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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-06-12 11:01:13 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-07-02 12:33:24 -0700
commit6ce75a2326e6f8b3bdfb60e1de7934b89858e87b (patch)
treec3ecd512422ad9f445f69c78037142a99bc8db2c
parent1bca8cf1a2c3c6683b12ad28a3e826ca7a834978 (diff)
rcu: Introduce for_each_rcu_flavor() and use it
The arrival of TREE_PREEMPT_RCU some years back included some ugly code involving either #ifdef or #ifdef'ed wrapper functions to iterate over all non-SRCU flavors of RCU. This commit therefore introduces a for_each_rcu_flavor() iterator over the rcu_state structures for each flavor of RCU to clean up a bit of the ugliness. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
-rw-r--r--kernel/rcutree.c53
-rw-r--r--kernel/rcutree.h12
-rw-r--r--kernel/rcutree_plugin.h116
3 files changed, 37 insertions, 144 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 5376a156be8..b61c3ffc80e 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -84,6 +84,7 @@ struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh, call_rcu_bh);
DEFINE_PER_CPU(struct rcu_data, rcu_bh_data);
static struct rcu_state *rcu_state;
+LIST_HEAD(rcu_struct_flavors);
/* Increase (but not decrease) the CONFIG_RCU_FANOUT_LEAF at boot time. */
static int rcu_fanout_leaf = CONFIG_RCU_FANOUT_LEAF;
@@ -860,9 +861,10 @@ static int rcu_panic(struct notifier_block *this, unsigned long ev, void *ptr)
*/
void rcu_cpu_stall_reset(void)
{
- rcu_sched_state.jiffies_stall = jiffies + ULONG_MAX / 2;
- rcu_bh_state.jiffies_stall = jiffies + ULONG_MAX / 2;
- rcu_preempt_stall_reset();
+ struct rcu_state *rsp;
+
+ for_each_rcu_flavor(rsp)
+ rsp->jiffies_stall = jiffies + ULONG_MAX / 2;
}
static struct notifier_block rcu_panic_block = {
@@ -1827,10 +1829,11 @@ __rcu_process_callbacks(struct rcu_state *rsp)
*/
static void rcu_process_callbacks(struct softirq_action *unused)
{
+ struct rcu_state *rsp;
+
trace_rcu_utilization("Start RCU core");
- __rcu_process_callbacks(&rcu_sched_state);
- __rcu_process_callbacks(&rcu_bh_state);
- rcu_preempt_process_callbacks();
+ for_each_rcu_flavor(rsp)
+ __rcu_process_callbacks(rsp);
trace_rcu_utilization("End RCU core");
}
@@ -2241,9 +2244,12 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp)
*/
static int rcu_pending(int cpu)
{
- return __rcu_pending(&rcu_sched_state, &per_cpu(rcu_sched_data, cpu)) ||
- __rcu_pending(&rcu_bh_state, &per_cpu(rcu_bh_data, cpu)) ||
- rcu_preempt_pending(cpu);
+ struct rcu_state *rsp;
+
+ for_each_rcu_flavor(rsp)
+ if (__rcu_pending(rsp, per_cpu_ptr(rsp->rda, cpu)))
+ return 1;
+ return 0;
}
/*
@@ -2253,10 +2259,13 @@ static int rcu_pending(int cpu)
*/
static int rcu_cpu_has_callbacks(int cpu)
{
+ struct rcu_state *rsp;
+
/* RCU callbacks either ready or pending? */
- return per_cpu(rcu_sched_data, cpu).nxtlist ||
- per_cpu(rcu_bh_data, cpu).nxtlist ||
- rcu_preempt_cpu_has_callbacks(cpu);
+ for_each_rcu_flavor(rsp)
+ if (per_cpu_ptr(rsp->rda, cpu)->nxtlist)
+ return 1;
+ return 0;
}
/*
@@ -2551,9 +2560,11 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptible)
static void __cpuinit rcu_prepare_cpu(int cpu)
{
- rcu_init_percpu_data(cpu, &rcu_sched_state, 0);
- rcu_init_percpu_data(cpu, &rcu_bh_state, 0);
- rcu_preempt_init_percpu_data(cpu);
+ struct rcu_state *rsp;
+
+ for_each_rcu_flavor(rsp)
+ rcu_init_percpu_data(cpu, rsp,
+ strcmp(rsp->name, "rcu_preempt") == 0);
}
/*
@@ -2565,6 +2576,7 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
long cpu = (long)hcpu;
struct rcu_data *rdp = per_cpu_ptr(rcu_state->rda, cpu);
struct rcu_node *rnp = rdp->mynode;
+ struct rcu_state *rsp;
trace_rcu_utilization("Start CPU hotplug");
switch (action) {
@@ -2589,18 +2601,16 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
* touch any data without introducing corruption. We send the
* dying CPU's callbacks to an arbitrarily chosen online CPU.
