mirror of
https://github.com/koverstreet/bcachefs-tools.git
synced 2025-01-23 00:07:07 +03:00
Add a real mempool implementation
Imported from the kernel. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This commit is contained in:
Kent Overstreet
parent
ceac31bcb6
commit
30f72f75f5
@ -1,6 +1,7 @@
|
||||
#ifndef _LINUX_JIFFIES_H
|
||||
#define _LINUX_JIFFIES_H
|
||||
|
||||
#include <time.h>
|
||||
#include <linux/kernel.h>
|
||||
#include <linux/time64.h>
|
||||
#include <linux/typecheck.h>
|
||||
|
||||
@ -1,11 +1,12 @@
|
||||
/* SPDX-License-Identifier: GPL-2.0 */
|
||||
/*
|
||||
* memory buffer pool support
|
||||
*/
|
||||
#ifndef _LINUX_MEMPOOL_H
|
||||
#define _LINUX_MEMPOOL_H
|
||||
|
||||
#include <linux/wait.h>
|
||||
#include <linux/compiler.h>
|
||||
#include <linux/bug.h>
|
||||
#include <linux/slab.h>
|
||||
|
||||
struct kmem_cache;
|
||||
@ -14,74 +15,98 @@ typedef void * (mempool_alloc_t)(gfp_t gfp_mask, void *pool_data);
|
||||
typedef void (mempool_free_t)(void *element, void *pool_data);
|
||||
|
||||
typedef struct mempool_s {
|
||||
size_t elem_size;
|
||||
void *pool_data;
|
||||
mempool_alloc_t *alloc;
|
||||
mempool_free_t *free;
|
||||
spinlock_t lock;
|
||||
int min_nr; /* nr of elements at *elements */
|
||||
int curr_nr; /* Current nr of elements at *elements */
|
||||
void **elements;
|
||||
|
||||
void *pool_data;
|
||||
mempool_alloc_t *alloc;
|
||||
mempool_free_t *free;
|
||||
wait_queue_head_t wait;
|
||||
} mempool_t;
|
||||
|
||||
static inline bool mempool_initialized(mempool_t *pool)
|
||||
{
|
||||
return true;
|
||||
return pool->elements != NULL;
|
||||
}
|
||||
|
||||
void mempool_exit(mempool_t *pool);
|
||||
int mempool_init_node(mempool_t *pool, int min_nr, mempool_alloc_t *alloc_fn,
|
||||
mempool_free_t *free_fn, void *pool_data,
|
||||
gfp_t gfp_mask, int node_id);
|
||||
int mempool_init(mempool_t *pool, int min_nr, mempool_alloc_t *alloc_fn,
|
||||
mempool_free_t *free_fn, void *pool_data);
|
||||
|
||||
extern mempool_t *mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
|
||||
mempool_free_t *free_fn, void *pool_data);
|
||||
extern mempool_t *mempool_create_node(int min_nr, mempool_alloc_t *alloc_fn,
|
||||
mempool_free_t *free_fn, void *pool_data,
|
||||
gfp_t gfp_mask, int nid);
|
||||
|
||||
extern int mempool_resize(mempool_t *pool, int new_min_nr);
|
||||
extern void mempool_destroy(mempool_t *pool);
|
||||
extern void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) __malloc;
|
||||
extern void mempool_free(void *element, mempool_t *pool);
|
||||
|
||||
static inline void mempool_free(void *element, mempool_t *pool)
|
||||
{
|
||||
free(element);
|
||||
}
|
||||
|
||||
static inline void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) __malloc
|
||||
{
|
||||
BUG_ON(!pool->elem_size);
|
||||
return kmalloc(pool->elem_size, gfp_mask);
|
||||
}
|
||||
|
||||
static inline void mempool_exit(mempool_t *pool) {}
|
||||
|
||||
static inline void mempool_destroy(mempool_t *pool)
|
||||
{
|
||||
free(pool);
|
||||
}
|
||||
/*
|
||||
* A mempool_alloc_t and mempool_free_t that get the memory from
|
||||
* a slab cache that is passed in through pool_data.
