diff options
Diffstat (limited to 'mm/percpu.c')
| -rw-r--r-- | mm/percpu.c | 1318 |
1 files changed, 1028 insertions, 290 deletions
diff --git a/mm/percpu.c b/mm/percpu.c index 5fe37842e0ea..3f9f182f9b44 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -8,12 +8,13 @@ * * This is percpu allocator which can handle both static and dynamic * areas. Percpu areas are allocated in chunks in vmalloc area. Each - * chunk is consisted of nr_cpu_ids units and the first chunk is used - * for static percpu variables in the kernel image (special boot time - * alloc/init handling necessary as these areas need to be brought up - * before allocation services are running). Unit grows as necessary - * and all units grow or shrink in unison. When a chunk is filled up, - * another chunk is allocated. ie. in vmalloc area + * chunk is consisted of boot-time determined number of units and the + * first chunk is used for static percpu variables in the kernel image + * (special boot time alloc/init handling necessary as these areas + * need to be brought up before allocation services are running). + * Unit grows as necessary and all units grow or shrink in unison. + * When a chunk is filled up, another chunk is allocated. ie. in + * vmalloc area * * c0 c1 c2 * ------------------- ------------------- ------------ @@ -22,11 +23,13 @@ * * Allocation is done in offset-size areas of single unit space. Ie, * an area of 512 bytes at 6k in c1 occupies 512 bytes at 6k of c1:u0, - * c1:u1, c1:u2 and c1:u3. Percpu access can be done by configuring - * percpu base registers pcpu_unit_size apart. + * c1:u1, c1:u2 and c1:u3. On UMA, units corresponds directly to + * cpus. On NUMA, the mapping can be non-linear and even sparse. + * Percpu access can be done by configuring percpu base registers + * according to cpu to unit mapping and pcpu_unit_size. * - * There are usually many small percpu allocations many of them as - * small as 4 bytes. The allocator organizes chunks into lists + * There are usually many small percpu allocations many of them being + * as small as 4 bytes. The allocator organizes chunks into lists * according to free size and tries to allocate from the fullest one. * Each chunk keeps the maximum contiguous area size hint which is * guaranteed to be eqaul to or larger than the maximum contiguous @@ -43,7 +46,7 @@ * * To use this allocator, arch code should do the followings. * - * - define CONFIG_HAVE_DYNAMIC_PER_CPU_AREA + * - drop CONFIG_HAVE_LEGACY_PER_CPU_AREA * * - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate * regular address to percpu pointer and back if they need to be @@ -56,6 +59,7 @@ #include <linux/bitmap.h> #include <linux/bootmem.h> #include <linux/list.h> +#include <linux/log2.h> #include <linux/mm.h> #include <linux/module.h> #include <linux/mutex.h> @@ -94,20 +98,27 @@ struct pcpu_chunk { int map_alloc; /* # of map entries allocated */ int *map; /* allocation map */ bool immutable; /* no [de]population allowed */ - struct page **page; /* points to page array */ - struct page *page_ar[]; /* #cpus * UNIT_PAGES */ + unsigned long populated[]; /* populated bitmap */ }; static int pcpu_unit_pages __read_mostly; static int pcpu_unit_size __read_mostly; +static int pcpu_nr_units __read_mostly; static int pcpu_chunk_size __read_mostly; static int pcpu_nr_slots __read_mostly; static size_t pcpu_chunk_struct_size __read_mostly; +/* cpus with the lowest and highest unit numbers */ +static unsigned int pcpu_first_unit_cpu __read_mostly; +static unsigned int pcpu_last_unit_cpu __read_mostly; + /* the address of the first chunk which starts with the kernel static area */ void *pcpu_base_addr __read_mostly; EXPORT_SYMBOL_GPL(pcpu_base_addr); +/* cpu -> unit map */ +const int *pcpu_unit_map __read_mostly; + /* * The first chunk which always exists. Note that unlike other * chunks, this one can be allocated and mapped in several different @@ -129,9 +140,9 @@ static int pcpu_reserved_chunk_limit; * Synchronization rules. * * There are two locks - pcpu_alloc_mutex and pcpu_lock. The former - * protects allocation/reclaim paths, chunks and chunk->page arrays. - * The latter is a spinlock and protects the index data structures - - * chunk slots, chunks and area maps in chunks. + * protects allocation/reclaim paths, chunks, populated bitmap and + * vmalloc mapping. The latter is a spinlock and protects the index + * data structures - chunk slots, chunks and area maps in chunks. * * During allocation, pcpu_alloc_mutex is kept locked all the time and * pcpu_lock is grabbed and released as necessary. All actual memory @@ -178,13 +189,7 @@ static int pcpu_chunk_slot(const struct pcpu_chunk *chunk) static int pcpu_page_idx(unsigned int cpu, int page_idx) { - return cpu * pcpu_unit_pages + page_idx; -} - -static struct page **pcpu_chunk_pagep(struct pcpu_chunk *chunk, - unsigned int cpu, int page_idx) -{ - return &chunk->page[pcpu_page_idx(cpu, page_idx)]; + return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx; } static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk, @@ -194,10 +199,13 @@ static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk, (pcpu_page_idx(cpu, page_idx) << PAGE_SHIFT); } -static bool pcpu_chunk_page_occupied(struct pcpu_chunk *chunk, - int page_idx) +static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk, + unsigned int cpu, int page_idx) { - return *pcpu_chunk_pagep(chunk, 0, page_idx) != NULL; + /* must not be used on pre-mapped chunk */ + WARN_ON(chunk->immutable); + + return vmalloc_to_page((void *)pcpu_chunk_addr(chunk, cpu, page_idx)); } /* set the pointer to a chunk in a page struct */ @@ -212,6 +220,34 @@ static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page) return (struct pcpu_chunk *)page->index; } +static void pcpu_next_unpop(struct pcpu_chunk *chunk, int *rs, int *re, int end) +{ + *rs = find_next_zero_bit(chunk->populated, end, *rs); + *re = find_next_bit(chunk->populated, end, *rs + 1); +} + +static void pcpu_next_pop(struct pcpu_chunk *chunk, int *rs, int *re, int end) +{ + *rs = find_next_bit(chunk->populated, end, *rs); + *re = find_next_zero_bit(chunk->populated, end, *rs + 1); +} + +/* + * (Un)populated page region iterators. Iterate over (un)populated + * page regions betwen @start and @end in @chunk. @rs and @re should + * be integer variables and will be set to start and end page index of + * the current region. + */ +#define pcpu_for_each_unpop_region(chunk, rs, re, start, end) \ + for ((rs) = (start), pcpu_next_unpop((chunk), &(rs), &(re), (end)); \ + (rs) < (re); \ + (rs) = (re) + 1, pcpu_next_unpop((chunk), &(rs), &(re), (end))) + +#define pcpu_for_each_pop_region(chunk, rs, re, start, end) \ + for ((rs) = (start), pcpu_next_pop((chunk), &(rs), &(re), (end)); \ + (rs) < (re); \ + (rs) = (re) + 1, pcpu_next_pop((chunk), &(rs), &(re), (end))) + /** * pcpu_mem_alloc - allocate memory * @size: bytes to allocate @@ -290,13 +326,21 @@ static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr) void *first_start = pcpu_first_chunk->vm->addr; /* is it in the first chunk? */ - if (addr >= first_start && addr < first_start + pcpu_chunk_size) { + if (addr >= first_start && addr < first_start + pcpu_unit_size) { /* is it in the reserved area? */ if (addr < first_start + pcpu_reserved_chunk_limit) return pcpu_reserved_chunk; return pcpu_first_chunk; } + /* + * The address is relative to unit0 which might be unused and + * thus unmapped. Offset the address to the unit space of the + * current processor before looking it up in the vmalloc + * space. Note that any possible cpu id can be used here, so + * there's no need to worry about preemption or cpu hotplug. + */ + addr += pcpu_unit_map[smp_processor_id()] * pcpu_unit_size; return pcpu_get_page_chunk(vmalloc_to_page(addr)); } @@ -545,125 +589,327 @@ static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme) } /** - * pcpu_unmap - unmap pages out of a pcpu_chunk + * pcpu_get_pages_and_bitmap - get temp pages array and bitmap * @chunk: chunk of interest - * @page_start: page index of the first page to unmap - * @page_end: page index of the last page to unmap + 1 - * @flush_tlb: whether to flush tlb or not + * @bitmapp: output parameter for bitmap + * @may_alloc: may allocate the array * - * For each cpu, unmap pages [@page_start,@page_end) out of @chunk. - * If @flush is true, vcache is flushed before unmapping and tlb - * after. + * Returns pointer to array of pointers to struct page and bitmap, + * both of which can be indexed with pcpu_page_idx(). The returned + * array is cleared to zero and *@bitmapp is copied from + * @chunk->populated. Note that there is only one array and bitmap + * and access exclusion is the caller's responsibility. + * + * CONTEXT: + * pcpu_alloc_mutex and does GFP_KERNEL allocation if @may_alloc. + * Otherwise, don't care. + * + * RETURNS: + * Pointer to temp pages array on success, NULL on failure. */ -static void pcpu_unmap(struct pcpu_chunk *chunk, int page_start, int page_end, - bool flush_tlb) +static struct page **pcpu_get_pages_and_bitmap(struct pcpu_chunk *chunk, + unsigned long **bitmapp, + bool may_alloc) { - unsigned int last = nr_cpu_ids - 1; - unsigned int cpu; + static struct page **pages; + static unsigned long *bitmap; + size_t pages_size = pcpu_nr_units * pcpu_unit_pages * sizeof(pages[0]); + size_t bitmap_size = BITS_TO_LONGS(pcpu_unit_pages) * + sizeof(unsigned long); + + if (!pages || !bitmap) { + if (may_alloc && !pages) + pages = pcpu_mem_alloc(pages_size); + if (may_alloc && !bitmap) + bitmap = pcpu_mem_alloc(bitmap_size); + if (!pages || !bitmap) + return NULL; + } - /* unmap must not be done on immutable chunk */ - WARN_ON(chunk->immutable); + memset(pages, 0, pages_size); + bitmap_copy(bitmap, chunk->populated, pcpu_unit_pages); - /* - * Each flushing trial can be very expensive, issue flush on - * the whole region at once rather than doing it for each cpu. - * This could be an overkill but is more scalable. - */ - flush_cache_vunmap(pcpu_chunk_addr(chunk, 0, page_start), - pcpu_chunk_addr(chunk, last, page_end)); + *bitmapp = bitmap; + return pages; +} - for_each_possible_cpu(cpu) - unmap_kernel_range_noflush( - pcpu_chunk_addr(chunk, cpu, page_start), - (page_end - page_start) << PAGE_SHIFT); - - /* ditto as flush_cache_vunmap() */ - if (flush_tlb) - flush_tlb_kernel_range(pcpu_chunk_addr(chunk, 0, page_start), - pcpu_chunk_addr(chunk, last, page_end)); +/** + * pcpu_free_pages - free pages which were allocated for @chunk + * @chunk: chunk pages were allocated for + * @pages: array of pages to be freed, indexed by pcpu_page_idx() + * @populated: populated bitmap + * @page_start: page index of the first page to be freed + * @page_end: page index of the last page to be freed + 1 + * + * Free pages [@page_start and @page_end) in @pages for all units. + * The pages were allocated for @chunk. + */ +static void pcpu_free_pages(struct pcpu_chunk *chunk, + struct page **pages, unsigned long *populated, + int page_start, int page_end) +{ + unsigned int cpu; + int i; + + for_each_possible_cpu(cpu) { + for (i = page_start; i < page_end; i++) { + struct page *page = pages[pcpu_page_idx(cpu, i)]; + + if (page) + __free_page(page); + } + } } /** - * pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk - * @chunk: chunk to depopulate - * @off: offset to the area to depopulate - * @size: size of the area to depopulate in bytes - * @flush: whether to flush cache and tlb or not - * - * For each cpu, depopulate and unmap pages [@page_start,@page_end) - * from @chunk. If @flush is true, vcache is flushed before unmapping - * and tlb after. - * - * CONTEXT: - * pcpu_alloc_mutex. + * pcpu_alloc_pages - allocates pages for @chunk + * @chunk: target chunk + * @pages: array to put the allocated pages into, indexed by pcpu_page_idx() + * @populated: populated bitmap + * @page_start: page index of the first page to be allocated + * @page_end: page index of the last page to be allocated + 1 + * + * Allocate pages [@page_start,@page_end) into @pages for all units. + * The allocation is for @chunk. Percpu core doesn't care about the + * content of @pages and will pass it verbatim to pcpu_map_pages(). */ -static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size, - bool flush) +static int pcpu_alloc_pages(struct pcpu_chunk *chunk, + struct page **pages, unsigned long *populated, + int page_start, int page_end) { - int page_start = PFN_DOWN(off); - int page_end = PFN_UP(off + size); - int unmap_start = -1; - int uninitialized_var(unmap_end); + const gfp_t gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD; unsigned int cpu; int i; - for (i = page_start; i < page_end; i++) { - for_each_possible_cpu(cpu) { - struct page **pagep = pcpu_chunk_pagep(chunk, cpu, i); + for_each_possible_cpu(cpu) { + for (i = page_start; i < page_end; i++) { + struct page **pagep = &pages[pcpu_page_idx(cpu, i)]; + + *pagep = alloc_pages_node(cpu_to_node(cpu), gfp, 0); + if (!*pagep) { + pcpu_free_pages(chunk, pages, populated, + page_start, page_end); + return -ENOMEM; + } + } + } + return 0; +} - if (!