On Wed, Mar 11, 2026 at 09:50:15AM -0300, Wander Lairson Costa wrote:
> +extern void __trace_preempt_on(void);
> +extern void __trace_preempt_off(void);
> +
> +DECLARE_TRACEPOINT(preempt_enable);
> +DECLARE_TRACEPOINT(preempt_disable);
> +
> +#define __preempt_trace_enabled(type, val) \
> + (tracepoint_enabled(preempt_##type) && preempt_count() == (val))
> +
> +static __always_inline void preempt_count_add(int val)
> +{
> + __preempt_count_add(val);
> +
> + if (__preempt_trace_enabled(disable, val))
> + __trace_preempt_off();
> +}
> +
> +static __always_inline void preempt_count_sub(int val)
> +{
> + if (__preempt_trace_enabled(enable, val))
> + __trace_preempt_on();
> +
> + __preempt_count_sub(val);
> +}
> #else
> #define preempt_count_add(val) __preempt_count_add(val)
> #define preempt_count_sub(val) __preempt_count_sub(val)
> #define preempt_count_dec_and_test() __preempt_count_dec_and_test()
> #endif
>
> +#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_TRACE_PREEMPT_TOGGLE)
> +#define preempt_count_dec_and_test() \
> + ({ preempt_count_sub(1); should_resched(0); })
> +#endif
Why!?!
Why can't you simply have:
static __always_inline bool preempt_count_dec_and_test(void)
{
if (__preempt_trace_enabled(enable, 1))
__trace_preempt_on();
return __preempt_count_dec_and_test();
}
Also, given how !x86 architectures were just complaining about how
terrible their preempt_emable() is, I'm really not liking this much at
all.
Currently the x86 preempt_disable() is _1_ instruction and
preempt_enable() is all of 3. Adding in these tracepoints will bloat
every single such site by at least another 4-5.
That's significant bloat, for really very little gain. Realistically
nobody is going to need these.