|
||||
* Note: the slab cache may not have a ctor function.
|
||||
*/
|
||||
void *mempool_alloc_slab(gfp_t gfp_mask, void *pool_data);
|
||||
void mempool_free_slab(void *element, void *pool_data);
|
||||
|
||||
static inline int
|
||||
mempool_init_slab_pool(mempool_t *pool, int min_nr, struct kmem_cache *kc)
|
||||
{
|
||||
pool->elem_size = 0;
|
||||
return 0;
|
||||
return mempool_init(pool, min_nr, mempool_alloc_slab,
|
||||
mempool_free_slab, (void *) kc);
|
||||
}
|
||||
|
||||
static inline mempool_t *
|
||||
mempool_create_slab_pool(int min_nr, struct kmem_cache *kc)
|
||||
{
|
||||
mempool_t *pool = malloc(sizeof(*pool));
|
||||
pool->elem_size = 0;
|
||||
return pool;
|
||||
return mempool_create(min_nr, mempool_alloc_slab, mempool_free_slab,
|
||||
(void *) kc);
|
||||
}
|
||||
|
||||
/*
|
||||
* a mempool_alloc_t and a mempool_free_t to kmalloc and kfree the
|
||||
* amount of memory specified by pool_data
|
||||
*/
|
||||
void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data);
|
||||
void mempool_kfree(void *element, void *pool_data);
|
||||
|
||||
static inline int mempool_init_kmalloc_pool(mempool_t *pool, int min_nr, size_t size)
|
||||
{
|
||||
pool->elem_size = size;
|
||||
return 0;
|
||||
return mempool_init(pool, min_nr, mempool_kmalloc,
|
||||
mempool_kfree, (void *) size);
|
||||
}
|
||||
|
||||
static inline mempool_t *mempool_create_kmalloc_pool(int min_nr, size_t size)
|
||||
{
|
||||
return mempool_create(min_nr, mempool_kmalloc, mempool_kfree,
|
||||
(void *) size);
|
||||
}
|
||||
|
||||
/*
|
||||
* A mempool_alloc_t and mempool_free_t for a simple page allocator that
|
||||
* allocates pages of the order specified by pool_data
|
||||
*/
|
||||
void *mempool_alloc_pages(gfp_t gfp_mask, void *pool_data);
|
||||
void mempool_free_pages(void *element, void *pool_data);
|
||||
|
||||
static inline int mempool_init_page_pool(mempool_t *pool, int min_nr, int order)
|
||||
{
|
||||
pool->elem_size = PAGE_SIZE << order;
|
||||
return 0;
|
||||
return mempool_init(pool, min_nr, mempool_alloc_pages,
|
||||
mempool_free_pages, (void *)(long)order);
|
||||
}
|
||||
|
||||
static inline int mempool_init(mempool_t *pool, int min_nr,
|
||||
mempool_alloc_t *alloc_fn,
|
||||
mempool_free_t *free_fn,
|
||||
void *pool_data)
|
||||
static inline mempool_t *mempool_create_page_pool(int min_nr, int order)
|
||||
{
|
||||
pool->elem_size = (size_t) pool_data;
|
||||
pool->pool_data = pool_data;
|
||||
pool->alloc = alloc_fn;
|
||||
pool->free = free_fn;
|
||||
return 0;
|
||||
return mempool_create(min_nr, mempool_alloc_pages, mempool_free_pages,
|
||||
(void *)(long)order);
|
||||
}
|
||||
|
||||
#endif /* _LINUX_MEMPOOL_H */
|
||||
|
||||
541
linux/mempool.c
Normal file
541
linux/mempool.c
Normal file
@ -0,0 +1,541 @@
|
||||
// SPDX-License-Identifier: GPL-2.0
|
||||
/*
|
||||
* linux/mm/mempool.c
|
||||
*
|
||||
* memory buffer pool support. Such pools are mostly used
|
||||
* for guaranteed, deadlock-free memory allocations during
|
||||
* extreme VM load.
