Mem: Get the numbe of pages that are free

corigan01 · Jan 19, 2025 · 7916a7f · 7916a7f
1 parent 1436b6e
commit 7916a7f
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Showing 3 changed files with 39 additions and 1 deletion.
diff --git a/crates/mem/src/pmm.rs b/crates/mem/src/pmm.rs
@@ -109,4 +109,8 @@ impl Pmm {
     pub fn free_page(&mut self, page: PhysPage) -> Result<(), MemoryError> {
         self.table.free_page(page)
     }
+
+    pub fn pages_free(&self) -> Result<usize, MemoryError> {
+        self.table.pages_free()
+    }
 }
diff --git a/crates/mem/src/pmm/backing.rs b/crates/mem/src/pmm/backing.rs
@@ -110,6 +110,8 @@ pub trait TableImpl: Sized {
         page: PhysPage,
         el_size: usize,
     ) -> Result<AllocationResult, MemoryError>;
+
+    fn pages_free(&self, el_size: usize) -> Result<usize, MemoryError>;
 }
 
 #[derive(Clone)]
@@ -157,6 +159,11 @@ impl<Table: TableImpl> MemoryTable<Table> {
     pub fn free_page(&mut self, page: PhysPage) -> Result<(), MemoryError> {
         self.table.free_page(page, self.element_size).map(|_| ())
     }
+
+    #[inline]
+    pub fn pages_free(&self) -> Result<usize, MemoryError> {
+        self.table.pages_free(self.element_size)
+    }
 }
 
 impl TableImpl for TableFlat {
@@ -380,6 +387,22 @@ impl TableImpl for TableFlat {
             new_size: self.healthy_tables.max(self.dirty_tables.min(1)),
         })
     }
+
+    fn pages_free(&self, el_size: usize) -> Result<usize, MemoryError> {
+        self.table.iter().try_fold(0, |acc, el| {
+            Ok(acc
+                + match el {
+                    TableElementKind::NotAllocated => 0,
+                    TableElementKind::Present => el_size / PAGE_4K,
+                    TableElementKind::TableFlat { ptr, .. } => {
+                        unsafe { ptr.as_ref() }.pages_free()?
+                    }
+                    TableElementKind::TableBits { ptr, .. } => {
+                        unsafe { ptr.as_ref() }.pages_free()?
+                    }
+                })
+        })
+    }
 }
 
 impl TableImpl for TableBits {
@@ -457,6 +480,10 @@ impl TableImpl for TableBits {
             new_size: self.atom_size,
         })
     }
+
+    fn pages_free(&self, el_size: usize) -> Result<usize, MemoryError> {
+        Ok(self.atom_size * (el_size / PAGE_4K))
+    }
 }
 
 #[cfg(test)]

diff --git a/kernel/src/main.rs b/kernel/src/main.rs
@@ -47,7 +47,7 @@ use mem::{
 use scheduler::Scheduler;
 use serial::{Serial, baud::SerialBaud};
 use timer::kernel_ticks;
-use util::bytes::HumanBytes;
+use util::{bytes::HumanBytes, consts::PAGE_4K};
 
 #[global_allocator]
 static ALLOC: KernelAllocator = KernelAllocator::new();
@@ -90,6 +90,13 @@ fn main(kbh: &KernelBootHeader) {
 
     logln!("Init PhysMemoryManager");
     let pmm = Pmm::new(kbh.phys_mem_map).unwrap();
+    let free_pages = pmm.pages_free().unwrap();
+
+    logln!(
+        "Pages Free {} ({})",
+        free_pages,
+        HumanBytes::from(free_pages * PAGE_4K)
+    );
     mem::pmm::set_physical_memory_manager(pmm);
 
     logln!("Init VirtMemoryManager");