*pagep) - continue; +/** + * pcpu_pre_unmap_flush - flush cache prior to unmapping + * @chunk: chunk the regions to be flushed belongs to + * @page_start: page index of the first page to be flushed + * @page_end: page index of the last page to be flushed + 1 + * + * Pages in [@page_start,@page_end) of @chunk are about to be + * unmapped. Flush cache. As each flushing trial can be very + * expensive, issue flush on the whole region at once rather than + * doing it for each cpu. This could be an overkill but is more + * scalable. + */ +static void pcpu_pre_unmap_flush(struct pcpu_chunk *chunk, + int page_start, int page_end) +{ + flush_cache_vunmap( + pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start), + pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end)); +} - __free_page(*pagep); +static void __pcpu_unmap_pages(unsigned long addr, int nr_pages) +{ + unmap_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT); +} - /* - * If it's partial depopulation, it might get - * populated or depopulated again. Mark the - * page gone. - */ - *pagep = NULL; +/** + * pcpu_unmap_pages - unmap pages out of a pcpu_chunk + * @chunk: chunk of interest + * @pages: pages array which can be used to pass information to free + * @populated: populated bitmap + * @page_start: page index of the first page to unmap + * @page_end: page index of the last page to unmap + 1 + * + * For each cpu, unmap pages [@page_start,@page_end) out of @chunk. + * Corresponding elements in @pages were cleared by the caller and can + * be used to carry information to pcpu_free_pages() which will be + * called after all unmaps are finished. The caller should call + * proper pre/post flush functions. + */ +static void pcpu_unmap_pages(struct pcpu_chunk *chunk, + struct page **pages, unsigned long *populated, + int page_start, int page_end) +{ + unsigned int cpu; + int i; - unmap_start = unmap_start < 0 ? i : unmap_start; - unmap_end = i + 1; + for_each_possible_cpu(cpu) { + for (i = page_start; i < page_end; i++) { + struct page *page; + + page = pcpu_chunk_page(chunk, cpu, i); + WARN_ON(!page); + pages[pcpu_page_idx(cpu, i)] = page; } + __pcpu_unmap_pages(pcpu_chunk_addr(chunk, cpu, page_start), + page_end - page_start); } - if (unmap_start >= 0) - pcpu_unmap(chunk, unmap_start, unmap_end, flush); + for (i = page_start; i < page_end; i++) + __clear_bit(i, populated); } /** - * pcpu_map - map pages into a pcpu_chunk + * pcpu_post_unmap_tlb_flush - flush TLB after unmapping + * @chunk: pcpu_chunk the regions to be flushed belong to + * @page_start: page index of the first page to be flushed + * @page_end: page index of the last page to be flushed + 1 + * + * Pages [@page_start,@page_end) of @chunk have been unmapped. Flush + * TLB for the regions. This can be skipped if the area is to be + * returned to vmalloc as vmalloc will handle TLB flushing lazily. + * + * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once + * for the whole region. + */ +static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk, + int page_start, int page_end) +{ + flush_tlb_kernel_range( + pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start), + pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end)); +} + +static int __pcpu_map_pages(unsigned long addr, struct page **pages, + int nr_pages) +{ + return map_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT, + PAGE_KERNEL, pages); +} + +/** + * pcpu_map_pages - map pages into a pcpu_chunk * @chunk: chunk of interest + * @pages: pages array containing pages to be mapped + * @populated: populated bitmap * @page_start: page index of the first page to map * @page_end: page index of the last page to map + 1 * - * For each cpu, map pages [@page_start,@page_end) into @chunk. - * vcache is flushed afterwards. + * For each cpu, map pages [@page_start,@page_end) into @chunk. The + * caller is responsible for calling pcpu_post_map_flush() after all + * mappings are complete. + * + * This function is responsible for setting corresponding bits in + * @chunk->populated bitmap and whatever is necessary for reverse + * lookup (addr -> chunk). */ -static int pcpu_map(struct pcpu_chunk *chunk, int page_start, int page_end) +static int pcpu_map_pages(struct pcpu_chunk *chunk, + struct page **pages, unsigned long *populated, + int page_start, int page_end) { - unsigned int last = nr_cpu_ids - 1; - unsigned int cpu; - int err; - - /* map must not be done on immutable chunk */ - WARN_ON(chunk->immutable); + unsigned int cpu, tcpu; + int i, err; for_each_possible_cpu(cpu) { - err = map_kernel_range_noflush( - pcpu_chunk_addr(chunk, cpu, page_start), - (page_end - page_start) << PAGE_SHIFT, - PAGE_KERNEL, - pcpu_chunk_pagep(chunk, cpu, page_start)); + err = __pcpu_map_pages(pcpu_chunk_addr(chunk, cpu, page_start), + &pages[pcpu_page_idx(cpu, page_start)], + page_end - page_start); if (err < 0) - return err; + goto err; + } + + /* mapping successful, link chunk and mark populated */ + for (i = page_start; i < page_end; i++) { + for_each_possible_cpu(cpu) + pcpu_set_page_chunk(pages[pcpu_page_idx(cpu, i)], + chunk); + __set_bit(i, populated); } - /* flush at once, please read comments in pcpu_unmap() */ - flush_cache_vmap(pcpu_chunk_addr(chunk, 0, page_start), - pcpu_chunk_addr(chunk, last, page_end)); return 0; + +err: + for_each_possible_cpu(tcpu) { + if (tcpu == cpu) + break; + __pcpu_unmap_pages(pcpu_chunk_addr(chunk, tcpu, page_start), + page_end - page_start); + } + return err; +} + +/** + * pcpu_post_map_flush - flush cache after mapping + * @chunk: pcpu_chunk the regions to be flushed belong to + * @page_start: page index of the first page to be flushed + * @page_end: page index of the last page to be flushed + 1 + * + * Pages [@page_start,@page_end) of @chunk have been mapped. Flush + * cache. + * + * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once + * for the whole region. + */ +static void pcpu_post_map_flush(struct pcpu_chunk *chunk, + int page_start, int page_end) +{ + flush_cache_vmap( + pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start), + pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end)); +} + +/** + * pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk + * @chunk: chunk to depopulate + * @off: offset to the area to depopulate + * @size: size of the area to depopulate in bytes + * @flush: whether to flush cache and tlb or not + * + * For each cpu, depopulate and unmap pages [@page_start,@page_end) + * from @chunk. If @flush is true, vcache is flushed before unmapping + * and tlb after. + * + * CONTEXT: + * pcpu_alloc_mutex. + */ +static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size) +{ + int page_start = PFN_DOWN(off); + int page_end = PFN_UP(off + size); + struct page **pages; + unsigned long *populated; + int rs, re; + + /* quick path, check whether it's empty already */ + pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) { + if (rs == page_start && re == page_end) + return; + break; + } + + /* immutable chunks can't be depopulated */ + WARN_ON(chunk->immutable); + + /* + * If control reaches here, there must have been at least one + * successful population attempt so the temp pages array must + * be available now. + */ + pages = pcpu_get_pages_and_bitmap(chunk, &populated, false); + BUG_ON(!pages); + + /* unmap and free */ + pcpu_pre_unmap_flush(chunk, page_start, page_end); + + pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end) + pcpu_unmap_pages(chunk, pages, populated, rs, re); + + /* no need to flush tlb, vmalloc will handle it lazily */ + + pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end) + pcpu_free_pages(chunk, pages, populated, rs, re); + + /* commit new bitmap */ + bitmap_copy(chunk->populated, populated, pcpu_unit_pages); } /** @@ -680,50 +926,60 @@ static int pcpu_map(struct pcpu_chunk *chunk, int page_start, int page_end) */ static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size) { - const gfp_t alloc_mask = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD; int page_start = PFN_DOWN(off); int page_end = PFN_UP(off + size); - int map_start = -1; - int uninitialized_var(map_end); + int free_end = page_start, unmap_end = page_start; + struct page **pages; + unsigned long *populated; unsigned int cpu; - int i; + int rs, re, rc; - for (i = page_start; i < page_end; i++) { - if (pcpu_chunk_page_occupied(chunk, i)) { - if (map_start >= 0) { - if (pcpu_map(chunk, map_start, map_end)) - goto err; - map_start = -1; - } - continue; - } + /* quick path, check whether all pages are already there */ + pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end) { + if (rs == page_start && re == page_end) + goto clear; + break; + } - map_start = map_start < 0 ? i : map_start; - map_end = i + 1; + /* need to allocate and map pages, this chunk can't be immutable */ + WARN_ON(chunk->immutable); - for_each_possible_cpu(cpu) { - struct page **pagep = pcpu_chunk_pagep(chunk, cpu, i); + pages = pcpu_get_pages_and_bitmap(chunk, &populated, true); + if (!pages) + return -ENOMEM; - *pagep = alloc_pages_node(cpu_to_node(cpu), - alloc_mask, 0); - if (!*pagep) - goto err; - pcpu_set_page_chunk(*pagep, chunk); - } + /* alloc and map */ + pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) { + rc = pcpu_alloc_pages(chunk, pages, populated, rs, re); + if (rc) + goto err_free; + free_end = re; } - if (map_start >= 0 && pcpu_map(chunk, map_start, map_end)) - goto err; + pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) { + rc = pcpu_map_pages(chunk, pages, populated, rs, re); + if (rc) + goto err_unmap; + unmap_end = re; + } + pcpu_post_map_flush(chunk, page_start, page_end); + /* commit new bitmap */ + bitmap_copy(chunk->populated, populated, pcpu_unit_pages); +clear: for_each_possible_cpu(cpu) - memset(chunk->vm->addr + cpu * pcpu_unit_size + off, 0, - size); - + memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size); return 0; -err: - /* likely under heavy memory pressure, give memory back */ - pcpu_depopulate_chunk(chunk, off, size, true); - return -ENOMEM; + +err_unmap: + pcpu_pre_unmap_flush(chunk, page_start, unmap_end); + pcpu_for_each_unpop_region(chunk, rs, re, page_start, unmap_end) + pcpu_unmap_pages(chunk, pages, populated, rs, re); + pcpu_post_unmap_tlb_flush(chunk, page_start, unmap_end); +err_free: + pcpu_for_each_unpop_region(chunk, rs, re, page_start, free_end) + pcpu_free_pages(chunk, pages, populated, rs, re); + return rc; } static void free_pcpu_chunk(struct pcpu_chunk *chunk) @@ -747,7 +1003,6 @@ static struct pcpu_chunk *alloc_pcpu_chunk(void) chunk->map = pcpu_mem_alloc(PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0])); chunk->map_alloc = PCPU_DFL_MAP_ALLOC; chunk->map[chunk->map_used++] = pcpu_unit_size; - chunk->page = chunk->page_ar; chunk->vm = get_vm_area(pcpu_chunk_size, VM_ALLOC); if (!chunk->vm) { @@ -847,6 +1102,7 @@ area_found: mutex_unlock(&pcpu_alloc_mutex); + /* return address relative to unit0 */ return __addr_to_pcpu_ptr(chunk->vm->addr + off); fail_unlock: @@ -928,7 +1184,7 @@ static void pcpu_reclaim(struct work_struct *work) mutex_unlock(&pcpu_alloc_mutex); list_for_each_entry_safe(chunk, next, &todo, list) { - pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size, false); + pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size); free_pcpu_chunk(chunk); } } @@ -976,26 +1232,16 @@ EXPORT_SYMBOL_GPL(free_percpu); /** * pcpu_setup_first_chunk - initialize the first percpu chunk - * @get_page_fn: callback to fetch page pointer * @static_size: the size of static percpu area in bytes - * @reserved_size: the size of reserved percpu area in bytes + * @reserved_size: the size of reserved percpu area in bytes, 0 for none * @dyn_size: free size for dynamic allocation in bytes, -1 for auto - * @unit_size: unit size in bytes, must be multiple of PAGE_SIZE, -1 for auto - * @base_addr: mapped address, NULL for auto - * @populate_pte_fn: callback to allocate pagetable, NULL if unnecessary + * @unit_size: unit size in bytes, must be multiple of PAGE_SIZE + * @base_addr: mapped address + * @unit_map: cpu -> unit map, NULL for sequential mapping * * Initialize the first percpu chunk which contains the kernel static * perpcu area. This function is to be called from arch percpu area - * setup path. The first two parameters are mandatory. The rest are - * optional. - * - * @get_page_fn() should return pointer to percpu page given cpu - * number and page number. It should at least return enough pages to - * cover the static area. The returned pages for static area should - * have been initialized with valid data. If @unit_size is specified, - * it can also return pages after the static area. NULL return - * indicates end of pages for the cpu. Note that @get_page_fn() must - * return the same number of pages for all cpus. + * setup path. * * @reserved_size, if non-zero, specifies the amount of bytes to * reserve after the static area in the first chunk. This reserves @@ -1010,17 +1256,12 @@ EXPORT_SYMBOL_GPL(free_percpu); * non-negative value makes percpu leave alone the area beyond * @static_size + @reserved_size + @dyn_size. * - * @unit_size, if non-negative, specifies unit size and must be - * aligned to PAGE_SIZE and equal to or larger than @static_size + - * @reserved_size + if non-negative, @dyn_size. - * - * Non-null @base_addr means that the caller already allocated virtual - * region for the first chunk and mapped it. percpu must not mess - * with the chunk. Note that @base_addr with 0 @unit_size or non-NULL - * @populate_pte_fn doesn't make any sense. + * @unit_size specifies unit size and must be aligned to PAGE_SIZE and + * equal to or larger than @static_size + @reserved_size + if + * non-negative, @dyn_size. * - * @populate_pte_fn is used to populate the pagetable. NULL means the - * caller already populated the pagetable. + * The caller should have mapped the first chunk at @base_addr and + * copied static data to each unit. * * If the first chunk ends up with both reserved and dynamic areas, it * is served by two chunks - one to serve the core static and reserved @@ -1033,47 +1274,83 @@ EXPORT_SYMBOL_GPL(free_percpu); * The determined pcpu_unit_size which can be used to initialize * percpu access. */ -size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn, - size_t static_size, size_t reserved_size, - ssize_t dyn_size, ssize_t unit_size, - void *base_addr, - pcpu_populate_pte_fn_t populate_pte_fn) +size_t __init pcpu_setup_first_chunk(size_t static_size, size_t reserved_size, + ssize_t dyn_size, size_t unit_size, + void *base_addr, const int *unit_map) { static struct vm_struct first_vm; static int smap[2], dmap[2]; size_t size_sum = static_size + reserved_size + (dyn_size >= 0 ? dyn_size : 0); struct pcpu_chunk *schunk, *dchunk = NULL; - unsigned int cpu; - int nr_pages; - int err, i; + unsigned int cpu, tcpu; + int i; - /* santiy checks */ + /* sanity checks */ BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC || ARRAY_SIZE(dmap) >= PCPU_DFL_MAP_ALLOC); BUG_ON(!static_size); - if (unit_size >= 0) { - BUG_ON(unit_size < size_sum); - BUG_ON(unit_size & ~PAGE_MASK); - BUG_ON(unit_size < PCPU_MIN_UNIT_SIZE); - } else - BUG_ON(base_addr); - BUG_ON(base_addr && populate_pte_fn); - - if (unit_size >= 0) - pcpu_unit_pages = unit_size >> PAGE_SHIFT; - else - pcpu_unit_pages = max_t(int, PCPU_MIN_UNIT_SIZE >> PAGE_SHIFT, - PFN_UP(size_sum)); + BUG_ON(!base_addr); + BUG_ON(unit_size < size_sum); + BUG_ON(unit_size & ~PAGE_MASK); + BUG_ON(unit_size < PCPU_MIN_UNIT_SIZE); + + /* determine number of units and verify and initialize pcpu_unit_map */ + if (unit_map) { + int first_unit = INT_MAX, last_unit = INT_MIN; + + for_each_possible_cpu(cpu) { + int unit = unit_map[cpu]; + + BUG_ON(unit < 0); + for_each_possible_cpu(tcpu) { + if (tcpu == cpu) + break; + /* the mapping should be one-to-one */ + BUG_ON(unit_map[tcpu] == unit); + } + + if (unit < first_unit) { + pcpu_first_unit_cpu = cpu; + first_unit = unit; + } + if (unit > last_unit) { + pcpu_last_unit_cpu = cpu; + last_unit = unit; + } + } + pcpu_nr_units = last_unit + 1; + pcpu_unit_map = unit_map; + } else { + int *identity_map; + + /* #units == #cpus, identity mapped */ + identity_map = alloc_bootmem(nr_cpu_ids * + sizeof(identity_map[0])); + for_each_possible_cpu(cpu) + identity_map[cpu] = cpu; + + pcpu_first_unit_cpu = 0; + pcpu_last_unit_cpu = pcpu_nr_units - 1; + pcpu_nr_units = nr_cpu_ids; + pcpu_unit_map = identity_map; + } + + /* determine basic parameters */ + pcpu_unit_pages = unit_size >> PAGE_SHIFT; pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT; - pcpu_chunk_size = nr_cpu_ids * pcpu_unit_size; - pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) - + nr_cpu_ids * pcpu_unit_pages * sizeof(struct page *); + pcpu_chunk_size = pcpu_nr_units * pcpu_unit_size; + pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) + + BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long); if (dyn_size < 0) dyn_size = pcpu_unit_size - static_size - reserved_size; + first_vm.flags = VM_ALLOC; + first_vm.size = pcpu_chunk_size; + first_vm.addr = base_addr; + /* * Allocate chunk slots. The additional last slot is for * empty chunks. @@ -1095,7 +1372,8 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn, schunk->vm = &first_vm; schunk->map = smap; schunk->map_alloc = ARRAY_SIZE(smap); - schunk->page = schunk->page_ar; + schunk->immutable = true; + bitmap_fill(schunk->populated, pcpu_unit_pages); if (reserved_size) { schunk->free_size = reserved_size; @@ -1113,93 +1391,39 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn, /* init dynamic chunk if necessary */ if (dyn_size) { - dchunk = alloc_bootmem(sizeof(struct pcpu_chunk)); + dchunk = alloc_bootmem(pcpu_chunk_struct_size); INIT_LIST_HEAD(&dchunk->list); dchunk->vm = &first_vm; dchunk->map = dmap; dchunk->map_alloc = ARRAY_SIZE(dmap); - dchunk->page = schunk->page_ar; /* share page map with schunk */ + dchunk->immutable = true; + bitmap_fill(dchunk->populated, pcpu_unit_pages); dchunk->contig_hint = dchunk->free_size = dyn_size; dchunk->map[dchunk->map_used++] = -pcpu_reserved_chunk_limit; dchunk->map[dchunk->map_used++] = dchunk->free_size; } - /* allocate vm address */ - first_vm.flags = VM_ALLOC; - first_vm.size = pcpu_chunk_size; - - if (!base_addr) - vm_area_register_early(&first_vm, PAGE_SIZE); - else { - /* - * Pages already mapped. No need to remap into - * vmalloc area. In this case the first chunks can't - * be mapped or unmapped by percpu and are marked - * immutable. - */ - first_vm.addr = base_addr; - schunk->immutable = true; - if (dchunk) - dchunk->immutable = true; - } - - /* assign pages */ - nr_pages = -1; - for_each_possible_cpu(cpu) { - for (i = 0; i < pcpu_unit_pages; i++) { - struct page *page = get_page_fn(cpu, i); - - if (!page) - break; - *pcpu_chunk_pagep(schunk, cpu, i) = page; - } - - BUG_ON(i < PFN_UP(static_size)); - - if (nr_pages < 0) - nr_pages = i; - else - BUG_ON(nr_pages != i); - } - - /* map them */ - if (populate_pte_fn) { - for_each_possible_cpu(cpu) - for (i = 0; i < nr_pages; i++) - populate_pte_fn(pcpu_chunk_addr(schunk, - cpu, i)); - - err = pcpu_map(schunk, 0, nr_pages); - if (err) - panic("failed to setup static percpu area, err=%d\n", - err); - } - /* link the first chunk in */ pcpu_first_chunk = dchunk ?: schunk; pcpu_chunk_relocate(pcpu_first_chunk, -1); /* we're done */ - pcpu_base_addr = (void *)pcpu_chunk_addr(schunk, 0, 0); + pcpu_base_addr = schunk->vm->addr; return pcpu_unit_size; } -/* - * Embedding first chunk setup helper. - */ -static void *pcpue_ptr __initdata; -static size_t pcpue_size __initdata; -static size_t pcpue_unit_size __initdata; - -static struct page * __init pcpue_get_page(unsigned int cpu, int pageno) +static size_t