diff --git a/src/core/ngx_slab.h b/src/core/ngx_slab.h
index ea9e0ea..5bdacaf 100644
--- a/src/core/ngx_slab.h
+++ b/src/core/ngx_slab.h
@@ -39,7 +39,9 @@
 
 void ngx_slab_init(ngx_slab_pool_t *pool);
 void *ngx_slab_alloc(ngx_slab_pool_t *pool, size_t size);
+void *ngx_slab_alloc_locked(ngx_slab_pool_t *pool, size_t size);
 void ngx_slab_free(ngx_slab_pool_t *pool, void *p);
+void ngx_slab_free_locked(ngx_slab_pool_t *pool, void *p);
 
 
 #endif /* _NGX_SLAB_H_INCLUDED_ */