Add a fixed-size cache of frame allocation

osdk/deps/frame-allocator/src/lib.rs

@@ -22,11 +22,51 @@
 //! [`GlobalFrameAllocator`]: ostd::mm::GlobalFrameAllocator
 //! [`global_frame_allocator`]: ostd::global_frame_allocator
 
-mod allocator;
+use core::alloc::Layout;
+
+use ostd::{
+    mm::{frame::GlobalFrameAllocator, Paddr},
+    trap,
+};
+
+mod cache;
 mod chunk;
+mod per_cpu_counter;
+mod pools;
 mod set;
 
 #[cfg(ktest)]
 mod test;
 
-pub use allocator::{load_total_free_size, FrameAllocator};
+/// Loads the total size (in bytes) of free memory in the allocator.
+pub fn load_total_free_size() -> usize {
+    per_cpu_counter::read_total_free_size()
+}
+
+/// The global frame allocator provided by OSDK.
+///
+/// It is a singleton that provides frame allocation for the kernel. If
+/// multiple instances of this struct are created, all the member functions
+/// will eventually access the same allocator.
+pub struct FrameAllocator;
+
+impl GlobalFrameAllocator for FrameAllocator {
+    fn alloc(&self, layout: Layout) -> Option<Paddr> {
+        let guard = trap::disable_local();
+        let res = cache::alloc(&guard, layout);
+        if res.is_some() {
+            per_cpu_counter::sub_free_size(&guard, layout.size());
+        }
+        res
+    }
+
+    fn dealloc(&self, addr: Paddr, size: usize) {
+        self.add_free_memory(addr, size);
+    }
+
+    fn add_free_memory(&self, addr: Paddr, size: usize) {
+        let guard = trap::disable_local();
+        per_cpu_counter::add_free_size(&guard, size);
+        cache::add_free_memory(&guard, addr, size);
+    }
+}