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McKenney" , Ingo Molnar , Michal Hocko Subject: Re: [RFC PATCH 6/8] preempt/dynamic: Provide preempt_schedule[_notrace]() static calls Message-ID: <20210121215826.GB16371@worktop.programming.kicks-ass.net> References: <20210118141223.123667-1-frederic@kernel.org> <20210118141223.123667-7-frederic@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210118141223.123667-7-frederic@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 18, 2021 at 03:12:21PM +0100, Frederic Weisbecker wrote: > diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h > index 69485ca13665..3db9cb8b1a25 100644 > --- a/arch/x86/include/asm/preempt.h > +++ b/arch/x86/include/asm/preempt.h > @@ -5,6 +5,7 @@ > #include > #include > #include > +#include > > DECLARE_PER_CPU(int, __preempt_count); > > @@ -103,16 +104,33 @@ static __always_inline bool should_resched(int preempt_offset) > } > > #ifdef CONFIG_PREEMPTION > - extern asmlinkage void preempt_schedule_thunk(void); > -# define __preempt_schedule() \ > - asm volatile ("call preempt_schedule_thunk" : ASM_CALL_CONSTRAINT) > > - extern asmlinkage void preempt_schedule(void); > - extern asmlinkage void preempt_schedule_notrace_thunk(void); > -# define __preempt_schedule_notrace() \ > - asm volatile ("call preempt_schedule_notrace_thunk" : ASM_CALL_CONSTRAINT) > +extern asmlinkage void preempt_schedule(void); > +extern asmlinkage void preempt_schedule_thunk(void); > + > +#define __preempt_schedule_func() preempt_schedule_thunk > + > +DECLARE_STATIC_CALL(preempt_schedule, __preempt_schedule_func()); > + > +#define __preempt_schedule() \ > +do { \ > + __ADDRESSABLE(STATIC_CALL_KEY(preempt_schedule)); \ > + asm volatile ("call " STATIC_CALL_TRAMP_STR(preempt_schedule) : ASM_CALL_CONSTRAINT); \ > +} while (0) > + > +extern asmlinkage void preempt_schedule_notrace(void); > +extern asmlinkage void preempt_schedule_notrace_thunk(void); > + > +#define __preempt_schedule_notrace_func() preempt_schedule_notrace_thunk > + > +DECLARE_STATIC_CALL(preempt_schedule_notrace, __preempt_schedule_notrace_func()); > + > +#define __preempt_schedule_notrace() \ > +do { \ > + __ADDRESSABLE(STATIC_CALL_KEY(preempt_schedule_notrace)); \ > + asm volatile ("call " STATIC_CALL_TRAMP_STR(preempt_schedule_notrace) : ASM_CALL_CONSTRAINT); \ > +} while (0) > > - extern asmlinkage void preempt_schedule_notrace(void); > #endif I'm thinking the above doesn't build for !PREEMPT_DYNAMIC, given it relies on the STATIC_CALL unconditionally, but we only define it for PREEMPT_DYNAMIC: > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index d6de12b4eef2..faff4b546c5f 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -5251,6 +5251,12 @@ asmlinkage __visible void __sched notrace preempt_schedule(void) > NOKPROBE_SYMBOL(preempt_schedule); > EXPORT_SYMBOL(preempt_schedule); > > +#ifdef CONFIG_PREEMPT_DYNAMIC > +DEFINE_STATIC_CALL(preempt_schedule, __preempt_schedule_func()); > +EXPORT_STATIC_CALL(preempt_schedule); > +#endif > + > + > /** > * preempt_schedule_notrace - preempt_schedule called by tracing > * > @@ -5303,6 +5309,12 @@ asmlinkage __visible void __sched notrace preempt_schedule_notrace(void) > } > EXPORT_SYMBOL_GPL(preempt_schedule_notrace); > > +#ifdef CONFIG_PREEMPT_DYNAMIC > +DEFINE_STATIC_CALL(preempt_schedule_notrace, __preempt_schedule_notrace_func()); > +EXPORT_STATIC_CALL(preempt_schedule_notrace); > +#endif > + > + > #endif /* CONFIG_PREEMPTION */ > > /* > -- > 2.25.1 >