On Mon, 19 Sept 2022 at 12:18, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
None of these functions should ever be ran with RCU disabled anymore.
Specifically, do_handle_IPI() is only called from handle_IPI() which
explicitly does irq_enter()/irq_exit() which ensures RCU is watching.
The problem with smp_cross_call() was, per commit 7c64cc0531fa ("arm: Use
_rcuidle for smp_cross_call() tracepoints"), that
cpuidle_enter_state_coupled() already had RCU disabled, but that's
long been fixed by commit 1098582a0f6c ("sched,idle,rcu: Push rcu_idle
deeper into the idle path").
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
FWIW:
Reviewed-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Kind regards
Uffe
---
arch/arm/kernel/smp.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -639,7 +639,7 @@ static void do_handle_IPI(int ipinr)
unsigned int cpu = smp_processor_id();
if ((unsigned)ipinr < NR_IPI)
- trace_ipi_entry_rcuidle(ipi_types[ipinr]);
+ trace_ipi_entry(ipi_types[ipinr]);
switch (ipinr) {
case IPI_WAKEUP:
@@ -686,7 +686,7 @@ static void do_handle_IPI(int ipinr)
}
if ((unsigned)ipinr < NR_IPI)
- trace_ipi_exit_rcuidle(ipi_types[ipinr]);
+ trace_ipi_exit(ipi_types[ipinr]);
}
/* Legacy version, should go away once all irqchips have been converted */
@@ -709,7 +709,7 @@ static irqreturn_t ipi_handler(int irq,
static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
{
- trace_ipi_raise_rcuidle(target, ipi_types[ipinr]);
+ trace_ipi_raise(target, ipi_types[ipinr]);
__ipi_send_mask(ipi_desc[ipinr], target);
}
_______________________________________________
Virtualization mailing list
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
