| /* |
| * linux/mm/percpu.c - percpu memory allocator |
| * |
| * Copyright (C) 2009 SUSE Linux Products GmbH |
| * Copyright (C) 2009 Tejun Heo <tj@kernel.org> |
| * |
| * This file is released under the GPLv2. |
| * |
| * 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 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 |
| * ------------------- ------------------- ------------ |
| * | u0 | u1 | u2 | u3 | | u0 | u1 | u2 | u3 | | u0 | u1 | u |
| * ------------------- ...... ------------------- .... ------------ |
| * |
| * 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. 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 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 |
| * area in the chunk. This helps the allocator not to iterate the |
| * chunk maps unnecessarily. |
| * |
| * Allocation state in each chunk is kept using an array of integers |
| * on chunk->map. A positive value in the map represents a free |
| * region and negative allocated. Allocation inside a chunk is done |
| * by scanning this map sequentially and serving the first matching |
| * entry. This is mostly copied from the percpu_modalloc() allocator. |
| * Chunks can be determined from the address using the index field |
| * in the page struct. The index field contains a pointer to the chunk. |
| * |
| * To use this allocator, arch code should do the followings. |
| * |
| * - 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 |
| * different from the default |
| * |
| * - use pcpu_setup_first_chunk() during percpu area initialization to |
| * setup the first chunk containing the kernel static percpu area |
| */ |
| |
| #include <linux/bitmap.h> |
| #include <linux/bootmem.h> |
| #include <linux/list.h> |
| #include <linux/mm.h> |
| #include <linux/module.h> |
| #include <linux/mutex.h> |
| #include <linux/percpu.h> |
| #include <linux/pfn.h> |
| #include <linux/slab.h> |
| #include <linux/spinlock.h> |
| #include <linux/vmalloc.h> |
| #include <linux/workqueue.h> |
| |
| #include <asm/cacheflush.h> |
| #include <asm/sections.h> |
| #include <asm/tlbflush.h> |
| |
| #define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */ |
| #define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */ |
| |
| /* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */ |
| #ifndef __addr_to_pcpu_ptr |
| #define __addr_to_pcpu_ptr(addr) \ |
| (void *)((unsigned long)(addr) - (unsigned long)pcpu_base_addr \ |
| + (unsigned long)__per_cpu_start) |
| #endif |
| #ifndef __pcpu_ptr_to_addr |
| #define __pcpu_ptr_to_addr(ptr) \ |
| (void *)((unsigned long)(ptr) + (unsigned long)pcpu_base_addr \ |
| - (unsigned long)__per_cpu_start) |
| #endif |
| |
| struct pcpu_chunk { |
| struct list_head list; /* linked to pcpu_slot lists */ |
| int free_size; /* free bytes in the chunk */ |
| int contig_hint; /* max contiguous size hint */ |
| struct vm_struct *vm; /* mapped vmalloc region */ |
| int map_used; /* # of map entries used */ |
| int map_alloc; /* # of map entries allocated */ |
| int *map; /* allocation map */ |
| bool immutable; /* no [de]population allowed */ |
| 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 |
| * ways and thus often doesn't live in the vmalloc area. |
| */ |
| static struct pcpu_chunk *pcpu_first_chunk; |
| |
| /* |
| * Optional reserved chunk. This chunk reserves part of the first |
| * chunk and serves it for reserved allocations. The amount of |
| * reserved offset is in pcpu_reserved_chunk_limit. When reserved |
| * area doesn't exist, the following variables contain NULL and 0 |
| * respectively. |
| */ |
| static struct pcpu_chunk *pcpu_reserved_chunk; |
| 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, 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 |
| * allocations are done using GFP_KERNEL with pcpu_lock released. |
| * |
| * Free path accesses and alters only the index data structures, so it |
| * can be safely called from atomic context. When memory needs to be |
| * returned to the system, free path schedules reclaim_work which |
| * grabs both pcpu_alloc_mutex and pcpu_lock, unlinks chunks to be |
| * reclaimed, release both locks and frees the chunks. Note that it's |
| * necessary to grab both locks to remove a chunk from circulation as |
