Merge branch 'idle-cleanup' into scale-amd64

bc7ecffc · Silas Boyd-Wickizer · c62bb255 · 7af6576f · bc7ecffc · bc7ecffc
--- a/include/kernel.hh
+++ b/include/kernel.hh
@@ -126,7 +126,7 @@ void            ideintr(void);
 void            iderw(struct buf*);

 // idle.cc
-extern struct proc *idlep[NCPU];
+struct proc *   idleproc(void);

 // ioapic.c
 void            ioapicenable(int irq, int cpu);

--- a/include/lockstat.h
+++ b/include/lockstat.h
@@ -47,6 +47,7 @@ struct klockstat;
 #define LOCKSTAT_CRANGE    1
 #define LOCKSTAT_FS        1
 #define LOCKSTAT_GC        1
+#define LOCKSTAT_IDLE      1
 #define LOCKSTAT_KALLOC    1
 #define LOCKSTAT_KMALLOC   1
 #define LOCKSTAT_NET       1

--- a/kernel/async.cc
+++ b/kernel/async.cc
@@ -92,3 +92,4 @@ sys_async(int fd, size_t count, off_t off,
  msg->submitted = 1;
  return 0;
 }
+
--- a/kernel/idle.cc
+++ b/kernel/idle.cc
@@ -7,11 +7,60 @@
 #include "cpu.hh"
 #include "sched.hh"

-struct proc *idlep[NCPU] __mpalign__;
+// XXX(sbw) these should be padded out
+struct proc * idlep[NCPU] __mpalign__;
+
+struct heir {
+  struct proc *proc;
+  __padout__;
+} __mpalign__;
+
+struct heir heir[NCPU] __mpalign__;
+
+void idleloop(void);
+
+struct proc *
+idleproc(void)
+{
+  assert(mycpu()->ncli > 0);
+  return idlep[mycpu()->id];
+}
+
+void
+idlebequeath(void)
+{
+  // Only the current idle thread may call this function
+  struct heir *h;
+
+  assert(mycpu()->ncli > 0);
+  assert(myproc() == idlep[mycpu()->id]);
+
+  h = &heir[mycpu()->id];
+  assert(h->proc != nullptr);
+
+  idlep[mycpu()->id] = h->proc;
+  acquire(&h->proc->lock);
+  h->proc->set_state(RUNNABLE);
+  release(&h->proc->lock);
+}
+
+
+static void
+idleheir(void *x)
+{
+  post_swtch();
+
+  heir[mycpu()->id].proc = nullptr;
+  idleloop();
+}

 void
 idleloop(void)
 {
+  struct heir *h;
+
+  h = &heir[mycpu()->id];
+
  // Test the work queue
  //extern void testwq(void);
  //testwq();
@@ -33,7 +82,25 @@ idleloop(void)
      int worked;
      do {
        assert(mycpu()->ncli == 0);
+
+        // If we don't have an heir, try to allocate one
+        if (h->proc == nullptr) {
+          struct proc *p;
+          p = allocproc();
+          if (p == nullptr)
+            break;
+          snprintf(p->name, sizeof(p->name), "idleh_%u", mycpu()->id);          
+          p->cpuid = mycpu()->id;
+          p->cpu_pin = 1;
+          p->context->rip = (u64)idleheir;
+          p->cwd = nullptr;
+          h->proc = p;
+        }
+
        worked = wq_trywork();
+        // If we are no longer the idle thread, exit
+        if (worked && idlep[mycpu()->id] != myproc())
+          exit();
      } while(worked);
      sti();
    }
@@ -43,13 +110,13 @@ idleloop(void)
 void
 initidle(void)
 {
-  // allocate a fake PID for each scheduler thread
  struct proc *p = allocproc();
  if (!p)
    panic("initidle allocproc");

  snprintf(p->name, sizeof(p->name), "idle_%u", cpunum());
  mycpu()->proc = p;
+  myproc()->cpuid = cpunum();
  myproc()->cpu_pin = 1;
  idlep[cpunum()] = p;
 }
--- a/kernel/sched.cc
+++ b/kernel/sched.cc
@@ -26,7 +26,7 @@ void
 post_swtch(void)
 {
  if (mycpu()->prev->get_state() == RUNNABLE && 
-      mycpu()->prev != idlep[mycpu()->id])
+      mycpu()->prev != idleproc())
    addrun(mycpu()->prev);
  release(&mycpu()->prev->lock);
 }
@@ -42,6 +42,11 @@ sched(void)
  if(!holding(&myproc()->lock))
    panic("sched proc->lock");
 #endif
+  if (myproc() == idleproc() && 
+      myproc()->get_state() != RUNNABLE) {
+    extern void idlebequeath(void);
+    idlebequeath();
+  }
  if(mycpu()->ncli != 1)
    panic("sched locks");
  if(myproc()->get_state() == RUNNING)
@@ -59,7 +64,7 @@ sched(void)
  struct proc *next = schednext();
  if (next == nullptr) {
    if (myproc()->get_state() != RUNNABLE) {
-      next = idlep[mycpu()->id];
+      next = idleproc();
    } else {
      myproc()->set_state(RUNNING);
      mycpu()->intena = intena;

--- a/kernel/wq.cc
+++ b/kernel/wq.cc
@@ -175,11 +175,11 @@ wq_trywork(void)
  struct work *w;
  int i;

-  pushcli();
+  //pushcli();
  w = __wq_pop(mycpu()->id);
  if (w != nullptr) {
    __wq_run(w);
-    popcli();
+    //popcli();
    return 1;
  }
  // XXX(sbw) should be random
@@ -190,12 +190,12 @@ wq_trywork(void)
    w = __wq_steal(i);
    if (w != nullptr) {
      __wq_run(w);
-      popcli();
+      //popcli();
      return 1;
    }
  }

-  popcli();
+  //popcli();
  return 0;
 }