mirror of https://gitee.com/openkylin/linux.git
rcu: Remove ->gpnum and ->completed
Now that everything has been converted to use ->gp_seq instead of ->gpnum and ->completed, this commit removes ->gpnum and ->completed. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney
parent
fee5997c17
commit
ff3bb6f4d0
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@ -95,8 +95,6 @@ struct rcu_state sname##_state = { \
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.rda = &sname##_data, \
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.call = cr, \
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.gp_state = RCU_GP_IDLE, \
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.gpnum = 0UL - 300UL, \
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.completed = 0UL - 300UL, \
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.gp_seq = (0UL - 300UL) << RCU_SEQ_CTR_SHIFT, \
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.barrier_mutex = __MUTEX_INITIALIZER(sname##_state.barrier_mutex), \
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.name = RCU_STATE_NAME(sname), \
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@ -1349,8 +1347,6 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gp_seq)
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struct rcu_node *rnp = rcu_get_root(rsp);
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long totqlen = 0;
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WARN_ON_ONCE(gp_seq & 0x2); /* Remove when ->gpnum removed. */
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/* Kick and suppress, if so configured. */
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rcu_stall_kick_kthreads(rsp);
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if (rcu_cpu_stall_suppress)
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@ -1582,8 +1578,6 @@ static bool rcu_start_this_gp(struct rcu_node *rnp, struct rcu_data *rdp,
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* not be released.
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*/
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raw_lockdep_assert_held_rcu_node(rnp);
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WARN_ON_ONCE(c & 0x2); /* Catch any lingering use of ->gpnum. */
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WARN_ON_ONCE(((rnp->completed << RCU_SEQ_CTR_SHIFT) >> RCU_SEQ_CTR_SHIFT) != rcu_seq_ctr(rnp->gp_seq)); /* Catch any ->completed/->gp_seq mismatches. */
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trace_rcu_this_gp(rnp, rdp, c, TPS("Startleaf"));
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for (rnp_root = rnp; 1; rnp_root = rnp_root->parent) {
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if (rnp_root != rnp)
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@ -1757,8 +1751,6 @@ static bool __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp,
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if (rcu_seq_completed_gp(rdp->gp_seq, rnp->gp_seq) ||
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unlikely(READ_ONCE(rdp->gpwrap))) {
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ret = rcu_advance_cbs(rsp, rnp, rdp); /* Advance callbacks. */
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/* Remember that we saw this grace-period completion. */
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rdp->completed = rnp->completed;
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trace_rcu_grace_period(rsp->name, rdp->gp_seq, TPS("cpuend"));
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} else {
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ret = rcu_accelerate_cbs(rsp, rnp, rdp); /* Recent callbacks. */
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@ -1772,7 +1764,6 @@ static bool __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp,
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* set up to detect a quiescent state, otherwise don't
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* go looking for one.
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*/
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rdp->gpnum = rnp->gpnum;
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trace_rcu_grace_period(rsp->name, rdp->gp_seq, TPS("cpustart"));
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need_gp = !!(rnp->qsmask & rdp->grpmask);
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rdp->cpu_no_qs.b.norm = need_gp;
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@ -1843,13 +1834,8 @@ static bool rcu_gp_init(struct rcu_state *rsp)
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/* Advance to a new grace period and initialize state. */
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record_gp_stall_check_time(rsp);
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/* Record GP times before starting GP, hence smp_store_release(). */
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WARN_ON_ONCE(rsp->gpnum << RCU_SEQ_CTR_SHIFT != rsp->gp_seq);
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smp_store_release(&rsp->gpnum, rsp->gpnum + 1);
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smp_mb(); /* Pairs with barriers in stall-warning code. */
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/* Record GP times before starting GP, hence rcu_seq_start(). */
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rcu_seq_start(&rsp->gp_seq);
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if (WARN_ON_ONCE(((rnp->completed << RCU_SEQ_CTR_SHIFT) >> RCU_SEQ_CTR_SHIFT) != rcu_seq_ctr(rnp->gp_seq))) /* Catch any ->completed/->gp_seq mismatches. */
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pr_info("%s ->completed: %#lx (%#lx) ->gp_seq %#lx (%#lx)\n", __func__, rnp->completed, (rnp->completed << RCU_SEQ_CTR_SHIFT) >> RCU_SEQ_CTR_SHIFT, rnp->gp_seq, rcu_seq_ctr(rnp->gp_seq));
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trace_rcu_grace_period(rsp->name, rsp->gp_seq, TPS("start"));
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raw_spin_unlock_irq_rcu_node(rnp);
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@ -1920,9 +1906,6 @@ static bool rcu_gp_init(struct rcu_state *rsp)
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rdp = this_cpu_ptr(rsp->rda);
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rcu_preempt_check_blocked_tasks(rnp);
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rnp->qsmask = rnp->qsmaskinit;
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WRITE_ONCE(rnp->gpnum, rsp->gpnum);
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if (WARN_ON_ONCE(rnp->completed != rsp->completed))
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WRITE_ONCE(rnp->completed, rsp->completed);
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WRITE_ONCE(rnp->gp_seq, rsp->gp_seq);
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if (rnp == rdp->mynode)
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(void)__note_gp_changes(rsp, rnp, rdp);
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@ -2012,13 +1995,13 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
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raw_spin_unlock_irq_rcu_node(rnp);
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/*
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* Propagate new ->completed value to rcu_node structures so
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* that other CPUs don't have to wait until the start of the next
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* grace period to process their callbacks. This also avoids
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* some nasty RCU grace-period initialization races by forcing
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* the end of the current grace period to be completely recorded in
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* all of the rcu_node structures before the beginning of the next
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* grace period is recorded in any of the rcu_node structures.