| * allocation path might be referencing the chunk with only |
| * pcpu_alloc_mutex locked. |
| */ |
| static DEFINE_MUTEX(pcpu_alloc_mutex); /* protects whole alloc and reclaim */ |
| static DEFINE_SPINLOCK(pcpu_lock); /* protects index data structures */ |
| |
| static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */ |
| |
| /* reclaim work to release fully free chunks, scheduled from free path */ |
| static void pcpu_reclaim(struct work_struct *work); |
| static DECLARE_WORK(pcpu_reclaim_work, pcpu_reclaim); |
| |
| static int __pcpu_size_to_slot(int size) |
| { |
| int highbit = fls(size); /* size is in bytes */ |
| return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1); |
| } |
| |
| static int pcpu_size_to_slot(int size) |
| { |
| if (size == pcpu_unit_size) |
| return pcpu_nr_slots - 1; |
| return __pcpu_size_to_slot(size); |
| } |
| |
| static int pcpu_chunk_slot(const struct pcpu_chunk *chunk) |
| { |
| if (chunk->free_size < sizeof(int) || chunk->contig_hint < sizeof(int)) |
| return 0; |
| |
| return pcpu_size_to_slot(chunk->free_size); |
| } |
| |
| static int pcpu_page_idx(unsigned int cpu, int page_idx) |
| { |
| return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx; |
| } |
| |
| static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk, |
| unsigned int cpu, int page_idx) |
| { |
| return (unsigned long)chunk->vm->addr + |
| (pcpu_page_idx(cpu, page_idx) << PAGE_SHIFT); |
| } |
| |
| static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk, |
| unsigned int cpu, int page_idx) |
| { |
| /* 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 */ |
| static void pcpu_set_page_chunk(struct page *page, struct pcpu_chunk *pcpu) |
| { |
| page->index = (unsigned long)pcpu; |
| } |
| |
| /* obtain pointer to a chunk from a page struct */ |
| 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 |
| * |
| * Allocate @size bytes. If @size is smaller than PAGE_SIZE, |
| * kzalloc() is used; otherwise, vmalloc() is used. The returned |
| * memory is always zeroed. |
| * |
| * CONTEXT: |
| * Does GFP_KERNEL allocation. |
| * |
| * RETURNS: |
| * Pointer to the allocated area on success, NULL on failure. |
| */ |
| static void *pcpu_mem_alloc(size_t size) |
| { |
| if (size <= PAGE_SIZE) |
| return kzalloc(size, GFP_KERNEL); |
| else { |
| void *ptr = vmalloc(size); |
| if (ptr) |
| memset(ptr, 0, size); |
| return ptr; |
| } |
| } |
| |
| /** |
| * pcpu_mem_free - free memory |
| * @ptr: memory to free |
| * @size: size of the area |
| * |
| * Free @ptr. @ptr should have been allocated using pcpu_mem_alloc(). |
| */ |
| static void pcpu_mem_free(void *ptr, size_t size) |
| { |
| if (size <= PAGE_SIZE) |
| kfree(ptr); |
| else |
| vfree(ptr); |
| } |
| |
| /** |
| * pcpu_chunk_relocate - put chunk in the appropriate chunk slot |
| * @chunk: chunk of interest |
| * @oslot: the previous slot it was on |
| * |
| * This function is called after an allocation or free changed @chunk. |
| * New slot according to the changed state is determined and @chunk is |
| * moved to the slot. Note that the reserved chunk is never put on |
| * chunk slots. |
| * |
| * CONTEXT: |
| * pcpu_lock. |
| */ |
| static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot) |
| { |
| int nslot = pcpu_chunk_slot(chunk); |
| |
| if (chunk != pcpu_reserved_chunk && oslot != nslot) { |
| if (oslot < nslot) |
| list_move(&chunk->list, &pcpu_slot[nslot]); |
| else |
| list_move_tail(&chunk->list, &pcpu_slot[nslot]); |
| } |
| } |
| |
| /** |
| * pcpu_chunk_addr_search - determine chunk containing specified address |
| * @addr: address for which the chunk needs to be determined. |
| * |
| * RETURNS: |
| * The address of the found chunk. |
| */ |
| 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_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)); |
| } |
| |
| /** |
| * pcpu_extend_area_map - extend area map for allocation |
| * @chunk: target chunk |
| * |
| * Extend area map of @chunk so that it can accomodate an allocation. |
| * A single allocation can split an area into three areas, so this |
| * function makes sure that @chunk->map has at least two extra slots. |
| * |
| * CONTEXT: |
| * pcpu_alloc_mutex, pcpu_lock. pcpu_lock is released and reacquired |
| * if area map is extended. |
| * |
| * RETURNS: |
