From 121e6f3258fe393e22c36f61a319be8a4f2c05ae Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Thu, 29 Apr 2021 22:58:49 -0700 Subject: [PATCH] mm/vmalloc: hugepage vmalloc mappings Support huge page vmalloc mappings. Config option HAVE_ARCH_HUGE_VMALLOC enables support on architectures that define HAVE_ARCH_HUGE_VMAP and supports PMD sized vmap mappings. vmalloc will attempt to allocate PMD-sized pages if allocating PMD size or larger, and fall back to small pages if that was unsuccessful. Architectures must ensure that any arch specific vmalloc allocations that require PAGE_SIZE mappings (e.g., module allocations vs strict module rwx) use the VM_NOHUGE flag to inhibit larger mappings. This can result in more internal fragmentation and memory overhead for a given allocation, an option nohugevmalloc is added to disable at boot. [colin.king@canonical.com: fix read of uninitialized pointer area] Link: https://lkml.kernel.org/r/20210318155955.18220-1-colin.king@canonical.com Link: https://lkml.kernel.org/r/20210317062402.533919-14-npiggin@gmail.com Signed-off-by: Nicholas Piggin Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christoph Hellwig Cc: Ding Tianhong Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Miaohe Lin Cc: Michael Ellerman Cc: Russell King Cc: Thomas Gleixner Cc: Uladzislau Rezki (Sony) Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/Kconfig | 11 ++ include/linux/vmalloc.h | 21 ++++ mm/page_alloc.c | 5 +- mm/vmalloc.c | 222 +++++++++++++++++++++++++++++++--------- 4 files changed, 210 insertions(+), 49 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index 5e8f6680d4bf..bf27159be4d9 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -829,6 +829,17 @@ config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD config HAVE_ARCH_HUGE_VMAP bool +# +# Archs that select this would be capable of PMD-sized vmaps (i.e., +# arch_vmap_pmd_supported() returns true), and they must make no assumptions +# that vmalloc memory is mapped with PAGE_SIZE ptes. The VM_NO_HUGE_VMAP flag +# can be used to prohibit arch-specific allocations from using hugepages to +# help with this (e.g., modules may require it). +# +config HAVE_ARCH_HUGE_VMALLOC + depends on HAVE_ARCH_HUGE_VMAP + bool + config ARCH_WANT_HUGE_PMD_SHARE bool diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index ae9eb07d30d4..b4c82f2d40dc 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -26,6 +26,7 @@ struct notifier_block; /* in notifier.h */ #define VM_KASAN 0x00000080 /* has allocated kasan shadow memory */ #define VM_FLUSH_RESET_PERMS 0x00000100 /* reset direct map and flush TLB on unmap, can't be freed in atomic context */ #define VM_MAP_PUT_PAGES 0x00000200 /* put pages and free array in vfree */ +#define VM_NO_HUGE_VMAP 0x00000400 /* force PAGE_SIZE pte mapping */ /* * VM_KASAN is used slighly differently depending on CONFIG_KASAN_VMALLOC. @@ -54,6 +55,9 @@ struct vm_struct { unsigned long size; unsigned long flags; struct page **pages; +#ifdef CONFIG_HAVE_ARCH_HUGE_VMALLOC + unsigned int page_order; +#endif unsigned int nr_pages; phys_addr_t phys_addr; const void *caller; @@ -188,6 +192,22 @@ void free_vm_area(struct vm_struct *area); extern struct vm_struct *remove_vm_area(const void *addr); extern struct vm_struct *find_vm_area(const void *addr); +static inline bool is_vm_area_hugepages(const void *addr) +{ + /* + * This may not 100% tell if the area is mapped with > PAGE_SIZE + * page table entries, if for some reason the architecture indicates + * larger sizes are available but decides not to use them, nothing + * prevents that. This only indicates the size of the physical page + * allocated in the vmalloc layer. + */ +#ifdef CONFIG_HAVE_ARCH_HUGE_VMALLOC + return find_vm_area(addr)->page_order > 0; +#else + return false; +#endif +} + #ifdef CONFIG_MMU int vmap_range(unsigned long addr, unsigned long end, phys_addr_t phys_addr, pgprot_t prot, @@ -205,6 +225,7 @@ static inline void set_vm_flush_reset_perms(void *addr) if (vm) vm->flags |= VM_FLUSH_RESET_PERMS; } + #else static inline int map_kernel_range_noflush(unsigned long start, unsigned long size, diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 56a8103580d6..39ff5c604cef 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -72,6 +72,7 @@ #include #include #include +#include #include #include @@ -8222,6 +8223,7 @@ void *__init alloc_large_system_hash(const char *tablename, void *table = NULL; gfp_t gfp_flags; bool virt; + bool huge; /* allow the kernel cmdline to have a say */ if (!numentries) { @@ -8289,6 +8291,7 @@ void *__init alloc_large_system_hash(const char *tablename, } else if (get_order(size) >= MAX_ORDER || hashdist) { table = __vmalloc(size, gfp_flags); virt = true; + huge = is_vm_area_hugepages(table); } else { /* * If bucketsize is not a power-of-two, we may free @@ -8305,7 +8308,7 @@ void *__init alloc_large_system_hash(const char *tablename, pr_info("%s hash table entries: %ld (order: %d, %lu bytes, %s)\n", tablename, 1UL << log2qty, ilog2(size) - PAGE_SHIFT, size, - virt ? "vmalloc" : "linear"); + virt ? (huge ? "vmalloc hugepage" : "vmalloc") : "linear"); if (_hash_shift) *_hash_shift = log2qty; diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 41c1dbdd2677..59c815eb7e74 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -42,6 +42,19 @@ #include "internal.h" #include "pgalloc-track.h" +#ifdef CONFIG_HAVE_ARCH_HUGE_VMALLOC +static bool __ro_after_init vmap_allow_huge = true; + +static int __init set_nohugevmalloc(char *str) +{ + vmap_allow_huge = false; + return 0; +} +early_param("nohugevmalloc", set_nohugevmalloc); +#else /* CONFIG_HAVE_ARCH_HUGE_VMALLOC */ +static const bool vmap_allow_huge = false; +#endif /* CONFIG_HAVE_ARCH_HUGE_VMALLOC */ + bool is_vmalloc_addr(const void *x) { unsigned long addr = (unsigned long)x; @@ -483,6 +496,69 @@ static int vmap_pages_p4d_range(pgd_t *pgd, unsigned long addr, return 0; } +static int vmap_small_pages_range_noflush(unsigned long addr, unsigned long end, + pgprot_t prot, struct page **pages) +{ + unsigned long start = addr; + pgd_t *pgd; + unsigned long next; + int err = 0; + int nr = 0; + pgtbl_mod_mask mask = 0; + + BUG_ON(addr >= end); + pgd = pgd_offset_k(addr); + do { + next = pgd_addr_end(addr, end); + if (pgd_bad(*pgd)) + mask |= PGTBL_PGD_MODIFIED; + err = vmap_pages_p4d_range(pgd, addr, next, prot, pages, &nr, &mask); + if (err) + return err; + } while (pgd++, addr = next, addr != end); + + if (mask & ARCH_PAGE_TABLE_SYNC_MASK) + arch_sync_kernel_mappings(start, end); + + return 0; +} + +static int vmap_pages_range_noflush(unsigned long addr, unsigned long end, + pgprot_t prot, struct page **pages, unsigned int page_shift) +{ + unsigned int i, nr = (end - addr) >> PAGE_SHIFT; + + WARN_ON(page_shift < PAGE_SHIFT); + + if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMALLOC) || + page_shift == PAGE_SHIFT) + return vmap_small_pages_range_noflush(addr, end, prot, pages); + + for (i = 0; i < nr; i += 1U << (page_shift - PAGE_SHIFT)) { + int err; + + err = vmap_range_noflush(addr, addr + (1UL << page_shift), + __pa(page_address(pages[i])), prot, + page_shift); + if (err) + return err; + + addr += 1UL << page_shift; + } + + return 0; +} + +static int vmap_pages_range(unsigned long addr, unsigned long end, + pgprot_t prot, struct page **pages, unsigned int page_shift) +{ + int err; + + err = vmap_pages_range_noflush(addr, end, prot, pages, page_shift); + flush_cache_vmap(addr, end); + return err; +} + /** * map_kernel_range_noflush - map