rcu: Invert passed_quiesce and rename to cpu_no_qs
This commit inverts the sense of the rcu_data structure's ->passed_quiesce field and renames it to ->cpu_no_qs. This will allow a later commit to use an "aggregate OR" operation to test expedited as well as normal grace periods without added overhead. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney
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97c668b8e9
Коммит
0d43eb34f9
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@ -56,14 +56,14 @@ rcuboost:
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The output of "cat rcu/rcu_preempt/rcudata" looks as follows:
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0!c=30455 g=30456 pq=1/0 qp=1 dt=126535/140000000000000/0 df=2002 of=4 ql=0/0 qs=N... b=10 ci=74572 nci=0 co=1131 ca=716
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1!c=30719 g=30720 pq=1/0 qp=0 dt=132007/140000000000000/0 df=1874 of=10 ql=0/0 qs=N... b=10 ci=123209 nci=0 co=685 ca=982
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2!c=30150 g=30151 pq=1/1 qp=1 dt=138537/140000000000000/0 df=1707 of=8 ql=0/0 qs=N... b=10 ci=80132 nci=0 co=1328 ca=1458
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3 c=31249 g=31250 pq=1/1 qp=0 dt=107255/140000000000000/0 df=1749 of=6 ql=0/450 qs=NRW. b=10 ci=151700 nci=0 co=509 ca=622
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4!c=29502 g=29503 pq=1/0 qp=1 dt=83647/140000000000000/0 df=965 of=5 ql=0/0 qs=N... b=10 ci=65643 nci=0 co=1373 ca=1521
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5 c=31201 g=31202 pq=1/0 qp=1 dt=70422/0/0 df=535 of=7 ql=0/0 qs=.... b=10 ci=58500 nci=0 co=764 ca=698
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6!c=30253 g=30254 pq=1/0 qp=1 dt=95363/140000000000000/0 df=780 of=5 ql=0/0 qs=N... b=10 ci=100607 nci=0 co=1414 ca=1353
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7 c=31178 g=31178 pq=1/0 qp=0 dt=91536/0/0 df=547 of=4 ql=0/0 qs=.... b=10 ci=109819 nci=0 co=1115 ca=969
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0!c=30455 g=30456 cnq=1/0:1 dt=126535/140000000000000/0 df=2002 of=4 ql=0/0 qs=N... b=10 ci=74572 nci=0 co=1131 ca=716
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1!c=30719 g=30720 cnq=1/0:0 dt=132007/140000000000000/0 df=1874 of=10 ql=0/0 qs=N... b=10 ci=123209 nci=0 co=685 ca=982
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2!c=30150 g=30151 cnq=1/1:1 dt=138537/140000000000000/0 df=1707 of=8 ql=0/0 qs=N... b=10 ci=80132 nci=0 co=1328 ca=1458
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3 c=31249 g=31250 cnq=1/1:0 dt=107255/140000000000000/0 df=1749 of=6 ql=0/450 qs=NRW. b=10 ci=151700 nci=0 co=509 ca=622
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4!c=29502 g=29503 cnq=1/0:1 dt=83647/140000000000000/0 df=965 of=5 ql=0/0 qs=N... b=10 ci=65643 nci=0 co=1373 ca=1521
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5 c=31201 g=31202 cnq=1/0:1 dt=70422/0/0 df=535 of=7 ql=0/0 qs=.... b=10 ci=58500 nci=0 co=764 ca=698
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6!c=30253 g=30254 cnq=1/0:1 dt=95363/140000000000000/0 df=780 of=5 ql=0/0 qs=N... b=10 ci=100607 nci=0 co=1414 ca=1353
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7 c=31178 g=31178 cnq=1/0:0 dt=91536/0/0 df=547 of=4 ql=0/0 qs=.... b=10 ci=109819 nci=0 co=1115 ca=969
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This file has one line per CPU, or eight for this 8-CPU system.