|
||||
*
|
||||
* started by Ingo Molnar, Copyright (C) 2001
|
||||
* debugging by David Rientjes, Copyright (C) 2015
|
||||
*/
|
||||
|
||||
#include <linux/slab.h>
|
||||
//#include <linux/kasan.h>
|
||||
//#include <linux/kmemleak.h>
|
||||
#include <linux/export.h>
|
||||
#include <linux/jiffies.h>
|
||||
#include <linux/mempool.h>
|
||||
#include <linux/mempool.h>
|
||||
#include <linux/sched.h>
|
||||
|
||||
#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB_DEBUG_ON)
|
||||
static void poison_error(mempool_t *pool, void *element, size_t size,
|
||||
size_t byte)
|
||||
{
|
||||
const int nr = pool->curr_nr;
|
||||
const int start = max_t(int, byte - (BITS_PER_LONG / 8), 0);
|
||||
const int end = min_t(int, byte + (BITS_PER_LONG / 8), size);
|
||||
int i;
|
||||
|
||||
pr_err("BUG: mempool element poison mismatch\n");
|
||||
pr_err("Mempool %p size %zu\n", pool, size);
|
||||
pr_err(" nr=%d @ %p: %s0x", nr, element, start > 0 ? "... " : "");
|
||||
for (i = start; i < end; i++)
|
||||
pr_cont("%x ", *(u8 *)(element + i));
|
||||
pr_cont("%s\n", end < size ? "..." : "");
|
||||
dump_stack();
|
||||
}
|
||||
|
||||
static void __check_element(mempool_t *pool, void *element, size_t size)
|
||||
{
|
||||
u8 *obj = element;
|
||||
size_t i;
|
||||
|
||||
for (i = 0; i < size; i++) {
|
||||
u8 exp = (i < size - 1) ? POISON_FREE : POISON_END;
|
||||
|
||||
if (obj[i] != exp) {
|
||||
poison_error(pool, element, size, i);
|
||||
return;
|
||||
}
|
||||
}
|
||||
memset(obj, POISON_INUSE, size);
|
||||
}
|
||||
|
||||
static void check_element(mempool_t *pool, void *element)
|
||||
{
|
||||
/* Mempools backed by slab allocator */
|
||||
if (pool->free == mempool_free_slab || pool->free == mempool_kfree) {
|
||||
__check_element(pool, element, ksize(element));
|
||||
} else if (pool->free == mempool_free_pages) {
|
||||
/* Mempools backed by page allocator */
|
||||
int order = (int)(long)pool->pool_data;
|
||||
void *addr = kmap_atomic((struct page *)element);
|
||||
|
||||
__check_element(pool, addr, 1UL << (PAGE_SHIFT + order));
|
||||
kunmap_atomic(addr);
|
||||
}
|
||||
}
|
||||
|
||||
static void __poison_element(void *element, size_t size)
|
||||
{
|
||||
u8 *obj = element;
|
||||
|
||||
memset(obj, POISON_FREE, size - 1);
|
||||
obj[size - 1] = POISON_END;
|
||||
}
|
||||
|
||||
static void poison_element(mempool_t *pool, void *element)
|
||||
{
|
||||
/* Mempools backed by slab allocator */
|
||||
if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc) {
|
||||
__poison_element(element, ksize(element));
|
||||
} else if (pool->alloc == mempool_alloc_pages) {
|
||||
/* Mempools backed by page allocator */
|
||||
int order = (int)(long)pool->pool_data;
|
||||
void *addr = kmap_atomic((struct page *)element);
|
||||
|
||||
__poison_element(addr, 1UL << (PAGE_SHIFT + order));
|
||||
kunmap_atomic(addr);
|
||||
}
|
||||
}
|
||||
#else /* CONFIG_DEBUG_SLAB || CONFIG_SLUB_DEBUG_ON */
|
||||
static inline void check_element(mempool_t *pool, void *element)
|
||||
{
|
||||
}
|
||||
static inline void poison_element(mempool_t *pool, void *element)
|
||||
{
|
||||
}
|
||||