| * 0 if noop, 1 if successfully extended, -errno on failure. |
| */ |
| static int pcpu_extend_area_map(struct pcpu_chunk *chunk) |
| { |
| int new_alloc; |
| int *new; |
| size_t size; |
| |
| /* has enough? */ |
| if (chunk->map_alloc >= chunk->map_used + 2) |
| return 0; |
| |
| spin_unlock_irq(&pcpu_lock); |
| |
| new_alloc = PCPU_DFL_MAP_ALLOC; |
| while (new_alloc < chunk->map_used + 2) |
| new_alloc *= 2; |
| |
| new = pcpu_mem_alloc(new_alloc * sizeof(new[0])); |
| if (!new) { |
| spin_lock_irq(&pcpu_lock); |
| return -ENOMEM; |
| } |
| |
| /* |
| * Acquire pcpu_lock and switch to new area map. Only free |
| * could have happened inbetween, so map_used couldn't have |
| * grown. |
| */ |
| spin_lock_irq(&pcpu_lock); |
| BUG_ON(new_alloc < chunk->map_used + 2); |
| |
| size = chunk->map_alloc * sizeof(chunk->map[0]); |
| memcpy(new, chunk->map, size); |
| |
| /* |
| * map_alloc < PCPU_DFL_MAP_ALLOC indicates that the chunk is |
| * one of the first chunks and still using static map. |
| */ |
| if (chunk->map_alloc >= PCPU_DFL_MAP_ALLOC) |
| pcpu_mem_free(chunk->map, size); |
| |
| chunk->map_alloc = new_alloc; |
| chunk->map = new; |
| return 0; |
| } |
| |
| /** |
| * pcpu_split_block - split a map block |
| * @chunk: chunk of interest |
| * @i: index of map block to split |
| * @head: head size in bytes (can be 0) |
| * @tail: tail size in bytes (can be 0) |
| * |
| * Split the @i'th map block into two or three blocks. If @head is |
| * non-zero, @head bytes block is inserted before block @i moving it |
| * to @i+1 and reducing its size by @head bytes. |
| * |
| * If @tail is non-zero, the target block, which can be @i or @i+1 |
| * depending on @head, is reduced by @tail bytes and @tail byte block |
| * is inserted after the target block. |
| * |
| * @chunk->map must have enough free slots to accomodate the split. |
| * |
| * CONTEXT: |
| * pcpu_lock. |
| */ |
| static void pcpu_split_block(struct pcpu_chunk *chunk, int i, |
| int head, int tail) |
| { |
| int nr_extra = !!head + !!tail; |
| |
| BUG_ON(chunk->map_alloc < chunk->map_used + nr_extra); |
| |
| /* insert new subblocks */ |
| memmove(&chunk->map[i + nr_extra], &chunk->map[i], |
| sizeof(chunk->map[0]) * (chunk->map_used - i)); |
| chunk->map_used += nr_extra; |
| |
| if (head) { |
| chunk->map[i + 1] = chunk->map[i] - head; |
| chunk->map[i++] = head; |
| } |
| if (tail) { |
| chunk->map[i++] -= tail; |
| chunk->map[i] = tail; |
| } |
| } |
| |
| /** |
| * pcpu_alloc_area - allocate area from a pcpu_chunk |
| * @chunk: chunk of interest |
| * @size: wanted size in bytes |
| * @align: wanted align |
| * |
| * Try to allocate @size bytes area aligned at @align from @chunk. |
| * Note that this function only allocates the offset. It doesn't |
| * populate or map the area. |
| * |
| * @chunk->map must have at least two free slots. |
| * |
| * CONTEXT: |
| * pcpu_lock. |
| * |
| * RETURNS: |
| * Allocated offset in @chunk on success, -1 if no matching area is |
| * found. |
| */ |
| static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align) |
| { |
| int oslot = pcpu_chunk_slot(chunk); |
| int max_contig = 0; |
| int i, off; |
| |
| for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++])) { |
| bool is_last = i + 1 == chunk->map_used; |
| int head, tail; |
| |
| /* extra for alignment requirement */ |
| head = ALIGN(off, align) - off; |
| BUG_ON(i == 0 && head != 0); |
| |
| if (chunk->map[i] < 0) |
| continue; |
| if (chunk->map[i] < head + size) { |
| max_contig = max(chunk->map[i], max_contig); |
| continue; |
| } |
| |
| /* |
| * If head is small or the previous block is free, |
| * merge'em. Note that 'small' is defined as smaller |
| * than sizeof(int), which is very small but isn't too |
| * uncommon for percpu allocations. |
| */ |
| if (head && (head < sizeof(int) || chunk->map[i - 1] > 0)) { |
| if (chunk->map[i - 1] > 0) |
| chunk->map[i - 1] += head; |
| else { |
| chunk->map[i - 1] -= head; |
| chunk->free_size -= head; |
| } |
| chunk->map[i] -= head; |
| off += head; |
| head = 0; |
| } |
| |
| /* if tail is small, just keep it around */ |
| tail = chunk->map[i] - head - size; |
| if (tail < sizeof(int)) |
| tail = 0; |
| |
| /* split if warranted */ |
| if (head || tail) { |
| pcpu_split_block(chunk, i, head, tail); |
