diff --git a/include/kernel/mr_fifo.h b/include/kernel/mr_fifo.h
index f17307c..9015ea6 100644
--- a/include/kernel/mr_fifo.h
+++ b/include/kernel/mr_fifo.h
@@ -49,13 +49,13 @@ mr_uint32_t mr_fifo_init(mr_fifo_t *fifo, void *buf, mr_uint32_t size,
  * @brief This function allocates a fifo.
  *
  * @param fifo The fifo.
- * @param size The buffer size(bytes).
+ * @param num The buffer number.
  * @param elem_size The element size(bytes).
  * @return The element capacity(number).
  *
  * @note The buffer will be aligned up to a power of 2.
  */
-mr_uint32_t mr_fifo_alloc(mr_fifo_t *fifo, mr_uint32_t size,
+mr_uint32_t mr_fifo_alloc(mr_fifo_t *fifo, mr_uint32_t num,
                           mr_uint32_t elem_size);
 
 /**
diff --git a/include/kernel/mr_list.h b/include/kernel/mr_list.h
index 97daac4..2919e50 100644
--- a/include/kernel/mr_list.h
+++ b/include/kernel/mr_list.h
@@ -152,7 +152,7 @@ MR_INLINE void mr_list_move(mr_list_t *entry, mr_list_t *head) {
  */
 MR_INLINE mr_bool_t mr_list_is_empty(mr_list_t *head) {
     /* Check if list is empty */
-    return (head->next == head) ? MR_TRUE : MR_FALSE;
+    return head->next == head;
 }
 
 /**
diff --git a/include/kernel/mr_workqueue.h b/include/kernel/mr_workqueue.h
index 370eb6b..fb0cd62 100644
--- a/include/kernel/mr_workqueue.h
+++ b/include/kernel/mr_workqueue.h
@@ -44,7 +44,7 @@ typedef struct mr_workqueue {
     mr_atomic_t running;
     mr_atomic_t dying;
     mr_list_t t_list;
-    mr_list_t list;
+    mr_list_t r_list;
 #if defined(MR_USE_WORKQUEUE_HOOK)
     mr_workqueue_hook_t hook;
 #endif /* defined(MR_USE_WORKQUEUE_HOOK) */
diff --git a/include/libc/mr_malloc.h b/include/libc/mr_malloc.h
index 1bb5030..eb8b5a7 100644
--- a/include/libc/mr_malloc.h
+++ b/include/libc/mr_malloc.h
@@ -58,7 +58,7 @@ void *mr_malloc(mr_size_t size);
 void mr_free(void *mem);
 
 /**
- * @brief This function returns the usable size of mem.
+ * @brief This function returns the usable size of memory.
  *
  * @param mem The memory.
  * @return The usable size.
diff --git a/include/mr_config.h b/include/mr_config.h
index 6dcd474..75e8706 100644
--- a/include/mr_config.h
+++ b/include/mr_config.h
@@ -5,27 +5,6 @@
 extern "C" {
 #endif /* __cplusplus */
 
-#define MR_USE_PRINTF
-#define MR_CFG_PRINTF_BUF_SIZE 64
-#define MR_USE_TIMER
-#define MR_USE_WORKQUEUE
-#define MR_USE_IRQ
-#define MR_USE_IRQ_DEFER
-#define MR_CFG_IRQ_TABLE_SIZE  32
-#define MR_CFG_CLOCK_HOOK_SIZE 2
-
-#define MR_USE_ENTRY
-#define MR_USE_64BIT_ARCH
-#define MR_USE_MALLOC
-#define MR_CFG_HEAP_SIZE 4096
-#define MR_USE_SPRINTF
-#define MR_USE_ASSERT
-#define MR_USE_STRING
-#define MR_USE_STRING_SAFE
-#define MR_USE_SCANF
-#define MR_USE_TYPES
-#define MR_USE_ERRNO
-
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
diff --git a/kernel/clock.c b/kernel/clock.c
index 76c6065..61bf989 100644
--- a/kernel/clock.c
+++ b/kernel/clock.c
@@ -72,5 +72,5 @@ mr_err_t mr_clock_hook_add(mr_clock_hook_t *entry) {
     MR_ASSERT(entry != MR_NULL);
 
     /* Add hook to clock */
-    return mr_hook_add(&__hook, (mr_ptr_t)entry);
+    return mr_hook_add(&__hook, entry);
 }
diff --git a/kernel/fifo.c b/kernel/fifo.c
index 055f10f..0eb3e95 100644
--- a/kernel/fifo.c
+++ b/kernel/fifo.c
@@ -33,16 +33,17 @@ mr_uint32_t mr_fifo_init(mr_fifo_t *fifo, void *buf, mr_uint32_t size,
     return size;
 }
 
-mr_uint32_t mr_fifo_alloc(mr_fifo_t *fifo, mr_uint32_t size,
+mr_uint32_t mr_fifo_alloc(mr_fifo_t *fifo, mr_uint32_t num,
                           mr_uint32_t elem_size) {
+    mr_uint32_t size;
     void *buf;
 
     /* Check parameter */
     MR_ASSERT(fifo != MR_NULL);
-    MR_ASSERT((size >= 2) && (elem_size > 0) && (elem_size <= size));
+    MR_ASSERT((num > 0) && (elem_size > 0));
 