#endif /* CONFIG_DEBUG_SLAB || CONFIG_SLUB_DEBUG_ON */
|
||||
|
||||
static __always_inline void kasan_poison_element(mempool_t *pool, void *element)
|
||||
{
|
||||
#if 0
|
||||
if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
|
||||
kasan_poison_kfree(element, _RET_IP_);
|
||||
else if (pool->alloc == mempool_alloc_pages)
|
||||
kasan_free_pages(element, (unsigned long)pool->pool_data);
|
||||
#endif
|
||||
}
|
||||
|
||||
static void kasan_unpoison_element(mempool_t *pool, void *element)
|
||||
{
|
||||
#if 0
|
||||
if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
|
||||
kasan_unpoison_slab(element);
|
||||
else if (pool->alloc == mempool_alloc_pages)
|
||||
kasan_alloc_pages(element, (unsigned long)pool->pool_data);
|
||||
#endif
|
||||
}
|
||||
|
||||
static __always_inline void add_element(mempool_t *pool, void *element)
|
||||
{
|
||||
BUG_ON(pool->curr_nr >= pool->min_nr);
|
||||
poison_element(pool, element);
|
||||
kasan_poison_element(pool, element);
|
||||
pool->elements[pool->curr_nr++] = element;
|
||||
}
|
||||
|
||||
static void *remove_element(mempool_t *pool)
|
||||
{
|
||||
void *element = pool->elements[--pool->curr_nr];
|
||||
|
||||
BUG_ON(pool->curr_nr < 0);
|
||||
kasan_unpoison_element(pool, element);
|
||||
check_element(pool, element);
|
||||
return element;
|
||||
}
|
||||
|
||||
/**
|
||||
* mempool_exit - exit a mempool initialized with mempool_init()
|
||||
* @pool: pointer to the memory pool which was initialized with
|
||||
* mempool_init().
|
||||
*
|
||||
* Free all reserved elements in @pool and @pool itself. This function
|
||||
* only sleeps if the free_fn() function sleeps.
|
||||
*
|
||||
* May be called on a zeroed but uninitialized mempool (i.e. allocated with
|
||||
* kzalloc()).
|
||||
*/
|
||||
void mempool_exit(mempool_t *pool)
|
||||
{
|
||||
while (pool->curr_nr) {
|
||||
void *element = remove_element(pool);
|
||||
pool->free(element, pool->pool_data);
|
||||
}
|
||||
kfree(pool->elements);
|
||||
pool->elements = NULL;
|
||||
}
|
||||
EXPORT_SYMBOL(mempool_exit);
|
||||
|
||||
/**
|
||||
* mempool_destroy - deallocate a memory pool
|
||||
* @pool: pointer to the memory pool which was allocated via
|
||||
* mempool_create().
|
||||
*
|
||||
* Free all reserved elements in @pool and @pool itself. This function
|
||||
* only sleeps if the free_fn() function sleeps.
|
||||
*/
|
||||
void mempool_destroy(mempool_t *pool)
|
||||
{
|
||||
if (unlikely(!pool))
|
||||
return;
|
||||
|
||||
mempool_exit(pool);
|
||||
kfree(pool);
|
||||
}
|
||||
EXPORT_SYMBOL(mempool_destroy);
|
||||
|
||||
int mempool_init_node(mempool_t *pool, int min_nr, mempool_alloc_t *alloc_fn,
|
||||
mempool_free_t *free_fn, void *pool_data,
|
||||
gfp_t gfp_mask, int node_id)
|
||||
{
|
||||
spin_lock_init(&pool->lock);
|
||||
pool->min_nr = min_nr;
|
||||
pool->pool_data = pool_data;
|
||||
pool->alloc = alloc_fn;
|
||||
pool->free = free_fn;
|
||||
init_waitqueue_head(&pool->wait);
|
||||
|
||||
pool->elements = kmalloc_array(min_nr, sizeof(void *), gfp_mask);
|
||||
if (!pool->elements)
|
||||
return -ENOMEM;
|
||||
|
||||
/*
|
||||
* First pre-allocate the guaranteed number of buffers.