kernel VM area with the specified pages * @addr: start of the VM area to map @@ -504,29 +580,7 @@ static int vmap_pages_p4d_range(pgd_t *pgd, unsigned long addr, int map_kernel_range_noflush(unsigned long addr, unsigned long size, pgprot_t prot, struct page **pages) { - unsigned long start = addr; - unsigned long end = addr + size; - unsigned long next; - pgd_t *pgd; - int err = 0; - int nr = 0; - pgtbl_mod_mask mask = 0; - - BUG_ON(addr >= end); - pgd = pgd_offset_k(addr); - do { - next = pgd_addr_end(addr, end); - if (pgd_bad(*pgd)) - mask |= PGTBL_PGD_MODIFIED; - err = vmap_pages_p4d_range(pgd, addr, next, prot, pages, &nr, &mask); - if (err) - return err; - } while (pgd++, addr = next, addr != end); - - if (mask & ARCH_PAGE_TABLE_SYNC_MASK) - arch_sync_kernel_mappings(start, end); - - return 0; + return vmap_pages_range_noflush(addr, addr + size, prot, pages, PAGE_SHIFT); } int map_kernel_range(unsigned long start, unsigned long size, pgprot_t prot, @@ -2112,6 +2166,24 @@ EXPORT_SYMBOL(vm_map_ram); static struct vm_struct *vmlist __initdata; +static inline unsigned int vm_area_page_order(struct vm_struct *vm) +{ +#ifdef CONFIG_HAVE_ARCH_HUGE_VMALLOC + return vm->page_order; +#else + return 0; +#endif +} + +static inline void set_vm_area_page_order(struct vm_struct *vm, unsigned int order) +{ +#ifdef CONFIG_HAVE_ARCH_HUGE_VMALLOC + vm->page_order = order; +#else + BUG_ON(order != 0); +#endif +} + /** * vm_area_add_early - add vmap area early during boot * @vm: vm_struct to add @@ -2422,6 +2494,7 @@ static inline void set_area_direct_map(const struct vm_struct *area, { int i; + /* HUGE_VMALLOC passes small pages to set_direct_map */ for (i = 0; i < area->nr_pages; i++) if (page_address(area->pages[i])) set_direct_map(area->pages[i]); @@ -2431,6 +2504,7 @@ static inline void set_area_direct_map(const struct vm_struct *area, static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages) { unsigned long start = ULONG_MAX, end = 0; + unsigned int page_order = vm_area_page_order(area); int flush_reset = area->flags & VM_FLUSH_RESET_PERMS; int flush_dmap = 0; int i; @@ -2455,11 +2529,14 @@ static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages) * map. Find the start and end range of the direct mappings to make sure * the vm_unmap_aliases() flush includes the direct map. */ - for (i = 0; i < area->nr_pages; i++) { + for (i = 0; i < area->nr_pages; i += 1U << page_order) { unsigned long addr = (unsigned long)page_address(area->pages[i]); if (addr) { + unsigned long page_size; + + page_size = PAGE_SIZE << page_order; start = min(addr, start); - end = max(addr + PAGE_SIZE, end); + end = max(addr + page_size, end); flush_dmap = 1; } } @@ -2500,13 +2577,14 @@ static void __vunmap(const void *addr, int deallocate_pages) vm_remove_mappings(area, deallocate_pages); if (deallocate_pages) { + unsigned int page_order = vm_area_page_order(area); int i; - for (i = 0; i < area->nr_pages; i++) { + for (i = 0; i < area->nr_pages; i += 1U << page_order) { struct page *page = area->pages[i]; BUG_ON(!page); - __free_pages(page, 0); + __free_pages(page, page_order); } atomic_long_sub(area->nr_pages, &nr_vmalloc_pages); @@ -2697,15 +2775,19 @@ EXPORT_SYMBOL_GPL(vmap_pfn); #endif /* CONFIG_VMAP_PFN */ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, - pgprot_t prot, int node) + pgprot_t prot, unsigned int page_shift, + int node) { const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO; - unsigned int nr_pages = get_vm_area_size(area) >> PAGE_SHIFT; + unsigned long addr = (unsigned long)area->addr; + unsigned long size = get_vm_area_size(area); unsigned long array_size; - unsigned int i; + unsigned int nr_small_pages = size >> PAGE_SHIFT; + unsigned int page_order; struct page **pages; + unsigned int i; - array_size = (unsigned long)nr_pages * sizeof(struct page *); + array_size = (unsigned long)nr_small_pages * sizeof(struct page *); gfp_mask |= __GFP_NOWARN; if (!