Commit 2dba2230 authored by Valentin Schneider's avatar Valentin Schneider Committed by Neeraj Upadhyay
Browse files

rcu: Rename struct rcu_data .dynticks_snap into .watching_snap 



The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, and the snapshot helpers are now prefix by
"rcu_watching". Reflect that change into the storage variables for these
snapshots.

Signed-off-by: default avatarValentin Schneider <vschneid@redhat.com>
Reviewed-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Signed-off-by: default avatarNeeraj Upadhyay <neeraj.upadhyay@kernel.org>
parent fc1096ab

Documentation/RCU/Design/Data-Structures/Data-Structures.rst

+2 −2
Original line number Diff line number Diff line
@@ -921,10 +921,10 @@ This portion of the ``rcu_data`` structure is declared as follows: 


::



     1   int dynticks_snap;

     1   int watching_snap;

     2   unsigned long dynticks_fqs;



The ``->dynticks_snap`` field is used to take a snapshot of the

The ``->watching_snap`` field is used to take a snapshot of the

corresponding CPU's dyntick-idle state when forcing quiescent states,

and is therefore accessed from other CPUs. Finally, the

``->dynticks_fqs`` field is used to count the number of times this CPU

kernel/rcu/tree.c

+3 −3
Original line number Diff line number Diff line
@@ -793,8 +793,8 @@ static int dyntick_save_progress_counter(struct rcu_data *rdp) 
	 * Ordering between remote CPU's pre idle accesses and post grace period

	 * updater's accesses is enforced by the below acquire semantic.

	 */

	rdp->dynticks_snap = ct_rcu_watching_cpu_acquire(rdp->cpu);

	if (rcu_watching_snap_in_eqs(rdp->dynticks_snap)) {

	rdp->watching_snap = ct_rcu_watching_cpu_acquire(rdp->cpu);

	if (rcu_watching_snap_in_eqs(rdp->watching_snap)) {

		trace_rcu_fqs(rcu_state.name, rdp->gp_seq, rdp->cpu, TPS("dti"));

		rcu_gpnum_ovf(rdp->mynode, rdp);

		return 1;
@@ -826,7 +826,7 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) 
	 * read-side critical section that started before the beginning

	 * of the current RCU grace period.

	 */

	if (rcu_watching_snap_stopped_since(rdp, rdp->dynticks_snap)) {

	if (rcu_watching_snap_stopped_since(rdp, rdp->watching_snap)) {

		trace_rcu_fqs(rcu_state.name, rdp->gp_seq, rdp->cpu, TPS("dti"));

		rcu_gpnum_ovf(rnp, rdp);

		return 1;

kernel/rcu/tree.h

+1 −1
Original line number Diff line number Diff line
@@ -206,7 +206,7 @@ struct rcu_data { 
	long		blimit;		/* Upper limit on a processed batch */



	/* 3) dynticks interface. */

	int dynticks_snap;		/* Per-GP tracking for dynticks. */

	int  watching_snap;		/* Per-GP tracking for dynticks. */

	bool rcu_need_heavy_qs;		/* GP old, so heavy quiescent state! */

	bool rcu_urgent_qs;		/* GP old need light quiescent state. */

	bool rcu_forced_tick;		/* Forced tick to provide QS. */