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x86/entry: Split out idtentry_exit_cond_resched()

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The XEN PV hypercall requires the ability of conditional rescheduling when
preemption is disabled because some hypercalls take ages.

Split out the rescheduling code from idtentry_exit_cond_rcu() so it can
be reused for that.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20200521202117.962199649@linutronix.de
This commit is contained in:
Thomas Gleixner
2020-05-21 22:05:25 +02:00
parent eb6555c839
commit 1de16e0c17
1 changed files with 15 additions and 15 deletions
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30
arch/x86/entry/common.c
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@@ -583,6 +583,20 @@ bool noinstr idtentry_enter_cond_rcu(struct pt_regs *regs)
return false; return false;
} }
static void idtentry_exit_cond_resched(struct pt_regs *regs, bool may_sched)
{
if (may_sched && !preempt_count()) {
/* Sanity check RCU and thread stack */
rcu_irq_exit_check_preempt();
if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
WARN_ON_ONCE(!on_thread_stack());
if (need_resched())
preempt_schedule_irq();
}
/* Covers both tracing and lockdep */
trace_hardirqs_on();
}
/** /**
* idtentry_exit_cond_rcu - Handle return from exception with conditional RCU * idtentry_exit_cond_rcu - Handle return from exception with conditional RCU
* handling * handling
@@ -624,21 +638,7 @@ void noinstr idtentry_exit_cond_rcu(struct pt_regs *regs, bool rcu_exit)
} }
instrumentation_begin(); instrumentation_begin();
idtentry_exit_cond_resched(regs, IS_ENABLED(CONFIG_PREEMPTION));
/* Check kernel preemption, if enabled */
if (IS_ENABLED(CONFIG_PREEMPTION)) {
if (!preempt_count()) {
/* Sanity check RCU and thread stack */
rcu_irq_exit_check_preempt();
if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
WARN_ON_ONCE(!on_thread_stack());
if (need_resched())
preempt_schedule_irq();
}
}
/* Covers both tracing and lockdep */
trace_hardirqs_on();
instrumentation_end(); instrumentation_end();
} else { } else {
/* /*