|
||||
*/
|
||||
while (pool->curr_nr < pool->min_nr) {
|
||||
void *element;
|
||||
|
||||
element = pool->alloc(gfp_mask, pool->pool_data);
|
||||
if (unlikely(!element)) {
|
||||
mempool_exit(pool);
|
||||
return -ENOMEM;
|
||||
}
|
||||
add_element(pool, element);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
EXPORT_SYMBOL(mempool_init_node);
|
||||
|
||||
/**
|
||||
* mempool_init - initialize a memory pool
|
||||
* @pool: pointer to the memory pool that should be initialized
|
||||
* @min_nr: the minimum number of elements guaranteed to be
|
||||
* allocated for this pool.
|
||||
* @alloc_fn: user-defined element-allocation function.
|
||||
* @free_fn: user-defined element-freeing function.
|
||||
* @pool_data: optional private data available to the user-defined functions.
|
||||
*
|
||||
* Like mempool_create(), but initializes the pool in (i.e. embedded in another
|
||||
* structure).
|
||||
*
|
||||
* Return: %0 on success, negative error code otherwise.
|
||||
*/
|
||||
int mempool_init(mempool_t *pool, int min_nr, mempool_alloc_t *alloc_fn,
|
||||
mempool_free_t *free_fn, void *pool_data)
|
||||
{
|
||||
return mempool_init_node(pool, min_nr, alloc_fn, free_fn,
|
||||
pool_data, GFP_KERNEL, 0);
|
||||
|
||||
}
|
||||
EXPORT_SYMBOL(mempool_init);
|
||||
|
||||
/**
|
||||
* mempool_create - create a memory pool
|
||||
* @min_nr: the minimum number of elements guaranteed to be
|
||||
* allocated for this pool.
|
||||
* @alloc_fn: user-defined element-allocation function.
|
||||
* @free_fn: user-defined element-freeing function.
|
||||
* @pool_data: optional private data available to the user-defined functions.
|
||||
*
|
||||
* this function creates and allocates a guaranteed size, preallocated
|
||||
* memory pool. The pool can be used from the mempool_alloc() and mempool_free()
|
||||
* functions. This function might sleep. Both the alloc_fn() and the free_fn()
|
||||
* functions might sleep - as long as the mempool_alloc() function is not called
|
||||
* from IRQ contexts.
|
||||
*
|
||||
* Return: pointer to the created memory pool object or %NULL on error.
|
||||
*/
|
||||
mempool_t *mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
|
||||
mempool_free_t *free_fn, void *pool_data)
|
||||
{
|
||||
return mempool_create_node(min_nr,alloc_fn,free_fn, pool_data,
|
||||
GFP_KERNEL, 0);
|
||||
}
|
||||
EXPORT_SYMBOL(mempool_create);
|
||||
|
||||
mempool_t *mempool_create_node(int min_nr, mempool_alloc_t *alloc_fn,
|
||||
mempool_free_t *free_fn, void *pool_data,
|
||||
gfp_t gfp_mask, int node_id)
|
||||
{
|
||||
mempool_t *pool;
|
||||
|
||||
pool = kzalloc(sizeof(*pool), gfp_mask);
|
||||
if (!pool)
|
||||
return NULL;
|
||||
|
||||
if (mempool_init_node(pool, min_nr, alloc_fn, free_fn, pool_data,
|
||||
gfp_mask, node_id)) {
|
||||
kfree(pool);
|
||||
return NULL;
|
||||
}
|
||||
|
||||
return pool;
|
||||
}
|
||||
EXPORT_SYMBOL(mempool_create_node);
|
||||
|
||||
/**
|
||||
* mempool_resize - resize an existing memory pool
|
||||
* @pool: pointer to the memory pool which was allocated via
|
||||
* mempool_create().
