Commit abb7962a authored by Anshuman Khandual's avatar Anshuman Khandual Committed by Catalin Marinas
Browse files

arm64/hugetlb: Reserve CMA areas for gigantic pages on 16K and 64K configs 



Currently 'hugetlb_cma=' command line argument does not create CMA area on
ARM64_16K_PAGES and ARM64_64K_PAGES based platforms. Instead, it just ends
up with the following warning message. Reason being, hugetlb_cma_reserve()
never gets called for these huge page sizes.

[   64.255669] hugetlb_cma: the option isn't supported by current arch

This enables CMA areas reservation on ARM64_16K_PAGES and ARM64_64K_PAGES
configs by defining an unified arm64_hugetlb_cma_reseve() that is wrapped
in CONFIG_CMA. Call site for arm64_hugetlb_cma_reserve() is also protected
as <asm/hugetlb.h> is conditionally included and hence cannot contain stub
for the inverse config i.e !(CONFIG_HUGETLB_PAGE && CONFIG_CMA).

Signed-off-by: default avatarAnshuman Khandual <anshuman.khandual@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Barry Song <song.bao.hua@hisilicon.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/1593578521-24672-1-git-send-email-anshuman.khandual@arm.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 0de674af

arch/arm64/include/asm/hugetlb.h

+2 −0
Original line number Diff line number Diff line
@@ -49,6 +49,8 @@ extern void set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr, 
				 pte_t *ptep, pte_t pte, unsigned long sz);

#define set_huge_swap_pte_at set_huge_swap_pte_at



void __init arm64_hugetlb_cma_reserve(void);



#include <asm-generic/hugetlb.h>



#endif /* __ASM_HUGETLB_H */

arch/arm64/mm/hugetlbpage.c

+38 −0
Original line number Diff line number Diff line
@@ -19,6 +19,44 @@ 
#include <asm/tlbflush.h>

#include <asm/pgalloc.h>



/*

 * HugeTLB Support Matrix

 *

 * ---------------------------------------------------

 * | Page Size | CONT PTE |  PMD  | CONT PMD |  PUD  |

 * ---------------------------------------------------

 * |     4K    |   64K    |   2M  |    32M   |   1G  |

 * |    16K    |    2M    |  32M  |     1G   |       |

 * |    64K    |    2M    | 512M  |    16G   |       |

 * ---------------------------------------------------

 */



/*

 * Reserve CMA areas for the largest supported gigantic

 * huge page when requested. Any other smaller gigantic

 * huge pages could still be served from those areas.

 */

#ifdef CONFIG_CMA

void __init arm64_hugetlb_cma_reserve(void)

{

	int order;



#ifdef CONFIG_ARM64_4K_PAGES

	order = PUD_SHIFT - PAGE_SHIFT;

#else

	order = CONT_PMD_SHIFT + PMD_SHIFT - PAGE_SHIFT;

#endif

	/*

	 * HugeTLB CMA reservation is required for gigantic

	 * huge pages which could not be allocated via the

	 * page allocator. Just warn if there is any change

	 * breaking this assumption.

	 */

	WARN_ON(order <= MAX_ORDER);

	hugetlb_cma_reserve(order);

}

#endif /* CONFIG_CMA */



#ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION

bool arch_hugetlb_migration_supported(struct hstate *h)

{

arch/arm64/mm/init.c

+2 −2
Original line number Diff line number Diff line
@@ -425,8 +425,8 @@ void __init bootmem_init(void) 
	 * initialize node_online_map that gets used in hugetlb_cma_reserve()

	 * while allocating required CMA size across online nodes.

	 */

#ifdef CONFIG_ARM64_4K_PAGES

	hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT);

#if defined(CONFIG_HUGETLB_PAGE) && defined(CONFIG_CMA)

	arm64_hugetlb_cma_reserve();

#endif



	/*

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