*/
- rcu_cleanup_dying_cpu(&rcu_bh_state);
- rcu_cleanup_dying_cpu(&rcu_sched_state);
- rcu_preempt_cleanup_dying_cpu();
+ for_each_rcu_flavor(rsp)
+ rcu_cleanup_dying_cpu(rsp);
rcu_cleanup_after_idle(cpu);
break;
case CPU_DEAD:
case CPU_DEAD_FROZEN:
case CPU_UP_CANCELED:
case CPU_UP_CANCELED_FROZEN:
- rcu_cleanup_dead_cpu(cpu, &rcu_bh_state);
- rcu_cleanup_dead_cpu(cpu, &rcu_sched_state);
- rcu_preempt_cleanup_dead_cpu(cpu);
+ for_each_rcu_flavor(rsp)
+ rcu_cleanup_dead_cpu(cpu, rsp);
break;
default:
break;
@@ -2717,6 +2727,7 @@ static void __init rcu_init_one(struct rcu_state *rsp,
per_cpu_ptr(rsp->rda, i)->mynode = rnp;
rcu_boot_init_percpu_data(i, rsp);
}
+ list_add(&rsp->flavors, &rcu_struct_flavors);
}
/*
diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index be10286ad38..b92c4550a6e 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -422,8 +422,13 @@ struct rcu_state {
unsigned long gp_max; /* Maximum GP duration in */
/* jiffies. */
char *name; /* Name of structure. */
+ struct list_head flavors; /* List of RCU flavors. */
};
+extern struct list_head rcu_struct_flavors;
+#define for_each_rcu_flavor(rsp) \
+ list_for_each_entry((rsp), &rcu_struct_flavors, flavors)
+
/* Return values for rcu_preempt_offline_tasks(). */
#define RCU_OFL_TASKS_NORM_GP 0x1 /* Tasks blocking normal */
@@ -466,25 +471,18 @@ static void rcu_stop_cpu_kthread(int cpu);
#endif /* #ifdef CONFIG_HOTPLUG_CPU */
static void rcu_print_detail_task_stall(struct rcu_state *rsp);
static int rcu_print_task_stall(struct rcu_node *rnp);
-static void rcu_preempt_stall_reset(void);
static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp);
#ifdef CONFIG_HOTPLUG_CPU
static int rcu_preempt_offline_tasks(struct rcu_state *rsp,
struct rcu_node *rnp,
struct rcu_data *rdp);
#endif /* #ifdef CONFIG_HOTPLUG_CPU */
-static void rcu_preempt_cleanup_dead_cpu(int cpu);
static void rcu_preempt_check_callbacks(int cpu);
-static void rcu_preempt_process_callbacks(void);
void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU)
static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
bool wake);
#endif /* #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU) */
-static int rcu_preempt_pending(int cpu);
-static int rcu_preempt_cpu_has_callbacks(int cpu);
-static void __cpuinit rcu_preempt_init_percpu_data(int cpu);
-static void rcu_preempt_cleanup_dying_cpu(void);
static void __init __rcu_init_preempt(void);
static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags);
static void rcu_preempt_boost_start_gp(struct rcu_node *rnp);
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 5a80cdd9a0a..d18b4d383af 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -545,16 +545,6 @@ static int rcu_print_task_stall(struct rcu_node *rnp)
}
/*
- * Suppress preemptible RCU's CPU stall warnings by pushing the
- * time of the next stall-warning message comfortably far into the
- * future.
- */
-static void rcu_preempt_stall_reset(void)
-{
- rcu_preempt_state.jiffies_stall = jiffies + ULONG_MAX / 2;
-}
-
-/*
* Check that the list of blocked tasks for the newly completed grace
* period is in fact empty. It is a serious bug to complete a grace
* period that still has RCU readers blocked! This function must be
@@ -655,14 +645,6 @@ static int rcu_preempt_offline_tasks(struct rcu_state *rsp,
#endif /* #ifdef CONFIG_HOTPLUG_CPU */
/*
- * Do CPU-offline processing for preemptible RCU.
- */
-static void rcu_preempt_cleanup_dead_cpu(int cpu)
-{
- rcu_cleanup_dead_cpu(cpu, &rcu_preempt_state);
-}
-
-/*
* Check for a quiescent state from the current CPU. When a task blocks,
* the task is recorded in the corresponding CPU's rcu_node structure,
* which is checked elsewhere.
