A dubious percpu class

ddfb7b66 · Silas Boyd-Wickizer · b6be0a0f · ddfb7b66 · ddfb7b66
--- a/include/percpu.hh
+++ b/include/percpu.hh
+struct pad {
+  __padout__;
+} __mpalign__;
+
+template <typename T>
+struct percpu {
+  int myid() {
+    return mycpu()->id;
+  }
+
+  const T* operator->() const {
+    return cpu(myid());
+  }
+
+  T* operator->() {
+    return cpu(myid());
+  }
+
+  T& operator[](int id) { 
+    return *cpu(id);
+  }
+
+  const T& operator[](int id) const { 
+    return *cpu(id);
+  }
+
+  T* cpu(int id) {
+    return &v_[id];
+  }
+
+  T v_[NCPU] __mpalign__;
+};
--- a/kernel/idle.cc
+++ b/kernel/idle.cc
@@ -6,16 +6,17 @@
 #include "proc.hh"
 #include "cpu.hh"
 #include "sched.hh"
+#include "percpu.hh"

 // XXX(sbw) these should be padded out
-struct idle {
+struct idle : public pad {
  struct proc *cur;
  struct proc *heir;
  SLIST_HEAD(zombies, proc) zombies;
  struct spinlock lock;
 };

-struct idle idlem[NCPU] __mpalign__;
+static percpu<idle> idlem;

 struct proc * idlep[NCPU] __mpalign__;