Messages in this thread Patch in this message | | | From | ira.weiny@intel ... | Subject | [PATCH V8 01/44] entry: Create an internal irqentry_exit_cond_resched() call | Date | Thu, 27 Jan 2022 09:54:22 -0800 |
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From: Ira Weiny <ira.weiny@intel.com>
The call to irqentry_exit_cond_resched() was not properly being overridden when called from xen_pv_evtchn_do_upcall().
Define __irqentry_exit_cond_resched() as the static call and place the override logic in irqentry_exit_cond_resched().
Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
--- Because this was found via code inspection and it does not actually fix any seen bug I've not added a fixes tag.
But for reference: Fixes: 40607ee97e4e ("preempt/dynamic: Provide irqentry_exit_cond_resched() static call") --- include/linux/entry-common.h | 5 ++++- kernel/entry/common.c | 23 +++++++++++++-------- kernel/sched/core.c | 40 ++++++++++++++++++------------------ 3 files changed, 38 insertions(+), 30 deletions(-)
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index 2e2b8d6140ed..ddaffc983e62 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -455,10 +455,13 @@ irqentry_state_t noinstr irqentry_enter(struct pt_regs *regs); * Conditional reschedule with additional sanity checks. */ void irqentry_exit_cond_resched(void); + +void __irqentry_exit_cond_resched(void); #ifdef CONFIG_PREEMPT_DYNAMIC -DECLARE_STATIC_CALL(irqentry_exit_cond_resched, irqentry_exit_cond_resched); +DECLARE_STATIC_CALL(__irqentry_exit_cond_resched, __irqentry_exit_cond_resched); #endif + /** * irqentry_exit - Handle return from exception that used irqentry_enter() * @regs: Pointer to pt_regs (exception entry regs) diff --git a/kernel/entry/common.c b/kernel/entry/common.c index bad713684c2e..490442a48332 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -380,7 +380,7 @@ noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs) return ret; } -void irqentry_exit_cond_resched(void) +void __irqentry_exit_cond_resched(void) { if (!preempt_count()) { /* Sanity check RCU and thread stack */ @@ -392,9 +392,20 @@ void irqentry_exit_cond_resched(void) } } #ifdef CONFIG_PREEMPT_DYNAMIC -DEFINE_STATIC_CALL(irqentry_exit_cond_resched, irqentry_exit_cond_resched); +DEFINE_STATIC_CALL(__irqentry_exit_cond_resched, __irqentry_exit_cond_resched); #endif +void irqentry_exit_cond_resched(void) +{ + if (IS_ENABLED(CONFIG_PREEMPTION)) { +#ifdef CONFIG_PREEMPT_DYNAMIC + static_call(__irqentry_exit_cond_resched)(); +#else + __irqentry_exit_cond_resched(); +#endif + } +} + noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state) { lockdep_assert_irqs_disabled(); @@ -420,13 +431,7 @@ noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state) } instrumentation_begin(); - if (IS_ENABLED(CONFIG_PREEMPTION)) { -#ifdef CONFIG_PREEMPT_DYNAMIC - static_call(irqentry_exit_cond_resched)(); -#else - irqentry_exit_cond_resched(); -#endif - } + irqentry_exit_cond_resched(); /* Covers both tracing and lockdep */ trace_hardirqs_on(); instrumentation_end(); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 848eaa0efe0e..7197c33beb39 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6562,29 +6562,29 @@ EXPORT_STATIC_CALL_TRAMP(preempt_schedule_notrace); * SC:might_resched * SC:preempt_schedule * SC:preempt_schedule_notrace - * SC:irqentry_exit_cond_resched + * SC:__irqentry_exit_cond_resched * * * NONE: - * cond_resched <- __cond_resched - * might_resched <- RET0 - * preempt_schedule <- NOP - * preempt_schedule_notrace <- NOP - * irqentry_exit_cond_resched <- NOP + * cond_resched <- __cond_resched + * might_resched <- RET0 + * preempt_schedule <- NOP + * preempt_schedule_notrace <- NOP + * __irqentry_exit_cond_resched <- NOP * * VOLUNTARY: - * cond_resched <- __cond_resched - * might_resched <- __cond_resched - * preempt_schedule <- NOP - * preempt_schedule_notrace <- NOP - * irqentry_exit_cond_resched <- NOP + * cond_resched <- __cond_resched + * might_resched <- __cond_resched + * preempt_schedule <- NOP + * preempt_schedule_notrace <- NOP + * __irqentry_exit_cond_resched <- NOP * * FULL: - * cond_resched <- RET0 - * might_resched <- RET0 - * preempt_schedule <- preempt_schedule - * preempt_schedule_notrace <- preempt_schedule_notrace - * irqentry_exit_cond_resched <- irqentry_exit_cond_resched + * cond_resched <- RET0 + * might_resched <- RET0 + * preempt_schedule <- preempt_schedule + * preempt_schedule_notrace <- preempt_schedule_notrace + * __irqentry_exit_cond_resched <- __irqentry_exit_cond_resched */ enum { @@ -6620,7 +6620,7 @@ void sched_dynamic_update(int mode) static_call_update(might_resched, __cond_resched); static_call_update(preempt_schedule, __preempt_schedule_func); static_call_update(preempt_schedule_notrace, __preempt_schedule_notrace_func); - static_call_update(irqentry_exit_cond_resched, irqentry_exit_cond_resched); + static_call_update(__irqentry_exit_cond_resched, __irqentry_exit_cond_resched); switch (mode) { case preempt_dynamic_none: @@ -6628,7 +6628,7 @@ void sched_dynamic_update(int mode) static_call_update(might_resched, (void *)&__static_call_return0); static_call_update(preempt_schedule, NULL); static_call_update(preempt_schedule_notrace, NULL); - static_call_update(irqentry_exit_cond_resched, NULL); + static_call_update(__irqentry_exit_cond_resched, NULL); pr_info("Dynamic Preempt: none\n"); break; @@ -6637,7 +6637,7 @@ void sched_dynamic_update(int mode) static_call_update(might_resched, __cond_resched); static_call_update(preempt_schedule, NULL); static_call_update(preempt_schedule_notrace, NULL); - static_call_update(irqentry_exit_cond_resched, NULL); + static_call_update(__irqentry_exit_cond_resched, NULL); pr_info("Dynamic Preempt: voluntary\n"); break; @@ -6646,7 +6646,7 @@ void sched_dynamic_update(int mode) static_call_update(might_resched, (void *)&__static_call_return0); static_call_update(preempt_schedule, __preempt_schedule_func); static_call_update(preempt_schedule_notrace, __preempt_schedule_notrace_func); - static_call_update(irqentry_exit_cond_resched, irqentry_exit_cond_resched); + static_call_update(__irqentry_exit_cond_resched, __irqentry_exit_cond_resched); pr_info("Dynamic Preempt: full\n"); break; } -- 2.31.1
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