From: "Peter Zijlstra (Intel)" <pet...@infradead.org>
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) <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Mel Gorman <mgor...@suse.de>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: Michal Hocko <mho...@kernel.org>
Cc: Paul E. McKenney <paul...@kernel.org>
[convert from static key to static call, only define static call when
PREEMPT_DYNAMIC]
Signed-off-by: Frederic Weisbecker <frede...@kernel.org>
---
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 474f29638d2c..36738f67f6ad 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>
@@ -385,6 +386,9 @@ 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 2b8366693d5c..c501c951f8bc 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -357,6 +357,9 @@ 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)
{
@@ -383,8 +386,13 @@ 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();
--
2.25.1
