The following commit has been merged into the sched/core branch of tip: Commit-ID: 74345075999752a7a9c805fe5e2ec770345cd1ca Gitweb: https://git.kernel.org/tip/74345075999752a7a9c805fe5e2ec770345cd1ca Author: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> AuthorDate: Mon, 18 Jan 2021 15:12:22 +01:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Fri, 05 Feb 2021 17:19:57 +01:00 preempt/dynamic: Provide irqentry_exit_cond_resched() static call Provide static call to control IRQ preemption (called in CONFIG_PREEMPT) so that we can override its behaviour when preempt= is overriden. Since the default behaviour is full preemption, its call is initialized to provide IRQ preemption when preempt= isn't passed. Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Link: https://lkml.kernel.org/r/20210118141223.123667-8-frederic@xxxxxxxxxx --- include/linux/entry-common.h | 4 ++++ kernel/entry/common.c | 10 +++++++++- 2 files changed, 13 insertions(+), 1 deletion(-) diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index ca86a00..1401c93 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -2,6 +2,7 @@ #ifndef __LINUX_ENTRYCOMMON_H #define __LINUX_ENTRYCOMMON_H +#include <linux/static_call_types.h> #include <linux/tracehook.h> #include <linux/syscalls.h> #include <linux/seccomp.h> @@ -453,6 +454,9 @@ irqentry_state_t noinstr irqentry_enter(struct pt_regs *regs); * Conditional reschedule with additional sanity checks. */ void irqentry_exit_cond_resched(void); +#ifdef CONFIG_PREEMPT_DYNAMIC +DECLARE_STATIC_CALL(irqentry_exit_cond_resched, irqentry_exit_cond_resched); +#endif /** * irqentry_exit - Handle return from exception that used irqentry_enter() diff --git a/kernel/entry/common.c b/kernel/entry/common.c index 3783416..84fa7ec 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -393,6 +393,9 @@ void irqentry_exit_cond_resched(void) preempt_schedule_irq(); } } +#ifdef CONFIG_PREEMPT_DYNAMIC +DEFINE_STATIC_CALL(irqentry_exit_cond_resched, irqentry_exit_cond_resched); +#endif noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state) { @@ -419,8 +422,13 @@ noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state) } instrumentation_begin(); - if (IS_ENABLED(CONFIG_PREEMPTION)) + if (IS_ENABLED(CONFIG_PREEMPTION)) { +#ifdef CONFIG_PREEMT_DYNAMIC + static_call(irqentry_exit_cond_resched)(); +#else irqentry_exit_cond_resched(); +#endif + } /* Covers both tracing and lockdep */ trace_hardirqs_on(); instrumentation_end();
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