diff --git a/kernel/proc.c b/kernel/proc.c
index 46ac128..0655783 100644
--- a/kernel/proc.c
+++ b/kernel/proc.c
@@ -64,8 +64,10 @@ allocpid() {
   int pid;
   
   acquire(&pid_lock);
-  pid = nextpid++;
+  pid = nextpid;
+  nextpid = nextpid + 1;
   release(&pid_lock);
+
   return pid;
 }
 
diff --git a/kernel/spinlock.c b/kernel/spinlock.c
index 5a44a46..52bd504 100644
--- a/kernel/spinlock.c
+++ b/kernel/spinlock.c
@@ -18,8 +18,6 @@ initlock(struct spinlock *lk, char *name)
 
 // Acquire the lock.
 // Loops (spins) until the lock is acquired.
-// Holding a lock for a long time may cause
-// other CPUs to waste time spinning to acquire it.
 void
 acquire(struct spinlock *lk)
 {
@@ -81,7 +79,7 @@ holding(struct spinlock *lk)
 }
 
 // push_off/pop_off are like intr_off()/intr_on() except that they are matched:
-// it takes two pop_off to undo two push_off.  Also, if interrupts
+// it takes two pop_off()s to undo two push_off()s.  Also, if interrupts
 // are initially off, then push_off, pop_off leaves them off.
 
 void
diff --git a/kernel/spinlock.h b/kernel/spinlock.h
index 5f244c9..4392820 100644
--- a/kernel/spinlock.h
+++ b/kernel/spinlock.h
@@ -5,7 +5,5 @@ struct spinlock {
   // For debugging:
   char *name;        // Name of lock.
   struct cpu *cpu;   // The cpu holding the lock.
-  struct cpu *last_release;
-  uint64 last_pc;
 };