From: Mike Kravetz <mike.kravetz@oracle.com> stable inclusion from stable-5.10.75 commit a31c33aa80a550b3848024533bda215a0aa52e0b bugzilla: 182987 https://gitee.com/openeuler/kernel/issues/I4I3MP Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 2e5809a4ddb15969503e43b06662a9a725f613ea upstream. For non-4K PAGE_SIZE configs, the largest gigantic huge page size is CONT_PMD_SHIFT order. On arm64 with 64K PAGE_SIZE, the gigantic page is 16G. Therefore, one should be able to specify 'hugetlb_cma=16G' on the kernel command line so that one gigantic page can be allocated from CMA. However, when adding such an option the following message is produced: hugetlb_cma: cma area should be at least 8796093022208 MiB This is because the calculation for non-4K gigantic page order is incorrect in the arm64 specific routine arm64_hugetlb_cma_reserve(). Fixes: abb7962adc80 ("arm64/hugetlb: Reserve CMA areas for gigantic pages on 16K and 64K configs") Cc: <stable@vger.kernel.org> # 5.9.x Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Link: https://lore.kernel.org/r/20211005202529.213812-1-mike.kravetz@oracle.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Chen Jun <chenjun102@huawei.com> Acked-by: Weilong Chen <chenweilong@huawei.com> Signed-off-by: Chen Jun <chenjun102@huawei.com> --- arch/arm64/mm/hugetlbpage.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index 55ecf6de9ff7..99cd6e718408 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -43,7 +43,7 @@ void __init arm64_hugetlb_cma_reserve(void) #ifdef CONFIG_ARM64_4K_PAGES order = PUD_SHIFT - PAGE_SHIFT; #else - order = CONT_PMD_SHIFT + PMD_SHIFT - PAGE_SHIFT; + order = CONT_PMD_SHIFT - PAGE_SHIFT; #endif /* * HugeTLB CMA reservation is required for gigantic -- 2.20.1