@@ -682,14 +664,6 @@ static void rcu_preempt_check_callbacks(int cpu)
t->rcu_read_unlock_special |= RCU_READ_UNLOCK_NEED_QS;
}
-/*
- * Process callbacks for preemptible RCU.
- */
-static void rcu_preempt_process_callbacks(void)
-{
- __rcu_process_callbacks(&rcu_preempt_state);
-}
-
#ifdef CONFIG_RCU_BOOST
static void rcu_preempt_do_callbacks(void)
@@ -921,24 +895,6 @@ mb_ret:
}
EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);
-/*
- * Check to see if there is any immediate preemptible-RCU-related work
- * to be done.
- */
-static int rcu_preempt_pending(int cpu)
-{
- return __rcu_pending(&rcu_preempt_state,
- &per_cpu(rcu_preempt_data, cpu));
-}
-
-/*
- * Does preemptible RCU have callbacks on this CPU?
- */
-static int rcu_preempt_cpu_has_callbacks(int cpu)
-{
- return !!per_cpu(rcu_preempt_data, cpu).nxtlist;
-}
-
/**
* rcu_barrier - Wait until all in-flight call_rcu() callbacks complete.
*/
@@ -949,23 +905,6 @@ void rcu_barrier(void)
EXPORT_SYMBOL_GPL(rcu_barrier);
/*
- * Initialize preemptible RCU's per-CPU data.
- */
-static void __cpuinit rcu_preempt_init_percpu_data(int cpu)
-{
- rcu_init_percpu_data(cpu, &rcu_preempt_state, 1);
-}
-
-/*
- * Move preemptible RCU's callbacks from dying CPU to other online CPU
- * and record a quiescent state.
- */
-static void rcu_preempt_cleanup_dying_cpu(void)
-{
- rcu_cleanup_dying_cpu(&rcu_preempt_state);
-}
-
-/*
* Initialize preemptible RCU's state structures.
*/
static void __init __rcu_init_preempt(void)
@@ -1050,14 +989,6 @@ static int rcu_print_task_stall(struct rcu_node *rnp)
}
/*
- * Because preemptible RCU does not exist, there is no need to suppress
- * its CPU stall warnings.
- */
-static void rcu_preempt_stall_reset(void)
-{
-}
-
-/*
* Because there is no preemptible RCU, there can be no readers blocked,
* so there is no need to check for blocked tasks. So check only for
* bogus qsmask values.
@@ -1085,14 +1016,6 @@ static int rcu_preempt_offline_tasks(struct rcu_state *rsp,
#endif /* #ifdef CONFIG_HOTPLUG_CPU */
/*
- * Because preemptible RCU does not exist, it never needs CPU-offline
- * processing.
- */
-static void rcu_preempt_cleanup_dead_cpu(int cpu)
-{
-}
-
-/*
* Because preemptible RCU does not exist, it never has any callbacks
* to check.
*/
@@ -1101,14 +1024,6 @@ static void rcu_preempt_check_callbacks(int cpu)
}
/*
- * Because preemptible RCU does not exist, it never has any callbacks
- * to process.
- */
-static void rcu_preempt_process_callbacks(void)
-{
-}
-
-/*
* Queue an RCU callback for lazy invocation after a grace period.
* This will likely be later named something like "call_rcu_lazy()",
* but this change will require some way of tagging the lazy RCU
@@ -1149,22 +1064,6 @@ static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
#endif /* #ifdef CONFIG_HOTPLUG_CPU */
/*
- * Because preemptible RCU does not exist, it never has any work to do.
- */
-static int rcu_preempt_pending(int cpu)
-{
- return 0;
-}
-
-/*
- * Because preemptible RCU does not exist, it never has callbacks
- */
-static int rcu_preempt_cpu_has_callbacks(int cpu)
-{
- return 0;
-}
-
-/*
* Because preemptible RCU does not exist, rcu_barrier() is just
* another name for rcu_barrier_sched().
*/
@@ -1175,21 +1074,6 @@ void rcu_barrier(void)
EXPORT_SYMBOL_GPL(rcu_barrier);
/*
- * Because preemptible RCU does not exist, there is no per-CPU
- * data to initialize.
- */
-static void __cpuinit rcu_preempt_init_percpu_data(int cpu)
-{
-}
-
-/*
- * Because there is no preemptible RCU, there is no cleanup to do.
- */
-static void rcu_preempt_cleanup_dying_cpu(void)
-{
-}
-
-/*
* Because preemptible RCU does not exist, it need not be initialized.
*/
static void __init __rcu_init_preempt(void)