     /* Align size(up to power of 2) */
-    size = FIFO_ALIGN_POW2_UP(size);
+    size = FIFO_ALIGN_POW2_UP(num * elem_size);
 
     /* Allocate buffer */
     buf = mr_realloc(fifo->buf, size);
@@ -146,7 +147,7 @@ mr_uint32_t mr_fifo_in(mr_fifo_t *fifo, const void *buf, mr_uint32_t num) {
 
     /* Push buffer */
     mr_memcpy((mr_uint8_t *)fifo->buf + in, buf, n);
-    mr_memcpy(fifo->buf, ((mr_uint8_t *)buf) + n, num - n);
+    mr_memcpy(fifo->buf, (mr_uint8_t *)buf + n, num - n);
     fifo->in += num2;
     return num2;
 }
@@ -162,7 +163,7 @@ mr_uint32_t mr_fifo_in_overwrite(mr_fifo_t *fifo, const void *buf,
     /* Limit number */
     capacity = fifo->mask + 1;
     if (num > capacity) {
-        buf = ((mr_uint8_t *)buf) + ((num - capacity) * fifo->elem_size);
+        buf = (mr_uint8_t *)buf + ((num - capacity) * fifo->elem_size);
         num = capacity;
     }
 
diff --git a/kernel/hook.c b/kernel/hook.c
index e071a7c..2d92dc1 100644
--- a/kernel/hook.c
+++ b/kernel/hook.c
@@ -19,8 +19,8 @@ void mr_hook_init(mr_hook_t *hook, mr_ptr_t *entry, mr_size_t size) {
     MR_ASSERT((entry != MR_NULL) || (size == 0));
 
     /* Initialize hook */
-    hook->size = entry ? size : 0;
     hook->entry = entry;
+    hook->size = size;
     hook->next = 0;
 }
 
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 0ea571b..9a1b05b 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -73,7 +73,7 @@ static void queue_timer_entry(mr_timer_t *timer, void *param) {
         }
 
         /* Move work to workqueue work list */
-        mr_list_move(&work->list, &queue->list);
+        mr_list_move(&work->list, &queue->r_list);
     }
 
     /* Check if workqueue need set timer tick */
@@ -114,7 +114,7 @@ static mr_err_t workqueue_init(mr_workqueue_t *queue, const mr_class_t *class) {
     mr_atomic_init(&queue->running, MR_FALSE);
     mr_atomic_init(&queue->dying, MR_FALSE);
     mr_list_init(&queue->t_list);
-    mr_list_init(&queue->list);
+    mr_list_init(&queue->r_list);
 #if defined(MR_USE_WORKQUEUE_HOOK)
     queue->hook.suspend = MR_NULL;
     queue->hook.wakeup = MR_NULL;
@@ -201,7 +201,7 @@ mr_err_t mr_workqueue_execute(mr_workqueue_t *queue) {
     MR_ASSERT(MR_OBJECT_CLASS_IS_OR(queue, &__class1, &__class2));
 
     /* Reduce unnecessary lock operations */
-    if (mr_list_is_empty(&queue->list)
+    if (mr_list_is_empty(&queue->r_list)
 #if defined(MR_USE_WORKQUEUE_HOOK)
         && (!queue->hook.suspend)
 #endif /* defined(MR_USE_WORKQUEUE_HOOK) */
@@ -213,8 +213,8 @@ mr_err_t mr_workqueue_execute(mr_workqueue_t *queue) {
     mask = mr_spinlock_lock_irqsave(&__lock);
 
     /* Check workqueue work list */
-    while (!mr_list_is_empty(&queue->list)) {
-        work = MR_LIST_ENTRY(queue->list.next, mr_work_t, list);
+    while (!mr_list_is_empty(&queue->r_list)) {
+        work = MR_LIST_ENTRY(queue->r_list.next, mr_work_t, list);
 
         /* Remove work from running list */
         mr_list_del(&work->list);
@@ -265,7 +265,7 @@ mr_err_t mr_workqueue_work(mr_workqueue_t *queue, mr_work_t *work) {
     }
 
     /* Add work to running list */
-    mr_list_add(&queue->list, &work->list);
+    mr_list_add(&queue->r_list, &work->list);
     work->queue = queue;
 
     /* Unlock */
@@ -463,8 +463,8 @@ static void queue_del(mr_workqueue_t *queue) {
     }
 
     /* Remove work from workqueue running list */
-    while (!mr_list_is_empty(&queue->list)) {
-        work = MR_LIST_ENTRY(&queue->list.next, mr_work_t, list);
+    while (!mr_list_is_empty(&queue->r_list)) {
+        work = MR_LIST_ENTRY(&queue->r_list.next, mr_work_t, list);
         mr_list_del(&work->list);
     }
 
diff --git a/libc/string.c b/libc/string.c
index 4292484..81ea721 100644
--- a/libc/string.c
+++ b/libc/string.c
@@ -90,7 +90,7 @@ void *mr_memcpy(void *dst, const void *src, mr_size_t size) {
         }
     } else {
         /* Copy aligned bytes */
-        for (d = dst, s = src; (size >= sizeof(mr_uintptr_t));
+        for (d = dst, s = src; size >= sizeof(mr_uintptr_t);
              size -= sizeof(mr_uintptr_t)) {
             *(mr_uintptr_t *)d = *(mr_uintptr_t *)s;
             d += sizeof(mr_uintptr_t);