pcpu_calc_fc_sizes(size_t static_size, size_t reserved_size, + ssize_t *dyn_sizep) { - size_t off = (size_t)pageno << PAGE_SHIFT; + size_t size_sum; - if (off >= pcpue_size) - return NULL; + size_sum = PFN_ALIGN(static_size + reserved_size + + (*dyn_sizep >= 0 ? *dyn_sizep : 0)); + if (*dyn_sizep != 0) + *dyn_sizep = size_sum - static_size - reserved_size; - return virt_to_page(pcpue_ptr + cpu * pcpue_unit_size + off); + return size_sum; } /** @@ -1207,7 +1431,6 @@ static struct page * __init pcpue_get_page(unsigned int cpu, int pageno) * @static_size: the size of static percpu area in bytes * @reserved_size: the size of reserved percpu area in bytes * @dyn_size: free size for dynamic allocation in bytes, -1 for auto - * @unit_size: unit size in bytes, must be multiple of PAGE_SIZE, -1 for auto * * This is a helper to ease setting up embedded first percpu chunk and * can be called where pcpu_setup_first_chunk() is expected. @@ -1219,9 +1442,9 @@ static struct page * __init pcpue_get_page(unsigned int cpu, int pageno) * page size. * * When @dyn_size is positive, dynamic area might be larger than - * specified to fill page alignment. Also, when @dyn_size is auto, - * @dyn_size does not fill the whole first chunk but only what's - * necessary for page alignment after static and reserved areas. + * specified to fill page alignment. When @dyn_size is auto, + * @dyn_size is just big enough to fill page alignment after static + * and reserved areas. * * If the needed size is smaller than the minimum or specified unit * size, the leftover is returned to the bootmem allocator. @@ -1231,28 +1454,21 @@ static struct page * __init pcpue_get_page(unsigned int cpu, int pageno) * percpu access on success, -errno on failure. */ ssize_t __init pcpu_embed_first_chunk(size_t static_size, size_t reserved_size, - ssize_t dyn_size, ssize_t unit_size) + ssize_t dyn_size) { - size_t chunk_size; + size_t size_sum, unit_size, chunk_size; + void *base; unsigned int cpu; /* determine parameters and allocate */ - pcpue_size = PFN_ALIGN(static_size + reserved_size + - (dyn_size >= 0 ? dyn_size : 0)); - if (dyn_size != 0) - dyn_size = pcpue_size - static_size - reserved_size; - - if (unit_size >= 0) { - BUG_ON(unit_size < pcpue_size); - pcpue_unit_size = unit_size; - } else - pcpue_unit_size = max_t(size_t, pcpue_size, PCPU_MIN_UNIT_SIZE); - - chunk_size = pcpue_unit_size * nr_cpu_ids; - - pcpue_ptr = __alloc_bootmem_nopanic(chunk_size, PAGE_SIZE, - __pa(MAX_DMA_ADDRESS)); - if (!pcpue_ptr) { + size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size); + + unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE); + chunk_size = unit_size * nr_cpu_ids; + + base = __alloc_bootmem_nopanic(chunk_size, PAGE_SIZE, + __pa(MAX_DMA_ADDRESS)); + if (!base) { pr_warning("PERCPU: failed to allocate %zu bytes for " "embedding\n", chunk_size); return -ENOMEM; @@ -1260,21 +1476,543 @@ ssize_t __init pcpu_embed_first_chunk(size_t static_size, size_t reserved_size, /* return the leftover and copy */ for (cpu = 0; cpu < nr_cpu_ids; cpu++) { - void *ptr = pcpue_ptr + cpu * pcpue_unit_size; + void *ptr = base + cpu * unit_size; if (cpu_possible(cpu)) { - free_bootmem(__pa(ptr + pcpue_size), - pcpue_unit_size - pcpue_size); + free_bootmem(__pa(ptr + size_sum), + unit_size - size_sum); memcpy(ptr, __per_cpu_load, static_size); } else - free_bootmem(__pa(ptr), pcpue_unit_size); + free_bootmem(__pa(ptr), unit_size); } /* we're ready, commit */ pr_info("PERCPU: Embedded %zu pages at %p, static data %zu bytes\n", - pcpue_size >> PAGE_SHIFT, pcpue_ptr, static_size); + size_sum >> PAGE_SHIFT, base, static_size); + + return pcpu_setup_first_chunk(static_size, reserved_size, dyn_size, + unit_size, base, NULL); +} + +/** + * pcpu_4k_first_chunk - map the first chunk using PAGE_SIZE pages + * @static_size: the size of static percpu area in bytes + * @reserved_size: the size of reserved percpu area in bytes + * @alloc_fn: function to allocate percpu page, always called with PAGE_SIZE + * @free_fn: funtion to free percpu page, always called with PAGE_SIZE + * @populate_pte_fn: function to populate pte + * + * This is a helper to ease setting up embedded first percpu chunk and + * can be called where pcpu_setup_first_chunk() is expected. + * + * This is the basic allocator. Static percpu area is allocated + * page-by-page into vmalloc area. + * + * RETURNS: + * The determined pcpu_unit_size which can be used to initialize + * percpu access on success, -errno on failure. + */ +ssize_t __init pcpu_4k_first_chunk(size_t static_size, size_t reserved_size, + pcpu_fc_alloc_fn_t alloc_fn, + pcpu_fc_free_fn_t free_fn, + pcpu_fc_populate_pte_fn_t populate_pte_fn) +{ + static struct vm_struct vm; + int unit_pages; + size_t pages_size; + struct page **pages; + unsigned int cpu; + int i, j; + ssize_t ret; + + unit_pages = PFN_UP(max_t(size_t, static_size + reserved_size, + PCPU_MIN_UNIT_SIZE)); + + /* unaligned allocations can't be freed, round up to page size */ + pages_size = PFN_ALIGN(unit_pages * nr_cpu_ids * sizeof(pages[0])); + pages = alloc_bootmem(pages_size); + + /* allocate pages */ + j = 0; + for_each_possible_cpu(cpu) + for (i = 0; i < unit_pages; i++) { + void *ptr; + + ptr = alloc_fn(cpu, PAGE_SIZE); + if (!ptr) { + pr_warning("PERCPU: failed to allocate " + "4k page for cpu%u\n", cpu); + goto enomem; + } + pages[j++] = virt_to_page(ptr); + } + + /* allocate vm area, map the pages and copy static data */ + vm.flags = VM_ALLOC; + vm.size = nr_cpu_ids * unit_pages << PAGE_SHIFT; + vm_area_register_early(&vm, PAGE_SIZE); + + for_each_possible_cpu(cpu) { + unsigned long unit_addr = (unsigned long)vm.addr + + (cpu * unit_pages << PAGE_SHIFT); + + for (i = 0; i < unit_pages; i++) + populate_pte_fn(unit_addr + (i << PAGE_SHIFT)); + + /* pte already populated, the following shouldn't fail */ + ret = __pcpu_map_pages(unit_addr, &pages[cpu * unit_pages], + unit_pages); + if (ret < 0) + panic("failed to map percpu area, err=%zd\n", ret); + + /* + * FIXME: Archs with virtual cache should flush local + * cache for the linear mapping here - something + * equivalent to flush_cache_vmap() on the local cpu. + * flush_cache_vmap() can't be used as most supporting + * data structures are not set up yet. + */ + + /* copy static data */ + memcpy((void *)unit_addr, __per_cpu_load, static_size); + } + + /* we're ready, commit */ + pr_info("PERCPU: %d 4k pages per cpu, static data %zu bytes\n", + unit_pages, static_size); + + ret = pcpu_setup_first_chunk(static_size, reserved_size, -1, + unit_pages << PAGE_SHIFT, vm.addr, NULL); + goto