🆕 释放内存对象的函数slab_free()

kernel/mm/slab.c

@@ -235,7 +235,8 @@ void *slab_malloc(struct slab *slab_pool, ul arg)
                     return slab_pool->constructor((char *)slab_obj_ptr->vaddr + slab_pool->size * i, arg);
                 }
                 // 返回内存对象指针
-                else return (void*)((char*)slab_obj_ptr->vaddr+slab_pool->size*i);
+                else
+                    return (void *)((char *)slab_obj_ptr->vaddr + slab_pool->size * i);
             }
         }
 
@@ -267,7 +268,55 @@ void *slab_malloc(struct slab *slab_pool, ul arg)
  */
 ul slab_free(struct slab *slab_pool, void *addr, ul arg)
 {
+    struct slab_obj *slab_obj_ptr = slab_pool->cache_pool;
 
+    do
+    {
+        // 虚拟地址不在当前内存池对象的管理范围内
+        if (!(slab_obj_ptr->vaddr <= addr && addr <= (slab_obj_ptr->vaddr + PAGE_2M_SIZE)))
+        {
+            slab_obj_ptr = container_of(list_next(&slab_obj_ptr->list), struct slab_obj, list);
+            continue;
+        }
+
+        // 计算出给定内存对象是第几个
+        int index = (addr - slab_obj_ptr->vaddr) / slab_pool->size;
+
+        // 复位位图中对应的位
+        *(slab_obj_ptr->bmp + (index >> 6)) ^= (1UL << index % 64);
+
+        ++(slab_obj_ptr->count_free);
+        --(slab_obj_ptr->count_using);
+
+        ++(slab_pool->count_total_free);
+        --(slab_pool->count_total_using);
+
+        // 有对应的析构函数，调用析构函数
+        if (slab_pool->destructor != NULL)
+            slab_pool->destructor((char *)slab_obj_ptr->vaddr + slab_pool->size * index, arg);
+        
+        // 当前内存对象池的正在使用的内存对象为0，且内存池的空闲对象大于当前对象池的2倍，则销毁当前对象池，以减轻系统内存压力
+        if((slab_obj_ptr->count_using==0)&&((slab_pool->count_total_free>>1)>=slab_obj_ptr->count_free))
+        {
+            // 防止删除了slab_pool的cache_pool入口
+            if(slab_pool->cache_pool==slab_obj_ptr)
+                slab_pool->cache_pool = container_of(list_next(&slab_obj_ptr->list), struct slab_obj, list);
+            
+            list_del(&slab_obj_ptr->list);
+            slab_pool->count_total_free -= slab_obj_ptr->count_free;
+            
+            kfree(slab_obj_ptr->bmp);
+            page_clean(slab_obj_ptr->page);
+            free_pages(slab_obj_ptr->page,1);
+            kfree(slab_obj_ptr);
+            
+        }
+
+        return 0;
+    } while (slab_obj_ptr != slab_pool->cache_pool);
+
+    kwarn("slab_free(): address not in current slab");
+    return ENOT_IN_SLAB;
 }
 
 /**

kernel/mm/slab.h

@@ -10,6 +10,7 @@
 
 // SLAB存储池count_using不为空
 #define ESLAB_NOTNULL 101
+#define ENOT_IN_SLAB 102
 
 
 struct slab_obj