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* Propagate new ->gp_seq value to rcu_node structures so that
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* other CPUs don't have to wait until the start of the next grace
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* period to process their callbacks. This also avoids some nasty
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* RCU grace-period initialization races by forcing the end of
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* the current grace period to be completely recorded in all of
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* the rcu_node structures before the beginning of the next grace
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* period is recorded in any of the rcu_node structures.
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*/
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new_gp_seq = rsp->gp_seq;
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rcu_seq_end(&new_gp_seq);
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@ -2027,7 +2010,6 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
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if (WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)))
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dump_blkd_tasks(rnp, 10);
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WARN_ON_ONCE(rnp->qsmask);
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WRITE_ONCE(rnp->completed, rsp->gpnum);
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WRITE_ONCE(rnp->gp_seq, new_gp_seq);
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rdp = this_cpu_ptr(rsp->rda);
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if (rnp == rdp->mynode)
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@ -2045,7 +2027,6 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
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raw_spin_lock_irq_rcu_node(rnp); /* GP before rsp->gp_seq update. */
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/* Declare grace period done. */
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WRITE_ONCE(rsp->completed, rsp->gpnum);
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rcu_seq_end(&rsp->gp_seq);
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trace_rcu_grace_period(rsp->name, rsp->gp_seq, TPS("end"));
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rsp->gp_state = RCU_GP_IDLE;
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@ -3496,9 +3477,9 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)
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/*
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* Initialize a CPU's per-CPU RCU data. Note that only one online or
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* offline event can be happening at a given time. Note also that we
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* can accept some slop in the rsp->completed access due to the fact
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* that this CPU cannot possibly have any RCU callbacks in flight yet.
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* offline event can be happening at a given time. Note also that we can
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* accept some slop in the rsp->gp_seq access due to the fact that this
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* CPU cannot possibly have any RCU callbacks in flight yet.
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*/
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static void
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rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
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@ -3527,8 +3508,6 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
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rnp = rdp->mynode;
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raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */
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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->gp_seq = rnp->gp_seq;
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rdp->gp_seq_needed = rnp->gp_seq;
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rdp->cpu_no_qs.b.norm = true;
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@ -3908,8 +3887,6 @@ static void __init rcu_init_one(struct rcu_state *rsp)
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raw_spin_lock_init(&rnp->fqslock);
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lockdep_set_class_and_name(&rnp->fqslock,
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&rcu_fqs_class[i], fqs[i]);
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rnp->gpnum = rsp->gpnum;
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rnp->completed = rsp->completed;
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rnp->gp_seq = rsp->gp_seq;
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rnp->gp_seq_needed = rsp->gp_seq;
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rnp->completedqs = rsp->gp_seq;
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@ -81,12 +81,6 @@ struct rcu_node {
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raw_spinlock_t __private lock; /* Root rcu_node's lock protects */
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/* some rcu_state fields as well as */
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/* following. */
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unsigned long gpnum; /* Current grace period for this node. */
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/* This will either be equal to or one */
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/* behind the root rcu_node's gpnum. */
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unsigned long completed; /* Last GP completed for this node. */
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/* This will either be equal to or one */
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/* behind the root rcu_node's gpnum. */
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unsigned long gp_seq; /* Track rsp->rcu_gp_seq. */
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unsigned long gp_seq_needed; /* Track rsp->rcu_gp_seq_needed. */
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unsigned long completedqs; /* All QSes done for this node. */
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@ -192,10 +186,6 @@ union rcu_noqs {
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/* Per-CPU data for read-copy update. */
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struct rcu_data {
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/* 1) quiescent-state and grace-period handling : */
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unsigned long completed; /* Track rsp->completed gp number */
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/* in order to detect GP end. */
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unsigned long gpnum; /* Highest gp number that this CPU */
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/* is aware of having started. */
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unsigned long gp_seq; /* Track rsp->rcu_gp_seq counter. */
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unsigned long gp_seq_needed; /* Track rsp->rcu_gp_seq_needed ctr. */
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unsigned long rcu_qs_ctr_snap;/* Snapshot of rcu_qs_ctr to check */
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@ -203,7 +193,7 @@ struct rcu_data {
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union rcu_noqs cpu_no_qs; /* No QSes 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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bool gpwrap; /* Possible ->gp_seq wrap. */
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struct rcu_node *mynode; /* This CPU's leaf of hierarchy */
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unsigned long grpmask; /* Mask to apply to leaf qsmask. */
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unsigned long ticks_this_gp; /* The number of scheduling-clock */
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@ -328,8 +318,6 @@ struct rcu_state {
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u8 boost ____cacheline_internodealigned_in_smp;
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/* Subject to priority boost. */
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unsigned long gpnum; /* Current gp number. */
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unsigned long completed; /* # of last completed gp. */
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unsigned long gp_seq; /* Grace-period sequence #. */
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struct task_struct *gp_kthread; /* Task for grace periods. */
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struct swait_queue_head gp_wq; /* Where GP task waits. */
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@ -690,7 +690,7 @@ static int rcu_print_task_exp_stall(struct rcu_node *rnp)
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* Check that the list of blocked tasks for the newly completed grace
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* period is in fact empty. It is a serious bug to complete a grace
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* period that still has RCU readers blocked! This function must be
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* invoked -before- updating this rnp's ->gpnum, and the rnp's ->lock
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* invoked -before- updating this rnp's ->gp_seq, and the rnp's ->lock
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* must be held by the caller.
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*
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* Also, if there are blocked tasks on the list, they automatically
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