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>

diff --git a/Documentation/RCU/trace.txt b/Documentation/RCU/trace.txt
index 97f17e9decdaeced345689e9eb410a79f642b10d..ec6998b1b6d04f3139ed6c066537cc059c89838d 100644 (file)
--- a/Documentation/RCU/trace.txt
+++ b/Documentation/RCU/trace.txt
@@ -56,14 +56,14 @@ rcuboost:
 
 The output of "cat rcu/rcu_preempt/rcudata" looks as follows:
 
-  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
-  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
-  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
-  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
-  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
-  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
-  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
-  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
+  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
+  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
+  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
+  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
+  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
+  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
+  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
+  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
 
 This file has one line per CPU, or eight for this 8-CPU system.
 The fields are as follows:
@@ -188,14 +188,14 @@ o "ca" is the number of RCU callbacks that have been adopted by this
 Kernels compiled with CONFIG_RCU_BOOST=y display the following from
 /debug/rcu/rcu_preempt/rcudata:
 
-  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
-  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
-  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
-  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
-  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
-  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
-  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
-  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
+  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
+  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
+  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
+  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
+  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
+  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
+  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
+  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
 
 This is similar to the output discussed above, but contains the following
 additional fields:

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 7c158ffc77699c16d13f1ebde5d6c28d5e8b2853..31e7021ced4d22bd5cee28b28f0f3384ed11d271 100644 (file)
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -245,21 +245,21 @@ static int rcu_gp_in_progress(struct rcu_state *rsp)
  */
 void rcu_sched_qs(void)
 {
-       if (!__this_cpu_read(rcu_sched_data.passed_quiesce)) {
+       if (__this_cpu_read(rcu_sched_data.cpu_no_qs)) {
                trace_rcu_grace_period(TPS("rcu_sched"),
                                       __this_cpu_read(rcu_sched_data.gpnum),
                                       TPS("cpuqs"));
-               __this_cpu_write(rcu_sched_data.passed_quiesce, 1);
+               __this_cpu_write(rcu_sched_data.cpu_no_qs, false);
        }
 }
 
 void rcu_bh_qs(void)
 {
-       if (!__this_cpu_read(rcu_bh_data.passed_quiesce)) {
+       if (__this_cpu_read(rcu_bh_data.cpu_no_qs)) {
                trace_rcu_grace_period(TPS("rcu_bh"),
                                       __this_cpu_read(rcu_bh_data.gpnum),
                                       TPS("cpuqs"));
-               __this_cpu_write(rcu_bh_data.passed_quiesce, 1);
+               __this_cpu_write(rcu_bh_data.cpu_no_qs, false);
        }
 }
 
@@ -1744,7 +1744,7 @@ static bool __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp,
                 */
                rdp->gpnum = rnp->gpnum;
                trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("cpustart"));
-               rdp->passed_quiesce = 0;
+               rdp->cpu_no_qs = true;
                rdp->rcu_qs_ctr_snap = __this_cpu_read(rcu_qs_ctr);
                rdp->core_needs_qs = !!(rnp->qsmask & rdp->grpmask);
                zero_cpu_stall_ticks(rdp);
@@ -2337,7 +2337,7 @@ rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp)
        rnp = rdp->mynode;
        raw_spin_lock_irqsave(&rnp->lock, flags);
        smp_mb__after_unlock_lock();
-       if ((rdp->passed_quiesce == 0 &&
+       if ((rdp->cpu_no_qs &&
             rdp->rcu_qs_ctr_snap == __this_cpu_read(rcu_qs_ctr)) ||
            rdp->gpnum != rnp->gpnum || rnp->completed == rnp->gpnum ||
            rdp->gpwrap) {
@@ -2348,7 +2348,7 @@ rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp)
                 * We will instead need a new quiescent state that lies
                 * within the current grace period.
                 */
-               rdp->passed_quiesce = 0;        /* need qs for new gp. */
+               rdp->cpu_no_qs = true;  /* need qs for new gp. */
                rdp->rcu_qs_ctr_snap = __this_cpu_read(rcu_qs_ctr);
                raw_spin_unlock_irqrestore(&rnp->lock, flags);
                return;
@@ -2395,7 +2395,7 @@ rcu_check_quiescent_state(struct rcu_state *rsp, struct rcu_data *rdp)
         * Was there a quiescent state since the beginning of the grace
         * period? If no, then exit and wait for the next call.
         */
-       if (!rdp->passed_quiesce &&
+       if (rdp->cpu_no_qs &&
            rdp->rcu_qs_ctr_snap == __this_cpu_read(rcu_qs_ctr))
                return;
 
