* Uses for this includes on-device special memory, uncached memory
* etc.
*
+ * This code is based on the buddy allocator found in the sym53c8xx_2
+ * driver Copyright (C) 1999-2001 Gerard Roudier <groudier@free.fr>,
+ * and adapted for general purpose use.
+ *
* Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org>
*
* This source code is licensed under the GNU General Public License,
*/
#include <linux/module.h>
+#include <linux/stddef.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/spinlock.h>
#include <linux/genalloc.h>
+#include <asm/page.h>
-/*
- * Create a new special memory pool.
- *
- * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
- * @nid: node id of the node the pool structure should be allocated on, or -1
- */
-struct gen_pool *gen_pool_create(int min_alloc_order, int nid)
-{
- struct gen_pool *pool;
- pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid);
- if (pool != NULL) {
- rwlock_init(&pool->lock);
- INIT_LIST_HEAD(&pool->chunks);
- pool->min_alloc_order = min_alloc_order;
+struct gen_pool *gen_pool_create(int nr_chunks, int max_chunk_shift,
+ unsigned long (*fp)(struct gen_pool *),
+ unsigned long data)
+{
+ struct gen_pool *poolp;
+ unsigned long tmp;
+ int i;
+
+ /*
+ * This is really an arbitrary limit, +10 is enough for
+ * IA64_GRANULE_SHIFT, aka 16MB. If anyone needs a large limit
+ * this can be increased without problems.
+ */
+ if ((max_chunk_shift > (PAGE_SHIFT + 10)) ||
+ ((max_chunk_shift < ALLOC_MIN_SHIFT) && max_chunk_shift))
+ return NULL;
+
+ if (!max_chunk_shift)
+ max_chunk_shift = PAGE_SHIFT;
+
+ poolp = kmalloc(sizeof(struct gen_pool), GFP_KERNEL);
+ if (!poolp)
+ return NULL;
+ memset(poolp, 0, sizeof(struct gen_pool));
+ poolp->h = kmalloc(sizeof(struct gen_pool_link) *
+ (max_chunk_shift - ALLOC_MIN_SHIFT + 1),
+ GFP_KERNEL);
+ if (!poolp->h) {
+ printk(KERN_WARNING "gen_pool_alloc() failed to allocate\n");
+ kfree(poolp);
+ return NULL;
+ }
+ memset(poolp->h, 0, sizeof(struct gen_pool_link) *
+ (max_chunk_shift - ALLOC_MIN_SHIFT + 1));
+
+ spin_lock_init(&poolp->lock);
+ poolp->get_new_chunk = fp;
+ poolp->max_chunk_shift = max_chunk_shift;
+ poolp->private = data;
+
+ for (i = 0; i < nr_chunks; i++) {
+ tmp = poolp->get_new_chunk(poolp);
+ printk(KERN_INFO "allocated %lx\n", tmp);
+ if (!tmp)
+ break;
+ gen_pool_free(poolp, tmp, (1 << poolp->max_chunk_shift));
}
- return pool;
+
+ return poolp;
}
EXPORT_SYMBOL(gen_pool_create);
/*
- * Add a new chunk of memory to the specified pool.
- *
- * @pool: pool to add new memory chunk to
- * @addr: starting address of memory chunk to add to pool
- * @size: size in bytes of the memory chunk to add to pool
- * @nid: node id of the node the chunk structure and bitmap should be
- * allocated on, or -1
+ * Simple power of two buddy-like generic allocator.
+ * Provides naturally aligned memory chunks.
*/
-int gen_pool_add(struct gen_pool *pool, unsigned long addr, size_t size,
- int nid)
+unsigned long gen_pool_alloc(struct gen_pool *poolp, int size)
{
- struct gen_pool_chunk *chunk;
- int nbits = size >> pool->min_alloc_order;
- int nbytes = sizeof(struct gen_pool_chunk) +
- (nbits + BITS_PER_BYTE - 1) / BITS_PER_BYTE;
+ int j, i, s, max_chunk_size;
+ unsigned long a, flags;
+ struct gen_pool_link *h = poolp->h;
- chunk = kmalloc_node(nbytes, GFP_KERNEL, nid);
- if (unlikely(chunk == NULL))
- return -1;
+ max_chunk_size = 1 << poolp->max_chunk_shift;
- memset(chunk, 0, nbytes);
- spin_lock_init(&chunk->lock);
- chunk->start_addr = addr;
- chunk->end_addr = addr + size;
-
- write_lock(&pool->lock);
- list_add(&chunk->next_chunk, &pool->chunks);
- write_unlock(&pool->lock);
+ if (size > max_chunk_size)
+ return 0;
- return 0;
+ size = max(size, 1 << ALLOC_MIN_SHIFT);
+ i = fls(size - 1);
+ s = 1 << i;
+ j = i -= ALLOC_MIN_SHIFT;
+
+ spin_lock_irqsave(&poolp->lock, flags);
+ while (!h[j].next) {
+ if (s == max_chunk_size) {
+ struct gen_pool_link *ptr;
+ spin_unlock_irqrestore(&poolp->lock, flags);
+ ptr = (struct gen_pool_link *)poolp->get_new_chunk(poolp);
+ spin_lock_irqsave(&poolp->lock, flags);
+ h[j].next = ptr;
+ if (h[j].next)
+ h[j].next->next = NULL;
+ break;
+ }
+ j++;
+ s <<= 1;
+ }
+ a = (unsigned long) h[j].next;
+ if (a) {
+ h[j].next = h[j].next->next;
+ /*
+ * This should be split into a seperate function doing
+ * the chunk split in order to support custom
+ * handling memory not physically accessible by host
+ */
+ while (j > i) {
+ j -= 1;
+ s >>= 1;
+ h[j].next = (struct gen_pool_link *) (a + s);
+ h[j].next->next = NULL;
+ }
+ }
+ spin_unlock_irqrestore(&poolp->lock, flags);
+ return a;
}
-EXPORT_SYMBOL(gen_pool_add);
+EXPORT_SYMBOL(gen_pool_alloc);
/*
- * Allocate the requested number of bytes from the specified pool.
