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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-07-02 18:08:42 +0400
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-07-02 22:39:19 +0400
commitcba6d0d64ee53772b285d0c0c288deefbeaf7775 (patch)
treeb2d3de62d15a77d23708c1af6f188c86f0d87fb9 /include/linux/rcutiny.h
parent6887a4131da3adaab011613776d865f4bcfb5678 (diff)
downloadlinux-cba6d0d64ee53772b285d0c0c288deefbeaf7775.tar.xz
Revert "rcu: Move PREEMPT_RCU preemption to switch_to() invocation"
This reverts commit 616c310e83b872024271c915c1b9ab505b9efad9. (Move PREEMPT_RCU preemption to switch_to() invocation). Testing by Sasha Levin <levinsasha928@gmail.com> showed that this can result in deadlock due to invoking the scheduler when one of the runqueue locks is held. Because this commit was simply a performance optimization, revert it. Reported-by: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Sasha Levin <levinsasha928@gmail.com>
Diffstat (limited to 'include/linux/rcutiny.h')
-rw-r--r--include/linux/rcutiny.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index 854dc4c5c271..4e56a9c69a35 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -87,6 +87,10 @@ static inline void kfree_call_rcu(struct rcu_head *head,
#ifdef CONFIG_TINY_RCU
+static inline void rcu_preempt_note_context_switch(void)
+{
+}
+
static inline int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies)
{
*delta_jiffies = ULONG_MAX;
@@ -95,6 +99,7 @@ static inline int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies)
#else /* #ifdef CONFIG_TINY_RCU */
+void rcu_preempt_note_context_switch(void);
int rcu_preempt_needs_cpu(void);
static inline int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies)
@@ -108,6 +113,7 @@ static inline int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies)
static inline void rcu_note_context_switch(int cpu)
{
rcu_sched_qs(cpu);
+ rcu_preempt_note_context_switch();
}
/*