diff options
| author | Andi Kleen | 2006-09-26 10:52:40 +0200 |
|---|---|---|
| committer | Andi Kleen | 2006-09-26 10:52:40 +0200 |
| commit | a15da49debaf7f09460a886b0ecd08588410715e (patch) | |
| tree | 685ed022695ff03cec167c6690815e08191a803c | |
| parent | [PATCH] Remove experimental mark of kexec (diff) | |
| download | kernel-qcow2-linux-a15da49debaf7f09460a886b0ecd08588410715e.tar.gz kernel-qcow2-linux-a15da49debaf7f09460a886b0ecd08588410715e.tar.xz kernel-qcow2-linux-a15da49debaf7f09460a886b0ecd08588410715e.zip | |
[PATCH] Fix idle notifiers
Previously exit_idle would be called more often than enter_idle
Now instead of using complicated tests just keep track of it
using the per CPU variable as a flip flop. I moved the idle state into the
PDA to make the access more efficient.
Original bug report and an initial patch from Stephane Eranian,
but redone by AK.
Cc: Stephane Eranian <eranian@hpl.hp.com>
Signed-off-by: Andi Kleen <ak@suse.de>
| -rw-r--r-- | arch/x86_64/kernel/process.c | 15 | ||||
| -rw-r--r-- | include/asm-x86_64/pda.h | 3 |
2 files changed, 11 insertions, 7 deletions
diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c index 885c318f76ab..458006ae19f3 100644 --- a/arch/x86_64/kernel/process.c +++ b/arch/x86_64/kernel/process.c @@ -80,25 +80,25 @@ void idle_notifier_unregister(struct notifier_block *n) } EXPORT_SYMBOL(idle_notifier_unregister); -enum idle_state { CPU_IDLE, CPU_NOT_IDLE }; -static DEFINE_PER_CPU(enum idle_state, idle_state) = CPU_NOT_IDLE; - void enter_idle(void) { - __get_cpu_var(idle_state) = CPU_IDLE; + write_pda(isidle, 1); atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL); } static void __exit_idle(void) { - __get_cpu_var(idle_state) = CPU_NOT_IDLE; + if (read_pda(isidle) == 0) + return; + write_pda(isidle, 0); atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL); } /* Called from interrupts to signify idle end */ void exit_idle(void) { - if (current->pid | read_pda(irqcount)) + /* idle loop has pid 0 */ + if (current->pid) return; __exit_idle(); } @@ -220,6 +220,9 @@ void cpu_idle (void) play_dead(); enter_idle(); idle(); + /* In many cases the interrupt that ended idle + has already called exit_idle. But some idle + loops can be woken up without interrupt. */ __exit_idle(); } diff --git a/include/asm-x86_64/pda.h b/include/asm-x86_64/pda.h index 531f48a6c3af..14996d962bac 100644 --- a/include/asm-x86_64/pda.h +++ b/include/asm-x86_64/pda.h @@ -25,7 +25,8 @@ struct x8664_pda { int nodenumber; /* number of current node */ unsigned int __softirq_pending; unsigned int __nmi_count; /* number of NMI on this CPUs */ - int mmu_state; + short mmu_state; + short isidle; struct mm_struct *active_mm; unsigned apic_timer_irqs; } ____cacheline_aligned_in_smp; |