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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2013-03-27 10:11:15 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2013-06-10 13:45:51 -0700
commit9dc5ad32488a75504349372330cc228d4dd678db (patch)
tree794a5a4ac485fa4e6141dc6f14d23b0963c4bbab /kernel
parent58c4e69d43df91fd6a55bc070474aad6b7cfb18d (diff)
downloadlinux-9dc5ad32488a75504349372330cc228d4dd678db.tar.bz2
rcu: Simplify RCU_TINY RCU callback invocation
TINY_PREEMPT_RCU could use a kthread to handle RCU callback invocation, which required an API to abstract kthread vs. softirq invocation. Now that TINY_PREEMPT_RCU is no longer with us, this commit retires this API in favor of direct use of the relevant softirq primitives. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/rcutiny.c14
-rw-r--r--kernel/rcutiny_plugin.h33
2 files changed, 9 insertions, 38 deletions
diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c
index 7fc2339b0859..4adc9e26da34 100644
--- a/kernel/rcutiny.c
+++ b/kernel/rcutiny.c
@@ -44,7 +44,6 @@
/* Forward declarations for rcutiny_plugin.h. */
struct rcu_ctrlblk;
-static void invoke_rcu_callbacks(void);
static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp);
static void rcu_process_callbacks(struct softirq_action *unused);
static void __call_rcu(struct rcu_head *head,
@@ -227,7 +226,7 @@ void rcu_sched_qs(int cpu)
local_irq_save(flags);
if (rcu_qsctr_help(&rcu_sched_ctrlblk) +
rcu_qsctr_help(&rcu_bh_ctrlblk))
- invoke_rcu_callbacks();
+ raise_softirq(RCU_SOFTIRQ);
local_irq_restore(flags);
}
@@ -240,7 +239,7 @@ void rcu_bh_qs(int cpu)
local_irq_save(flags);
if (rcu_qsctr_help(&rcu_bh_ctrlblk))
- invoke_rcu_callbacks();
+ raise_softirq(RCU_SOFTIRQ);
local_irq_restore(flags);
}
@@ -277,7 +276,7 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp)
ACCESS_ONCE(rcp->rcucblist),
need_resched(),
is_idle_task(current),
- rcu_is_callbacks_kthread()));
+ false));
return;
}
@@ -307,7 +306,7 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp)
RCU_TRACE(rcu_trace_sub_qlen(rcp, cb_count));
RCU_TRACE(trace_rcu_batch_end(rcp->name, cb_count, 0, need_resched(),
is_idle_task(current),
- rcu_is_callbacks_kthread()));
+ false));
}
static void rcu_process_callbacks(struct softirq_action *unused)
@@ -379,3 +378,8 @@ void call_rcu_bh(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
__call_rcu(head, func, &rcu_bh_ctrlblk);
}
EXPORT_SYMBOL_GPL(call_rcu_bh);
+
+void rcu_init(void)
+{
+ open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
+}
diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h
index bfe992407803..36fd83c544c8 100644
--- a/kernel/rcutiny_plugin.h
+++ b/kernel/rcutiny_plugin.h
@@ -102,39 +102,6 @@ static void check_cpu_stalls(void)
RCU_TRACE(check_cpu_stall_preempt());
}
-/* Hold off callback invocation until early_initcall() time. */
-static int rcu_scheduler_fully_active __read_mostly;
-
-/*
- * Start up softirq processing of callbacks.
- */
-void invoke_rcu_callbacks(void)
-{
- if (rcu_scheduler_fully_active)
- raise_softirq(RCU_SOFTIRQ);
-}
-
-#ifdef CONFIG_RCU_TRACE
-
-/*
- * There is no callback kthread, so this thread is never it.
- */
-static bool rcu_is_callbacks_kthread(void)
-{
- return false;
-}
-
-#endif /* #ifdef CONFIG_RCU_TRACE */
-
-static int __init rcu_scheduler_really_started(void)
-{
- rcu_scheduler_fully_active = 1;
- open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
- raise_softirq(RCU_SOFTIRQ); /* Invoke any callbacks from early boot. */
- return 0;
-}
-early_initcall(rcu_scheduler_really_started);
-
#ifdef CONFIG_DEBUG_LOCK_ALLOC
#include <linux/kernel_stat.h>