From 348ad1606f4c09e3dc28092baac474e10a252471 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Tue, 25 Jul 2023 00:37:47 +0530 Subject: [PATCH] mm/hugepage pud: allow arch-specific helper function to check huge page pud support Patch series "Add support for DAX vmemmap optimization for ppc64", v6. This patch series implements changes required to support DAX vmemmap optimization for ppc64. The vmemmap optimization is only enabled with radix MMU translation and 1GB PUD mapping with 64K page size. The patch series also splits the hugetlb vmemmap optimization as a separate Kconfig variable so that architectures can enable DAX vmemmap optimization without enabling hugetlb vmemmap optimization. This should enable architectures like arm64 to enable DAX vmemmap optimization while they can't enable hugetlb vmemmap optimization. More details of the same are in patch "mm/vmemmap optimization: Split hugetlb and devdax vmemmap optimization". With 64K page size for 16384 pages added (1G) we save 14 pages With 4K page size for 262144 pages added (1G) we save 4094 pages With 4K page size for 512 pages added (2M) we save 6 pages This patch (of 13): Architectures like powerpc would like to enable transparent huge page pud support only with radix translation. To support that add has_transparent_pud_hugepage() helper that architectures can override. [aneesh.kumar@linux.ibm.com: use the new has_transparent_pud_hugepage()] Link: https://lkml.kernel.org/r/87tttrvtaj.fsf@linux.ibm.com Link: https://lkml.kernel.org/r/20230724190759.483013-1-aneesh.kumar@linux.ibm.com Link: https://lkml.kernel.org/r/20230724190759.483013-2-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Reviewed-by: Christophe Leroy Cc: Catalin Marinas Cc: Dan Williams Cc: Joao Martins Cc: Michael Ellerman Cc: Mike Kravetz Cc: Muchun Song Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Will Deacon Signed-off-by: Andrew Morton --- drivers/nvdimm/pfn_devs.c | 2 +- include/linux/pgtable.h | 3 +++ mm/debug_vm_pgtable.c | 16 +++++++--------- 3 files changed, 11 insertions(+), 10 deletions(-) diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c index af7d930..18ad315 100644 --- a/drivers/nvdimm/pfn_devs.c +++ b/drivers/nvdimm/pfn_devs.c @@ -100,7 +100,7 @@ static unsigned long *nd_pfn_supported_alignments(unsigned long *alignments) if (has_transparent_hugepage()) { alignments[1] = HPAGE_PMD_SIZE; - if (IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)) + if (has_transparent_pud_hugepage()) alignments[2] = HPAGE_PUD_SIZE; } diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 5f36c05..5eb6bdf 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -1505,6 +1505,9 @@ typedef unsigned int pgtbl_mod_mask; #define has_transparent_hugepage() IS_BUILTIN(CONFIG_TRANSPARENT_HUGEPAGE) #endif +#ifndef has_transparent_pud_hugepage +#define has_transparent_pud_hugepage() IS_BUILTIN(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) +#endif /* * On some architectures it depends on the mm if the p4d/pud or pmd * layer of the page table hierarchy is folded or not. diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c index ee119e3..844fdfd 100644 --- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -302,7 +302,7 @@ static void __init pud_basic_tests(struct pgtable_debug_args *args, int idx) unsigned long val = idx, *ptr = &val; pud_t pud; - if (!has_transparent_hugepage()) + if (!has_transparent_pud_hugepage()) return; pr_debug("Validating PUD basic (%pGv)\n", ptr); @@ -343,7 +343,7 @@ static void __init pud_advanced_tests(struct pgtable_debug_args *args) unsigned long vaddr = args->vaddr; pud_t pud; - if (!has_transparent_hugepage()) + if (!has_transparent_pud_hugepage()) return; page = (args->pud_pfn != ULONG_MAX) ? pfn_to_page(args->pud_pfn) : NULL; @@ -405,7 +405,7 @@ static void __init pud_leaf_tests(struct pgtable_debug_args *args) { pud_t pud; - if (!has_transparent_hugepage()) + if (!has_transparent_pud_hugepage()) return; pr_debug("Validating PUD leaf\n"); @@ -732,7 +732,7 @@ static void __init pud_devmap_tests(struct pgtable_debug_args *args) { pud_t pud; - if (!has_transparent_hugepage()) + if (!has_transparent_pud_hugepage()) return; pr_debug("Validating PUD devmap\n"); @@ -981,7 +981,7 @@ static void __init pud_thp_tests(struct pgtable_debug_args *args) { pud_t pud; - if (!has_transparent_hugepage()) + if (!has_transparent_pud_hugepage()) return; pr_debug("Validating PUD based THP\n"); @@ -1022,8 +1022,7 @@ static void __init destroy_args(struct pgtable_debug_args *args) /* Free (huge) page */ if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && - IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) && - has_transparent_hugepage() && + has_transparent_pud_hugepage() && args->pud_pfn != ULONG_MAX) { if (args->is_contiguous_page) { free_contig_range(args->pud_pfn, @@ -1274,8 +1273,7 @@ static int __init init_args(struct pgtable_debug_args *args) * if we fail to allocate (huge) pages. */ if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && - IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) && - has_transparent_hugepage()) { + has_transparent_pud_hugepage()) { page = debug_vm_pgtable_alloc_huge_page(args, HPAGE_PUD_SHIFT - PAGE_SHIFT); if (page) { -- 2.7.4