continuous quality management

asm.h

@@ -1,5 +1,5 @@
 //
-// macros to create x86 segments from assembler
+// assembler macros to create x86 segments
 //
 
 #define SEG_NULLASM                                             \

spinlock.c

@@ -20,8 +20,8 @@ initlock(struct spinlock *lock, char *name)
 
 // Acquire the lock.
 // Loops (spins) until the lock is acquired.
-// (Because contention is handled by spinning,
-// must not go to sleep holding any locks.)
+// Holding a lock for a long time may cause
+// other CPUs to waste time spinning to acquire it.
 void
 acquire(struct spinlock *lock)
 {

x86.h

@@ -1,5 +1,4 @@
-// Special assembly routines to access x86-specific
-// hardware instructions.
+// Routines to let C code use special x86 instructions.
 
 static inline uchar
 inb(ushort port)
@@ -131,7 +130,8 @@ sti(void)
   asm volatile("sti");
 }
 
-// Layout of the trap frame on the stack upon entry to trap.
+// Layout of the trap frame built on the stack by the
+// hardware and by trapasm.S, and passed to trap().
 struct trapframe {
   // registers as pushed by pusha
   uint edi;