From 0386aaa6e9c826bc494169a914e01a86befe6edf Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Sat, 5 Oct 2024 21:01:16 +0100 Subject: [PATCH] bootmem: stop using page->index Encode the type into the bottom four bits of page->private and the info into the remaining bits. Also turn the bootmem type into a named enum. [arnd@arndb.de: bootmem: add bootmem_type stub function] Link: https://lkml.kernel.org/r/20241015143802.577613-1-arnd@kernel.org [akpm@linux-foundation.org: fix build with !CONFIG_HAVE_BOOTMEM_INFO_NODE] Link: https://lore.kernel.org/oe-kbuild-all/202410090311.eaqcL7IZ-lkp@intel.com/ Link: https://lkml.kernel.org/r/20241005200121.3231142-6-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: Arnd Bergmann Cc: kernel test robot Signed-off-by: Andrew Morton --- arch/x86/mm/init_64.c | 28 +++++++++++++++++++--------- include/linux/bootmem_info.h | 35 +++++++++++++++++++++++++++-------- mm/bootmem_info.c | 11 ++++++----- mm/sparse.c | 8 ++++---- 4 files changed, 56 insertions(+), 26 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 5a564130b9d0..01ea7c6df303 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -985,22 +985,32 @@ int arch_add_memory(int nid, u64 start, u64 size, return add_pages(nid, start_pfn, nr_pages, params); } +static void free_reserved_pages(struct page *page, unsigned long nr_pages) +{ + while (nr_pages--) + free_reserved_page(page++); +} + static void __meminit free_pagetable(struct page *page, int order) { - unsigned long magic; - unsigned int nr_pages = 1 << order; - /* bootmem page has reserved flag */ if (PageReserved(page)) { - magic = page->index; - if (magic == SECTION_INFO || magic == MIX_SECTION_INFO) { + unsigned long nr_pages = 1 << order; +#ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE + enum bootmem_type type = bootmem_type(page); + + if (type == SECTION_INFO || type == MIX_SECTION_INFO) { while (nr_pages--) put_page_bootmem(page++); - } else - while (nr_pages--) - free_reserved_page(page++); - } else + } else { + free_reserved_pages(page, nr_pages); + } +#else + free_reserved_pages(page, nr_pages); +#endif + } else { free_pages((unsigned long)page_address(page), order); + } } static void __meminit free_hugepage_table(struct page *page, diff --git a/include/linux/bootmem_info.h b/include/linux/bootmem_info.h index cffa38a73618..d8a8d245824a 100644 --- a/include/linux/bootmem_info.h +++ b/include/linux/bootmem_info.h @@ -6,11 +6,10 @@ #include /* - * Types for free bootmem stored in page->lru.next. These have to be in - * some random range in unsigned long space for debugging purposes. + * Types for free bootmem stored in the low bits of page->private. */ -enum { - MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE = 12, +enum bootmem_type { + MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE = 1, SECTION_INFO = MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE, MIX_SECTION_INFO, NODE_INFO, @@ -21,9 +20,19 @@ enum { void __init register_page_bootmem_info_node(struct pglist_data *pgdat); void get_page_bootmem(unsigned long info, struct page *page, - unsigned long type); + enum bootmem_type type); void put_page_bootmem(struct page *page); +static inline enum bootmem_type bootmem_type(const struct page *page) +{ + return (unsigned long)page->private & 0xf; +} + +static inline unsigned long bootmem_info(const struct page *page) +{ + return (unsigned long)page->private >> 4; +} + /* * Any memory allocated via the memblock allocator and not via the * buddy will be marked reserved already in the memmap. For those @@ -31,7 +40,7 @@ void put_page_bootmem(struct page *page); */ static inline void free_bootmem_page(struct page *page) { - unsigned long magic = page->index; + enum bootmem_type type = bootmem_type(page); /* * The reserve_bootmem_region sets the reserved flag on bootmem @@ -39,7 +48,7 @@ static inline void free_bootmem_page(struct page *page) */ VM_BUG_ON_PAGE(page_ref_count(page) != 2, page); - if (magic == SECTION_INFO || magic == MIX_SECTION_INFO) + if (type == SECTION_INFO || type == MIX_SECTION_INFO) put_page_bootmem(page); else VM_BUG_ON_PAGE(1, page); @@ -53,8 +62,18 @@ static inline void put_page_bootmem(struct page *page) { } +static inline enum bootmem_type bootmem_type(const struct page *page) +{ + return SECTION_INFO; +} + +static inline unsigned long bootmem_info(const struct page *page) +{ + return 0; +} + static inline void get_page_bootmem(unsigned long info, struct page *page, - unsigned long type) + enum bootmem_type type) { } diff --git a/mm/bootmem_info.c b/mm/bootmem_info.c index fa7cb0c87c03..95f288169a38 100644 --- a/mm/bootmem_info.c +++ b/mm/bootmem_info.c @@ -14,23 +14,24 @@ #include #include -void get_page_bootmem(unsigned long info, struct page *page, unsigned long type) +void get_page_bootmem(unsigned long info, struct page *page, + enum bootmem_type type) { - page->index = type; + BUG_ON(type > 0xf); + BUG_ON(info > (ULONG_MAX >> 4)); SetPagePrivate(page); - set_page_private(page, info); + set_page_private(page, info << 4 | type); page_ref_inc(page); } void put_page_bootmem(struct page *page) { - unsigned long type = page->index; + enum bootmem_type type = bootmem_type(page); BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE || type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE); if (page_ref_dec_return(page) == 1) { - page->index = 0; ClearPagePrivate(page); set_page_private(page, 0); INIT_LIST_HEAD(&page->lru); diff --git a/mm/sparse.c b/mm/sparse.c index 4cb9793f0b52..13b6624d3562 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -720,19 +720,19 @@ static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages, static void free_map_bootmem(struct page *memmap) { unsigned long maps_section_nr, removing_section_nr, i; - unsigned long magic, nr_pages; + unsigned long type, nr_pages; struct page *page = virt_to_page(memmap); nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page)) >> PAGE_SHIFT; for (i = 0; i < nr_pages; i++, page++) { - magic = page->index; + type = bootmem_type(page); - BUG_ON(magic == NODE_INFO); + BUG_ON(type == NODE_INFO); maps_section_nr = pfn_to_section_nr(page_to_pfn(page)); - removing_section_nr = page_private(page); + removing_section_nr = bootmem_info(page); /* * When this function is called, the removing section is