On 03/21/2016 11:42 AM, Peter Zijlstra wrote:
On Wed, Mar 16, 2016 at 01:02:13PM -0400, Chris Metcalf wrote:diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 9f7c21c22477..d569ae7fde37 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -298,7 +298,7 @@ void arch_cpu_idle(void) /* * We use this if we don't have any better idle routine.. */ -void default_idle(void) +void __cpuidle default_idle(void) { trace_cpu_idle_rcuidle(1, smp_processor_id()); safe_halt(); @@ -413,7 +413,7 @@ static int prefer_mwait_c1_over_halt(const struct cpuinfo_x86 *c) * with interrupts enabled and no flags, which is backwards compatible with the * original MWAIT implementation. */ -static void mwait_idle(void) +static __cpuidle void mwait_idle(void) { if (!current_set_polling_and_test()) { trace_cpu_idle_rcuidle(1, smp_processor_id());The most common idle function for x86 is: mwait_idle_with_hints(), trouble is, its an inline, so I'm not sure adding __cpuidle to it does anything.
No, you're right, it wouldn't help. I didn't look at the drivers/cpuidle subsystem at all in my patch, since I'm not that familiar with it, but it seems like tagging acpi_processor_ffh_cstate_enter(), as the only user of mwait_idle_with_hints(), will do the job. I do see that native_play_dead() also uses mwait/monitor, but since that's hotplug I don't think it's relevant to this patch series.
I've yet to find the magic objdump incantation to check. Or rather objdump -h doesn't appear to list .cpuidle.text at all :/ I'm probably doing something silly...
The easiest way to check for a given function is just to look at the "nm -n" output and see that all the functions you expect to reflect idle behavior are in the cpuidle begin/end range. Or, to look at "objdump -dr" and search for monitor/mwait. objdump -h certainly works to show .cpuidle.text if you look at individual objects (e.g. arch/x86/kernel/process.o) but by the time you're looking at the linked vmlinux image they have all been linked into the giant .text section. -- Chris Metcalf, Mellanox Technologies http://www.mellanox.com
