From 6be24bed9da367c29b04e6fba8c9f27db39aa665 Mon Sep 17 00:00:00 2001 From: Muchun Song Date: Wed, 30 Jun 2021 18:47:04 -0700 Subject: [PATCH] mm: hugetlb: introduce a new config HUGETLB_PAGE_FREE_VMEMMAP The option HUGETLB_PAGE_FREE_VMEMMAP allows for the freeing of some vmemmap pages associated with pre-allocated HugeTLB pages. For example, on X86_64 6 vmemmap pages of size 4KB each can be saved for each 2MB HugeTLB page. 4094 vmemmap pages of size 4KB each can be saved for each 1GB HugeTLB page. When a HugeTLB page is allocated or freed, the vmemmap array representing the range associated with the page will need to be remapped. When a page is allocated, vmemmap pages are freed after remapping. When a page is freed, previously discarded vmemmap pages must be allocated before remapping. The config option is introduced early so that supporting code can be written to depend on the option. The initial version of the code only provides support for x86-64. If config HAVE_BOOTMEM_INFO_NODE is enabled, the freeing vmemmap page code denpend on it to free vmemmap pages. Otherwise, just use free_reserved_page() to free vmemmmap pages. The routine register_page_bootmem_info() is used to register bootmem info. Therefore, make sure register_page_bootmem_info is enabled if HUGETLB_PAGE_FREE_VMEMMAP is defined. Link: https://lkml.kernel.org/r/20210510030027.56044-3-songmuchun@bytedance.com Signed-off-by: Muchun Song Reviewed-by: Oscar Salvador Acked-by: Mike Kravetz Reviewed-by: Miaohe Lin Tested-by: Chen Huang Tested-by: Bodeddula Balasubramaniam Reviewed-by: Balbir Singh Cc: Alexander Viro Cc: Andy Lutomirski Cc: Anshuman Khandual Cc: Barry Song Cc: Borislav Petkov Cc: Dave Hansen Cc: David Hildenbrand Cc: David Rientjes Cc: HORIGUCHI NAOYA Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Joao Martins Cc: Joerg Roedel Cc: Jonathan Corbet Cc: Matthew Wilcox Cc: Michal Hocko Cc: Mina Almasry Cc: Oliver Neukum Cc: Paul E. McKenney Cc: Pawan Gupta Cc: Peter Zijlstra Cc: Randy Dunlap Cc: Thomas Gleixner Cc: Xiongchun Duan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86/mm/init_64.c | 2 +- fs/Kconfig | 5 +++++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 3aaf1d30c777..65ea58527176 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -1270,7 +1270,7 @@ static struct kcore_list kcore_vsyscall; static void __init register_page_bootmem_info(void) { -#ifdef CONFIG_NUMA +#if defined(CONFIG_NUMA) || defined(CONFIG_HUGETLB_PAGE_FREE_VMEMMAP) int i; for_each_online_node(i) diff --git a/fs/Kconfig b/fs/Kconfig index 141a856c50e7..58a53455d1fe 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -240,6 +240,11 @@ config HUGETLBFS config HUGETLB_PAGE def_bool HUGETLBFS +config HUGETLB_PAGE_FREE_VMEMMAP + def_bool HUGETLB_PAGE + depends on X86_64 + depends on SPARSEMEM_VMEMMAP + config MEMFD_CREATE def_bool TMPFS || HUGETLBFS -- 2.20.1