|
||||
* @new_min_nr: the new minimum number of elements guaranteed to be
|
||||
* allocated for this pool.
|
||||
*
|
||||
* This function shrinks/grows the pool. In the case of growing,
|
||||
* it cannot be guaranteed that the pool will be grown to the new
|
||||
* size immediately, but new mempool_free() calls will refill it.
|
||||
* This function may sleep.
|
||||
*
|
||||
* Note, the caller must guarantee that no mempool_destroy is called
|
||||
* while this function is running. mempool_alloc() & mempool_free()
|
||||
* might be called (eg. from IRQ contexts) while this function executes.
|
||||
*
|
||||
* Return: %0 on success, negative error code otherwise.
|
||||
*/
|
||||
int mempool_resize(mempool_t *pool, int new_min_nr)
|
||||
{
|
||||
void *element;
|
||||
void **new_elements;
|
||||
unsigned long flags;
|
||||
|
||||
BUG_ON(new_min_nr <= 0);
|
||||
might_sleep();
|
||||
|
||||
spin_lock_irqsave(&pool->lock, flags);
|
||||
if (new_min_nr <= pool->min_nr) {
|
||||
while (new_min_nr < pool->curr_nr) {
|
||||
element = remove_element(pool);
|
||||
spin_unlock_irqrestore(&pool->lock, flags);
|
||||
pool->free(element, pool->pool_data);
|
||||
spin_lock_irqsave(&pool->lock, flags);
|
||||
}
|
||||
pool->min_nr = new_min_nr;
|
||||
goto out_unlock;
|
||||
}
|
||||
spin_unlock_irqrestore(&pool->lock, flags);
|
||||
|
||||
/* Grow the pool */
|
||||
new_elements = kmalloc_array(new_min_nr, sizeof(*new_elements),
|
||||
GFP_KERNEL);
|
||||
if (!new_elements)
|
||||
return -ENOMEM;
|
||||
|
||||
spin_lock_irqsave(&pool->lock, flags);
|
||||
if (unlikely(new_min_nr <= pool->min_nr)) {
|
||||
/* Raced, other resize will do our work */
|
||||
spin_unlock_irqrestore(&pool->lock, flags);
|
||||
kfree(new_elements);
|
||||
goto out;
|
||||
}
|
||||
memcpy(new_elements, pool->elements,
|
||||
pool->curr_nr * sizeof(*new_elements));
|
||||
kfree(pool->elements);
|
||||
pool->elements = new_elements;
|
||||
pool->min_nr = new_min_nr;
|
||||
|
||||
while (pool->curr_nr < pool->min_nr) {
|
||||
spin_unlock_irqrestore(&pool->lock, flags);
|
||||
element = pool->alloc(GFP_KERNEL, pool->pool_data);
|
||||
if (!element)
|
||||
goto out;
|
||||
spin_lock_irqsave(&pool->lock, flags);
|
||||
if (pool->curr_nr < pool->min_nr) {
|
||||
add_element(pool, element);
|
||||
} else {
|
||||
spin_unlock_irqrestore(&pool->lock, flags);
|
||||
pool->free(element, pool->pool_data); /* Raced */
|
||||
goto out;
|
||||
}
|
||||
}
|
||||
out_unlock:
|
||||
spin_unlock_irqrestore(&pool->lock, flags);
|
||||
out:
|
||||
return 0;
|
||||
}
|
||||
EXPORT_SYMBOL(mempool_resize);
|
||||
|
||||
/**
|
||||
* mempool_alloc - allocate an element from a specific memory pool
|
||||
* @pool: pointer to the memory pool which was allocated via
|
||||
* mempool_create().
|
||||
* @gfp_mask: the usual allocation bitmask.