- * Uses a first-fit algorithm.
- *
- * @pool: pool to allocate from
- * @size: number of bytes to allocate from the pool
+ * Counter-part of the generic allocator.
*/
-unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
+void gen_pool_free(struct gen_pool *poolp, unsigned long ptr, int size)
{
- struct list_head *_chunk;
- struct gen_pool_chunk *chunk;
- unsigned long addr, flags;
- int order = pool->min_alloc_order;
- int nbits, bit, start_bit, end_bit;
+ struct gen_pool_link *q;
+ struct gen_pool_link *h = poolp->h;
+ unsigned long a, b, flags;
+ int i, s, max_chunk_size;
- if (size == 0)
- return 0;
+ max_chunk_size = 1 << poolp->max_chunk_shift;
- nbits = (size + (1UL << order) - 1) >> order;
-
- read_lock(&pool->lock);
- list_for_each(_chunk, &pool->chunks) {
- chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
-
- end_bit = (chunk->end_addr - chunk->start_addr) >> order;
- end_bit -= nbits + 1;
-
- spin_lock_irqsave(&chunk->lock, flags);
- bit = -1;
- while (bit + 1 < end_bit) {
- bit = find_next_zero_bit(chunk->bits, end_bit, bit + 1);
- if (bit >= end_bit)
- break;
-
- start_bit = bit;
- if (nbits > 1) {
- bit = find_next_bit(chunk->bits, bit + nbits,
- bit + 1);
- if (bit - start_bit < nbits)
- continue;
- }
-
- addr = chunk->start_addr +
- ((unsigned long)start_bit << order);
- while (nbits--)
- __set_bit(start_bit++, &chunk->bits);
- spin_unlock_irqrestore(&chunk->lock, flags);
- read_unlock(&pool->lock);
- return addr;
+ if (size > max_chunk_size)
+ return;
+
+ size = max(size, 1 << ALLOC_MIN_SHIFT);
+ i = fls(size - 1);
+ s = 1 << i;
+ i -= ALLOC_MIN_SHIFT;
+
+ a = ptr;
+
+ spin_lock_irqsave(&poolp->lock, flags);
+ while (1) {
+ if (s == max_chunk_size) {
+ ((struct gen_pool_link *)a)->next = h[i].next;
+ h[i].next = (struct gen_pool_link *)a;
+ break;
}
- spin_unlock_irqrestore(&chunk->lock, flags);
- }
- read_unlock(&pool->lock);
- return 0;
-}
-EXPORT_SYMBOL(gen_pool_alloc);
+ b = a ^ s;
+ q = &h[i];
+ while (q->next && q->next != (struct gen_pool_link *)b)
+ q = q->next;
-/*
- * Free the specified memory back to the specified pool.
- *
- * @pool: pool to free to
- * @addr: starting address of memory to free back to pool
- * @size: size in bytes of memory to free
- */
-void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size)
-{
- struct list_head *_chunk;
- struct gen_pool_chunk *chunk;
- unsigned long flags;
- int order = pool->min_alloc_order;
- int bit, nbits;
-
- nbits = (size + (1UL << order) - 1) >> order;
-
- read_lock(&pool->lock);
- list_for_each(_chunk, &pool->chunks) {
- chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
-
- if (addr >= chunk->start_addr && addr < chunk->end_addr) {
- BUG_ON(addr + size > chunk->end_addr);
- spin_lock_irqsave(&chunk->lock, flags);
- bit = (addr - chunk->start_addr) >> order;
- while (nbits--)
- __clear_bit(bit++, &chunk->bits);
- spin_unlock_irqrestore(&chunk->lock, flags);
+ if (!q->next) {
+ ((struct gen_pool_link *)a)->next = h[i].next;
+ h[i].next = (struct gen_pool_link *)a;
break;
}
+ q->next = q->next->next;
+ a = a & b;
+ s <<= 1;
+ i++;
}
- BUG_ON(nbits > 0);
- read_unlock(&pool->lock);
+ spin_unlock_irqrestore(&poolp->lock, flags);
}
EXPORT_SYMBOL(gen_pool_free);
git://git.onelab.eu / linux-2.6.git / blobdiff