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The fields are as follows:
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@ -188,14 +188,14 @@ o "ca" is the number of RCU callbacks that have been adopted by this
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Kernels compiled with CONFIG_RCU_BOOST=y display the following from
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/debug/rcu/rcu_preempt/rcudata:
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0!c=12865 g=12866 pq=1/0 qp=1 dt=83113/140000000000000/0 df=288 of=11 ql=0/0 qs=N... kt=0/O ktl=944 b=10 ci=60709 nci=0 co=748 ca=871
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1 c=14407 g=14408 pq=1/0 qp=0 dt=100679/140000000000000/0 df=378 of=7 ql=0/119 qs=NRW. kt=0/W ktl=9b6 b=10 ci=109740 nci=0 co=589 ca=485
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2 c=14407 g=14408 pq=1/0 qp=0 dt=105486/0/0 df=90 of=9 ql=0/89 qs=NRW. kt=0/W ktl=c0c b=10 ci=83113 nci=0 co=533 ca=490
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3 c=14407 g=14408 pq=1/0 qp=0 dt=107138/0/0 df=142 of=8 ql=0/188 qs=NRW. kt=0/W ktl=b96 b=10 ci=121114 nci=0 co=426 ca=290
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4 c=14405 g=14406 pq=1/0 qp=1 dt=50238/0/0 df=706 of=7 ql=0/0 qs=.... kt=0/W ktl=812 b=10 ci=34929 nci=0 co=643 ca=114
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5!c=14168 g=14169 pq=1/0 qp=0 dt=45465/140000000000000/0 df=161 of=11 ql=0/0 qs=N... kt=0/O ktl=b4d b=10 ci=47712 nci=0 co=677 ca=722
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6 c=14404 g=14405 pq=1/0 qp=0 dt=59454/0/0 df=94 of=6 ql=0/0 qs=.... kt=0/W ktl=e57 b=10 ci=55597 nci=0 co=701 ca=811
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7 c=14407 g=14408 pq=1/0 qp=1 dt=68850/0/0 df=31 of=8 ql=0/0 qs=.... kt=0/W ktl=14bd b=10 ci=77475 nci=0 co=508 ca=1042
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0!c=12865 g=12866 cnq=1/0:1 dt=83113/140000000000000/0 df=288 of=11 ql=0/0 qs=N... kt=0/O ktl=944 b=10 ci=60709 nci=0 co=748 ca=871
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1 c=14407 g=14408 cnq=1/0:0 dt=100679/140000000000000/0 df=378 of=7 ql=0/119 qs=NRW. kt=0/W ktl=9b6 b=10 ci=109740 nci=0 co=589 ca=485
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2 c=14407 g=14408 cnq=1/0:0 dt=105486/0/0 df=90 of=9 ql=0/89 qs=NRW. kt=0/W ktl=c0c b=10 ci=83113 nci=0 co=533 ca=490
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3 c=14407 g=14408 cnq=1/0:0 dt=107138/0/0 df=142 of=8 ql=0/188 qs=NRW. kt=0/W ktl=b96 b=10 ci=121114 nci=0 co=426 ca=290
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4 c=14405 g=14406 cnq=1/0:1 dt=50238/0/0 df=706 of=7 ql=0/0 qs=.... kt=0/W ktl=812 b=10 ci=34929 nci=0 co=643 ca=114
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5!c=14168 g=14169 cnq=1/0:0 dt=45465/140000000000000/0 df=161 of=11 ql=0/0 qs=N... kt=0/O ktl=b4d b=10 ci=47712 nci=0 co=677 ca=722
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6 c=14404 g=14405 cnq=1/0:0 dt=59454/0/0 df=94 of=6 ql=0/0 qs=.... kt=0/W ktl=e57 b=10 ci=55597 nci=0 co=701 ca=811
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7 c=14407 g=14408 cnq=1/0:1 dt=68850/0/0 df=31 of=8 ql=0/0 qs=.... kt=0/W ktl=14bd b=10 ci=77475 nci=0 co=508 ca=1042
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This is similar to the output discussed above, but contains the following
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additional fields:
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@ -245,21 +245,21 @@ static int rcu_gp_in_progress(struct rcu_state *rsp)
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*/
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void rcu_sched_qs(void)
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{
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if (!__this_cpu_read(rcu_sched_data.passed_quiesce)) {
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if (__this_cpu_read(rcu_sched_data.cpu_no_qs)) {
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trace_rcu_grace_period(TPS("rcu_sched"),
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__this_cpu_read(rcu_sched_data.gpnum),
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TPS("cpuqs"));
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__this_cpu_write(rcu_sched_data.passed_quiesce, 1);
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__this_cpu_write(rcu_sched_data.cpu_no_qs, false);
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}
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}
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void rcu_bh_qs(void)
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{
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if (!__this_cpu_read(rcu_bh_data.passed_quiesce)) {
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if (__this_cpu_read(rcu_bh_data.cpu_no_qs)) {
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trace_rcu_grace_period(TPS("rcu_bh"),
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__this_cpu_read(rcu_bh_data.gpnum),
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TPS("cpuqs"));
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__this_cpu_write(rcu_bh_data.passed_quiesce, 1);
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__this_cpu_write(rcu_bh_data.cpu_no_qs, false);
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}
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}
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@ -1744,7 +1744,7 @@ static bool __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp,
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*/
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rdp->gpnum = rnp->gpnum;
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trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("cpustart"));
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rdp->passed_quiesce = 0;
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rdp->cpu_no_qs = true;
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rdp->rcu_qs_ctr_snap = __this_cpu_read(rcu_qs_ctr);
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rdp->core_needs_qs = !!(rnp->qsmask & rdp->grpmask);
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zero_cpu_stall_ticks(rdp);
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@ -2337,7 +2337,7 @@ rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp)
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rnp = rdp->mynode;
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raw_spin_lock_irqsave(&rnp->lock, flags);
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smp_mb__after_unlock_lock();
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if ((rdp->passed_quiesce == 0 &&
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if ((rdp->cpu_no_qs &&
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rdp->rcu_qs_ctr_snap == __this_cpu_read(rcu_qs_ctr)) ||
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rdp->gpnum != rnp->gpnum || rnp->completed == rnp->gpnum ||
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rdp->gpwrap) {
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@ -2348,7 +2348,7 @@ rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp)
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* We will instead need a new quiescent state that lies
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* within the current grace period.