| if (head) { |
| i++; |
| off += head; |
| max_contig = max(chunk->map[i - 1], max_contig); |
| } |
| if (tail) |
| max_contig = max(chunk->map[i + 1], max_contig); |
| } |
| |
| /* update hint and mark allocated */ |
| if (is_last) |
| chunk->contig_hint = max_contig; /* fully scanned */ |
| else |
| chunk->contig_hint = max(chunk->contig_hint, |
| max_contig); |
| |
| chunk->free_size -= chunk->map[i]; |
| chunk->map[i] = -chunk->map[i]; |
| |
| pcpu_chunk_relocate(chunk, oslot); |
| return off; |
| } |
| |
| chunk->contig_hint = max_contig; /* fully scanned */ |
| pcpu_chunk_relocate(chunk, oslot); |
| |
| /* tell the upper layer that this chunk has no matching area */ |
| return -1; |
| } |
| |
| /** |
| * pcpu_free_area - free area to a pcpu_chunk |
| * @chunk: chunk of interest |
| * @freeme: offset of area to free |
| * |
| * Free area starting from @freeme to @chunk. Note that this function |
| * only modifies the allocation map. It doesn't depopulate or unmap |
| * the area. |
| * |
| * CONTEXT: |
| * pcpu_lock. |
| */ |
| static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme) |
| { |
| int oslot = pcpu_chunk_slot(chunk); |
| int i, off; |
| |
| for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++])) |
| if (off == freeme) |
| break; |
| BUG_ON(off != freeme); |
| BUG_ON(chunk->map[i] > 0); |
| |
| chunk->map[i] = -chunk->map[i]; |
| chunk->free_size += chunk->map[i]; |
| |
| /* merge with previous? */ |
| if (i > 0 && chunk->map[i - 1] >= 0) { |
| chunk->map[i - 1] += chunk->map[i]; |
| chunk->map_used--; |
| memmove(&chunk->map[i], &chunk->map[i + 1], |
| (chunk->map_used - i) * sizeof(chunk->map[0])); |
| i--; |
| } |
| /* merge with next? */ |
| if (i + 1 < chunk->map_used && chunk->map[i + 1] >= 0) { |
| chunk->map[i] += chunk->map[i + 1]; |
| chunk->map_used--; |
| memmove(&chunk->map[i + 1], &chunk->map[i + 2], |
| (chunk->map_used - (i + 1)) * sizeof(chunk->map[0])); |
| } |
| |
| chunk->contig_hint = max(chunk->map[i], chunk->contig_hint); |
| pcpu_chunk_relocate(chunk, oslot); |
| } |
| |
| /** |
| * pcpu_get_pages_and_bitmap - get temp pages array and bitmap |
| * @chunk: chunk of interest |
| * @bitmapp: output parameter for bitmap |
| * @may_alloc: may allocate the array |
| * |
| * 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 struct page **pcpu_get_pages_and_bitmap(struct pcpu_chunk *chunk, |
| unsigned long **bitmapp, |
| bool may_alloc) |
| { |
| 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; |
| } |
| |
| memset(pages, 0, pages_size); |
| bitmap_copy(bitmap, chunk->populated, pcpu_unit_pages); |
| |
| *bitmapp = bitmap; |
| return pages; |
| } |
| |
| /** |
| * 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_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 int pcpu_alloc_pages(struct pcpu_chunk *chunk, |
| struct page **pages, unsigned long *populated, |
| int page_start, int page_end) |
| { |
| const gfp_t gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD; |
| unsigned int cpu; |
| int 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; |
| } |
| |
| /** |
| * 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)); |
| } |
| |
| static void __pcpu_unmap_pages(unsigned long addr, int nr_pages) |
| { |
| unmap_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT); |
| } |
| |
| /** |
| * 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; |
| |
| 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); |
| } |
| |
| for (i = page_start; i < page_end; i++) |
| __clear_bit(i, populated); |
| } |
| |
| /** |
| * 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. 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_pages(struct pcpu_chunk *chunk, |
| struct page **pages, unsigned long *populated, |
| int page_start, int page_end) |
| { |
| unsigned int cpu, tcpu; |
| int i, err; |
| |
| for_each_possible_cpu(cpu) { |
| 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) |
| 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); |
| } |
| |
| 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); |
| } |
| |
| /** |
| * pcpu_populate_chunk - populate and map an area of a pcpu_chunk |
| * @chunk: chunk of interest |
| * @off: offset to the area to populate |
| * @size: size of the area to populate in bytes |
