1 files changed, 45 insertions, 18 deletions

diff --git a/sys/vm/vm_physmem.c b/sys/vm/vm_physmem.c
index c7fcedb..89f9ee6 100644
--- a/sys/vm/vm_physmem.c
+++ b/sys/vm/vm_physmem.c
@@ -36,11 +36,12 @@
 #include <vm/vm.h>
 #include <string.h>
 
-size_t highest_frame_idx = 0;
-size_t bitmap_size = 0;
-size_t bitmap_free_start = 0;
+static size_t highest_frame_idx = 0;
+static size_t bitmap_size = 0;
+static size_t bitmap_free_start = 0;
+static ssize_t last_idx = 0;
 
-uint8_t *bitmap;
+static uint8_t *bitmap;
 static struct limine_memmap_response *resp = NULL;
 static struct spinlock lock = {0};
 
@@ -137,27 +138,51 @@ physmem_init_bitmap(void)
  *
  * @count: Number of frames to allocate.
  */
-uintptr_t
-vm_alloc_frame(size_t count)
+static uintptr_t
+__vm_alloc_frame(size_t count)
 {
     size_t frames = 0;
+    ssize_t idx = -1;
     uintptr_t ret = 0;
 
-    spinlock_acquire(&lock);
-    for (size_t i = 0; i < highest_frame_idx; ++i) {
+    for (size_t i = last_idx; i < highest_frame_idx; ++i) {
         if (!testbit(bitmap, i)) {
-            /* We have a free page */
-            if (++frames != count) {
-                continue;
-            }
+            if (idx < 0)
+                idx = i;
+            if (++frames >= count)
+                break;
 
-            for (size_t j = i; j < i + count; ++j) {
-                setbit(bitmap, j);
-            }
-
-            ret = i * DEFAULT_PAGESIZE;
-            break;
+            continue;
         }
+
+        idx = -1;
+        frames = 0;
+    }
+
+    if (idx < 0 || frames != count) {
+        ret = 0;
+        goto done;
+    }
+
+    for (size_t i = idx; i < idx + count; ++i) {
+        setbit(bitmap, i);
+    }
+    ret = idx * DEFAULT_PAGESIZE;
+    last_idx = idx;
+    memset(PHYS_TO_VIRT(ret), 0, count * DEFAULT_PAGESIZE);
+done:
+    return ret;
+}
+
+uintptr_t
+vm_alloc_frame(size_t count)
+{
+    uintptr_t ret;
+
+    spinlock_acquire(&lock);
+    if ((ret = __vm_alloc_frame(count)) == 0) {
+        last_idx = 0;
+        ret = __vm_alloc_frame(count);
     }
 
     spinlock_release(&lock);
@@ -169,6 +194,8 @@ vm_free_frame(uintptr_t base, size_t count)
 {
     size_t stop_at = base + (count * DEFAULT_PAGESIZE);
 
+    base = ALIGN_UP(base, DEFAULT_PAGESIZE);
+
     spinlock_acquire(&lock);
     for (uintptr_t p = base; p < stop_at; p += DEFAULT_PAGESIZE) {
         clrbit(bitmap, p / DEFAULT_PAGESIZE);