Memory allocator ok

kernel/kalloc.c

@@ -19,14 +19,19 @@ struct run {
 };
 
 struct {
-  struct spinlock lock;
-  struct run *freelist;
+  struct spinlock lock[NCPU];
+  struct run *freelist[NCPU];
 } kmem;
 
+static char kmem_lock_names [NCPU][10]; // ugly but have-to impl
+
 void
 kinit()
 {
-  initlock(&kmem.lock, "kmem");
+  for (int i = 0; i < NCPU; ++ i) {
+    snprintf(kmem_lock_names[i], NELEM(kmem_lock_names[0]), "kmem%d", i);
+    initlock(&kmem.lock[i], kmem_lock_names[i]);
+  }
   freerange(end, (void*)PHYSTOP);
 }
 
@@ -55,11 +60,13 @@ kfree(void *pa)
   memset(pa, 1, PGSIZE);
 
   r = (struct run*)pa;
-
-  acquire(&kmem.lock);
-  r->next = kmem.freelist;
-  kmem.freelist = r;
-  release(&kmem.lock);
+  push_off();
+  int _cpu = cpuid();
+  acquire(&kmem.lock[_cpu]);
+  r->next = kmem.freelist[_cpu];
+  kmem.freelist[_cpu] = r;
+  release(&kmem.lock[_cpu]);
+  pop_off();
 }
 
 // Allocate one 4096-byte page of physical memory.
@@ -69,13 +76,27 @@ void *
 kalloc(void)
 {
   struct run *r;
-
-  acquire(&kmem.lock);
-  r = kmem.freelist;
+  push_off();
+  int _cpu = cpuid();
+  acquire(&kmem.lock[_cpu]);
+  r = kmem.freelist[_cpu];
   if(r)
-    kmem.freelist = r->next;
-  release(&kmem.lock);
-
+    kmem.freelist[_cpu] = r->next;
+  else {
+    for (int i = 0, found = 0; i < NCPU && !found; ++ i) {
+      if (i != _cpu) {
+        acquire(&kmem.lock[i]);
+        if (kmem.freelist[i]) {
+          r = kmem.freelist[i];
+          kmem.freelist[i] = r->next;
+          found = 1;
+        }
+        release(&kmem.lock[i]);
+      }
+    }
+  }
+  release(&kmem.lock[_cpu]);
+  pop_off();
   if(r)
     memset((char*)r, 5, PGSIZE); // fill with junk
   return (void*)r;