Re: [RFC][PATCH] Runtime switching of the idle function [take 2]

[Andrew Morton]

Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>
> This patch creates a directory in /sys/kernel called idle.
>

At no point do you appear to explain _why_ the kernel needs this feature?

> ...
> -		pm_idle = pm_idle_save;
> +		int tries = 0;
> +		int ret;
> +		set_idle(NULL);
> +		do {
> +			if ((ret = unregister_idle(PM_IDLE_NAME)) == 0)
> +				break;
> +			/*
> +			 * for some reason the idle function is being used.
> +			 * Wait a little and then try again.
> +			 */
> +			if (ret == -EINVAL) {
> +				printk(KERN_WARNING
> +				       "ACPI idle function never registered?\n");
> +				break;
> +			}
> +			yield();
> +		} while (tries++ < 10);

The use of yield() could be problematic - its semantics are rather
ill-defined.  Maybe msleep(1) or something?

What's this loop here for anyway?  Looks kludgy.

> +		if (tries > 10) {
> +			printk(KERN_WARNING
> +			       "Unable to unresgister ACPI idle function\n");

tpyo

> +	memset(&idle_kobj, 0, sizeof(idle_kobj));

There are several memsets of statically allocated structures which are
already all-zero.

-
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