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*/
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rdp->passed_quiesce = 0; /* need qs for new gp. */
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rdp->cpu_no_qs = true; /* need qs for new gp. */
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rdp->rcu_qs_ctr_snap = __this_cpu_read(rcu_qs_ctr);
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raw_spin_unlock_irqrestore(&rnp->lock, flags);
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return;
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@ -2395,7 +2395,7 @@ rcu_check_quiescent_state(struct rcu_state *rsp, struct rcu_data *rdp)
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* Was there a quiescent state since the beginning of the grace
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* period? If no, then exit and wait for the next call.
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*/
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if (!rdp->passed_quiesce &&
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if (rdp->cpu_no_qs &&
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rdp->rcu_qs_ctr_snap == __this_cpu_read(rcu_qs_ctr))
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return;
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@ -3828,11 +3828,11 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp)
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/* Is the RCU core waiting for a quiescent state from this CPU? */
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if (rcu_scheduler_fully_active &&
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rdp->core_needs_qs && !rdp->passed_quiesce &&
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rdp->core_needs_qs && rdp->cpu_no_qs &&
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rdp->rcu_qs_ctr_snap == __this_cpu_read(rcu_qs_ctr)) {
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rdp->n_rp_core_needs_qs++;
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} else if (rdp->core_needs_qs &&
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(rdp->passed_quiesce ||
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(!rdp->cpu_no_qs ||
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rdp->rcu_qs_ctr_snap != __this_cpu_read(rcu_qs_ctr))) {
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rdp->n_rp_report_qs++;
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return 1;
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@ -4155,7 +4155,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
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rdp->beenonline = true; /* We have now been online. */
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rdp->gpnum = rnp->completed; /* Make CPU later note any new GP. */
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rdp->completed = rnp->completed;
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rdp->passed_quiesce = false;
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rdp->cpu_no_qs = true;
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rdp->rcu_qs_ctr_snap = per_cpu(rcu_qs_ctr, cpu);
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rdp->core_needs_qs = false;
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trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("cpuonl"));
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@ -302,7 +302,7 @@ struct rcu_data {
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/* is aware of having started. */
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unsigned long rcu_qs_ctr_snap;/* Snapshot of rcu_qs_ctr to check */
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/* for rcu_all_qs() invocations. */
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bool passed_quiesce; /* User-mode/idle loop etc. */
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bool cpu_no_qs; /* No QS yet for this CPU. */
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bool core_needs_qs; /* Core waits for quiesc state. */
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bool beenonline; /* CPU online at least once. */
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bool gpwrap; /* Possible gpnum/completed wrap. */
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@ -265,11 +265,11 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp,
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*/
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static void rcu_preempt_qs(void)
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{
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if (!__this_cpu_read(rcu_data_p->passed_quiesce)) {
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if (__this_cpu_read(rcu_data_p->cpu_no_qs)) {
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trace_rcu_grace_period(TPS("rcu_preempt"),
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__this_cpu_read(rcu_data_p->gpnum),
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TPS("cpuqs"));
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__this_cpu_write(rcu_data_p->passed_quiesce, 1);
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__this_cpu_write(rcu_data_p->cpu_no_qs, false);
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barrier(); /* Coordinate with rcu_preempt_check_callbacks(). */
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current->rcu_read_unlock_special.b.need_qs = false;
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}
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@ -620,7 +620,7 @@ static void rcu_preempt_check_callbacks(void)
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}
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if (t->rcu_read_lock_nesting > 0 &&
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__this_cpu_read(rcu_data_p->core_needs_qs) &&
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!__this_cpu_read(rcu_data_p->passed_quiesce))
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__this_cpu_read(rcu_data_p->cpu_no_qs))
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t->rcu_read_unlock_special.b.need_qs = true;
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}
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@ -117,11 +117,11 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
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if (!rdp->beenonline)
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return;
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seq_printf(m, "%3d%cc=%ld g=%ld pq=%d/%d qp=%d",
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seq_printf(m, "%3d%cc=%ld g=%ld cnq=%d/%d:%d",
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rdp->cpu,
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cpu_is_offline(rdp->cpu) ? '!' : ' ',
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ulong2long(rdp->completed), ulong2long(rdp->gpnum),
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rdp->passed_quiesce,
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rdp->cpu_no_qs,
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rdp->rcu_qs_ctr_snap == per_cpu(rcu_qs_ctr, rdp->cpu),
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rdp->core_needs_qs);
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seq_printf(m, " dt=%d/%llx/%d df=%lu",
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