(gfp_mask & (GFP_DMA | GFP_DMA32))) gfp_mask |= __GFP_HIGHMEM; @@ -2724,30 +2806,38 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, } area->pages = pages; - area->nr_pages = nr_pages; + area->nr_pages = nr_small_pages; + set_vm_area_page_order(area, page_shift - PAGE_SHIFT); - for (i = 0; i < area->nr_pages; i++) { + page_order = vm_area_page_order(area); + + /* + * Careful, we allocate and map page_order pages, but tracking is done + * per PAGE_SIZE page so as to keep the vm_struct APIs independent of + * the physical/mapped size. + */ + for (i = 0; i < area->nr_pages; i += 1U << page_order) { struct page *page; + int p; - if (node == NUMA_NO_NODE) - page = alloc_page(gfp_mask); - else - page = alloc_pages_node(node, gfp_mask, 0); - + /* Compound pages required for remap_vmalloc_page */ + page = alloc_pages_node(node, gfp_mask | __GFP_COMP, page_order); if (unlikely(!page)) { /* Successfully allocated i pages, free them in __vfree() */ area->nr_pages = i; atomic_long_add(area->nr_pages, &nr_vmalloc_pages); goto fail; } - area->pages[i] = page; + + for (p = 0; p < (1U << page_order); p++) + area->pages[i + p] = page + p; + if (gfpflags_allow_blocking(gfp_mask)) cond_resched(); } atomic_long_add(area->nr_pages, &nr_vmalloc_pages); - if (map_kernel_range((unsigned long)area->addr, get_vm_area_size(area), - prot, pages) < 0) + if (vmap_pages_range(addr, addr + size, prot, pages, page_shift) < 0) goto fail; return area->addr; @@ -2755,7 +2845,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, fail: warn_alloc(gfp_mask, NULL, "vmalloc: allocation failure, allocated %ld of %ld bytes", - (area->nr_pages*PAGE_SIZE), area->size); + (area->nr_pages*PAGE_SIZE), size); __vfree(area->addr); return NULL; } @@ -2786,19 +2876,45 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, struct vm_struct *area; void *addr; unsigned long real_size = size; + unsigned long real_align = align; + unsigned int shift = PAGE_SHIFT; - size = PAGE_ALIGN(size); - if (!size || (size >> PAGE_SHIFT) > totalram_pages()) + if (!size || (size >> PAGE_SHIFT) > totalram_pages()) { + area = NULL; goto fail; + } - area = __get_vm_area_node(real_size, align, VM_ALLOC | VM_UNINITIALIZED | + if (vmap_allow_huge && !(vm_flags & VM_NO_HUGE_VMAP) && + arch_vmap_pmd_supported(prot)) { + unsigned long size_per_node; + + /* + * Try huge pages. Only try for PAGE_KERNEL allocations, + * others like modules don't yet expect huge pages in + * their allocations due to apply_to_page_range not + * supporting them. + */ + + size_per_node = size; + if (node == NUMA_NO_NODE) + size_per_node /= num_online_nodes(); + if (size_per_node >= PMD_SIZE) { + shift = PMD_SHIFT; + align = max(real_align, 1UL << shift); + size = ALIGN(real_size, 1UL << shift); + } + } + +again: + size = PAGE_ALIGN(size); + area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNINITIALIZED | vm_flags, start, end, node, gfp_mask, caller); if (!area) goto fail; - addr = __vmalloc_area_node(area, gfp_mask, prot, node); + addr = __vmalloc_area_node(area, gfp_mask, prot, shift, node); if (!addr) - return NULL; + goto fail; /* * In this function, newly allocated vm_struct has VM_UNINITIALIZED @@ -2812,8 +2928,18 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, return addr; fail: - warn_alloc(gfp_mask, NULL, + if (shift > PAGE_SHIFT) { + shift = PAGE_SHIFT; + align = real_align; + size = real_size; + goto again; + } + + if (!area) { + /* Warn for area allocation, page allocations already warn */ + warn_alloc(gfp_mask, NULL, "vmalloc: allocation failure: %lu bytes", real_size); + } return NULL; }