#include <linux/mm.h>
#include <linux/slab.h>
-#include <linux/module.h>
+#include <linux/export.h>
#include <linux/mempool.h>
#include <linux/blkdev.h>
#include <linux/writeback.h>
return pool->elements[--pool->curr_nr];
}
-static void free_pool(mempool_t *pool)
+/**
+ * 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)
{
while (pool->curr_nr) {
void *element = remove_element(pool);
kfree(pool->elements);
kfree(pool);
}
+EXPORT_SYMBOL(mempool_destroy);
/**
* mempool_create - create a memory pool
* @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
+ * 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
+ * functions might sleep - as long as the mempool_alloc() function is not called
* from IRQ contexts.
*/
-mempool_t * mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
+mempool_t *mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
mempool_free_t *free_fn, void *pool_data)
{
- mempool_t *pool;
+ return mempool_create_node(min_nr,alloc_fn,free_fn, pool_data,-1);
+}
+EXPORT_SYMBOL(mempool_create);
- pool = kmalloc(sizeof(*pool), GFP_KERNEL);
+mempool_t *mempool_create_node(int min_nr, mempool_alloc_t *alloc_fn,
+ mempool_free_t *free_fn, void *pool_data, int node_id)
+{
+ mempool_t *pool;
+ pool = kmalloc_node(sizeof(*pool), GFP_KERNEL | __GFP_ZERO, node_id);
if (!pool)
return NULL;
- memset(pool, 0, sizeof(*pool));
- pool->elements = kmalloc(min_nr * sizeof(void *), GFP_KERNEL);
+ pool->elements = kmalloc_node(min_nr * sizeof(void *),
+ GFP_KERNEL, node_id);
if (!pool->elements) {
kfree(pool);
return NULL;
element = pool->alloc(GFP_KERNEL, pool->pool_data);
if (unlikely(!element)) {
- free_pool(pool);
+ mempool_destroy(pool);
return NULL;
}
add_element(pool, element);
}
return pool;
}
+EXPORT_SYMBOL(mempool_create_node);
/**
* mempool_resize - resize an existing memory pool
* while this function is running. mempool_alloc() & mempool_free()
* might be called (eg. from IRQ contexts) while this function executes.
*/
-int mempool_resize(mempool_t *pool, int new_min_nr, int gfp_mask)
+int mempool_resize(mempool_t *pool, int new_min_nr, gfp_t gfp_mask)
{
void *element;
void **new_elements;
BUG_ON(new_min_nr <= 0);
spin_lock_irqsave(&pool->lock, flags);
- if (new_min_nr < pool->min_nr) {
- while (pool->curr_nr > new_min_nr) {
+ 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);
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);
if (!element)
goto out;
spin_lock_irqsave(&pool->lock, flags);
- if (pool->curr_nr < pool->min_nr)
+ if (pool->curr_nr < pool->min_nr) {
add_element(pool, element);
- else
- kfree(element); /* Raced */
+ } 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;
}
-
-/**
- * mempool_destroy - deallocate a memory pool
- * @pool: pointer to the memory pool which was allocated via
- * mempool_create().
- *
- * this function only sleeps if the free_fn() function sleeps. The caller
- * has to guarantee that all elements have been returned to the pool (ie:
- * freed) prior to calling mempool_destroy().
- */
-void mempool_destroy(mempool_t *pool)
-{
- if (pool->curr_nr != pool->min_nr)
- BUG(); /* There were outstanding elements */
- free_pool(pool);
-}
+EXPORT_SYMBOL(mempool_resize);
/**
* mempool_alloc - allocate an element from a specific memory pool
* mempool_create().
* @gfp_mask: the usual allocation bitmask.
*
- * this function only sleeps if the alloc_fn function sleeps or
+ * 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.)
*/
-void * mempool_alloc(mempool_t *pool, int gfp_mask)
+void * mempool_alloc(mempool_t *pool, gfp_t gfp_mask)
{
void *element;
unsigned long flags;
- DEFINE_WAIT(wait);
- int gfp_nowait = gfp_mask & ~(__GFP_WAIT | __GFP_IO);
- int pf_flags = current->flags;
+ wait_queue_t wait;
+ gfp_t gfp_temp;
+
+ might_sleep_if(gfp_mask & __GFP_WAIT);
+
+ gfp_mask |= __GFP_NOMEMALLOC; /* don't allocate emergency reserves */
+ gfp_mask |= __GFP_NORETRY; /* don't loop in __alloc_pages */
+ gfp_mask |= __GFP_NOWARN; /* failures are OK */
+
+ gfp_temp = gfp_mask & ~(__GFP_WAIT|__GFP_IO);
repeat_alloc:
- current->flags |= PF_NOWARN;
- element = pool->alloc(gfp_nowait, pool->pool_data);
- current->flags = pf_flags;
+
+ element = pool->alloc(gfp_temp, pool->pool_data);
if (likely(element != NULL))
return element;
- /*
- * If the pool is less than 50% full and we can perform effective
- * page reclaim then try harder to allocate an element.
- */
- if ((gfp_mask & __GFP_FS) && (gfp_mask != gfp_nowait) &&
- (pool->curr_nr <= pool->min_nr/2)) {
- element = pool->alloc(gfp_mask, pool->pool_data);
- if (likely(element != NULL))
- return element;
- }
-
- /*
- * Kick the VM at this point.
- */
- wakeup_bdflush(0);
-
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;
}
- spin_unlock_irqrestore(&pool->lock, flags);
- /* We must not sleep in the GFP_ATOMIC case */
- if (gfp_mask == gfp_nowait)
- return NULL;
+ /*
+ * We use gfp mask w/o __GFP_WAIT 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;
+ }
- blk_run_queues();
+ /* We must not sleep if !__GFP_WAIT */
+ if (!(gfp_mask & __GFP_WAIT)) {
+ spin_unlock_irqrestore(&pool->lock, flags);
+ return NULL;
+ }
+ /* Let's wait for someone else to return an element to @pool */
+ init_wait(&wait);
prepare_to_wait(&pool->wait, &wait, TASK_UNINTERRUPTIBLE);
- if (!pool->curr_nr)
- io_schedule();
- finish_wait(&pool->wait, &wait);
+ 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.
{
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 (pool->curr_nr < pool->min_nr) {
spin_lock_irqsave(&pool->lock, flags);
if (pool->curr_nr < pool->min_nr) {
}
pool->free(element, pool->pool_data);
}
-
-EXPORT_SYMBOL(mempool_create);
-EXPORT_SYMBOL(mempool_resize);
-EXPORT_SYMBOL(mempool_destroy);
-EXPORT_SYMBOL(mempool_alloc);
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);
projects / linux-flexiantxendom0-3.2.10.git / blobdiff