@@ -3828,11 +3828,11 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp)
 
        /* Is the RCU core waiting for a quiescent state from this CPU? */
        if (rcu_scheduler_fully_active &&
-           rdp->core_needs_qs && !rdp->passed_quiesce &&
+           rdp->core_needs_qs && rdp->cpu_no_qs &&
            rdp->rcu_qs_ctr_snap == __this_cpu_read(rcu_qs_ctr)) {
                rdp->n_rp_core_needs_qs++;
        } else if (rdp->core_needs_qs &&
-                  (rdp->passed_quiesce ||
+                  (!rdp->cpu_no_qs ||
                    rdp->rcu_qs_ctr_snap != __this_cpu_read(rcu_qs_ctr))) {
                rdp->n_rp_report_qs++;
                return 1;
@@ -4155,7 +4155,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
        rdp->beenonline = true;  /* We have now been online. */
        rdp->gpnum = rnp->completed; /* Make CPU later note any new GP. */
        rdp->completed = rnp->completed;
-       rdp->passed_quiesce = false;
+       rdp->cpu_no_qs = true;
        rdp->rcu_qs_ctr_snap = per_cpu(rcu_qs_ctr, cpu);
        rdp->core_needs_qs = false;
        trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("cpuonl"));

diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 4a0f30676ba82d9de267a7e6f78a45eff29b4da3..ded4ceebed765d1e57ee346d724e33e6a5d125a3 100644 (file)
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -302,7 +302,7 @@ struct rcu_data {
                                        /*  is aware of having started. */
        unsigned long   rcu_qs_ctr_snap;/* Snapshot of rcu_qs_ctr to check */
                                        /*  for rcu_all_qs() invocations. */
-       bool            passed_quiesce; /* User-mode/idle loop etc. */
+       bool            cpu_no_qs;      /* No QS yet for this CPU. */
        bool            core_needs_qs;  /* Core waits for quiesc state. */
        bool            beenonline;     /* CPU online at least once. */
        bool            gpwrap;         /* Possible gpnum/completed wrap. */

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index e33b4f3b8e0a833d428e5d5eb90834104b1a2736..6977ff0dccb94295843675da7973eb0e364421b8 100644 (file)
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -265,11 +265,11 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp,
  */
 static void rcu_preempt_qs(void)
 {
-       if (!__this_cpu_read(rcu_data_p->passed_quiesce)) {
+       if (__this_cpu_read(rcu_data_p->cpu_no_qs)) {
                trace_rcu_grace_period(TPS("rcu_preempt"),
                                       __this_cpu_read(rcu_data_p->gpnum),
                                       TPS("cpuqs"));
-               __this_cpu_write(rcu_data_p->passed_quiesce, 1);
+               __this_cpu_write(rcu_data_p->cpu_no_qs, false);
                barrier(); /* Coordinate with rcu_preempt_check_callbacks(). */
                current->rcu_read_unlock_special.b.need_qs = false;
        }
@@ -620,7 +620,7 @@ static void rcu_preempt_check_callbacks(void)
        }
        if (t->rcu_read_lock_nesting > 0 &&
            __this_cpu_read(rcu_data_p->core_needs_qs) &&
-           !__this_cpu_read(rcu_data_p->passed_quiesce))
+           __this_cpu_read(rcu_data_p->cpu_no_qs))
                t->rcu_read_unlock_special.b.need_qs = true;
 }
 

diff --git a/kernel/rcu/tree_trace.c b/kernel/rcu/tree_trace.c
index 4ac25f8520d6c5d86e9d322ced0602fbe0b34af8..d373e57109b89043f6641d18b85bb83e249e538d 100644 (file)
--- a/kernel/rcu/tree_trace.c
+++ b/kernel/rcu/tree_trace.c
@@ -117,11 +117,11 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
 
        if (!rdp->beenonline)
                return;
-       seq_printf(m, "%3d%cc=%ld g=%ld pq=%d/%d qp=%d",
+       seq_printf(m, "%3d%cc=%ld g=%ld cnq=%d/%d:%d",
                   rdp->cpu,
                   cpu_is_offline(rdp->cpu) ? '!' : ' ',
                   ulong2long(rdp->completed), ulong2long(rdp->gpnum),
-                  rdp->passed_quiesce,
+                  rdp->cpu_no_qs,
                   rdp->rcu_qs_ctr_snap == per_cpu(rcu_qs_ctr, rdp->cpu),
                   rdp->core_needs_qs);
        seq_printf(m, " dt=%d/%llx/%d df=%lu",