tree 0b9dd19406c53a93452dd345bb05f76aa712a757
parent cb4ad1ffc7c0d8ea7dc8cd8ba303d83551716d46
author Ingo Molnar <mingo@elte.hu> 1208935446 +0200
committer Ingo Molnar <mingo@elte.hu> 1210024578 +0200

sched: fix cpu clock

David Miller pointed it out that nothing in cpu_clock() sets
prev_cpu_time. This caused __sync_cpu_clock() to be called
all the time - against the intention of this code.

The result was that in practice we hit a global spinlock every
time cpu_clock() is called - which - even though cpu_clock()
is used for tracing and debugging, is suboptimal.

While at it, also:

- move the irq disabling to the outest layer,
  this should make cpu_clock() warp-free when called with irqs
  enabled.

- use long long instead of cycles_t - for platforms where cycles_t
  is 32-bit.

Reported-by: David Miller <davem@davemloft.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>