perf_events: Update the context time on exit

[safe/jmp/linux-2.6] / kernel / rcutree.c

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index ddbf111..f3077c0 100644 (file)
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -59,7 +59,7 @@
                NUM_RCU_LVL_2, \
                NUM_RCU_LVL_3, /* == MAX_RCU_LVLS */ \
        }, \
-       .signaled = RCU_SIGNAL_INIT, \
+       .signaled = RCU_GP_IDLE, \
        .gpnum = -300, \
        .completed = -300, \
        .onofflock = __SPIN_LOCK_UNLOCKED(&name.onofflock), \
@@ -657,14 +657,17 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags)
         * irqs disabled.
         */
        rcu_for_each_node_breadth_first(rsp, rnp) {
-               spin_lock(&rnp->lock);  /* irqs already disabled. */
+               spin_lock(&rnp->lock);          /* irqs already disabled. */
                rcu_preempt_check_blocked_tasks(rnp);
                rnp->qsmask = rnp->qsmaskinit;
                rnp->gpnum = rsp->gpnum;
-               spin_unlock(&rnp->lock);        /* irqs already disabled. */
+               spin_unlock(&rnp->lock);        /* irqs remain disabled. */
        }
 
+       rnp = rcu_get_root(rsp);
+       spin_lock(&rnp->lock);                  /* irqs already disabled. */
        rsp->signaled = RCU_SIGNAL_INIT; /* force_quiescent_state now OK. */
+       spin_unlock(&rnp->lock);                /* irqs remain disabled. */
        spin_unlock_irqrestore(&rsp->onofflock, flags);
 }
 
@@ -706,6 +709,7 @@ static void cpu_quiet_msk_finish(struct rcu_state *rsp, unsigned long flags)
 {
        WARN_ON_ONCE(!rcu_gp_in_progress(rsp));
        rsp->completed = rsp->gpnum;
+       rsp->signaled = RCU_GP_IDLE;
        rcu_process_gp_end(rsp, rsp->rda[smp_processor_id()]);
        rcu_start_gp(rsp, flags);  /* releases root node's rnp->lock. */
 }
@@ -913,7 +917,20 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp)
                        spin_unlock(&rnp->lock); /* irqs remain disabled. */
                        break;
                }
-               rcu_preempt_offline_tasks(rsp, rnp, rdp);
+
+               /*
+                * If there was a task blocking the current grace period,
+                * and if all CPUs have checked in, we need to propagate
+                * the quiescent state up the rcu_node hierarchy.  But that
+                * is inconvenient at the moment due to deadlock issues if
+                * this should end the current grace period.  So set the
+                * offlined CPU's bit in ->qsmask in order to force the
+                * next force_quiescent_state() invocation to clean up this
+                * mess in a deadlock-free manner.
+                */
+               if (rcu_preempt_offline_tasks(rsp, rnp, rdp) && !rnp->qsmask)
+                       rnp->qsmask |= mask;
+
                mask = rnp->grpmask;
                spin_unlock(&rnp->lock);        /* irqs remain disabled. */
                rnp = rnp->parent;
@@ -1149,9 +1166,10 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
        }
        spin_unlock(&rnp->lock);
        switch (signaled) {
+       case RCU_GP_IDLE:
        case RCU_GP_INIT:
 
-               break; /* grace period still initializing, ignore. */
+               break; /* grace period idle or initializing, ignore. */
 
        case RCU_SAVE_DYNTICK:
 
@@ -1165,7 +1183,8 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
 
                /* Update state, record completion counter. */
                spin_lock(&rnp->lock);
-               if (lastcomp == rsp->completed) {
+               if (lastcomp == rsp->completed &&
+                   rsp->signaled == RCU_SAVE_DYNTICK) {
                        rsp->signaled = RCU_FORCE_QS;
                        dyntick_record_completed(rsp, lastcomp);
                }