| * |
| * For each cpu, populate and map pages [@page_start,@page_end) into |
| * @chunk. The area is cleared on return. |
| * |
| * CONTEXT: |
| * pcpu_alloc_mutex, does GFP_KERNEL allocation. |
| */ |
| static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size) |
| { |
| int page_start = PFN_DOWN(off); |
| int page_end = PFN_UP(off + size); |
| int free_end = page_start, unmap_end = page_start; |
| struct page **pages; |
| unsigned long *populated; |
| unsigned int cpu; |
| int rs, re, rc; |
| |
| /* 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; |
| } |
| |
| /* need to allocate and map pages, this chunk can't be immutable */ |
| WARN_ON(chunk->immutable); |
| |
| pages = pcpu_get_pages_and_bitmap(chunk, &populated, true); |
| if (!pages) |
| return -ENOMEM; |
| |
| /* 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; |
| } |
| |
| 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((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size); |
| return 0; |
| |
| 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) |
| { |
| if (!chunk) |
| return; |
| if (chunk->vm) |
| free_vm_area(chunk->vm); |
| pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0])); |
| kfree(chunk); |
| } |
| |
| static struct pcpu_chunk *alloc_pcpu_chunk(void) |
| { |
| struct pcpu_chunk *chunk; |
| |
| chunk = kzalloc(pcpu_chunk_struct_size, GFP_KERNEL); |
| if (!chunk) |
| return NULL; |
| |
| 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->vm = get_vm_area(pcpu_chunk_size, GFP_KERNEL); |
| if (!chunk->vm) { |
| free_pcpu_chunk(chunk); |
| return NULL; |
| } |
| |
| INIT_LIST_HEAD(&chunk->list); |
| chunk->free_size = pcpu_unit_size; |
| chunk->contig_hint = pcpu_unit_size; |
| |
| return chunk; |
| } |
| |
| /** |
| * pcpu_alloc - the percpu allocator |
| * @size: size of area to allocate in bytes |
| * @align: alignment of area (max PAGE_SIZE) |
| * @reserved: allocate from the reserved chunk if available |
| * |
| * Allocate percpu area of @size bytes aligned at @align. |
| * |
| * CONTEXT: |
| * Does GFP_KERNEL allocation. |
| * |
| * RETURNS: |
| * Percpu pointer to the allocated area on success, NULL on failure. |
| */ |
| static void *pcpu_alloc(size_t size, size_t align, bool reserved) |
| { |
| struct pcpu_chunk *chunk; |
| int slot, off; |
| |
| if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) { |
| WARN(true, "illegal size (%zu) or align (%zu) for " |
| "percpu allocation\n", size, align); |
| return NULL; |
| } |
| |
| mutex_lock(&pcpu_alloc_mutex); |
| spin_lock_irq(&pcpu_lock); |
| |
| /* serve reserved allocations from the reserved chunk if available */ |
| if (reserved && pcpu_reserved_chunk) { |
| chunk = pcpu_reserved_chunk; |
| if (size > chunk->contig_hint || |
| pcpu_extend_area_map(chunk) < 0) |
| goto fail_unlock; |
| off = pcpu_alloc_area(chunk, size, align); |
| if (off >= 0) |
| goto area_found; |
| goto fail_unlock; |
| } |
| |
| restart: |
| /* search through normal chunks */ |
| for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) { |
| list_for_each_entry(chunk, &pcpu_slot[slot], list) { |
| if (size > chunk->contig_hint) |
| continue; |
| |
| switch (pcpu_extend_area_map(chunk)) { |
| case 0: |
| break; |
| case 1: |
| goto restart; /* pcpu_lock dropped, restart */ |
| default: |
| goto fail_unlock; |
| } |
| |
| off = pcpu_alloc_area(chunk, size, align); |
| if (off >= 0) |
| goto area_found; |
| } |
| } |
| |
| /* hmmm... no space left, create a new chunk */ |
| spin_unlock_irq(&pcpu_lock); |
| |
| chunk = alloc_pcpu_chunk(); |
| if (!chunk) |
| goto fail_unlock_mutex; |
| |
| spin_lock_irq(&pcpu_lock); |
| pcpu_chunk_relocate(chunk, -1); |
| goto restart; |
| |
| area_found: |
| spin_unlock_irq(&pcpu_lock); |
| |
| /* populate, map and clear the area */ |
| if (pcpu_populate_chunk(chunk, off, size)) { |
| spin_lock_irq(&pcpu_lock); |
| pcpu_free_area(chunk, off); |
| goto fail_unlock; |
| } |
| |
| mutex_unlock(&pcpu_alloc_mutex); |
| |
| /* return address relative to unit0 */ |
| return __addr_to_pcpu_ptr(chunk->vm->addr + off); |
| |
| fail_unlock: |
| spin_unlock_irq(&pcpu_lock); |
| fail_unlock_mutex: |
| mutex_unlock(&pcpu_alloc_mutex); |
| return NULL; |
| } |
| |
| /** |
| * __alloc_percpu - allocate dynamic percpu area |
