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authorPaul E. McKenney <paul.mckenney@linaro.org>2012-10-19 21:49:17 +0200
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2013-01-29 07:06:21 +0100
commit6bfc09e2327dfbffc312004c16188dbf8dfb0297 (patch)
treef36ac34ec671ea5eaa926ebabba8486bbda9c175 /kernel/rcutiny.c
parentrcu: Make rcu_nocb_poll an early_param instead of module_param (diff)
downloadlinux-6bfc09e2327dfbffc312004c16188dbf8dfb0297.tar.xz
linux-6bfc09e2327dfbffc312004c16188dbf8dfb0297.zip
rcu: Provide RCU CPU stall warnings for tiny RCU
Tiny RCU has historically omitted RCU CPU stall warnings in order to reduce memory requirements, however, lack of these warnings caused Thomas Gleixner some debugging pain recently. Therefore, this commit adds RCU CPU stall warnings to tiny RCU if RCU_TRACE=y. This keeps the memory footprint small, while still enabling CPU stall warnings in kernels built to enable them. Updated to include Josh Triplett's suggested use of RCU_STALL_COMMON config variable to simplify #if expressions. Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'kernel/rcutiny.c')
-rw-r--r--kernel/rcutiny.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c
index e7dce58f9c2a..b899df317edc 100644
--- a/kernel/rcutiny.c
+++ b/kernel/rcutiny.c
@@ -51,10 +51,10 @@ static void __call_rcu(struct rcu_head *head,
void (*func)(struct rcu_head *rcu),
struct rcu_ctrlblk *rcp);
-#include "rcutiny_plugin.h"
-
static long long rcu_dynticks_nesting = DYNTICK_TASK_EXIT_IDLE;
+#include "rcutiny_plugin.h"
+
/* Common code for rcu_idle_enter() and rcu_irq_exit(), see kernel/rcutree.c. */
static void rcu_idle_enter_common(long long newval)
{
@@ -205,6 +205,7 @@ int rcu_is_cpu_rrupt_from_idle(void)
*/
static int rcu_qsctr_help(struct rcu_ctrlblk *rcp)
{
+ reset_cpu_stall_ticks(rcp);
if (rcp->rcucblist != NULL &&
rcp->donetail != rcp->curtail) {
rcp->donetail = rcp->curtail;
@@ -251,6 +252,7 @@ void rcu_bh_qs(int cpu)
*/
void rcu_check_callbacks(int cpu, int user)
{
+ check_cpu_stalls();
if (user || rcu_is_cpu_rrupt_from_idle())
rcu_sched_qs(cpu);
else if (!in_softirq())