@@ -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 */
@@ -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)
{
@@ -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
/*
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). Cc: Catalin Marinas <catalin.marinas@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 Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> --- Applies on 5.8-rc3. Changes in V3: - Dropped the stub, protected call site, moved the declaration to a header Changes in V2: (https://patchwork.kernel.org/patch/11630503/) - Moved arm64_hugetlb_cma_reserve() stub and declaration near call site Changes in V1: (https://patchwork.kernel.org/patch/11619839/) arch/arm64/include/asm/hugetlb.h | 2 ++ arch/arm64/mm/hugetlbpage.c | 38 ++++++++++++++++++++++++++++++++ arch/arm64/mm/init.c | 4 ++-- 3 files changed, 42 insertions(+), 2 deletions(-)