diff options
Diffstat (limited to 'mm/percpu.c')
| -rw-r--r-- | mm/percpu.c | 593 |
1 files changed, 420 insertions, 173 deletions
diff --git a/mm/percpu.c b/mm/percpu.c index 3d0f5456827c..bfe6a3afaf45 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -62,7 +62,9 @@ #include <linux/pfn.h> #include <linux/rbtree.h> #include <linux/slab.h> +#include <linux/spinlock.h> #include <linux/vmalloc.h> +#include <linux/workqueue.h> #include <asm/cacheflush.h> #include <asm/tlbflush.h> @@ -80,7 +82,8 @@ struct pcpu_chunk { int map_alloc; /* # of map entries allocated */ int *map; /* allocation map */ bool immutable; /* no [de]population allowed */ - struct page *page[]; /* #cpus * UNIT_PAGES */ + struct page **page; /* points to page array */ + struct page *page_ar[]; /* #cpus * UNIT_PAGES */ }; static int pcpu_unit_pages __read_mostly; @@ -93,28 +96,42 @@ static size_t pcpu_chunk_struct_size __read_mostly; void *pcpu_base_addr __read_mostly; EXPORT_SYMBOL_GPL(pcpu_base_addr); -/* the size of kernel static area */ -static int pcpu_static_size __read_mostly; +/* optional reserved chunk, only accessible for reserved allocations */ +static struct pcpu_chunk *pcpu_reserved_chunk; +/* offset limit of the reserved chunk */ +static int pcpu_reserved_chunk_limit; /* - * One mutex to rule them all. - * - * The following mutex is grabbed in the outermost public alloc/free - * interface functions and released only when the operation is - * complete. As such, every function in this file other than the - * outermost functions are called under pcpu_mutex. - * - * It can easily be switched to use spinlock such that only the area - * allocation and page population commit are protected with it doing - * actual [de]allocation without holding any lock. However, given - * what this allocator does, I think it's better to let them run - * sequentially. + * Synchronization rules. + * + * There are two locks - pcpu_alloc_mutex and pcpu_lock. The former + * protects allocation/reclaim paths, chunks and chunk->page arrays. + * The latter is a spinlock and protects the index data structures - + * chunk slots, rbtree, 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_mutex); +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 */ static struct rb_root pcpu_addr_root = RB_ROOT; /* chunks by address */ +/* 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 */ @@ -161,39 +178,44 @@ static bool pcpu_chunk_page_occupied(struct pcpu_chunk *chunk, } /** - * pcpu_realloc - versatile realloc - * @p: the current pointer (can be NULL for new allocations) - * @size: the current size in bytes (can be 0 for new allocations) - * @new_size: the wanted new size in bytes (can be 0 for free) + * 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. * - * More robust realloc which can be used to allocate, resize or free a - * memory area of arbitrary size. If the needed size goes over - * PAGE_SIZE, kernel VM is used. + * CONTEXT: + * Does GFP_KERNEL allocation. * * RETURNS: - * The new pointer on success, NULL on failure. + * Pointer to the allocated area on success, NULL on failure. */ -static void *pcpu_realloc(void *p, size_t size, size_t new_size) +static void *pcpu_mem_alloc(size_t size) { - void *new; - - if (new_size <= PAGE_SIZE) - new = kmalloc(new_size, GFP_KERNEL); - else - new = vmalloc(new_size); - if (new_size && !new) - return NULL; - - memcpy(new, p, min(size, new_size)); - if (new_size > size) - memset(new + size, 0, new_size - 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(p); + kfree(ptr); else - vfree(p); - - return new; + vfree(ptr); } /** @@ -203,13 +225,17 @@ static void *pcpu_realloc(void *p, size_t size, size_t new_size) * * 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. + * 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 (oslot != nslot) { + if (chunk != pcpu_reserved_chunk && oslot != nslot) { if (oslot < nslot) list_move(&chunk->list, &pcpu_slot[nslot]); else @@ -249,6 +275,9 @@ static struct rb_node **pcpu_chunk_rb_search(void *addr, * searchs for the chunk with the highest start address which isn't * beyond @addr. * + * CONTEXT: + * pcpu_lock. + * * RETURNS: * The address of the found chunk. */ @@ -257,6 +286,15 @@ static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr) struct rb_node *n, *parent; struct pcpu_chunk *chunk; + /* is it in the reserved chunk? */ + if (pcpu_reserved_chunk) { + void *start = pcpu_reserved_chunk->vm->addr; + + if (addr >= start && addr < start + pcpu_reserved_chunk_limit) + return pcpu_reserved_chunk; + } + + /* nah... search the regular ones */ n = *pcpu_chunk_rb_search(addr, &parent); if (!n) { /* no exactly matching chunk, the parent is the closest */ @@ -280,6 +318,9 @@ static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr) * @new: chunk to insert * * Insert @new into address rb tree. + * + * CONTEXT: + * pcpu_lock. */ static void pcpu_chunk_addr_insert(struct pcpu_chunk *new) { @@ -292,6 +333,66 @@ static void pcpu_chunk_addr_insert(struct pcpu_chunk *new) } /** + * 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 @@ -306,33 +407,19 @@ static void pcpu_chunk_addr_insert(struct pcpu_chunk *new) * depending on @head, is reduced by @tail bytes and @tail byte block * is inserted after the target block. * - * RETURNS: - * 0 on success, -errno on failure. + * @chunk->map must have enough free slots to accomodate the split. + * + * CONTEXT: + * pcpu_lock. */ -static int pcpu_split_block(struct pcpu_chunk *chunk, int i, int head, int tail) +static void pcpu_split_block(struct pcpu_chunk *chunk, int i, + int head, int tail) { int nr_extra = !!head + !!tail; - int target = chunk->map_used + nr_extra; - - /* reallocation required? */ - if (chunk->map_alloc < target) { - int new_alloc = chunk->map_alloc; - int *new; - while (new_alloc < target) - new_alloc *= 2; + BUG_ON(chunk->map_alloc < chunk->map_used + nr_extra); - new = pcpu_realloc(chunk->map, - chunk->map_alloc * sizeof(new[0]), - new_alloc * sizeof(new[0])); - if (!new) - return -ENOMEM; - - chunk->map_alloc = new_alloc; - chunk->map = new; - } - - /* insert a new subblock */ + /* 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; @@ -345,7 +432,6 @@ static int pcpu_split_block(struct pcpu_chunk *chunk, int i, int head, int tail) chunk->map[i++] -= tail; chunk->map[i] = tail; } - return 0; } /** @@ -358,8 +444,14 @@ static int pcpu_split_block(struct pcpu_chunk *chunk, int i, int head, int tail) * 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, -errno on failure. + * 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) { @@ -367,22 +459,6 @@ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align) int max_contig = 0; int i, off; - /* - * The static chunk initially doesn't have map attached - * because kmalloc wasn't available during init. Give it one. - */ - if (unlikely(!chunk->map)) { - chunk->map = pcpu_realloc(NULL, 0, - PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0])); - if (!chunk->map) - return -ENOMEM; - - chunk->map_alloc = PCPU_DFL_MAP_ALLOC; - chunk->map[chunk->map_used++] = -pcpu_static_size; - if (chunk->free_size) - chunk->map[chunk->map_used++] = chunk->free_size; - } - 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; @@ -423,8 +499,7 @@ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align) /* split if warranted */ if (head || tail) { - if (pcpu_split_block(chunk, i, head, tail)) - return -ENOMEM; + pcpu_split_block(chunk, i, head, tail); if (head) { i++; off += head; @@ -451,14 +526,8 @@ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align) chunk->contig_hint = max_contig; /* fully scanned */ pcpu_chunk_relocate(chunk, oslot); - /* - * Tell the upper layer that this chunk has no area left. - * Note that this is not an error condition but a notification - * to upper layer that it needs to look at other chunks. - * -ENOSPC is chosen as it isn't used in memory subsystem and - * matches the meaning in a way. - */ - return -ENOSPC; + /* tell the upper layer that this chunk has no matching area */ + return -1; } /** @@ -469,6 +538,9 @@ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align) * 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) { @@ -554,6 +626,9 @@ static void pcpu_unmap(struct pcpu_chunk *chunk, int page_start, int page_end, * 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, bool flush) @@ -632,6 +707,9 @@ static int pcpu_map(struct pcpu_chunk *chunk, int page_start, int page_end) * * 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) { @@ -686,7 +764,7 @@ static void free_pcpu_chunk(struct pcpu_chunk *chunk) return; if (chunk->vm) free_vm_area(chunk->vm); - pcpu_realloc(chunk->map, chunk->map_alloc * sizeof(chunk->map[0]), 0); + pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0])); kfree(chunk); } @@ -698,10 +776,10 @@ static struct pcpu_chunk *alloc_pcpu_chunk(void) if (!chunk) return NULL; - chunk->map = pcpu_realloc(NULL, 0, - PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0])); + chunk->map = pcpu_mem_alloc(PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0])); chunk->map_alloc = PCPU_DFL_MAP_ALLOC; chunk->map[chunk->map_used++] = pcpu_unit_size; + chunk->page = chunk->page_ar; chunk->vm = get_vm_area(pcpu_chunk_size, GFP_KERNEL); if (!chunk->vm) { @@ -717,19 +795,21 @@ static struct pcpu_chunk *alloc_pcpu_chunk(void) } /** - * __alloc_percpu - allocate percpu area + * 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. Might - * sleep. Might trigger writeouts. + * 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. */ -void *__alloc_percpu(size_t size, size_t align) +static void *pcpu_alloc(size_t size, size_t align, bool reserved) { - void *ptr = NULL; struct pcpu_chunk *chunk; int slot, off; @@ -739,90 +819,192 @@ void *__alloc_percpu(size_t size, size_t align) return NULL; } - mutex_lock(&pcpu_mutex); + 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; + } - /* allocate area */ +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; - if (off != -ENOSPC) - goto out_unlock; } } /* hmmm... no space left, create a new chunk */ + spin_unlock_irq(&pcpu_lock); + chunk = alloc_pcpu_chunk(); if (!chunk) - goto out_unlock; + goto fail_unlock_mutex; + + spin_lock_irq(&pcpu_lock); pcpu_chunk_relocate(chunk, -1); pcpu_chunk_addr_insert(chunk); - - off = pcpu_alloc_area(chunk, size, align); - if (off < 0) - goto out_unlock; + 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 out_unlock; + goto fail_unlock; } - ptr = __addr_to_pcpu_ptr(chunk->vm->addr + off); -out_unlock: - mutex_unlock(&pcpu_mutex); - return ptr; + mutex_unlock(&pcpu_alloc_mutex); + + 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); -static void pcpu_kill_chunk(struct pcpu_chunk *chunk) +/** + * __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) { - WARN_ON(chunk->immutable); - pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size, false); - list_del(&chunk->list); - rb_erase(&chunk->rb_node, &pcpu_addr_root); - free_pcpu_chunk(chunk); + 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; + + rb_erase(&chunk->rb_node, &pcpu_addr_root); + 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, false); + free_pcpu_chunk(chunk); + } } /** * free_percpu - free percpu area * @ptr: pointer to area to free * - * Free percpu area @ptr. Might sleep. + * 