Add memory information

arch/x86_64/src/memory/area_frame_allocator.rs

@@ -43,6 +43,48 @@ impl AreaFrameAllocator {
 }
 
 impl FrameAllocator for AreaFrameAllocator {
+    fn free_frames(&self) -> usize {
+        let mut count = 0;
+
+        for area in self.areas.clone() {
+            let start_frame = Frame::containing_address(PhysicalAddress::new(area.base_addr as usize));
+            let end_frame = Frame::containing_address(PhysicalAddress::new((area.base_addr + area.length - 1) as usize));
+            for frame in Frame::range_inclusive(start_frame, end_frame) {
+                if frame >= self.kernel_start && frame <= self.kernel_end {
+                    // Inside of kernel range
+                } else if frame >= self.next_free_frame {
+                    // Frame is in free range
+                    count += 1;
+                } else {
+                    // Inside of used range
+                }
+            }
+        }
+
+        count
+    }
+
+    fn used_frames(&self) -> usize {
+        let mut count = 0;
+
+        for area in self.areas.clone() {
+            let start_frame = Frame::containing_address(PhysicalAddress::new(area.base_addr as usize));
+            let end_frame = Frame::containing_address(PhysicalAddress::new((area.base_addr + area.length - 1) as usize));
+            for frame in Frame::range_inclusive(start_frame, end_frame) {
+                if frame >= self.kernel_start && frame <= self.kernel_end {
+                    // Inside of kernel range
+                    count += 1
+                } else if frame >= self.next_free_frame {
+                    // Frame is in free range
+                } else {
+                    count += 1;
+                }
+            }
+        }
+
+        count
+    }
+
     fn allocate_frames(&mut self, count: usize) -> Option<Frame> {
         if count == 0 {
             None

arch/x86_64/src/memory/mod.rs

@@ -90,6 +90,24 @@ pub fn deallocate_frame(frame: Frame) {
     deallocate_frames(frame, 1)
 }
 
+/// Get the number of frames available
+pub fn free_frames() -> usize {
+    if let Some(ref allocator) = *ALLOCATOR.lock() {
+        allocator.free_frames()
+    } else {
+        panic!("frame allocator not initialized");
+    }
+}
+
+/// Get the number of frames used
+pub fn used_frames() -> usize {
+    if let Some(ref allocator) = *ALLOCATOR.lock() {
+        allocator.used_frames()
+    } else {
+        panic!("frame allocator not initialized");
+    }
+}
+
 /// Allocate a range of frames
 pub fn allocate_frames(count: usize) -> Option<Frame> {
     if let Some(ref mut allocator) = *ALLOCATOR.lock() {
@@ -164,6 +182,8 @@ impl Iterator for FrameIter {
 }
 
 pub trait FrameAllocator {
+    fn free_frames(&self) -> usize;
+    fn used_frames(&self) -> usize;
     fn allocate_frames(&mut self, size: usize) -> Option<Frame>;
     fn deallocate_frames(&mut self, frame: Frame, size: usize);
 }