If we are interrupting userspace, we don't need to keep
the tick for RCU: quiescent states don't need to be reported
because we soon run in userspace and local callbacks are handled
by the nocb threads.
CHECKME: Do the nocb threads actually handle the global
grace period completion for local callbacks?
Signed-off-by: Frederic Weisbecker <fweis...@gmail.com>
Cc: Alessio Igor Bogani <abog...@kernel.org>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Chris Metcalf <cmetc...@tilera.com>
Cc: Christoph Lameter <c...@linux.com>
Cc: Geoff Levand <ge...@infradead.org>
Cc: Gilad Ben Yossef <gi...@benyossef.com>
Cc: Hakan Akkan <hakanak...@gmail.com>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Paul E. McKenney <paul...@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortma...@windriver.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Thomas Gleixner <t...@linutronix.de>
---
kernel/time/tick-sched.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 0e1ebff..76d1b08 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -22,6 +22,7 @@
#include <linux/module.h>
#include <linux/irq_work.h>
#include <linux/posix-timers.h>
+#include <linux/context_tracking.h>
#include <asm/irq_regs.h>
@@ -604,10 +605,9 @@ static bool can_stop_full_tick(int cpu)
/*
* Keep the tick if we are asked to report a quiescent state.
- * This must be further optimized (avoid checks for local callbacks,
- * ignore RCU in userspace, etc...
+ * This must be further optimized (avoid checks for local callbacks)
*/
- if (rcu_pending(cpu)) {
+ if (!context_tracking_in_user() && rcu_pending(cpu)) {
trace_printk("Can't stop: RCU pending\n");
return false;
}
--
1.7.5.4
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