 0; +} diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index e2318fa9b1bb..e1efe3975aa0 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1189,10 +1189,6 @@ void __init setup_arch(char **cmdline_p) initmem_init(); dma_contiguous_reserve(max_pfn_mapped << PAGE_SHIFT); =20 - if (boot_cpu_has(X86_FEATURE_GBPAGES)) { - hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT); - } - /* * Reserve memory for crash kernel after SRAT is parsed so that it * won't consume hotpluggable memory. diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c index 58f7f2bd535d..3b26621c9128 100644 --- a/arch/x86/mm/hugetlbpage.c +++ b/arch/x86/mm/hugetlbpage.c @@ -42,3 +42,11 @@ static __init int gigantic_pages_init(void) arch_initcall(gigantic_pages_init); #endif #endif + +unsigned int __init arch_hugetlb_cma_order(void) +{ + if (boot_cpu_has(X86_FEATURE_GBPAGES)) + return PUD_SHIFT - PAGE_SHIFT; + + return 0; +} diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 019a1c5281e4..08fc332e88a7 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -279,6 +279,8 @@ void fixup_hugetlb_reservations(struct vm_area_struct *= vma); void hugetlb_split(struct vm_area_struct *vma, unsigned long addr); int hugetlb_vma_lock_alloc(struct vm_area_struct *vma); =20 +unsigned int arch_hugetlb_cma_order(void); + #else /* !CONFIG_HUGETLB_PAGE */ =20 static inline void hugetlb_dup_vma_private(struct vm_area_struct *vma) @@ -1316,9 +1318,9 @@ static inline spinlock_t *huge_pte_lock(struct hstate= *h, } =20 #if defined(CONFIG_HUGETLB_PAGE) && defined(CONFIG_CMA) -extern void __init hugetlb_cma_reserve(int order); +extern void __init hugetlb_cma_reserve(void); #else -static inline __init void hugetlb_cma_reserve(int order) +static inline __init void hugetlb_cma_reserve(void) { } #endif diff --git a/mm/hugetlb_cma.c b/mm/hugetlb_cma.c index e8e4dc7182d5..b1eb5998282c 100644 --- a/mm/hugetlb_cma.c +++ b/mm/hugetlb_cma.c @@ -134,12 +134,24 @@ static int __init cmdline_parse_hugetlb_cma_only(char= *p) =20 early_param("hugetlb_cma_only", cmdline_parse_hugetlb_cma_only); =20 -void __init hugetlb_cma_reserve(int order) +unsigned int __weak arch_hugetlb_cma_order(void) { - unsigned long size, reserved, per_node; + return 0; +} + +void __init hugetlb_cma_reserve(void) +{ + unsigned long size, reserved, per_node, order; bool node_specific_cma_alloc =3D false; int nid; =20 + if (!hugetlb_cma_size) + return; + + order =3D arch_hugetlb_cma_order(); + if (!order) + return; + /* * HugeTLB CMA reservation is required for gigantic * huge pages which could not be allocated via the @@ -149,9 +161,6 @@ void __init hugetlb_cma_reserve(int order) VM_WARN_ON(order <=3D MAX_PAGE_ORDER); cma_reserve_called =3D true; =20 - if (!hugetlb_cma_size) - return; - hugetlb_bootmem_set_nodes(); =20 for (nid =3D 0; nid < MAX_NUMNODES; nid++) { diff --git a/mm/mm_init.c b/mm/mm_init.c index 4cfe722da062..5099a973be5b 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -2680,6 +2680,7 @@ void __init __weak mem_init(void) =20 void __init mm_core_init_early(void) { + hugetlb_cma_reserve(); hugetlb_bootmem_alloc(); =20 free_area_init(); --=20 2.51.0