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; - mutex_lock(&pcpu_mutex); + spin_lock_irqsave(&pcpu_lock, flags); chunk = pcpu_chunk_addr_search(addr); off = addr - chunk->vm->addr; pcpu_free_area(chunk, off); - /* the chunk became fully free, kill one if there are other free ones */ + /* 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_chunk_slot(chunk)], list) + list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list) if (pos != chunk) { - pcpu_kill_chunk(pos); + schedule_work(&pcpu_reclaim_work); break; } } - mutex_unlock(&pcpu_mutex); + spin_unlock_irqrestore(&pcpu_lock, flags); } EXPORT_SYMBOL_GPL(free_percpu); @@ -830,8 +1012,9 @@ EXPORT_SYMBOL_GPL(free_percpu); * pcpu_setup_first_chunk - initialize the first percpu chunk * @get_page_fn: callback to fetch page pointer * @static_size: the size of static percpu area in bytes - * @unit_size: unit size in bytes, must be multiple of PAGE_SIZE, 0 for auto - * @free_size: free size in bytes, 0 for auto + * @reserved_size: the size of reserved percpu area in bytes + * @unit_size: unit size in bytes, must be multiple of PAGE_SIZE, -1 for auto + * @dyn_size: free size for dynamic allocation in bytes, -1 for auto * @base_addr: mapped address, NULL for auto * @populate_pte_fn: callback to allocate pagetable, NULL if unnecessary * @@ -848,13 +1031,22 @@ EXPORT_SYMBOL_GPL(free_percpu); * indicates end of pages for the cpu. Note that @get_page_fn() must * return the same number of pages for all cpus. * - * @unit_size, if non-zero, determines unit size and must be aligned - * to PAGE_SIZE and equal to or larger than @static_size + @free_size. + * @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. * - * @free_size determines the number of free bytes after the static - * area in the first chunk. If zero, whatever left is available. - * Specifying non-zero value make percpu leave the area after - * @static_size + @free_size alone. + * @unit_size, if non-negative, specifies unit size and must be + * aligned to PAGE_SIZE and equal to or larger than @static_size + + * @reserved_size + @dyn_size. + * + * @dyn_size, if non-negative, limits the number of bytes available + * for dynamic allocation in the first chunk. Specifying non-negative + * value make percpu leave alone the area beyond @static_size + + * @reserved_size + @dyn_size. * * Non-null @base_addr means that the caller already allocated virtual * region for the first chunk and mapped it. percpu must not mess @@ -864,41 +1056,58 @@ EXPORT_SYMBOL_GPL(free_percpu); * @populate_pte_fn is used to populate the pagetable. NULL means the * caller already populated the pagetable. * + * 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(pcpu_get_page_fn_t get_page_fn, - size_t static_size, size_t unit_size, - size_t free_size, void *base_addr, + size_t static_size, size_t reserved_size, + ssize_t unit_size, ssize_t dyn_size, + void *base_addr, pcpu_populate_pte_fn_t populate_pte_fn) { - static struct vm_struct static_vm; - struct pcpu_chunk *static_chunk; + static struct vm_struct first_vm; + static int smap[2], dmap[2]; + struct pcpu_chunk *schunk, *dchunk = NULL; unsigned int cpu; int nr_pages; int err, i; /* santiy checks */ + BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC || + ARRAY_SIZE(dmap) >= PCPU_DFL_MAP_ALLOC); BUG_ON(!static_size); - BUG_ON(!unit_size && free_size); - BUG_ON(unit_size && unit_size < static_size + free_size); - BUG_ON(unit_size & ~PAGE_MASK); - BUG_ON(base_addr && !unit_size); + if (unit_size >= 0) { + BUG_ON(unit_size < static_size + reserved_size + + (dyn_size >= 0 ? dyn_size : 0)); + BUG_ON(unit_size & ~PAGE_MASK); + } else { + BUG_ON(dyn_size >= 0); + BUG_ON(base_addr); + } BUG_ON(base_addr && populate_pte_fn); - if (unit_size) + if (unit_size >= 0) pcpu_unit_pages = unit_size >> PAGE_SHIFT; else