|
||||
*
|
||||
* this function only sleeps if the alloc_fn() function sleeps or
|
||||
* returns NULL. Note that due to preallocation, this function
|
||||
* *never* fails when called from process contexts. (it might
|
||||
* fail if called from an IRQ context.)
|
||||
* Note: using __GFP_ZERO is not supported.
|
||||
*
|
||||
* Return: pointer to the allocated element or %NULL on error.
|
||||
*/
|
||||
void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask)
|
||||
{
|
||||
void *element;
|
||||
unsigned long flags;
|
||||
DEFINE_WAIT(wait);
|
||||
gfp_t gfp_temp;
|
||||
|
||||
WARN_ON_ONCE(gfp_mask & __GFP_ZERO);
|
||||
|
||||
gfp_mask |= __GFP_NORETRY; /* don't loop in __alloc_pages */
|
||||
gfp_mask |= __GFP_NOWARN; /* failures are OK */
|
||||
|
||||
gfp_temp = gfp_mask & ~(__GFP_IO);
|
||||
|
||||
repeat_alloc:
|
||||
|
||||
element = pool->alloc(gfp_temp, pool->pool_data);
|
||||
if (likely(element != NULL))
|
||||
return element;
|
||||
|
||||
spin_lock_irqsave(&pool->lock, flags);
|
||||
if (likely(pool->curr_nr)) {
|
||||
element = remove_element(pool);
|
||||
spin_unlock_irqrestore(&pool->lock, flags);
|
||||
/* paired with rmb in mempool_free(), read comment there */
|
||||
smp_wmb();
|
||||
return element;
|
||||
}
|
||||
|
||||
/*
|
||||
* We use gfp mask w/o direct reclaim or IO for the first round. If
|
||||
* alloc failed with that and @pool was empty, retry immediately.
|
||||
*/
|
||||
if (gfp_temp != gfp_mask) {
|
||||
spin_unlock_irqrestore(&pool->lock, flags);
|
||||
gfp_temp = gfp_mask;
|
||||
goto repeat_alloc;
|
||||
}
|
||||
|
||||
/* Let's wait for someone else to return an element to @pool */
|
||||
prepare_to_wait(&pool->wait, &wait, TASK_UNINTERRUPTIBLE);
|
||||
|
||||
spin_unlock_irqrestore(&pool->lock, flags);
|
||||
|
||||
/*
|
||||
* FIXME: this should be io_schedule(). The timeout is there as a
|
||||
* workaround for some DM problems in 2.6.18.
|
||||
*/
|
||||
io_schedule_timeout(5*HZ);
|
||||
|
||||
finish_wait(&pool->wait, &wait);
|
||||
goto repeat_alloc;
|
||||
}
|
||||
EXPORT_SYMBOL(mempool_alloc);
|
||||
|
||||
/**
|
||||
* mempool_free - return an element to the pool.
|
||||
* @element: pool element pointer.
|
||||
* @pool: pointer to the memory pool which was allocated via
|
||||
* mempool_create().
|
||||
*
|
||||
* this function only sleeps if the free_fn() function sleeps.
|
||||
*/
|
||||
void mempool_free(void *element, mempool_t *pool)
|
||||
{
|
||||
unsigned long flags;
|
||||
|
||||
if (unlikely(element == NULL))
|
||||
return;
|
||||
|
||||
/*
|
||||
* Paired with the wmb in mempool_alloc(). The preceding read is
|
||||
* for @element and the following @pool->curr_nr. This ensures
|
||||
* that the visible value of @pool->curr_nr is from after the
|
||||
* allocation of @element. This is necessary for fringe cases
|
||||
* where @element was passed to this task without going through
|
||||
* barriers.
|
||||
*
|
||||
* For example, assume @p is %NULL at the beginning and one task
|
||||
* performs "p = mempool_alloc(...);" while another task is doing
|
||||
* "while (!p) cpu_relax(); mempool_free(p, ...);". This function
|
||||
* may end up using curr_nr value which is from before allocation
|
||||
* of @p without the following rmb.
