Auto deallocate frame

src/arch/x86_64/paging/mapper.rs

@@ -94,7 +94,7 @@ impl Mapper {
         self.map_to(page, frame, flags)
     }
 
-    pub fn unmap(&mut self, page: Page)
+    pub fn unmap(&mut self, page: Page) -> Frame
     {
         use x86_64::instructions::tlb;
         use x86_64::VirtualAddress;
@@ -110,5 +110,6 @@ impl Mapper {
         p1[page.p1_index()].set_unused();
         tlb::flush(VirtualAddress(page.start_address()));
         // TODO free p(1,2,3) table if empty
+        frame
     }
 }

src/arch/x86_64/paging/mod.rs

@@ -185,6 +185,7 @@ impl InactivePageTable {
 
 impl Drop for InactivePageTable {
     fn drop(&mut self) {
-        warn!("PageTable dropped: {:?}", self);
+        info!("PageTable dropping: {:?}", self);
+        dealloc_frame(self.p4_frame.clone());
     }
 }

src/arch/x86_64/paging/temporary_page.rs

@@ -25,7 +25,7 @@ impl TemporaryPage {
     }
 
     /// Unmaps the temporary page in the active table.
-    pub fn unmap(&self, active_table: &mut ActivePageTable) {
+    pub fn unmap(&self, active_table: &mut ActivePageTable) -> Frame {
         active_table.unmap(self.page)
     }
 

src/memory/memory_set.rs

@@ -67,7 +67,7 @@ impl MemoryArea {
             Some(phys_start) => {
                 for page in Page::range_of(self.start_addr, self.end_addr) {
                     let frame = Frame::of_addr(phys_start.get() + page.start_address() - self.start_addr);
-                    pt.map_to(page, frame.clone(), self.flags.0);
+                    pt.map_to(page, frame, self.flags.0);
                 }
             }
             None => {
@@ -79,7 +79,10 @@ impl MemoryArea {
     }
     fn unmap(&self, pt: &mut Mapper) {
         for page in Page::range_of(self.start_addr, self.end_addr) {
-            pt.unmap(page);
+            let frame = pt.unmap(page);
+            if self.phys_start_addr.is_none() {
+                dealloc_frame(frame);
+            }
         }
     }
 }

src/memory/mod.rs

@@ -22,8 +22,14 @@ lazy_static! {
 static STACK_ALLOCATOR: Mutex<Option<StackAllocator>> = Mutex::new(None);
 
 pub fn alloc_frame() -> Frame {
-    FRAME_ALLOCATOR.lock()
-        .allocate_frame().expect("no more frame")
+    let frame = FRAME_ALLOCATOR.lock().allocate_frame().expect("no more frame");
+    trace!("alloc: {:?}", frame);
+    frame
+}
+
+pub fn dealloc_frame(frame: Frame) {
+    trace!("dealloc: {:?}", frame);
+    FRAME_ALLOCATOR.lock().deallocate_frame(frame);
 }
 
 fn alloc_stack(size_in_pages: usize) -> Stack {