out_free_ar; + +enomem: + while (--j >= 0) + free_fn(page_address(pages[j]), PAGE_SIZE); + ret = -ENOMEM; +out_free_ar: + free_bootmem(__pa(pages), pages_size); + return ret; +} + +/* + * Large page remapping first chunk setup helper + */ +#ifdef CONFIG_NEED_MULTIPLE_NODES + +/** + * pcpu_lpage_build_unit_map - build unit_map for large page remapping + * @static_size: the size of static percpu area in bytes + * @reserved_size: the size of reserved percpu area in bytes + * @dyn_sizep: in/out parameter for dynamic size, -1 for auto + * @unit_sizep: out parameter for unit size + * @unit_map: unit_map to be filled + * @cpu_distance_fn: callback to determine distance between cpus + * + * This function builds cpu -> unit map and determine other parameters + * considering needed percpu size, large page size and distances + * between CPUs in NUMA. + * + * CPUs which are of LOCAL_DISTANCE both ways are grouped together and + * may share units in the same large page. The returned configuration + * is guaranteed to have CPUs on different nodes on different large + * pages and >=75% usage of allocated virtual address space. + * + * RETURNS: + * On success, fills in @unit_map, sets *@dyn_sizep, *@unit_sizep and + * returns the number of units to be allocated. -errno on failure. + */ +int __init pcpu_lpage_build_unit_map(size_t static_size, size_t reserved_size, + ssize_t *dyn_sizep, size_t *unit_sizep, + size_t lpage_size, int *unit_map, + pcpu_fc_cpu_distance_fn_t cpu_distance_fn) +{ + static int group_map[NR_CPUS] __initdata; + static int group_cnt[NR_CPUS] __initdata; + int group_cnt_max = 0; + size_t size_sum, min_unit_size, alloc_size; + int upa, max_upa, uninitialized_var(best_upa); /* units_per_alloc */ + int last_allocs; + unsigned int cpu, tcpu; + int group, unit; + + /* + * Determine min_unit_size, alloc_size and max_upa such that + * alloc_size is multiple of lpage_size and is the smallest + * which can accomodate 4k aligned segments which are equal to + * or larger than min_unit_size. + */ + size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, dyn_sizep); + min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE); + + alloc_size = roundup(min_unit_size, lpage_size); + upa = alloc_size / min_unit_size; + while (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK)) + upa--; + max_upa = upa; + + /* group cpus according to their proximity */ + for_each_possible_cpu(cpu) { + group = 0; + next_group: + for_each_possible_cpu(tcpu) { + if (cpu == tcpu) + break; + if (group_map[tcpu] == group && + (cpu_distance_fn(cpu, tcpu) > LOCAL_DISTANCE || + cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) { + group++; + goto next_group; + } + } + group_map[cpu] = group; + group_cnt[group]++; + group_cnt_max = max(group_cnt_max, group_cnt[group]); + } + + /* + * Expand unit size until address space usage goes over 75% + * and then as much as possible without using more address + * space. + */ + last_allocs = INT_MAX; + for (upa = max_upa; upa; upa--) { + int allocs = 0, wasted = 0; + + if (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK)) + continue; + + for (group = 0; group_cnt[group]; group++) { + int this_allocs = DIV_ROUND_UP(group_cnt[group], upa); + allocs += this_allocs; + wasted += this_allocs * upa - group_cnt[group]; + } + + /* + * Don't accept if wastage is over 25%. The + * greater-than comparison ensures upa==1 always + * passes the following check. + */ + if (wasted > num_possible_cpus() / 3) + continue; + + /* and then don't consume more memory */ + if (allocs > last_allocs) + break; + last_allocs = allocs; + best_upa = upa; + } + *unit_sizep = alloc_size / best_upa; - return pcpu_setup_first_chunk(pcpue_get_page, static_size, - reserved_size, dyn_size, - pcpue_unit_size, pcpue_ptr, NULL); + /* assign units to cpus accordingly */ + unit = 0; + for (group = 0; group_cnt[group]; group++) { + for_each_possible_cpu(cpu) + if (group_map[cpu] == group) + unit_map[cpu] = unit++; + unit = roundup(unit, best_upa); + } + + return unit; /* unit contains aligned number of units */ +} + +struct pcpul_ent { + void *ptr; + void *map_addr; +}; + +static size_t pcpul_size; +static size_t pcpul_lpage_size; +static int pcpul_nr_lpages; +static struct pcpul_ent *pcpul_map; + +static bool __init pcpul_unit_to_cpu(int unit, const int *unit_map, + unsigned int *cpup) +{ + unsigned int cpu; + + for_each_possible_cpu(cpu) + if (unit_map[cpu] == unit) { + if (cpup) + *cpup = cpu; + return true; + } + + return false; +} + +static void __init pcpul_lpage_dump_cfg(const char *lvl, size_t static_size, + size_t reserved_size, size_t dyn_size, + size_t unit_size, size_t lpage_size, + const int *unit_map, int nr_units) +{ + int width = 1, v = nr_units; + char empty_str[] = "--------"; + int upl, lpl; /* units per lpage, lpage per line */ + unsigned int cpu; + int lpage, unit; + + while (v /= 10) + width++; + empty_str[min_t(int, width, sizeof(empty_str) - 1)] = '\0'; + + upl = max_t(int, lpage_size / unit_size, 1); + lpl = rounddown_pow_of_two(max_t(int, 60 / (upl * (width + 1) + 2), 1)); + + printk("%spcpu-lpage: sta/res/dyn=%zu/%zu/%zu unit=%zu lpage=%zu", lvl, + static_size, reserved_size, dyn_size, unit_size, lpage_size); + + for (lpage = 0, unit = 0; unit < nr_units; unit++) { + if (!(unit % upl)) { + if (!(lpage++ % lpl)) { + printk("\n"); + printk("%spcpu-lpage: ", lvl); + } else + printk("| "); + } + if (pcpul_unit_to_cpu(unit, unit_map, &cpu)) + printk("%0*d ", width, cpu); + else + printk("%s ", empty_str); + } + printk("\n"); +} + +/** + * pcpu_lpage_first_chunk - remap the first percpu chunk using large page + * @static_size: the size of static percpu area in bytes + * @reserved_size: the size of reserved percpu area in bytes + * @dyn_size: free size for dynamic allocation in bytes + * @unit_size: unit size in bytes + * @lpage_size: the size of a large page + * @unit_map: cpu -> unit mapping + * @nr_units: the number of units + * @alloc_fn: function to allocate percpu lpage, always called with lpage_size + * @free_fn: function to free percpu memory, @size <= lpage_size + * @map_fn: function to map percpu lpage, always called with lpage_size + * + * This allocator uses large page to build and map the first chunk. + * Unlike other helpers, the caller should always specify @dyn_size + * and @unit_size. These parameters along with @unit_map and + * @nr_units can be determined using pcpu_lpage_build_unit_map(). + * This two stage initialization is to allow arch code to evaluate the + * parameters before committing to