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authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-02-06 11:36:10 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-02-06 11:36:10 +0300
commita769f30c7bd7cf917eea05a2b448f3588a87d767 (patch)
tree10a06089a9525926e23675528dd8190d05849143 /kernel/rcu/tree.c
parent307a082484eb0201ad123f39f95510a9da11985b (diff)
parentd5adbfcd5f7bcc6fa58a41c5c5ada0e5c826ce2c (diff)
downloadlinux-a769f30c7bd7cf917eea05a2b448f3588a87d767.tar.xz
Merge 4.10-rc7 into staging-next
This resolves the merge errors that were reported in linux-next and it picks up the staging and IIO fixes that we need/want in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/rcu/tree.c')
-rw-r--r--kernel/rcu/tree.c33
1 files changed, 20 insertions, 13 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 96c52e43f7ca..cb4e2056ccf3 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -127,13 +127,16 @@ int rcu_num_nodes __read_mostly = NUM_RCU_NODES; /* Total # rcu_nodes in use. */
int sysctl_panic_on_rcu_stall __read_mostly;
/*
- * The rcu_scheduler_active variable transitions from zero to one just
- * before the first task is spawned. So when this variable is zero, RCU
- * can assume that there is but one task, allowing RCU to (for example)
+ * The rcu_scheduler_active variable is initialized to the value
+ * RCU_SCHEDULER_INACTIVE and transitions RCU_SCHEDULER_INIT just before the
+ * first task is spawned. So when this variable is RCU_SCHEDULER_INACTIVE,
+ * RCU can assume that there is but one task, allowing RCU to (for example)
* optimize synchronize_rcu() to a simple barrier(). When this variable
- * is one, RCU must actually do all the hard work required to detect real
- * grace periods. This variable is also used to suppress boot-time false
- * positives from lockdep-RCU error checking.
+ * is RCU_SCHEDULER_INIT, RCU must actually do all the hard work required
+ * to detect real grace periods. This variable is also used to suppress
+ * boot-time false positives from lockdep-RCU error checking. Finally, it
+ * transitions from RCU_SCHEDULER_INIT to RCU_SCHEDULER_RUNNING after RCU
+ * is fully initialized, including all of its kthreads having been spawned.
*/
int rcu_scheduler_active __read_mostly;
EXPORT_SYMBOL_GPL(rcu_scheduler_active);
@@ -3980,18 +3983,22 @@ static int __init rcu_spawn_gp_kthread(void)
early_initcall(rcu_spawn_gp_kthread);
/*
- * This function is invoked towards the end of the scheduler's initialization
- * process. Before this is called, the idle task might contain
- * RCU read-side critical sections (during which time, this idle
- * task is booting the system). After this function is called, the
- * idle tasks are prohibited from containing RCU read-side critical
- * sections. This function also enables RCU lockdep checking.
+ * This function is invoked towards the end of the scheduler's
+ * initialization process. Before this is called, the idle task might
+ * contain synchronous grace-period primitives (during which time, this idle
+ * task is booting the system, and such primitives are no-ops). After this
+ * function is called, any synchronous grace-period primitives are run as
+ * expedited, with the requesting task driving the grace period forward.
+ * A later core_initcall() rcu_exp_runtime_mode() will switch to full
+ * runtime RCU functionality.
*/
void rcu_scheduler_starting(void)
{
WARN_ON(num_online_cpus() != 1);
WARN_ON(nr_context_switches() > 0);
- rcu_scheduler_active = 1;
+ rcu_test_sync_prims();
+ rcu_scheduler_active = RCU_SCHEDULER_INIT;
+ rcu_test_sync_prims();
}
/*