| * @size: size of area to allocate in bytes |
| * @align: alignment of area (max PAGE_SIZE) |
| * |
| * Allocate percpu area of @size bytes aligned at @align. Might |
| * sleep. Might trigger writeouts. |
| * |
| * CONTEXT: |
| * Does GFP_KERNEL allocation. |
| * |
| * RETURNS: |
| * Percpu pointer to the allocated area on success, NULL on failure. |
| */ |
| void *__alloc_percpu(size_t size, size_t align) |
| { |
| return pcpu_alloc(size, align, false); |
| } |
| EXPORT_SYMBOL_GPL(__alloc_percpu); |
| |
| /** |
| * __alloc_reserved_percpu - allocate reserved percpu area |
| * @size: size of area to allocate in bytes |
| * @align: alignment of area (max PAGE_SIZE) |
| * |
| * Allocate percpu area of @size bytes aligned at @align from reserved |
| * percpu area if arch has set it up; otherwise, allocation is served |
| * from the same dynamic area. Might sleep. Might trigger writeouts. |
| * |
| * CONTEXT: |
| * Does GFP_KERNEL allocation. |
| * |
| * RETURNS: |
| * Percpu pointer to the allocated area on success, NULL on failure. |
| */ |
| void *__alloc_reserved_percpu(size_t size, size_t align) |
| { |
| return pcpu_alloc(size, align, true); |
| } |
| |
| /** |
| * pcpu_reclaim - reclaim fully free chunks, workqueue function |
| * @work: unused |
| * |
| * Reclaim all fully free chunks except for the first one. |
| * |
| * CONTEXT: |
| * workqueue context. |
| */ |
| static void pcpu_reclaim(struct work_struct *work) |
| { |
| LIST_HEAD(todo); |
| struct list_head *head = &pcpu_slot[pcpu_nr_slots - 1]; |
| struct pcpu_chunk *chunk, *next; |
| |
| mutex_lock(&pcpu_alloc_mutex); |
| spin_lock_irq(&pcpu_lock); |
| |
| list_for_each_entry_safe(chunk, next, head, list) { |
| WARN_ON(chunk->immutable); |
| |
| /* spare the first one */ |
| if (chunk == list_first_entry(head, struct pcpu_chunk, list)) |
| continue; |
| |
| list_move(&chunk->list, &todo); |
| } |
| |
| spin_unlock_irq(&pcpu_lock); |
| mutex_unlock(&pcpu_alloc_mutex); |
| |
| list_for_each_entry_safe(chunk, next, &todo, list) { |
| pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size); |
| free_pcpu_chunk(chunk); |
| } |
| } |
| |
| /** |
| * free_percpu - free percpu area |
| * @ptr: pointer to area to free |
| * |
| * Free percpu area @ptr. |
| * |
| * CONTEXT: |
| * Can be called from atomic context. |
| */ |
| void free_percpu(void *ptr) |
| { |
| void *addr = __pcpu_ptr_to_addr(ptr); |
| struct pcpu_chunk *chunk; |
| unsigned long flags; |
| int off; |
| |
| if (!ptr) |
| return; |
| |
| spin_lock_irqsave(&pcpu_lock, flags); |
| |
| chunk = pcpu_chunk_addr_search(addr); |
| off = addr - chunk->vm->addr; |
| |
| pcpu_free_area(chunk, off); |
| |
| /* if there are more than one fully free chunks, wake up grim reaper */ |
| if (chunk->free_size == pcpu_unit_size) { |
| struct pcpu_chunk *pos; |
| |
| list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list) |
| if (pos != chunk) { |
| schedule_work(&pcpu_reclaim_work); |
| break; |
| } |
| } |
| |
| spin_unlock_irqrestore(&pcpu_lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(free_percpu); |
| |
| /** |
| * pcpu_setup_first_chunk - initialize the first percpu chunk |
| * @static_size: the size of static 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 |
| * @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. |
| * |
| * @reserved_size, if non-zero, specifies the amount of bytes to |
| * reserve after the static area in the first chunk. This reserves |
| * the first chunk such that it's available only through reserved |
| * percpu allocation. This is primarily used to serve module percpu |
| * static areas on architectures where the addressing model has |
| * limited offset range for symbol relocations to guarantee module |
| * percpu symbols fall inside the relocatable range. |
| * |
| * @dyn_size, if non-negative, determines the number of bytes |
| * available for dynamic allocation in the first chunk. Specifying |
| * non-negative value makes percpu leave alone the area beyond |
| * @static_size + @reserved_size + @dyn_size. |
| * |
| * @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. |
| * |
| * 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 |
| * areas and the other for the dynamic area. They share the same vm |
| * and page map but uses different area allocation map to stay away |