|
||||
*/
|
||||
smp_rmb();
|
||||
|
||||
/*
|
||||
* For correctness, we need a test which is guaranteed to trigger
|
||||
* if curr_nr + #allocated == min_nr. Testing curr_nr < min_nr
|
||||
* without locking achieves that and refilling as soon as possible
|
||||
* is desirable.
|
||||
*
|
||||
* Because curr_nr visible here is always a value after the
|
||||
* allocation of @element, any task which decremented curr_nr below
|
||||
* min_nr is guaranteed to see curr_nr < min_nr unless curr_nr gets
|
||||
* incremented to min_nr afterwards. If curr_nr gets incremented
|
||||
* to min_nr after the allocation of @element, the elements
|
||||
* allocated after that are subject to the same guarantee.
|
||||
*
|
||||
* Waiters happen iff curr_nr is 0 and the above guarantee also
|
||||
* ensures that there will be frees which return elements to the
|
||||
* pool waking up the waiters.
|
||||
*/
|
||||
if (unlikely(READ_ONCE(pool->curr_nr) < pool->min_nr)) {
|
||||
spin_lock_irqsave(&pool->lock, flags);
|
||||
if (likely(pool->curr_nr < pool->min_nr)) {
|
||||
add_element(pool, element);
|
||||
spin_unlock_irqrestore(&pool->lock, flags);
|
||||
wake_up(&pool->wait);
|
||||
return;
|
||||
}
|
||||
spin_unlock_irqrestore(&pool->lock, flags);
|
||||
}
|
||||
pool->free(element, pool->pool_data);
|
||||
}
|
||||
EXPORT_SYMBOL(mempool_free);
|
||||
|
||||
/*
|
||||
* A commonly used alloc and free fn.
|
||||
*/
|
||||
void *mempool_alloc_slab(gfp_t gfp_mask, void *pool_data)
|
||||
{
|
||||
struct kmem_cache *mem = pool_data;
|
||||
return kmem_cache_alloc(mem, gfp_mask);
|
||||
}
|
||||
EXPORT_SYMBOL(mempool_alloc_slab);
|
||||
|
||||
void mempool_free_slab(void *element, void *pool_data)
|
||||
{
|
||||
struct kmem_cache *mem = pool_data;
|
||||
kmem_cache_free(mem, element);
|
||||
}
|
||||
EXPORT_SYMBOL(mempool_free_slab);
|
||||
|
||||
/*
|
||||
* A commonly used alloc and free fn that kmalloc/kfrees the amount of memory
|
||||
* specified by pool_data
|
||||
*/
|
||||
void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data)
|
||||
{
|
||||
size_t size = (size_t)pool_data;
|
||||
return kmalloc(size, gfp_mask);
|
||||
}
|
||||
EXPORT_SYMBOL(mempool_kmalloc);
|
||||
|
||||
void mempool_kfree(void *element, void *pool_data)
|
||||
{
|
||||
kfree(element);
|
||||
}
|
||||
EXPORT_SYMBOL(mempool_kfree);
|
||||
|
||||
/*
|
||||
* A simple mempool-backed page allocator that allocates pages
|
||||
* of the order specified by pool_data.
|
||||
*/
|
||||
void *mempool_alloc_pages(gfp_t gfp_mask, void *pool_data)
|
||||
{
|
||||
int order = (int)(long)pool_data;
|
||||
return alloc_pages(gfp_mask, order);
|
||||
}
|
||||
EXPORT_SYMBOL(mempool_alloc_pages);
|
||||
|
||||
void mempool_free_pages(void *element, void *pool_data)
|
||||
{
|
||||
int order = (int)(long)pool_data;
|
||||
__free_pages(element, order);
|
||||
}
|
||||
EXPORT_SYMBOL(mempool_free_pages);
|
||||
Loading…
Reference in New Issue
Block a user