[PATCH] Add irq flag to disable balancing for an interrupt

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

diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index 6df1559..3554b76 100644 (file)
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -53,13 +53,13 @@
 static struct rcu_ctrlblk rcu_ctrlblk = {
        .cur = -300,
        .completed = -300,
-       .lock = SPIN_LOCK_UNLOCKED,
+       .lock = __SPIN_LOCK_UNLOCKED(&rcu_ctrlblk.lock),
        .cpumask = CPU_MASK_NONE,
 };
 static struct rcu_ctrlblk rcu_bh_ctrlblk = {
        .cur = -300,
        .completed = -300,
-       .lock = SPIN_LOCK_UNLOCKED,
+       .lock = __SPIN_LOCK_UNLOCKED(&rcu_bh_ctrlblk.lock),
        .cpumask = CPU_MASK_NONE,
 };
 
@@ -71,9 +71,6 @@ static DEFINE_PER_CPU(struct tasklet_struct, rcu_tasklet) = {NULL};
 static int blimit = 10;
 static int qhimark = 10000;
 static int qlowmark = 100;
-#ifdef CONFIG_SMP
-static int rsinterval = 1000;
-#endif
 
 static atomic_t rcu_barrier_cpu_count;
 static DEFINE_MUTEX(rcu_barrier_mutex);
@@ -86,8 +83,8 @@ static void force_quiescent_state(struct rcu_data *rdp,
        int cpu;
        cpumask_t cpumask;
        set_need_resched();
-       if (unlikely(rdp->qlen - rdp->last_rs_qlen > rsinterval)) {
-               rdp->last_rs_qlen = rdp->qlen;
+       if (unlikely(!rcp->signaled)) {
+               rcp->signaled = 1;
                /*
                 * Don't send IPI to itself. With irqs disabled,
                 * rdp->cpu is the current cpu.
@@ -182,6 +179,15 @@ long rcu_batches_completed(void)
        return rcu_ctrlblk.completed;
 }
 
+/*
+ * Return the number of RCU batches processed thus far.  Useful
+ * for debug and statistics.
+ */
+long rcu_batches_completed_bh(void)
+{
+       return rcu_bh_ctrlblk.completed;
+}
+
 static void rcu_barrier_callback(struct rcu_head *notused)
 {
        if (atomic_dec_and_test(&rcu_barrier_cpu_count))
@@ -229,15 +235,21 @@ static void rcu_do_batch(struct rcu_data *rdp)
 
        list = rdp->donelist;
        while (list) {
-               next = rdp->donelist = list->next;
+               next = list->next;
+               prefetch(next);
                list->func(list);
                list = next;
-               rdp->qlen--;
                if (++count >= rdp->blimit)
                        break;
        }
+       rdp->donelist = list;
+
+       local_irq_disable();
+       rdp->qlen -= count;
+       local_irq_enable();
        if (rdp->blimit == INT_MAX && rdp->qlen <= qlowmark)
                rdp->blimit = blimit;
+
        if (!rdp->donelist)
                rdp->donetail = &rdp->donelist;
        else
@@ -288,6 +300,7 @@ static void rcu_start_batch(struct rcu_ctrlblk *rcp)
                smp_mb();
                cpus_andnot(rcp->cpumask, cpu_online_map, nohz_cpu_mask);
 
+               rcp->signaled = 0;
        }
 }
 
@@ -416,8 +429,8 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp,
                rdp->curtail = &rdp->curlist;
        }
 
-       local_irq_disable();
        if (rdp->nxtlist && !rdp->curlist) {
+               local_irq_disable();
                rdp->curlist = rdp->nxtlist;
                rdp->curtail = rdp->nxttail;
                rdp->nxtlist = NULL;
@@ -442,9 +455,8 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp,
                        rcu_start_batch(rcp);
                        spin_unlock(&rcp->lock);
                }
-       } else {
-               local_irq_enable();
        }
+
        rcu_check_quiescent_state(rcp, rdp);
        if (rdp->donelist)
                rcu_do_batch(rdp);
@@ -480,12 +492,31 @@ static int __rcu_pending(struct rcu_ctrlblk *rcp, struct rcu_data *rdp)
        return 0;
 }
 
+/*
+ * Check to see if there is any immediate RCU-related work to be done
+ * by the current CPU, returning 1 if so.  This function is part of the
+ * RCU implementation; it is -not- an exported member of the RCU API.
+ */
 int rcu_pending(int cpu)
 {
        return __rcu_pending(&rcu_ctrlblk, &per_cpu(rcu_data, cpu)) ||
                __rcu_pending(&rcu_bh_ctrlblk, &per_cpu(rcu_bh_data, cpu));
 }
 
+/*
+ * Check to see if any future RCU-related work will need to be done
+ * by the current CPU, even if none need be done immediately, returning
+ * 1 if so.  This function is part of the RCU implementation; it is -not-
+ * an exported member of the RCU API.
+ */
+int rcu_needs_cpu(int cpu)
+{
+       struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
+       struct rcu_data *rdp_bh = &per_cpu(rcu_bh_data, cpu);
+
+       return (!!rdp->curlist || !!rdp_bh->curlist || rcu_pending(cpu));
+}
+
 void rcu_check_callbacks(int cpu, int user)
 {
        if (user || 
@@ -521,7 +552,7 @@ static void __devinit rcu_online_cpu(int cpu)
        tasklet_init(&per_cpu(rcu_tasklet, cpu), rcu_process_callbacks, 0UL);
 }
 
-static int __devinit rcu_cpu_notify(struct notifier_block *self, 
+static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
                                unsigned long action, void *hcpu)
 {
        long cpu = (long)hcpu;
@@ -538,7 +569,7 @@ static int __devinit rcu_cpu_notify(struct notifier_block *self,
        return NOTIFY_OK;
 }
 
-static struct notifier_block __devinitdata rcu_nb = {
+static struct notifier_block __cpuinitdata rcu_nb = {
        .notifier_call  = rcu_cpu_notify,
 };
 
@@ -594,22 +625,11 @@ void synchronize_rcu(void)
        wait_for_completion(&rcu.completion);
 }
 
-/*
- * Deprecated, use synchronize_rcu() or synchronize_sched() instead.
- */
-void synchronize_kernel(void)
-{
-       synchronize_rcu();
-}
-
 module_param(blimit, int, 0);
 module_param(qhimark, int, 0);
 module_param(qlowmark, int, 0);
-#ifdef CONFIG_SMP
-module_param(rsinterval, int, 0);
-#endif
 EXPORT_SYMBOL_GPL(rcu_batches_completed);
-EXPORT_SYMBOL_GPL_FUTURE(call_rcu);    /* WARNING: GPL-only in April 2006. */
-EXPORT_SYMBOL_GPL_FUTURE(call_rcu_bh); /* WARNING: GPL-only in April 2006. */
+EXPORT_SYMBOL_GPL(rcu_batches_completed_bh);
+EXPORT_SYMBOL_GPL(call_rcu);
+EXPORT_SYMBOL_GPL(call_rcu_bh);
 EXPORT_SYMBOL_GPL(synchronize_rcu);
-EXPORT_SYMBOL_GPL_FUTURE(synchronize_kernel); /* WARNING: GPL-only in April 2006. */