[Qemu-devel] [PATCH RFC 06/14] qemu/obj_pool.h: introduce object allocation pool

[Ming Lei <ming.lei@canonical.com>]

This patch introduces object allocation pool for speeding up
object allocation in fast path.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
---
 include/qemu/obj_pool.h |   64 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 include/qemu/obj_pool.h

diff --git a/include/qemu/obj_pool.h b/include/qemu/obj_pool.h
new file mode 100644
index 0000000..94b5f49
--- /dev/null
+++ b/include/qemu/obj_pool.h
@@ -0,0 +1,64 @@
+#ifndef QEMU_OBJ_POOL_HEAD
+#define QEMU_OBJ_POOL_HEAD
+
+typedef struct {
+    unsigned int size;
+    unsigned int cnt;
+
+    void **free_obj;
+    int free_idx;
+
+    char *objs;
+} ObjPool;
+
+static inline void obj_pool_init(ObjPool *op, void *objs_buf, void **free_objs,
+                                 unsigned int obj_size, unsigned cnt)
+{
+    int i;
+
+    op->objs = (char *)objs_buf;
+    op->free_obj = free_objs;
+    op->size = obj_size;
+    op->cnt = cnt;
+
+    for (i = 0; i < op->cnt; i++) {
+        op->free_obj[i] = (void *)&op->objs[i * op->size];
+    }
+    op->free_idx = op->cnt;
+}
+
+static inline void *obj_pool_get(ObjPool *op)
+{
+    void *obj;
+
+    if (!op) {
+        return NULL;
+    }
+
+    if (op->free_idx <= 0) {
+        return NULL;
+    }
+
+    obj = op->free_obj[--op->free_idx];
+    return obj;
+}
+
+static inline bool obj_pool_has_obj(ObjPool *op, void *obj)
+{
+    return op && (unsigned long)obj >= (unsigned long)&op->objs[0] &&
+           (unsigned long)obj <=
+           (unsigned long)&op->objs[(op->cnt - 1) * op->size];
+}
+
+static inline void obj_pool_put(ObjPool *op, void *obj)
+{
+    if (!op || !obj_pool_has_obj(op, obj)) {
+        return;
+    }
+
+    assert(op->free_idx < op->cnt);
+
+    op->free_obj[op->free_idx++] = obj;
+}
+
+#endif
-- 
1.7.9.5