| * from each other. The latter chunk is circulated in the chunk slots |
| * and available for dynamic allocation like any other chunks. |
| * |
| * RETURNS: |
| * The determined pcpu_unit_size which can be used to initialize |
| * percpu access. |
| */ |
| 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, tcpu; |
| int i; |
| |
| /* sanity checks */ |
| BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC || |
| ARRAY_SIZE(dmap) >= PCPU_DFL_MAP_ALLOC); |
| BUG_ON(!static_size); |
| 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(num_possible_cpus() * |
| 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 = num_possible_cpus(); |
| 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 = 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. |
| */ |
| pcpu_nr_slots = __pcpu_size_to_slot(pcpu_unit_size) + 2; |
| pcpu_slot = alloc_bootmem(pcpu_nr_slots * sizeof(pcpu_slot[0])); |
| for (i = 0; i < pcpu_nr_slots; i++) |
| INIT_LIST_HEAD(&pcpu_slot[i]); |
| |
| /* |
| * Initialize static chunk. If reserved_size is zero, the |
| * static chunk covers static area + dynamic allocation area |
| * in the first chunk. If reserved_size is not zero, it |
| * covers static area + reserved area (mostly used for module |
| * static percpu allocation). |
| */ |
| schunk = alloc_bootmem(pcpu_chunk_struct_size); |
| INIT_LIST_HEAD(&schunk->list); |
| schunk->vm = &first_vm; |
| schunk->map = smap; |
| schunk->map_alloc = ARRAY_SIZE(smap); |
| schunk->immutable = true; |
| bitmap_fill(schunk->populated, pcpu_unit_pages); |
| |
| if (reserved_size) { |
| schunk->free_size = reserved_size; |
| pcpu_reserved_chunk = schunk; |
| pcpu_reserved_chunk_limit = static_size + reserved_size; |
| } else { |
| schunk->free_size = dyn_size; |
| dyn_size = 0; /* dynamic area covered */ |
| } |
| schunk->contig_hint = schunk->free_size; |
| |
| schunk->map[schunk->map_used++] = -static_size; |
| if (schunk->free_size) |
| schunk->map[schunk->map_used++] = schunk->free_size; |
| |
| /* init dynamic chunk if necessary */ |
| if (dyn_size) { |
| 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->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; |
| } |
| |
| /* link the first chunk in */ |
| pcpu_first_chunk = dchunk ?: schunk; |
| pcpu_chunk_relocate(pcpu_first_chunk, -1); |
| |
| /* we're done */ |
| pcpu_base_addr = schunk->vm->addr; |
| return pcpu_unit_size; |
| } |
| |
| static size_t pcpu_calc_fc_sizes(size_t static_size, size_t reserved_size, |
| ssize_t *dyn_sizep) |
| { |
| size_t size_sum; |
| |
| 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 size_sum; |
| } |
| |
| /** |
| * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem |
| * @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 |
| * |
| * This is a helper to ease setting up embedded first percpu chunk and |
| * can be called where pcpu_setup_first_chunk() is expected. |
| * |
| * If this function is used to setup the first chunk, it is allocated |
| * as a contiguous area using bootmem allocator and used as-is without |
| * being mapped into vmalloc area. This enables the first chunk to |
| * piggy back on the linear physical mapping which often uses larger |
| * page size. |
| * |
| * When @dyn_size is positive, dynamic area might be larger than |
| * 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. |
| * |
| * RETURNS: |
| * The determined pcpu_unit_size which can be used to initialize |
| * 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) |
| { |
| size_t size_sum, unit_size, chunk_size; |
| void *base; |
| unsigned int cpu; |
| |
| /* determine parameters and allocate */ |
| 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 * num_possible_cpus(); |
| |
| 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; |
| } |
| |
| /* return the leftover and copy */ |
| for_each_possible_cpu(cpu) { |
| void *ptr = base + cpu * unit_size; |
| |
| free_bootmem(__pa(ptr + size_sum), unit_size - size_sum); |
| memcpy(ptr, __per_cpu_load, static_size); |
| } |
| |
| /* we're ready, commit */ |
| pr_info("PERCPU: Embedded %zu pages at %p, static data %zu bytes\n", |
| 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 * num_possible_cpus() * |
