xmalloc: Add pooled allocator interface.

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

1 files changed, 78 insertions, 3 deletions

diff --git a/xen/include/xen/xmalloc.h b/xen/include/xen/xmalloc.h
index dbfdce4fa4..e41cc36e74 100644
--- a/xen/include/xen/xmalloc.h
+++ b/xen/include/xen/xmalloc.h
@@ -2,11 +2,16 @@
 #ifndef __XMALLOC_H__
 #define __XMALLOC_H__
 
+/*
+ * Xen malloc/free-style interface.
+ */
+
 /* Allocate space for typed object. */
 #define xmalloc(_type) ((_type *)_xmalloc(sizeof(_type), __alignof__(_type)))
 
 /* Allocate space for array of typed objects. */
-#define xmalloc_array(_type, _num) ((_type *)_xmalloc_array(sizeof(_type), __alignof__(_type), _num))
+#define xmalloc_array(_type, _num) \
+    ((_type *)_xmalloc_array(sizeof(_type), __alignof__(_type), _num))
 
 /* Allocate untyped storage. */
 #define xmalloc_bytes(_bytes) (_xmalloc(_bytes, SMP_CACHE_BYTES))
@@ -15,8 +20,9 @@
 extern void xfree(void *);
 
 /* Underlying functions */
-extern void *_xmalloc(size_t size, size_t align);
-static inline void *_xmalloc_array(size_t size, size_t align, size_t num)
+extern void *_xmalloc(unsigned long size, unsigned long align);
+static inline void *_xmalloc_array(
+    unsigned long size, unsigned long align, unsigned long num)
 {
 	/* Check for overflow. */
 	if (size && num > UINT_MAX / size)
@@ -24,4 +30,73 @@ static inline void *_xmalloc_array(size_t size, size_t align, size_t num)
  	return _xmalloc(size * num, align);
 }
 
+/*
+ * Pooled allocator interface.
+ */
+
+struct xmem_pool;
+
+typedef void *(xmem_pool_get_memory)(unsigned long bytes);
+typedef void (xmem_pool_put_memory)(void *ptr);
+
+/**
+ * xmem_pool_create - create dynamic memory pool
+ * @name: name of the pool
+ * @get_mem: callback function used to expand pool
+ * @put_mem: callback function used to shrink pool
+ * @init_size: inital pool size (in bytes)
+ * @max_size: maximum pool size (in bytes) - set this as 0 for no limit
+ * @grow_size: amount of memory (in bytes) added to pool whenever required
+ *
+ * All size values are rounded up to next page boundary.
+ */
+struct xmem_pool *xmem_pool_create(
+    const char *name,
+    xmem_pool_get_memory get_mem,
+    xmem_pool_put_memory put_mem,
+    unsigned long init_size,
+    unsigned long max_size,
+    unsigned long grow_size);
+
+/**
+ * xmem_pool_destroy - cleanup given pool
+ * @mem_pool: Pool to be destroyed
+ *
+ * Data structures associated with pool are freed.
+ * All memory allocated from pool must be freed before
+ * destorying it.
+ */
+void xmem_pool_destroy(struct xmem_pool *pool);
+
+/**
+ * xmem_pool_alloc - allocate memory from given pool
+ * @size: no. of bytes
+ * @mem_pool: pool to allocate from
+ */
+void *xmem_pool_alloc(unsigned long size, struct xmem_pool *pool);
+
+/**
+ * xmem_pool_free - free memory from given pool
+ * @ptr: address of memory to be freed
+ * @mem_pool: pool to free from
+ */
+void xmem_pool_free(void *ptr, struct xmem_pool *pool);
+
+/**
+ * xmem_pool_get_used_size - get memory currently used by given pool
+ *
+ * Used memory includes stored data + metadata + internal fragmentation
+ */
+unsigned long xmem_pool_get_used_size(struct xmem_pool *pool);
+
+/**
+ * xmem_pool_get_total_size - get total memory currently allocated for pool
+ *
+ * This is the total memory currently allocated for this pool which includes
+ * used size + free size.
+ *
+ * (Total - Used) is good indicator of memory efficiency of allocator.
+ */
+unsigned long xmem_pool_get_total_size(struct xmem_pool *pool);
+
 #endif /* __XMALLOC_H__ */