diff --git a/crate/memory/src/memory_set/handler/shared.rs b/crate/memory/src/memory_set/handler/shared.rs
index bacaa443..f3deae13 100644
--- a/crate/memory/src/memory_set/handler/shared.rs
+++ b/crate/memory/src/memory_set/handler/shared.rs
@@ -16,11 +16,12 @@ impl<T: FrameAllocator> SharedGuard<T> {
     pub fn new(allocator: T) -> Self {
         SharedGuard {
             allocator: allocator,
+            // size meaningful only for sys_shm
             size: 0,
             target: BTreeMap::new(),
         }
-        // size meaningful only for sys_shm
     }
+
     pub fn new_with_size(allocator: T, size: usize) -> Self {
         SharedGuard {
             allocator: allocator,
@@ -28,22 +29,24 @@ impl<T: FrameAllocator> SharedGuard<T> {
             target: BTreeMap::new(),
         }
     }
+
     pub fn alloc(&mut self, virt_addr: usize) -> Option<usize> {
         let phys_addr = self.allocator.alloc().expect("failed to allocate frame");
         self.target.insert(virt_addr, phys_addr);
         Some(phys_addr)
     }
+    
     pub fn dealloc(&mut self, virt_addr: usize) {
         let phys_addr = self.target.get(&virt_addr).unwrap().clone();
         self.allocator.dealloc(phys_addr);
         self.target.remove(&virt_addr);
     }
+
     pub fn get(&self, addr: usize) -> Option<usize> {
         match self.target.get(&addr) {
             Some(phys_addr) => Some(phys_addr.clone()),
             None => None,
         }
-        //Some(self.target.get(&addr).unwrap().clone())
     }
 }
 
@@ -131,7 +134,7 @@ impl<T: FrameAllocator> MemoryHandler for Shared<T> {
             entry.set_present(true);
             entry.update();
 
-            //init with zero for delay mmap mode
+            // init with zero for delay mmap mode
             let data = pt.get_page_slice_mut(addr);
             let len = data.len();
             for x in data {
@@ -157,6 +160,7 @@ impl<T: FrameAllocator> Shared<T> {
             guard: Arc::new(Mutex::new(SharedGuard::new(allocator))),
         }
     }
+
     pub fn new_with_guard(allocator: T, guard: Arc<Mutex<SharedGuard<T>>>) -> Self {
         Shared {
             allocator: allocator.clone(),
diff --git a/kernel/src/ipc/mod.rs b/kernel/src/ipc/mod.rs
index 60b5b9ac..38c00c27 100644
--- a/kernel/src/ipc/mod.rs
+++ b/kernel/src/ipc/mod.rs
@@ -42,14 +42,17 @@ impl SemProc {
         self.arrays.insert(id, array);
         id
     }
+
     /// Get a free ID
     fn get_free_id(&self) -> SemId {
         (0..).find(|i| self.arrays.get(i).is_none()).unwrap()
     }
+
     /// Get an semaphore set by `id`
     pub fn get(&self, id: SemId) -> Option<Arc<SemArray>> {
         self.arrays.get(&id).map(|a| a.clone())
     }
+
     /// Add an undo operation
     pub fn add_undo(&mut self, id: SemId, num: SemNum, op: SemOp) {
         let old_val = *self.undos.get(&(id, num)).unwrap_or(&0);
@@ -95,12 +98,14 @@ impl ShmProc {
         self.shm_identifiers.insert(id, shm_identifier);
         id
     }
+
     /// Get a free ID
     fn get_free_id(&self) -> ShmId {
         (0..)
             .find(|i| self.shm_identifiers.get(i).is_none())
             .unwrap()
     }
+
     /// Get an semaphore set by `id`
     pub fn get(&self, id: ShmId) -> Option<ShmIdentifier> {
         self.shm_identifiers.get(&id).map(|a| a.clone())
@@ -120,6 +125,7 @@ impl ShmProc {
         }
         None
     }
+
     /// Pop Shared Area
     pub fn pop(&mut self, id: ShmId) {
         self.shm_identifiers.remove(&id);
diff --git a/kernel/src/syscall/mod.rs b/kernel/src/syscall/mod.rs
index 2323d9ee..ab82d056 100644
--- a/kernel/src/syscall/mod.rs
+++ b/kernel/src/syscall/mod.rs
@@ -363,11 +363,6 @@ impl Syscall<'_> {
             SYS_SHMAT => self.sys_shmat(args[0], args[1], args[2]),
             #[cfg(not(target_arch = "mips"))]
             SYS_SHMDT => self.sys_shmdt(args[0], args[1], args[2]),
-            /*SYS_SHMCTL => self.sys_shmctl(
-                args[0],
-                args[1],
-                args[2] /* should be shmid_ds *buf */
-            ),*/
             // system
             SYS_GETPID => self.sys_getpid(),
             SYS_GETTID => self.sys_gettid(),