Messages in this thread | | | Date | Thu, 3 Feb 2022 12:52:18 +0100 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 2/6] sched/preempt: refactor sched_dynamic_update() |
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On Wed, Feb 02, 2022 at 06:08:27PM +0000, Mark Rutland wrote: > On Wed, Feb 02, 2022 at 05:01:44PM +0100, Frederic Weisbecker wrote: > > On Wed, Feb 02, 2022 at 03:13:57PM +0000, Mark Rutland wrote: > > > > > +#define preempt_schedule_notrace_dynamic_enabled preempt_schedule_notrace_thunk > > > > > +#define preempt_schedule_notrace_dynamic_disabled NULL > > > > > > > > I'm worried about un-greppable macro definitions like this. > > > I assume you mean that it's hard to go from: > > > > > > preempt_dynamic_enable(preempt_schedule_notrace); > > > > > > ... to this, because the `_dynamic_enabled` or `_dynamic_disabled` part gets > > > token-pasted on? > > > > Right. > > Looking at this some more, I'm probably going to need to do token-pasting at > some level no matter what we do, so how big of a concern is this? Searching > for 'foo_function' should also find 'foo_function_dynamic_enabled' and > 'foo_function_dynamic_disabled', and searching for either of those will find > their original definition. > > If others aren't concerned, could we just live with that for now?
Sure, I don't have a better idea right now. I'll try to think of something after the next iteration.
> > I was hoping to make a default backend based on static keys to implement these > > toggeable static calls, but I had some issues on the way, although I can't > > remember exactly which. > > > > So eventually I don't know if this stuff will be useful for you.... > > Having had a play with this, since you need to generate a wrapper for the > static_key case, you either need to match the prototype or have a generic > macro (and you likely end up back in token-pasting hell again anyhow). > > So as above, how much does this matter for now? > > > Well, I guess this can still ease a wrapper like: > > > > preempt_dynamic_enable(sym) > > ---> CONFIG_STATIC_CALL=y? -----> static_call_enable(sym) > > else > > ---> CONFIG_STATIC_KEY=y? -----> static_key_enable(sym) > > In this series I just define preempt_dynamic_enable() dependent on > CONFIG_STATIC_CALL or CONFIG_STATIC_KEY, which is functionally equivalent.
You're right.
It's just that instead of:
#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) #ifndef preempt_schedule_notrace_dynamic_enabled #define preempt_schedule_notrace_dynamic_enabled preempt_schedule_notrace #define preempt_schedule_notrace_dynamic_disabled NULL #endif
#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) #define preempt_dynamic_enable(f) static_call_update(f, f##_dynamic_enabled) #define preempt_dynamic_disable(f) static_call_update(f, #f##_dynamic_disabled)
You have:
DECLARE_STATIC_CALL_TOGGLE(preempt_schedule_notrace, __preempt_schedule_notrace_func);
#define preempt_dynamic_enable(f) static_call_enable(f) #define preempt_dynamic_disable(f) static_call_disable(f)
Thanks.
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