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rcu: Record ->gp_state for both phases of grace-period initialization

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Grace-period initialization first processes any recent CPU-hotplug
operations, and then initializes state for the new grace period.  These
two phases of initialization are currently not distinguished in debug
prints, but the distinction is valuable in a number of debug situations.
This commit therefore introduces two new values for ->gp_state,
RCU_GP_ONOFF and RCU_GP_INIT, in order to make this distinction.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2018-05-15 15:47:30 -07:00
parent 5773894231
commit fea3f222d3
2 changed files with 10 additions and 4 deletions
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2
kernel/rcu/tree.c
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@ -1891,6 +1891,7 @@ static bool rcu_gp_init(struct rcu_state *rsp)
* for subsequent online CPUs, and that quiescent-state forcing
* will handle subsequent offline CPUs.
*/
rsp->gp_state = RCU_GP_ONOFF;
rcu_for_each_leaf_node(rsp, rnp) {
spin_lock(&rsp->ofl_lock);
raw_spin_lock_irq_rcu_node(rnp);
@ -1950,6 +1951,7 @@ static bool rcu_gp_init(struct rcu_state *rsp)
* The grace period cannot complete until the initialization
* process finishes, because this kthread handles both.
*/
rsp->gp_state = RCU_GP_INIT;
rcu_for_each_node_breadth_first(rsp, rnp) {
rcu_gp_slow(rsp, gp_init_delay);
raw_spin_lock_irqsave_rcu_node(rnp, flags);

12
kernel/rcu/tree.h
View File

@ -380,16 +380,20 @@ struct rcu_state {
#define RCU_GP_IDLE 0 /* Initial state and no GP in progress. */
#define RCU_GP_WAIT_GPS 1 /* Wait for grace-period start. */
#define RCU_GP_DONE_GPS 2 /* Wait done for grace-period start. */
#define RCU_GP_WAIT_FQS 3 /* Wait for force-quiescent-state time. */
#define RCU_GP_DOING_FQS 4 /* Wait done for force-quiescent-state time. */
#define RCU_GP_CLEANUP 5 /* Grace-period cleanup started. */
#define RCU_GP_CLEANED 6 /* Grace-period cleanup complete. */
#define RCU_GP_ONOFF 3 /* Grace-period initialization hotplug. */
#define RCU_GP_INIT 4 /* Grace-period initialization. */
#define RCU_GP_WAIT_FQS 5 /* Wait for force-quiescent-state time. */
#define RCU_GP_DOING_FQS 6 /* Wait done for force-quiescent-state time. */
#define RCU_GP_CLEANUP 7 /* Grace-period cleanup started. */
#define RCU_GP_CLEANED 8 /* Grace-period cleanup complete. */
#ifndef RCU_TREE_NONCORE
static const char * const gp_state_names[] = {
"RCU_GP_IDLE",
"RCU_GP_WAIT_GPS",
"RCU_GP_DONE_GPS",
"RCU_GP_ONOFF",
"RCU_GP_INIT",
"RCU_GP_WAIT_FQS",
"RCU_GP_DOING_FQS",
"RCU_GP_CLEANUP",