pcpu_unit_pages = max_t(int, PCPU_MIN_UNIT_SIZE >> PAGE_SHIFT, - PFN_UP(static_size)); + PFN_UP(static_size + reserved_size)); - pcpu_static_size = static_size; pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT; pcpu_chunk_size = num_possible_cpus() * pcpu_unit_size; pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) + num_possible_cpus() * pcpu_unit_pages * sizeof(struct page *); + if (dyn_size < 0) + dyn_size = pcpu_unit_size - static_size - reserved_size; + /* * Allocate chunk slots. The additional last slot is for * empty chunks. @@ -908,33 +1117,66 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn, for (i = 0; i < pcpu_nr_slots; i++) INIT_LIST_HEAD(&pcpu_slot[i]); - /* init static_chunk */ - static_chunk = alloc_bootmem(pcpu_chunk_struct_size); - INIT_LIST_HEAD(&static_chunk->list); - static_chunk->vm = &static_vm; - - if (free_size) - static_chunk->free_size = free_size; - else - static_chunk->free_size = pcpu_unit_size - pcpu_static_size; - - static_chunk->contig_hint = static_chunk->free_size; + /* + * 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->page = schunk->page_ar; + + if (reserved_size) { + schunk->free_size = reserved_size; + pcpu_reserved_chunk = schunk; /* not for dynamic alloc */ + } 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; + + pcpu_reserved_chunk_limit = static_size + schunk->free_size; + + /* init dynamic chunk if necessary */ + if (dyn_size) { + dchunk = alloc_bootmem(sizeof(struct pcpu_chunk)); + INIT_LIST_HEAD(&dchunk->list); + dchunk->vm = &first_vm; + dchunk->map = dmap; + dchunk->map_alloc = ARRAY_SIZE(dmap); + dchunk->page = schunk->page_ar; /* share page map with schunk */ + + dchunk->contig_hint = dchunk->free_size = dyn_size; + dchunk->map[dchunk->map_used++] = -pcpu_reserved_chunk_limit; + dchunk->map[dchunk->map_used++] = dchunk->free_size; + } /* allocate vm address */ - static_vm.flags = VM_ALLOC; - static_vm.size = pcpu_chunk_size; + first_vm.flags = VM_ALLOC; + first_vm.size = pcpu_chunk_size; if (!base_addr) - vm_area_register_early(&static_vm, PAGE_SIZE); + vm_area_register_early(&first_vm, PAGE_SIZE); else { /* * Pages already mapped. No need to remap into - * vmalloc area. In this case the static chunk can't - * be mapped or unmapped by percpu and is marked + * vmalloc area. In this case the first chunks can't + * be mapped or unmapped by percpu and are marked * immutable. */ - static_vm.addr = base_addr; - static_chunk->immutable = true; + first_vm.addr = base_addr; + schunk->immutable = true; + if (dchunk) + dchunk->immutable = true; } /* assign pages */ @@ -945,10 +1187,10 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn, if (!page) break; - *pcpu_chunk_pagep(static_chunk, cpu, i) = page; + *pcpu_chunk_pagep(schunk, cpu, i) = page; } - BUG_ON(i < PFN_UP(pcpu_static_size)); + BUG_ON(i < PFN_UP(static_size)); if (nr_pages < 0) nr_pages = i; @@ -960,20 +1202,25 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn, if (populate_pte_fn) { for_each_possible_cpu(cpu) for (i = 0; i < nr_pages; i++) - populate_pte_fn(pcpu_chunk_addr(static_chunk, + populate_pte_fn(pcpu_chunk_addr(schunk, cpu, i)); - err = pcpu_map(static_chunk, 0, nr_pages); + err = pcpu_map(schunk, 0, nr_pages); if (err) panic("failed to setup static percpu area, err=%d\n", err); } - /* link static_chunk in */ - pcpu_chunk_relocate(static_chunk, -1); - pcpu_chunk_addr_insert(static_chunk); + /* link the first chunk in */ + if (!dchunk) { + pcpu_chunk_relocate(schunk, -1); + pcpu_chunk_addr_insert(schunk); + } else { + pcpu_chunk_relocate(dchunk, -1); + pcpu_chunk_addr_insert(dchunk); + } /* we're done */ - pcpu_base_addr = (void *)pcpu_chunk_addr(static_chunk, 0, 0); + pcpu_base_addr = (void *)pcpu_chunk_addr(schunk, 0, 0); return pcpu_unit_size; } |