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authorIngo Molnar <mingo@kernel.org>2012-07-06 05:18:50 -0400
committerIngo Molnar <mingo@kernel.org>2012-07-06 05:18:50 -0400
commit40b3c43f042c2ba8915aff5c63708207ed7639cb (patch)
tree3249ad124f33aa664c79df44e6d7c3948d5e73d5 /kernel
parent9e85a6f9dc231f3ed3c1dc1b12217505d970142a (diff)
parentcba6d0d64ee53772b285d0c0c288deefbeaf7775 (diff)
Merge branch 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/urgent
Pull low probability CONFIG_RCU_BOOST=y deadlock fix from Paul E. McKenney. Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/rcutree.c1
-rw-r--r--kernel/rcutree.h1
-rw-r--r--kernel/rcutree_plugin.h14
-rw-r--r--kernel/sched/core.c1
4 files changed, 13 insertions, 4 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 38ecdda3f55f..4b97bba7396e 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -201,6 +201,7 @@ void rcu_note_context_switch(int cpu)
201{ 201{
202 trace_rcu_utilization("Start context switch"); 202 trace_rcu_utilization("Start context switch");
203 rcu_sched_qs(cpu); 203 rcu_sched_qs(cpu);
204 rcu_preempt_note_context_switch(cpu);
204 trace_rcu_utilization("End context switch"); 205 trace_rcu_utilization("End context switch");
205} 206}
206EXPORT_SYMBOL_GPL(rcu_note_context_switch); 207EXPORT_SYMBOL_GPL(rcu_note_context_switch);
diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index ea056495783e..19b61ac1079f 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -444,6 +444,7 @@ DECLARE_PER_CPU(char, rcu_cpu_has_work);
444/* Forward declarations for rcutree_plugin.h */ 444/* Forward declarations for rcutree_plugin.h */
445static void rcu_bootup_announce(void); 445static void rcu_bootup_announce(void);
446long rcu_batches_completed(void); 446long rcu_batches_completed(void);
447static void rcu_preempt_note_context_switch(int cpu);
447static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp); 448static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp);
448#ifdef CONFIG_HOTPLUG_CPU 449#ifdef CONFIG_HOTPLUG_CPU
449static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, 450static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp,
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 5271a020887e..3e4899459f3d 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -153,7 +153,7 @@ static void rcu_preempt_qs(int cpu)
153 * 153 *
154 * Caller must disable preemption. 154 * Caller must disable preemption.
155 */ 155 */
156void rcu_preempt_note_context_switch(void) 156static void rcu_preempt_note_context_switch(int cpu)
157{ 157{
158 struct task_struct *t = current; 158 struct task_struct *t = current;
159 unsigned long flags; 159 unsigned long flags;
@@ -164,7 +164,7 @@ void rcu_preempt_note_context_switch(void)
164 (t->rcu_read_unlock_special & RCU_READ_UNLOCK_BLOCKED) == 0) { 164 (t->rcu_read_unlock_special & RCU_READ_UNLOCK_BLOCKED) == 0) {
165 165
166 /* Possibly blocking in an RCU read-side critical section. */ 166 /* Possibly blocking in an RCU read-side critical section. */
167 rdp = __this_cpu_ptr(rcu_preempt_state.rda); 167 rdp = per_cpu_ptr(rcu_preempt_state.rda, cpu);
168 rnp = rdp->mynode; 168 rnp = rdp->mynode;
169 raw_spin_lock_irqsave(&rnp->lock, flags); 169 raw_spin_lock_irqsave(&rnp->lock, flags);
170 t->rcu_read_unlock_special |= RCU_READ_UNLOCK_BLOCKED; 170 t->rcu_read_unlock_special |= RCU_READ_UNLOCK_BLOCKED;
@@ -228,7 +228,7 @@ void rcu_preempt_note_context_switch(void)
228 * means that we continue to block the current grace period. 228 * means that we continue to block the current grace period.
229 */ 229 */
230 local_irq_save(flags); 230 local_irq_save(flags);
231 rcu_preempt_qs(smp_processor_id()); 231 rcu_preempt_qs(cpu);
232 local_irq_restore(flags); 232 local_irq_restore(flags);
233} 233}
234 234
@@ -1002,6 +1002,14 @@ void rcu_force_quiescent_state(void)
1002EXPORT_SYMBOL_GPL(rcu_force_quiescent_state); 1002EXPORT_SYMBOL_GPL(rcu_force_quiescent_state);
1003 1003
1004/* 1004/*
1005 * Because preemptible RCU does not exist, we never have to check for
1006 * CPUs being in quiescent states.
1007 */
1008static void rcu_preempt_note_context_switch(int cpu)
1009{
1010}
1011
1012/*
1005 * Because preemptible RCU does not exist, there are never any preempted 1013 * Because preemptible RCU does not exist, there are never any preempted
1006 * RCU readers. 1014 * RCU readers.
1007 */ 1015 */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index d5594a4268d4..eaead2df6aa8 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2081,7 +2081,6 @@ context_switch(struct rq *rq, struct task_struct *prev,
2081#endif 2081#endif
2082 2082
2083 /* Here we just switch the register state and the stack. */ 2083 /* Here we just switch the register state and the stack. */
2084 rcu_switch_from(prev);
2085 switch_to(prev, next, prev); 2084 switch_to(prev, next, prev);
2086 2085
2087 barrier(); 2086 barrier();