| 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 = num_possible_cpus() * 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 |
| struct pcpul_ent { |
| unsigned int cpu; |
| void *ptr; |
| }; |
| |
| static size_t pcpul_size; |
| static size_t pcpul_unit_size; |
| static struct pcpul_ent *pcpul_map; |
| static struct vm_struct pcpul_vm; |
| |
| /** |
| * 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, -1 for auto |
| * @lpage_size: the size of a large page |
| * @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 as unit. A large page is allocated |
| * for each cpu and each is remapped into vmalloc area using large |
| * page mapping. As large page can be quite large, only part of it is |
| * used for the first chunk. Unused part is returned to the bootmem |
| * allocator. |
| * |
| * So, the large pages are mapped twice - once to the physical mapping |
| * and to the vmalloc area for the first percpu chunk. The double |
| * mapping does add one more large TLB entry pressure but still is |
| * much better than only using 4k mappings while still being NUMA |
| * friendly. |
| * |
| * 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, |
| ssize_t dyn_size, size_t lpage_size, |
| pcpu_fc_alloc_fn_t alloc_fn, |
| pcpu_fc_free_fn_t free_fn, |
| pcpu_fc_map_fn_t map_fn) |
| { |
| size_t size_sum; |
| size_t map_size; |
| unsigned int cpu; |
| int i, j; |
| ssize_t ret; |
| |
| /* |
| * Currently supports only single page. Supporting multiple |
| * pages won't be too difficult if it ever becomes necessary. |
| */ |
| size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size); |
| |
| pcpul_unit_size = lpage_size; |
| pcpul_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE); |
| if (pcpul_size > pcpul_unit_size) { |
| pr_warning("PERCPU: static data is larger than large page, " |
| "can't use large page\n"); |
| return -EINVAL; |
| } |
| |
| /* allocate pointer array and alloc large pages */ |
| map_size = PFN_ALIGN(num_possible_cpus() * sizeof(pcpul_map[0])); |
| pcpul_map = alloc_bootmem(map_size); |
| |
| for_each_possible_cpu(cpu) { |
| void *ptr; |
| |
| ptr = alloc_fn(cpu, lpage_size); |
| if (!ptr) { |
| pr_warning("PERCPU: failed to allocate large page " |
| "for cpu%u\n", cpu); |
| goto enomem; |
| } |
| |
| /* |
| * Only use pcpul_size bytes and give back the rest. |
| * |
| * Ingo: The lpage_size up-rounding bootmem is needed |
| * to make sure the partial lpage is still fully RAM - |
| * it's not well-specified to have a incompatible area |
| * (unmapped RAM, device memory, etc.) in that hole. |
| */ |
| free_fn(ptr + pcpul_size, lpage_size - pcpul_size); |
| |
| pcpul_map[cpu].cpu = cpu; |
| pcpul_map[cpu].ptr = ptr; |
| |
| memcpy(ptr, __per_cpu_load, static_size); |
| } |
| |
| /* allocate address and map */ |
| pcpul_vm.flags = VM_ALLOC; |
| pcpul_vm.size = num_possible_cpus() * pcpul_unit_size; |
| vm_area_register_early(&pcpul_vm, pcpul_unit_size); |
| |
| for_each_possible_cpu(cpu) |
| map_fn(pcpul_map[cpu].ptr, pcpul_unit_size, |
| pcpul_vm.addr + cpu * pcpul_unit_size); |
| |
| /* we're ready, commit */ |
| pr_info("PERCPU: Remapped at %p with large pages, static data " |
| "%zu bytes\n", pcpul_vm.addr, static_size); |
| |
| ret = pcpu_setup_first_chunk(static_size, reserved_size, dyn_size, |
| pcpul_unit_size, pcpul_vm.addr, NULL); |
| |
| /* sort pcpul_map array for pcpu_lpage_remapped() */ |
| for (i = 0; i < num_possible_cpus() - 1; i++) |
| for (j = i + 1; j < num_possible_cpus(); j++) |
| if (pcpul_map[i].ptr > pcpul_map[j].ptr) { |
| struct pcpul_ent tmp = pcpul_map[i]; |
| pcpul_map[i] = pcpul_map[j]; |
| pcpul_map[j] = tmp; |
| } |
| |
| return ret; |
| |
| enomem: |
| for_each_possible_cpu(cpu) |
| if (pcpul_map[cpu].ptr) |
| free_fn(pcpul_map[cpu].ptr, pcpul_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 unit_mask = pcpul_unit_size - 1; |
| void *lpage_addr = (void *)((unsigned long)kaddr & ~unit_mask); |
| unsigned long offset = (unsigned long)kaddr & unit_mask; |
| int left = 0, right = num_possible_cpus() - 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 { |
| /* it shouldn't be in the area for the first chunk */ |
| WARN_ON(offset < pcpul_size); |
| |
| return pcpul_vm.addr + |
| pcpul_map[pos].cpu * pcpul_unit_size + 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 */ |