it. + * + * Large pages are allocated as directed by @unit_map and other + * parameters and mapped to vmalloc space. Unused holes are returned + * to the page allocator. Note that these holes end up being actively + * mapped twice - once to the physical mapping and to the vmalloc area + * for the first percpu chunk. Depending on architecture, this might + * cause problem when changing page attributes of the returned area. + * These double mapped areas can be detected using + * pcpu_lpage_remapped(). + * + * RETURNS: + * The determined pcpu_unit_size which can be used to initialize + * percpu access on success, -errno on failure. + */ +ssize_t __init pcpu_lpage_first_chunk(size_t static_size, size_t reserved_size, + size_t dyn_size, size_t unit_size, + size_t lpage_size, const int *unit_map, + int nr_units, + pcpu_fc_alloc_fn_t alloc_fn, + pcpu_fc_free_fn_t free_fn, + pcpu_fc_map_fn_t map_fn) +{ + static struct vm_struct vm; + size_t chunk_size = unit_size * nr_units; + size_t map_size; + unsigned int cpu; + ssize_t ret; + int i, j, unit; + + pcpul_lpage_dump_cfg(KERN_DEBUG, static_size, reserved_size, dyn_size, + unit_size, lpage_size, unit_map, nr_units); + + BUG_ON(chunk_size % lpage_size); + + pcpul_size = static_size + reserved_size + dyn_size; + pcpul_lpage_size = lpage_size; + pcpul_nr_lpages = chunk_size / lpage_size; + + /* allocate pointer array and alloc large pages */ + map_size = pcpul_nr_lpages * sizeof(pcpul_map[0]); + pcpul_map = alloc_bootmem(map_size); + + /* allocate all pages */ + for (i = 0; i < pcpul_nr_lpages; i++) { + size_t offset = i * lpage_size; + int first_unit = offset / unit_size; + int last_unit = (offset + lpage_size - 1) / unit_size; + void *ptr; + + /* find out which cpu is mapped to this unit */ + for (unit = first_unit; unit <= last_unit; unit++) + if (pcpul_unit_to_cpu(unit, unit_map, &cpu)) + goto found; + continue; + found: + ptr = alloc_fn(cpu, lpage_size); + if (!ptr) { + pr_warning("PERCPU: failed to allocate large page " + "for cpu%u\n", cpu); + goto enomem; + } + + pcpul_map[i].ptr = ptr; + } + + /* return unused holes */ + for (unit = 0; unit < nr_units; unit++) { + size_t start = unit * unit_size; + size_t end = start + unit_size; + size_t off, next; + + /* don't free used part of occupied unit */ + if (pcpul_unit_to_cpu(unit, unit_map, NULL)) + start += pcpul_size; + + /* unit can span more than one page, punch the holes */ + for (off = start; off < end; off = next) { + void *ptr = pcpul_map[off / lpage_size].ptr; + next = min(roundup(off + 1, lpage_size), end); + if (ptr) + free_fn(ptr + off % lpage_size, next - off); + } + } + + /* allocate address, map and copy */ + vm.flags = VM_ALLOC; + vm.size = chunk_size; + vm_area_register_early(&vm, unit_size); + + for (i = 0; i < pcpul_nr_lpages; i++) { + if (!pcpul_map[i].ptr) + continue; + pcpul_map[i].map_addr = vm.addr + i * lpage_size; + map_fn(pcpul_map[i].ptr, lpage_size, pcpul_map[i].map_addr); + } + + for_each_possible_cpu(cpu) + memcpy(vm.addr + unit_map[cpu] * unit_size, __per_cpu_load, + static_size); + + /* we're ready, commit */ + pr_info("PERCPU: Remapped at %p with large pages, static data " + "%zu bytes\n", vm.addr, static_size); + + ret = pcpu_setup_first_chunk(static_size, reserved_size, dyn_size, + unit_size, vm.addr, unit_map); + + /* + * Sort pcpul_map array for pcpu_lpage_remapped(). Unmapped + * lpages are pushed to the end and trimmed. + */ + for (i = 0; i < pcpul_nr_lpages - 1; i++) + for (j = i + 1; j < pcpul_nr_lpages; j++) { + struct pcpul_ent tmp; + + if (!pcpul_map[j].ptr) + continue; + if (pcpul_map[i].ptr && + pcpul_map[i].ptr < pcpul_map[j].ptr) + continue; + + tmp = pcpul_map[i]; + pcpul_map[i] = pcpul_map[j]; + pcpul_map[j] = tmp; + } + + while (pcpul_nr_lpages && !pcpul_map[pcpul_nr_lpages - 1].ptr) + pcpul_nr_lpages--; + + return ret; + +enomem: + for (i = 0; i < pcpul_nr_lpages; i++) + if (pcpul_map[i].ptr) + free_fn(pcpul_map[i].ptr, lpage_size); + free_bootmem(__pa(pcpul_map), map_size); + return -ENOMEM; +} + +/** + * pcpu_lpage_remapped - determine whether a kaddr is in pcpul recycled area + * @kaddr: the kernel address in question + * + * Determine whether @kaddr falls in the pcpul recycled area. This is + * used by pageattr to detect VM aliases and break up the pcpu large + * page mapping such that the same physical page is not mapped under + * different attributes. + * + * The recycled area is always at the tail of a partially used large + * page. + * + * RETURNS: + * Address of corresponding remapped pcpu address if match is found; + * otherwise, NULL. + */ +void *pcpu_lpage_remapped(void *kaddr) +{ + unsigned long lpage_mask = pcpul_lpage_size - 1; + void *lpage_addr = (void *)((unsigned long)kaddr & ~lpage_mask); + unsigned long offset = (unsigned long)kaddr & lpage_mask; + int left = 0, right = pcpul_nr_lpages - 1; + int pos; + + /* pcpul in use at all? */ + if (!pcpul_map) + return NULL; + + /* okay, perform binary search */ + while (left <= right) { + pos = (left + right) / 2; + + if (pcpul_map[pos].ptr < lpage_addr) + left = pos + 1; + else if (pcpul_map[pos].ptr > lpage_addr) + right = pos - 1; + else + return pcpul_map[pos].map_addr + offset; + } + + return NULL; +} +#endif + +/* + * Generic percpu area setup. + * + * The embedding helper is used because its behavior closely resembles + * the original non-dynamic generic percpu area setup. This is + * important because many archs have addressing restrictions and might + * fail if the percpu area is located far away from the previous + * location. As an added bonus, in non-NUMA cases, embedding is + * generally a good idea TLB-wise because percpu area can piggy back + * on the physical linear memory mapping which uses large page + * mappings on applicable archs. + */ +#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA +unsigned long __per_cpu_offset[NR_CPUS] __read_mostly; +EXPORT_SYMBOL(__per_cpu_offset); + +void __init setup_per_cpu_areas(void) +{ + size_t static_size = __per_cpu_end - __per_cpu_start; + ssize_t unit_size; + unsigned long delta; + unsigned int cpu; + + /* + * Always reserve area for module percpu variables. That's + * what the legacy allocator did. + */ + unit_size = pcpu_embed_first_chunk(static_size, PERCPU_MODULE_RESERVE, + PERCPU_DYNAMIC_RESERVE); + if (unit_size < 0) + panic("Failed to initialized percpu areas."); + + delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start; + for_each_possible_cpu(cpu) + __per_cpu_offset[cpu] = delta + cpu * unit_size; } +#endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */ |