| /* |
| * 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. 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. |
| * |
| * 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. |
| * |
| * - 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/err.h> |
| #include <linux/list.h> |
| #include <linux/log2.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> |
| #include <asm/io.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 __percpu *)((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 __force *)((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 */ |
| void *base_addr; /* base address of this chunk */ |
| int map_used; /* # of map entries used */ |
| int map_alloc; /* # of map entries allocated */ |
| int *map; /* allocation map */ |
| void *data; /* chunk data */ |
| 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_atom_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); |
| |
| static const int *pcpu_unit_map __read_mostly; /* cpu -> unit */ |
| const unsigned long *pcpu_unit_offsets __read_mostly; /* cpu -> unit offset */ |
| |
| /* group information, used for vm allocation */ |
| static int pcpu_nr_groups __read_mostly; |
| static const unsigned long *pcpu_group_offsets __read_mostly; |
| static const size_t *pcpu_group_sizes __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. In |
| * general, percpu memory can't be allocated with irq off but |
| * irqsave/restore are still used in alloc path so that it can be used |
| * from early init path - sched_init() specifically. |
| * |
| * 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 bool pcpu_addr_in_first_chunk(void *addr) |
| { |
| void *first_start = pcpu_first_chunk->base_addr; |
| |
| return addr >= first_start && addr < first_start + pcpu_unit_size; |
| } |
| |
| static bool pcpu_addr_in_reserved_chunk(void *addr) |
| { |
| void *first_start = pcpu_first_chunk->base_addr; |
| |
| return addr >= first_start && |
| addr < first_start + pcpu_reserved_chunk_limit; |
| } |
| |
| 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); |
| } |
| |
| /* 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 int __maybe_unused 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->base_addr + pcpu_unit_offsets[cpu] + |
| (page_idx << PAGE_SHIFT); |
| } |
| |
| static void __maybe_unused 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 __maybe_unused 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 (WARN_ON_ONCE(!slab_is_available())) |
| return NULL; |
| |
| 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_need_to_extend - determine whether chunk area map needs to be extended |
| * @chunk: chunk of interest |
| * |
| * Determine whether area map of @chunk needs to be extended to |
| * accomodate a new allocation. |
| * |
| * CONTEXT: |
| * pcpu_lock. |
| * |
| * RETURNS: |
| * New target map allocation length if extension is necessary, 0 |
| * otherwise. |
| */ |
| static int pcpu_need_to_extend(struct pcpu_chunk *chunk) |
| { |
| int new_alloc; |
| |
| if (chunk->map_alloc >= chunk->map_used + 2) |
| return 0; |
| |
| new_alloc = PCPU_DFL_MAP_ALLOC; |
| while (new_alloc < chunk->map_used + 2) |
| new_alloc *= 2; |
| |
| return new_alloc; |
| } |
| |
| /** |
| * pcpu_extend_area_map - extend area map of a chunk |
| * @chunk: chunk of interest |
| * @new_alloc: new target allocation length of the area map |
| * |
| * Extend area map of @chunk to have @new_alloc entries. |
| * |
| * CONTEXT: |
| * Does GFP_KERNEL allocation. Grabs and releases pcpu_lock. |
| * |
| * RETURNS: |
| * 0 on success, -errno on failure. |
| */ |
| static int pcpu_extend_area_map(struct pcpu_chunk *chunk, int new_alloc) |
| { |
| int *old = NULL, *new = NULL; |
| size_t old_size = 0, new_size = new_alloc * sizeof(new[0]); |
| unsigned long flags; |
| |
| new = pcpu_mem_alloc(new_size); |
| if (!new) |
| return -ENOMEM; |
| |
| /* acquire pcpu_lock and switch to new area map */ |
| spin_lock_irqsave(&pcpu_lock, flags); |
| |
| if (new_alloc <= chunk->map_alloc) |
| goto out_unlock; |
| |
| old_size = chunk->map_alloc * sizeof(chunk->map[0]); |
| old = chunk->map; |
| |
| memcpy(new, old, old_size); |
| |
| chunk->map_alloc = new_alloc; |
| chunk->map = new; |
| new = NULL; |
| |
| out_unlock: |
| spin_unlock_irqrestore(&pcpu_lock, flags); |
| |
| /* |
| * pcpu_mem_free() might end up calling vfree() which uses |
| * IRQ-unsafe lock and thus can't be called under pcpu_lock. |
| */ |
| pcpu_mem_free(old, old_size); |
| pcpu_mem_free(new, new_size); |
| |
| 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); |
| } |
| |
| static struct pcpu_chunk *pcpu_alloc_chunk(void) |
| { |
| struct pcpu_chunk *chunk; |
| |
| chunk = pcpu_mem_alloc(pcpu_chunk_struct_size); |
| if (!chunk) |
| return NULL; |
| |
| chunk->map = pcpu_mem_alloc(PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0])); |
| if (!chunk->map) { |
| kfree(chunk); |
| return NULL; |
| } |
| |
| chunk->map_alloc = PCPU_DFL_MAP_ALLOC; |
| chunk->map[chunk->map_used++] = pcpu_unit_size; |
| |
| INIT_LIST_HEAD(&chunk->list); |
| chunk->free_size = pcpu_unit_size; |
| chunk->contig_hint = pcpu_unit_size; |
| |
| return chunk; |
| } |
| |
| static void pcpu_free_chunk(struct pcpu_chunk *chunk) |
| { |
| if (!chunk) |
| return; |
| pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0])); |
| kfree(chunk); |
| } |
| |
| /* |
| * Chunk management implementation. |
| * |
| * To allow different implementations, chunk alloc/free and |
| * [de]population are implemented in a separate file which is pulled |
| * into this file and compiled together. The following functions |
| * should be implemented. |
| * |
| * pcpu_populate_chunk - populate the specified range of a chunk |
| * pcpu_depopulate_chunk - depopulate the specified range of a chunk |
| * pcpu_create_chunk - create a new chunk |
| * pcpu_destroy_chunk - destroy a chunk, always preceded by full depop |
| * pcpu_addr_to_page - translate address to physical address |
| * pcpu_verify_alloc_info - check alloc_info is acceptable during init |
| */ |
| static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size); |
| static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size); |
| static struct pcpu_chunk *pcpu_create_chunk(void); |
| static void pcpu_destroy_chunk(struct pcpu_chunk *chunk); |
| static struct page *pcpu_addr_to_page(void *addr); |
| static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai); |
| |
| #ifdef CONFIG_NEED_PER_CPU_KM |
| #include "percpu-km.c" |
| #else |
| #include "percpu-vm.c" |
| #endif |
| |
| /** |
| * 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) |
| { |
| /* is it in the first chunk? */ |
| if (pcpu_addr_in_first_chunk(addr)) { |
| /* is it in the reserved area? */ |
| if (pcpu_addr_in_reserved_chunk(addr)) |
| 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_offsets[raw_smp_processor_id()]; |
| return pcpu_get_page_chunk(pcpu_addr_to_page(addr)); |
| } |
| |
| /** |
| * 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 __percpu *pcpu_alloc(size_t size, size_t align, bool reserved) |
| { |
| static int warn_limit = 10; |
| struct pcpu_chunk *chunk; |
| const char *err; |
| int slot, off, new_alloc; |
| unsigned long flags; |
| |
| 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_irqsave(&pcpu_lock, flags); |
| |
| /* serve reserved allocations from the reserved chunk if available */ |
| if (reserved && pcpu_reserved_chunk) { |
| chunk = pcpu_reserved_chunk; |
| |
| if (size > chunk->contig_hint) { |
| err = "alloc from reserved chunk failed"; |
| goto fail_unlock; |
| } |
| |
| while ((new_alloc = pcpu_need_to_extend(chunk))) { |
| spin_unlock_irqrestore(&pcpu_lock, flags); |
| if (pcpu_extend_area_map(chunk, new_alloc) < 0) { |
| err = "failed to extend area map of reserved chunk"; |
| goto fail_unlock_mutex; |
| } |
| spin_lock_irqsave(&pcpu_lock, flags); |
| } |
| |
| off = pcpu_alloc_area(chunk, size, align); |
| if (off >= 0) |
| goto area_found; |
| |
| err = "alloc from reserved chunk failed"; |
| 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; |
| |
| new_alloc = pcpu_need_to_extend(chunk); |
| if (new_alloc) { |
| spin_unlock_irqrestore(&pcpu_lock, flags); |
| if (pcpu_extend_area_map(chunk, |
| new_alloc) < 0) { |
| err = "failed to extend area map"; |
| goto fail_unlock_mutex; |
| } |
| spin_lock_irqsave(&pcpu_lock, flags); |
| /* |
| * pcpu_lock has been dropped, need to |
| * restart cpu_slot list walking. |
| */ |
| goto restart; |
| } |
| |
| off = pcpu_alloc_area(chunk, size, align); |
| if (off >= 0) |
| goto area_found; |
| } |
| } |
| |
| /* hmmm... no space left, create a new chunk */ |
| spin_unlock_irqrestore(&pcpu_lock, flags); |
| |
| chunk = pcpu_create_chunk(); |
| if (!chunk) { |
| err = "failed to allocate new chunk"; |
| goto fail_unlock_mutex; |
| } |
| |
| spin_lock_irqsave(&pcpu_lock, flags); |
| pcpu_chunk_relocate(chunk, -1); |
| goto restart; |
| |
| area_found: |
| spin_unlock_irqrestore(&pcpu_lock, flags); |
| |
| /* populate, map and clear the area */ |
| if (pcpu_populate_chunk(chunk, off, size)) { |
| spin_lock_irqsave(&pcpu_lock, flags); |
| pcpu_free_area(chunk, off); |
| err = "failed to populate"; |
| goto fail_unlock; |
| } |
| |
| mutex_unlock(&pcpu_alloc_mutex); |
| |
| /* return address relative to base address */ |
| return __addr_to_pcpu_ptr(chunk->base_addr + off); |
| |
| fail_unlock: |
| spin_unlock_irqrestore(&pcpu_lock, flags); |
| fail_unlock_mutex: |
| mutex_unlock(&pcpu_alloc_mutex); |
| if (warn_limit) { |
| pr_warning("PERCPU: allocation failed, size=%zu align=%zu, " |
| "%s\n", size, align, err); |
| dump_stack(); |
| if (!--warn_limit) |
| pr_info("PERCPU: limit reached, disable warning\n"); |
| } |
| 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 __percpu *__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 __percpu *__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); |
| |
| list_for_each_entry_safe(chunk, next, &todo, list) { |
| pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size); |
| pcpu_destroy_chunk(chunk); |
| } |
| |
| mutex_unlock(&pcpu_alloc_mutex); |
| } |
| |
| /** |
| * 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 __percpu *ptr) |
| { |
| void *addr; |
| struct pcpu_chunk *chunk; |
| unsigned long flags; |
| int off; |
| |
| if (!ptr) |
| return; |
| |
| addr = __pcpu_ptr_to_addr(ptr); |
| |
| spin_lock_irqsave(&pcpu_lock, flags); |
| |
| chunk = pcpu_chunk_addr_search(addr); |
| off = addr - chunk->base_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); |
| |
| /** |
| * is_kernel_percpu_address - test whether address is from static percpu area |
| * @addr: address to test |
| * |
| * Test whether @addr belongs to in-kernel static percpu area. Module |
| * static percpu areas are not considered. For those, use |
| * is_module_percpu_address(). |
| * |
| * RETURNS: |
| * %true if @addr is from in-kernel static percpu area, %false otherwise. |
| */ |
| bool is_kernel_percpu_address(unsigned long addr) |
| { |
| const size_t static_size = __per_cpu_end - __per_cpu_start; |
| void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr); |
| unsigned int cpu; |
| |
| for_each_possible_cpu(cpu) { |
| void *start = per_cpu_ptr(base, cpu); |
| |
| if ((void *)addr >= start && (void *)addr < start + static_size) |
| return true; |
| } |
| return false; |
| } |
| |
| /** |
| * per_cpu_ptr_to_phys - convert translated percpu address to physical address |
| * @addr: the address to be converted to physical address |
| * |
| * Given @addr which is dereferenceable address obtained via one of |
| * percpu access macros, this function translates it into its physical |
| * address. The caller is responsible for ensuring @addr stays valid |
| * until this function finishes. |
| * |
| * RETURNS: |
| * The physical address for @addr. |
| */ |
| phys_addr_t per_cpu_ptr_to_phys(void *addr) |
| { |
| void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr); |
| bool in_first_chunk = false; |
| unsigned long first_start, first_end; |
| unsigned int cpu; |
| |
| /* |
| * The following test on first_start/end isn't strictly |
| * necessary but will speed up lookups of addresses which |
| * aren't in the first chunk. |
| */ |
| first_start = pcpu_chunk_addr(pcpu_first_chunk, pcpu_first_unit_cpu, 0); |
| first_end = pcpu_chunk_addr(pcpu_first_chunk, pcpu_last_unit_cpu, |
| pcpu_unit_pages); |
| if ((unsigned long)addr >= first_start && |
| (unsigned long)addr < first_end) { |
| for_each_possible_cpu(cpu) { |
| void *start = per_cpu_ptr(base, cpu); |
| |
| if (addr >= start && addr < start + pcpu_unit_size) { |
| in_first_chunk = true; |
| break; |
| } |
| } |
| } |
| |
| if (in_first_chunk) { |
| if ((unsigned long)addr < VMALLOC_START || |
| (unsigned long)addr >= VMALLOC_END) |
| return __pa(addr); |
| else |
| return page_to_phys(vmalloc_to_page(addr)); |
| } else |
| return page_to_phys(pcpu_addr_to_page(addr)); |
| } |
| |
| /** |
| * pcpu_alloc_alloc_info - allocate percpu allocation info |
| * @nr_groups: the number of groups |
| * @nr_units: the number of units |
| * |
| * Allocate ai which is large enough for @nr_groups groups containing |
| * @nr_units units. The returned ai's groups[0].cpu_map points to the |
| * cpu_map array which is long enough for @nr_units and filled with |
| * NR_CPUS. It's the caller's responsibility to initialize cpu_map |
| * pointer of other groups. |
| * |
| * RETURNS: |
| * Pointer to the allocated pcpu_alloc_info on success, NULL on |
| * failure. |
| */ |
| struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups, |
| int nr_units) |
| { |
| struct pcpu_alloc_info *ai; |
| size_t base_size, ai_size; |
| void *ptr; |
| int unit; |
| |
| base_size = ALIGN(sizeof(*ai) + nr_groups * sizeof(ai->groups[0]), |
| __alignof__(ai->groups[0].cpu_map[0])); |
| ai_size = base_size + nr_units * sizeof(ai->groups[0].cpu_map[0]); |
| |
| ptr = alloc_bootmem_nopanic(PFN_ALIGN(ai_size)); |
| if (!ptr) |
| return NULL; |
| ai = ptr; |
| ptr += base_size; |
| |
| ai->groups[0].cpu_map = ptr; |
| |
| for (unit = 0; unit < nr_units; unit++) |
| ai->groups[0].cpu_map[unit] = NR_CPUS; |
| |
| ai->nr_groups = nr_groups; |
| ai->__ai_size = PFN_ALIGN(ai_size); |
| |
| return ai; |
| } |
| |
| /** |
| * pcpu_free_alloc_info - free percpu allocation info |
| * @ai: pcpu_alloc_info to free |
| * |
| * Free @ai which was allocated by pcpu_alloc_alloc_info(). |
| */ |
| void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai) |
| { |
| free_bootmem(__pa(ai), ai->__ai_size); |
| } |
| |
| /** |
| * pcpu_build_alloc_info - build alloc_info considering distances between CPUs |
| * @reserved_size: the size of reserved percpu area in bytes |
| * @dyn_size: minimum free size for dynamic allocation in bytes |
| * @atom_size: allocation atom size |
| * @cpu_distance_fn: callback to determine distance between cpus, optional |
| * |
| * This function determines grouping of units, their mappings to cpus |
| * and other parameters considering needed percpu size, allocation |
| * atom size and distances between CPUs. |
| * |
| * Groups are always mutliples of atom size and CPUs which are of |
| * LOCAL_DISTANCE both ways are grouped together and share space for |
| * units in the same group. The returned configuration is guaranteed |
| * to have CPUs on different nodes on different groups and >=75% usage |
| * of allocated virtual address space. |
| * |
| * RETURNS: |
| * On success, pointer to the new allocation_info is returned. On |
| * failure, ERR_PTR value is returned. |
| */ |
| static struct pcpu_alloc_info * __init pcpu_build_alloc_info( |
| size_t reserved_size, size_t dyn_size, |
| size_t atom_size, |
| pcpu_fc_cpu_distance_fn_t cpu_distance_fn) |
| { |
| static int group_map[NR_CPUS] __initdata; |
| static int group_cnt[NR_CPUS] __initdata; |
| const size_t static_size = __per_cpu_end - __per_cpu_start; |
| int nr_groups = 1, nr_units = 0; |
| size_t size_sum, min_unit_size, alloc_size; |
| int upa, max_upa, uninitialized_var(best_upa); /* units_per_alloc */ |
| int last_allocs, group, unit; |
| unsigned int cpu, tcpu; |
| struct pcpu_alloc_info *ai; |
| unsigned int *cpu_map; |
| |
| /* this function may be called multiple times */ |
| memset(group_map, 0, sizeof(group_map)); |
| memset(group_cnt, 0, sizeof(group_cnt)); |
| |
| /* calculate size_sum and ensure dyn_size is enough for early alloc */ |
| size_sum = PFN_ALIGN(static_size + reserved_size + |
| max_t(size_t, dyn_size, PERCPU_DYNAMIC_EARLY_SIZE)); |
| dyn_size = size_sum - static_size - reserved_size; |
| |
| /* |
| * Determine min_unit_size, alloc_size and max_upa such that |
| * alloc_size is multiple of atom_size and is the smallest |
| * which can accomodate 4k aligned segments which are equal to |
| * or larger than min_unit_size. |
| */ |
| min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE); |
| |
| alloc_size = roundup(min_unit_size, atom_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_distance_fn(cpu, tcpu) > LOCAL_DISTANCE || |
| cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) { |
| group++; |
| nr_groups = max(nr_groups, group + 1); |
| goto next_group; |
| } |
| } |
| group_map[cpu] = group; |
| 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 < nr_groups; 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; |
| } |
| upa = best_upa; |
| |
| /* allocate and fill alloc_info */ |
| for (group = 0; group < nr_groups; group++) |
| nr_units += roundup(group_cnt[group], upa); |
| |
| ai = pcpu_alloc_alloc_info(nr_groups, nr_units); |
| if (!ai) |
| return ERR_PTR(-ENOMEM); |
| cpu_map = ai->groups[0].cpu_map; |
| |
| for (group = 0; group < nr_groups; group++) { |
| ai->groups[group].cpu_map = cpu_map; |
| cpu_map += roundup(group_cnt[group], upa); |
| } |
| |
| ai->static_size = static_size; |
| ai->reserved_size = reserved_size; |
| ai->dyn_size = dyn_size; |
| ai->unit_size = alloc_size / upa; |
| ai->atom_size = atom_size; |
| ai->alloc_size = alloc_size; |
| |
| for (group = 0, unit = 0; group_cnt[group]; group++) { |
| struct pcpu_group_info *gi = &ai->groups[group]; |
| |
| /* |
| * Initialize base_offset as if all groups are located |
| * back-to-back. The caller should update this to |
| * reflect actual allocation. |
| */ |
| gi->base_offset = unit * ai->unit_size; |
| |
| for_each_possible_cpu(cpu) |
| if (group_map[cpu] == group) |
| gi->cpu_map[gi->nr_units++] = cpu; |
| gi->nr_units = roundup(gi->nr_units, upa); |
| unit += gi->nr_units; |
| } |
| BUG_ON(unit != nr_units); |
| |
| return ai; |
| } |
| |
| /** |
| * pcpu_dump_alloc_info - print out information about pcpu_alloc_info |
| * @lvl: loglevel |
| * @ai: allocation info to dump |
| * |
| * Print out information about @ai using loglevel @lvl. |
| */ |
| static void pcpu_dump_alloc_info(const char *lvl, |
| const struct pcpu_alloc_info *ai) |
| { |
| int group_width = 1, cpu_width = 1, width; |
| char empty_str[] = "--------"; |
| int alloc = 0, alloc_end = 0; |
| int group, v; |
| int upa, apl; /* units per alloc, allocs per line */ |
| |
| v = ai->nr_groups; |
| while (v /= 10) |
| group_width++; |
| |
| v = num_possible_cpus(); |
| while (v /= 10) |
| cpu_width++; |
| empty_str[min_t(int, cpu_width, sizeof(empty_str) - 1)] = '\0'; |
| |
| upa = ai->alloc_size / ai->unit_size; |
| width = upa * (cpu_width + 1) + group_width + 3; |
| apl = rounddown_pow_of_two(max(60 / width, 1)); |
| |
| printk("%spcpu-alloc: s%zu r%zu d%zu u%zu alloc=%zu*%zu", |
| lvl, ai->static_size, ai->reserved_size, ai->dyn_size, |
| ai->unit_size, ai->alloc_size / ai->atom_size, ai->atom_size); |
| |
| for (group = 0; group < ai->nr_groups; group++) { |
| const struct pcpu_group_info *gi = &ai->groups[group]; |
| int unit = 0, unit_end = 0; |
| |
| BUG_ON(gi->nr_units % upa); |
| for (alloc_end += gi->nr_units / upa; |
| alloc < alloc_end; alloc++) { |
| if (!(alloc % apl)) { |
| printk("\n"); |
| printk("%spcpu-alloc: ", lvl); |
| } |
| printk("[%0*d] ", group_width, group); |
| |
| for (unit_end += upa; unit < unit_end; unit++) |
| if (gi->cpu_map[unit] != NR_CPUS) |
| printk("%0*d ", cpu_width, |
| gi->cpu_map[unit]); |
| else |
| printk("%s ", empty_str); |
| } |
| } |
| printk("\n"); |
| } |
| |
| /** |
| * pcpu_setup_first_chunk - initialize the first percpu chunk |
| * @ai: pcpu_alloc_info describing how to percpu area is shaped |
| * @base_addr: mapped address |
| * |
| * Initialize the first percpu chunk which contains the kernel static |
| * perpcu area. This function is to be called from arch percpu area |
| * setup path. |
| * |
| * @ai contains all information necessary to initialize the first |
| * chunk and prime the dynamic percpu allocator. |
| * |
| * @ai->static_size is the size of static percpu area. |
| * |
| * @ai->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. |
| * |
| * @ai->dyn_size determines the number of bytes available for dynamic |
| * allocation in the first chunk. The area between @ai->static_size + |
| * @ai->reserved_size + @ai->dyn_size and @ai->unit_size is unused. |
| * |
| * @ai->unit_size specifies unit size and must be aligned to PAGE_SIZE |
| * and equal to or larger than @ai->static_size + @ai->reserved_size + |
| * @ai->dyn_size. |
| * |
| * @ai->atom_size is the allocation atom size and used as alignment |
| * for vm areas. |
| * |
| * @ai->alloc_size is the allocation size and always multiple of |
| * @ai->atom_size. This is larger than @ai->atom_size if |
| * @ai->unit_size is larger than @ai->atom_size. |
| * |
| * @ai->nr_groups and @ai->groups describe virtual memory layout of |
| * percpu areas. Units which should be colocated are put into the |
| * same group. Dynamic VM areas will be allocated according to these |
| * groupings. If @ai->nr_groups is zero, a single group containing |
| * all units is assumed. |
| * |
| * 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: |
| * 0 on success, -errno on failure. |
| */ |
| int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, |
| void *base_addr) |
| { |
| static char cpus_buf[4096] __initdata; |
| static int smap[PERCPU_DYNAMIC_EARLY_SLOTS] __initdata; |
| static int dmap[PERCPU_DYNAMIC_EARLY_SLOTS] __initdata; |
| size_t dyn_size = ai->dyn_size; |
| size_t size_sum = ai->static_size + ai->reserved_size + dyn_size; |
| struct pcpu_chunk *schunk, *dchunk = NULL; |
| unsigned long *group_offsets; |
| size_t *group_sizes; |
| unsigned long *unit_off; |
| unsigned int cpu; |
| int *unit_map; |
| int group, unit, i; |
| |
| cpumask_scnprintf(cpus_buf, sizeof(cpus_buf), cpu_possible_mask); |
| |
| #define PCPU_SETUP_BUG_ON(cond) do { \ |
| if (unlikely(cond)) { \ |
| pr_emerg("PERCPU: failed to initialize, %s", #cond); \ |
| pr_emerg("PERCPU: cpu_possible_mask=%s\n", cpus_buf); \ |
| pcpu_dump_alloc_info(KERN_EMERG, ai); \ |
| BUG(); \ |
| } \ |
| } while (0) |
| |
| /* sanity checks */ |
| PCPU_SETUP_BUG_ON(ai->nr_groups <= 0); |
| PCPU_SETUP_BUG_ON(!ai->static_size); |
| PCPU_SETUP_BUG_ON(!base_addr); |
| PCPU_SETUP_BUG_ON(ai->unit_size < size_sum); |
| PCPU_SETUP_BUG_ON(ai->unit_size & ~PAGE_MASK); |
| PCPU_SETUP_BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE); |
| PCPU_SETUP_BUG_ON(ai->dyn_size < PERCPU_DYNAMIC_EARLY_SIZE); |
| PCPU_SETUP_BUG_ON(pcpu_verify_alloc_info(ai) < 0); |
| |
| /* process group information and build config tables accordingly */ |
| group_offsets = alloc_bootmem(ai->nr_groups * sizeof(group_offsets[0])); |
| group_sizes = alloc_bootmem(ai->nr_groups * sizeof(group_sizes[0])); |
| unit_map = alloc_bootmem(nr_cpu_ids * sizeof(unit_map[0])); |
| unit_off = alloc_bootmem(nr_cpu_ids * sizeof(unit_off[0])); |
| |
| for (cpu = 0; cpu < nr_cpu_ids; cpu++) |
| unit_map[cpu] = UINT_MAX; |
| pcpu_first_unit_cpu = NR_CPUS; |
| |
| for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) { |
| const struct pcpu_group_info *gi = &ai->groups[group]; |
| |
| group_offsets[group] = gi->base_offset; |
| group_sizes[group] = gi->nr_units * ai->unit_size; |
| |
| for (i = 0; i < gi->nr_units; i++) { |
| cpu = gi->cpu_map[i]; |
| if (cpu == NR_CPUS) |
| continue; |
| |
| PCPU_SETUP_BUG_ON(cpu > nr_cpu_ids); |
| PCPU_SETUP_BUG_ON(!cpu_possible(cpu)); |
| PCPU_SETUP_BUG_ON(unit_map[cpu] != UINT_MAX); |
| |
| unit_map[cpu] = unit + i; |
| unit_off[cpu] = gi->base_offset + i * ai->unit_size; |
| |
| if (pcpu_first_unit_cpu == NR_CPUS) |
| pcpu_first_unit_cpu = cpu; |
| } |
| } |
| pcpu_last_unit_cpu = cpu; |
| pcpu_nr_units = unit; |
| |
| for_each_possible_cpu(cpu) |
| PCPU_SETUP_BUG_ON(unit_map[cpu] == UINT_MAX); |
| |
| /* we're done parsing the input, undefine BUG macro and dump config */ |
| #undef PCPU_SETUP_BUG_ON |
| pcpu_dump_alloc_info(KERN_INFO, ai); |
| |
| pcpu_nr_groups = ai->nr_groups; |
| pcpu_group_offsets = group_offsets; |
| pcpu_group_sizes = group_sizes; |
| pcpu_unit_map = unit_map; |
| pcpu_unit_offsets = unit_off; |
| |
| /* determine basic parameters */ |
| pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT; |
| pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT; |
| pcpu_atom_size = ai->atom_size; |
| pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) + |
| BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long); |
| |
| /* |
| * 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->base_addr = base_addr; |
| schunk->map = smap; |
| schunk->map_alloc = ARRAY_SIZE(smap); |
| schunk->immutable = true; |
| bitmap_fill(schunk->populated, pcpu_unit_pages); |
| |
| if (ai->reserved_size) { |
| schunk->free_size = ai->reserved_size; |
| pcpu_reserved_chunk = schunk; |
| pcpu_reserved_chunk_limit = ai->static_size + ai->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++] = -ai->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->base_addr = base_addr; |
| 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 = base_addr; |
| return 0; |
| } |
| |
| const char *pcpu_fc_names[PCPU_FC_NR] __initdata = { |
| [PCPU_FC_AUTO] = "auto", |
| [PCPU_FC_EMBED] = "embed", |
| [PCPU_FC_PAGE] = "page", |
| }; |
| |
| enum pcpu_fc pcpu_chosen_fc __initdata = PCPU_FC_AUTO; |
| |
| static int __init percpu_alloc_setup(char *str) |
| { |
| if (0) |
| /* nada */; |
| #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK |
| else if (!strcmp(str, "embed")) |
| pcpu_chosen_fc = PCPU_FC_EMBED; |
| #endif |
| #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK |
| else if (!strcmp(str, "page")) |
| pcpu_chosen_fc = PCPU_FC_PAGE; |
| #endif |
| else |
| pr_warning("PERCPU: unknown allocator %s specified\n", str); |
| |
| return 0; |
| } |
| early_param("percpu_alloc", percpu_alloc_setup); |
| |
| #if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \ |
| !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA) |
| /** |
| * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem |
| * @reserved_size: the size of reserved percpu area in bytes |
| * @dyn_size: minimum free size for dynamic allocation in bytes |
| * @atom_size: allocation atom size |
| * @cpu_distance_fn: callback to determine distance between cpus, optional |
| * @alloc_fn: function to allocate percpu page |
| * @free_fn: funtion to free percpu page |
| * |
| * 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 |
| * by calling @alloc_fn and used as-is without being mapped into |
| * vmalloc area. Allocations are always whole multiples of @atom_size |
| * aligned to @atom_size. |
| * |
| * This enables the first chunk to piggy back on the linear physical |
| * mapping which often uses larger page size. Please note that this |
| * can result in very sparse cpu->unit mapping on NUMA machines thus |
| * requiring large vmalloc address space. Don't use this allocator if |
| * vmalloc space is not orders of magnitude larger than distances |
| * between node memory addresses (ie. 32bit NUMA machines). |
| * |
| * @dyn_size specifies the minimum dynamic area size. |
| * |
| * If the needed size is smaller than the minimum or specified unit |
| * size, the leftover is returned using @free_fn. |
| * |
| * RETURNS: |
| * 0 on success, -errno on failure. |
| */ |
| int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size, |
| size_t atom_size, |
| pcpu_fc_cpu_distance_fn_t cpu_distance_fn, |
| pcpu_fc_alloc_fn_t alloc_fn, |
| pcpu_fc_free_fn_t free_fn) |
| { |
| void *base = (void *)ULONG_MAX; |
| void **areas = NULL; |
| struct pcpu_alloc_info *ai; |
| size_t size_sum, areas_size, max_distance; |
| int group, i, rc; |
| |
| ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size, |
| cpu_distance_fn); |
| if (IS_ERR(ai)) |
| return PTR_ERR(ai); |
| |
| size_sum = ai->static_size + ai->reserved_size + ai->dyn_size; |
| areas_size = PFN_ALIGN(ai->nr_groups * sizeof(void *)); |
| |
| areas = alloc_bootmem_nopanic(areas_size); |
| if (!areas) { |
| rc = -ENOMEM; |
| goto out_free; |
| } |
| |
| /* allocate, copy and determine base address */ |
| for (group = 0; group < ai->nr_groups; group++) { |
| struct pcpu_group_info *gi = &ai->groups[group]; |
| unsigned int cpu = NR_CPUS; |
| void *ptr; |
| |
| for (i = 0; i < gi->nr_units && cpu == NR_CPUS; i++) |
| cpu = gi->cpu_map[i]; |
| BUG_ON(cpu == NR_CPUS); |
| |
| /* allocate space for the whole group */ |
| ptr = alloc_fn(cpu, gi->nr_units * ai->unit_size, atom_size); |
| if (!ptr) { |
| rc = -ENOMEM; |
| goto out_free_areas; |
| } |
| areas[group] = ptr; |
| |
| base = min(ptr, base); |
| |
| for (i = 0; i < gi->nr_units; i++, ptr += ai->unit_size) { |
| if (gi->cpu_map[i] == NR_CPUS) { |
| /* unused unit, free whole */ |
| free_fn(ptr, ai->unit_size); |
| continue; |
| } |
| /* copy and return the unused part */ |
| memcpy(ptr, __per_cpu_load, ai->static_size); |
| free_fn(ptr + size_sum, ai->unit_size - size_sum); |
| } |
| } |
| |
| /* base address is now known, determine group base offsets */ |
| max_distance = 0; |
| for (group = 0; group < ai->nr_groups; group++) { |
| ai->groups[group].base_offset = areas[group] - base; |
| max_distance = max_t(size_t, max_distance, |
| ai->groups[group].base_offset); |
| } |
| max_distance += ai->unit_size; |
| |
| /* warn if maximum distance is further than 75% of vmalloc space */ |
| if (max_distance > (VMALLOC_END - VMALLOC_START) * 3 / 4) { |
| pr_warning("PERCPU: max_distance=0x%zx too large for vmalloc " |
| "space 0x%lx\n", |
| max_distance, VMALLOC_END - VMALLOC_START); |
| #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK |
| /* and fail if we have fallback */ |
| rc = -EINVAL; |
| goto out_free; |
| #endif |
| } |
| |
| pr_info("PERCPU: Embedded %zu pages/cpu @%p s%zu r%zu d%zu u%zu\n", |
| PFN_DOWN(size_sum), base, ai->static_size, ai->reserved_size, |
| ai->dyn_size, ai->unit_size); |
| |
| rc = pcpu_setup_first_chunk(ai, base); |
| goto out_free; |
| |
| out_free_areas: |
| for (group = 0; group < ai->nr_groups; group++) |
| free_fn(areas[group], |
| ai->groups[group].nr_units * ai->unit_size); |
| out_free: |
| pcpu_free_alloc_info(ai); |
| if (areas) |
| free_bootmem(__pa(areas), areas_size); |
| return rc; |
| } |
| #endif /* CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK || |
| !CONFIG_HAVE_SETUP_PER_CPU_AREA */ |
| |
| #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK |
| /** |
| * pcpu_page_first_chunk - map the first chunk using PAGE_SIZE pages |
| * @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 page-remapped 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: |
| * 0 on success, -errno on failure. |
| */ |
| int __init pcpu_page_first_chunk(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; |
| struct pcpu_alloc_info *ai; |
| char psize_str[16]; |
| int unit_pages; |
| size_t pages_size; |
| struct page **pages; |
| int unit, i, j, rc; |
| |
| snprintf(psize_str, sizeof(psize_str), "%luK", PAGE_SIZE >> 10); |
| |
| ai = pcpu_build_alloc_info(reserved_size, 0, PAGE_SIZE, NULL); |
| if (IS_ERR(ai)) |
| return PTR_ERR(ai); |
| BUG_ON(ai->nr_groups != 1); |
| BUG_ON(ai->groups[0].nr_units != num_possible_cpus()); |
| |
| unit_pages = ai->unit_size >> PAGE_SHIFT; |
| |
| /* 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 (unit = 0; unit < num_possible_cpus(); unit++) |
| for (i = 0; i < unit_pages; i++) { |
| unsigned int cpu = ai->groups[0].cpu_map[unit]; |
| void *ptr; |
| |
| ptr = alloc_fn(cpu, PAGE_SIZE, PAGE_SIZE); |
| if (!ptr) { |
| pr_warning("PERCPU: failed to allocate %s page " |
| "for cpu%u\n", psize_str, 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() * ai->unit_size; |
| vm_area_register_early(&vm, PAGE_SIZE); |
| |
| for (unit = 0; unit < num_possible_cpus(); unit++) { |
| unsigned long unit_addr = |
| (unsigned long)vm.addr + unit * ai->unit_size; |
| |
| for (i = 0; i < unit_pages; i++) |
| populate_pte_fn(unit_addr + (i << PAGE_SHIFT)); |
| |
| /* pte already populated, the following shouldn't fail */ |
| rc = __pcpu_map_pages(unit_addr, &pages[unit * unit_pages], |
| unit_pages); |
| if (rc < 0) |
| panic("failed to map percpu area, err=%d\n", rc); |
| |
| /* |
| * 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, ai->static_size); |
| } |
| |
| /* we're ready, commit */ |
| pr_info("PERCPU: %d %s pages/cpu @%p s%zu r%zu d%zu\n", |
| unit_pages, psize_str, vm.addr, ai->static_size, |
| ai->reserved_size, ai->dyn_size); |
| |
| rc = pcpu_setup_first_chunk(ai, vm.addr); |
| goto out_free_ar; |
| |
| enomem: |
| while (--j >= 0) |
| free_fn(page_address(pages[j]), PAGE_SIZE); |
| rc = -ENOMEM; |
| out_free_ar: |
| free_bootmem(__pa(pages), pages_size); |
| pcpu_free_alloc_info(ai); |
| return rc; |
| } |
| #endif /* CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK */ |
| |
| /* |
| * 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); |
| |
| static void * __init pcpu_dfl_fc_alloc(unsigned int cpu, size_t size, |
| size_t align) |
| { |
| return __alloc_bootmem_nopanic(size, align, __pa(MAX_DMA_ADDRESS)); |
| } |
| |
| static void __init pcpu_dfl_fc_free(void *ptr, size_t size) |
| { |
| free_bootmem(__pa(ptr), size); |
| } |
| |
| void __init setup_per_cpu_areas(void) |
| { |
| unsigned long delta; |
| unsigned int cpu; |
| int rc; |
| |
| /* |
| * Always reserve area for module percpu variables. That's |
| * what the legacy allocator did. |
| */ |
| rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE, |
| PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, NULL, |
| pcpu_dfl_fc_alloc, pcpu_dfl_fc_free); |
| if (rc < 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 + pcpu_unit_offsets[cpu]; |
| } |
| #endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */ |
| |
| /* |
| * First and reserved chunks are initialized with temporary allocation |
| * map in initdata so that they can be used before slab is online. |
| * This function is called after slab is brought up and replaces those |
| * with properly allocated maps. |
| */ |
| void __init percpu_init_late(void) |
| { |
| struct pcpu_chunk *target_chunks[] = |
| { pcpu_first_chunk, pcpu_reserved_chunk, NULL }; |
| struct pcpu_chunk *chunk; |
| unsigned long flags; |
| int i; |
| |
| for (i = 0; (chunk = target_chunks[i]); i++) { |
| int *map; |
| const size_t size = PERCPU_DYNAMIC_EARLY_SLOTS * sizeof(map[0]); |
| |
| BUILD_BUG_ON(size > PAGE_SIZE); |
| |
| map = pcpu_mem_alloc(size); |
| BUG_ON(!map); |
| |
| spin_lock_irqsave(&pcpu_lock, flags); |
| memcpy(map, chunk->map, size); |
| chunk->map = map; |
| spin_unlock_irqrestore(&pcpu_lock, flags); |
| } |
| } |