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Date: Wed, 29 Aug 2018 15:38:45 -0700
From: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To: linux-kernel@...r.kernel.org
Cc: mingo@...nel.org, jiangshanlai@...il.com, dipankar@...ibm.com,
akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com,
josh@...htriplett.org, tglx@...utronix.de, peterz@...radead.org,
rostedt@...dmis.org, dhowells@...hat.com, edumazet@...gle.com,
fweisbec@...il.com, oleg@...hat.com, joel@...lfernandes.org,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 43/52] rcu: Remove for_each_rcu_flavor() flavor-traversal macro
Now that there is only ever a single flavor of RCU in a given kernel
build, there isn't a whole lot of point in having a flavor-traversal
macro. This commit therefore removes it and converts calls to it to
straightline code, inlining trivial functions as appropriate.
Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
---
kernel/rcu/tree.c | 172 ++++++++++++++++-----------------------
kernel/rcu/tree.h | 7 --
kernel/rcu/tree_plugin.h | 59 +++++---------
3 files changed, 92 insertions(+), 146 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index bc52f8c16faf..cec025cc1f87 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -85,8 +85,6 @@ struct rcu_state rcu_state = {
.ofl_lock = __SPIN_LOCK_UNLOCKED(rcu_state.ofl_lock),
};
-LIST_HEAD(rcu_struct_flavors);
-
/* Dump rcu_node combining tree at boot to verify correct setup. */
static bool dump_tree;
module_param(dump_tree, bool, 0444);
@@ -568,31 +566,28 @@ void show_rcu_gp_kthreads(void)
int cpu;
struct rcu_data *rdp;
struct rcu_node *rnp;
- struct rcu_state *rsp;
- for_each_rcu_flavor(rsp) {
- pr_info("%s: wait state: %d ->state: %#lx\n",
- rsp->name, rsp->gp_state, rsp->gp_kthread->state);
- rcu_for_each_node_breadth_first(rnp) {
- if (ULONG_CMP_GE(rsp->gp_seq, rnp->gp_seq_needed))
- continue;
- pr_info("\trcu_node %d:%d ->gp_seq %lu ->gp_seq_needed %lu\n",
- rnp->grplo, rnp->grphi, rnp->gp_seq,
- rnp->gp_seq_needed);
- if (!rcu_is_leaf_node(rnp))
+ pr_info("%s: wait state: %d ->state: %#lx\n", rcu_state.name,
+ rcu_state.gp_state, rcu_state.gp_kthread->state);
+ rcu_for_each_node_breadth_first(rnp) {
+ if (ULONG_CMP_GE(rcu_state.gp_seq, rnp->gp_seq_needed))
+ continue;
+ pr_info("\trcu_node %d:%d ->gp_seq %lu ->gp_seq_needed %lu\n",
+ rnp->grplo, rnp->grphi, rnp->gp_seq,
+ rnp->gp_seq_needed);
+ if (!rcu_is_leaf_node(rnp))
+ continue;
+ for_each_leaf_node_possible_cpu(rnp, cpu) {
+ rdp = per_cpu_ptr(&rcu_data, cpu);
+ if (rdp->gpwrap ||
+ ULONG_CMP_GE(rcu_state.gp_seq,
+ rdp->gp_seq_needed))
continue;
- for_each_leaf_node_possible_cpu(rnp, cpu) {
- rdp = per_cpu_ptr(&rcu_data, cpu);
- if (rdp->gpwrap ||
- ULONG_CMP_GE(rsp->gp_seq,
- rdp->gp_seq_needed))
- continue;
- pr_info("\tcpu %d ->gp_seq_needed %lu\n",
- cpu, rdp->gp_seq_needed);
- }
+ pr_info("\tcpu %d ->gp_seq_needed %lu\n",
+ cpu, rdp->gp_seq_needed);
}
- /* sched_show_task(rsp->gp_kthread); */
}
+ /* sched_show_task(rcu_state.gp_kthread); */
}
EXPORT_SYMBOL_GPL(show_rcu_gp_kthreads);
@@ -638,7 +633,6 @@ static struct rcu_node *rcu_get_root(void)
*/
static void rcu_eqs_enter(bool user)
{
- struct rcu_state *rsp;
struct rcu_data *rdp;
struct rcu_dynticks *rdtp;
@@ -655,10 +649,8 @@ static void rcu_eqs_enter(bool user)
lockdep_assert_irqs_disabled();
trace_rcu_dyntick(TPS("Start"), rdtp->dynticks_nesting, 0, rdtp->dynticks);
WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !user && !is_idle_task(current));
- for_each_rcu_flavor(rsp) {
- rdp = this_cpu_ptr(&rcu_data);
- do_nocb_deferred_wakeup(rdp);
- }
+ rdp = this_cpu_ptr(&rcu_data);
+ do_nocb_deferred_wakeup(rdp);
rcu_prepare_for_idle();
rcu_preempt_deferred_qs(current);
WRITE_ONCE(rdtp->dynticks_nesting, 0); /* Avoid irq-access tearing. */
@@ -1023,21 +1015,17 @@ bool rcu_lockdep_current_cpu_online(void)
{
struct rcu_data *rdp;
struct rcu_node *rnp;
- struct rcu_state *rsp;
+ bool ret = false;
if (in_nmi() || !rcu_scheduler_fully_active)
return true;
preempt_disable();
- for_each_rcu_flavor(rsp) {
- rdp = this_cpu_ptr(&rcu_data);
- rnp = rdp->mynode;
- if (rdp->grpmask & rcu_rnp_online_cpus(rnp)) {
- preempt_enable();
- return true;
- }
- }
+ rdp = this_cpu_ptr(&rcu_data);
+ rnp = rdp->mynode;
+ if (rdp->grpmask & rcu_rnp_online_cpus(rnp))
+ ret = true;
preempt_enable();
- return false;
+ return ret;
}
EXPORT_SYMBOL_GPL(rcu_lockdep_current_cpu_online);
@@ -1515,10 +1503,7 @@ static void check_cpu_stall(struct rcu_data *rdp)
*/
void rcu_cpu_stall_reset(void)
{
- struct rcu_state *rsp;
-
- for_each_rcu_flavor(rsp)
- WRITE_ONCE(rsp->jiffies_stall, jiffies + ULONG_MAX / 2);
+ WRITE_ONCE(rcu_state.jiffies_stall, jiffies + ULONG_MAX / 2);
}
/* Trace-event wrapper function for trace_rcu_future_grace_period. */
@@ -3133,17 +3118,12 @@ static bool rcu_cpu_has_callbacks(bool *all_lazy)
bool al = true;
bool hc = false;
struct rcu_data *rdp;
- struct rcu_state *rsp;
- for_each_rcu_flavor(rsp) {
- rdp = this_cpu_ptr(&rcu_data);
- if (rcu_segcblist_empty(&rdp->cblist))
- continue;
+ rdp = this_cpu_ptr(&rcu_data);
+ if (!rcu_segcblist_empty(&rdp->cblist)) {
hc = true;
- if (rcu_segcblist_n_nonlazy_cbs(&rdp->cblist) || !all_lazy) {
+ if (rcu_segcblist_n_nonlazy_cbs(&rdp->cblist))
al = false;
- break;
- }
}
if (all_lazy)
*all_lazy = al;
@@ -3435,15 +3415,12 @@ int rcutree_online_cpu(unsigned int cpu)
unsigned long flags;
struct rcu_data *rdp;
struct rcu_node *rnp;
- struct rcu_state *rsp;
- for_each_rcu_flavor(rsp) {
- rdp = per_cpu_ptr(&rcu_data, cpu);
- rnp = rdp->mynode;
- raw_spin_lock_irqsave_rcu_node(rnp, flags);
- rnp->ffmask |= rdp->grpmask;
- raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
- }
+ rdp = per_cpu_ptr(&rcu_data, cpu);
+ rnp = rdp->mynode;
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
+ rnp->ffmask |= rdp->grpmask;
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
if (IS_ENABLED(CONFIG_TREE_SRCU))
srcu_online_cpu(cpu);
if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)
@@ -3462,15 +3439,12 @@ int rcutree_offline_cpu(unsigned int cpu)
unsigned long flags;
struct rcu_data *rdp;
struct rcu_node *rnp;
- struct rcu_state *rsp;
- for_each_rcu_flavor(rsp) {
- rdp = per_cpu_ptr(&rcu_data, cpu);
- rnp = rdp->mynode;
- raw_spin_lock_irqsave_rcu_node(rnp, flags);
- rnp->ffmask &= ~rdp->grpmask;
- raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
- }
+ rdp = per_cpu_ptr(&rcu_data, cpu);
+ rnp = rdp->mynode;
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
+ rnp->ffmask &= ~rdp->grpmask;
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
rcutree_affinity_setting(cpu, cpu);
if (IS_ENABLED(CONFIG_TREE_SRCU))
@@ -3499,34 +3473,32 @@ void rcu_cpu_starting(unsigned int cpu)
unsigned long oldmask;
struct rcu_data *rdp;
struct rcu_node *rnp;
- struct rcu_state *rsp;
+ struct rcu_state *rsp = &rcu_state;
if (per_cpu(rcu_cpu_started, cpu))
return;
per_cpu(rcu_cpu_started, cpu) = 1;
- for_each_rcu_flavor(rsp) {
- rdp = per_cpu_ptr(&rcu_data, cpu);
- rnp = rdp->mynode;
- mask = rdp->grpmask;
- raw_spin_lock_irqsave_rcu_node(rnp, flags);
- rnp->qsmaskinitnext |= mask;
- oldmask = rnp->expmaskinitnext;
- rnp->expmaskinitnext |= mask;
- oldmask ^= rnp->expmaskinitnext;
- nbits = bitmap_weight(&oldmask, BITS_PER_LONG);
- /* Allow lockless access for expedited grace periods. */
- smp_store_release(&rsp->ncpus, rsp->ncpus + nbits); /* ^^^ */
- rcu_gpnum_ovf(rnp, rdp); /* Offline-induced counter wrap? */
- rdp->rcu_onl_gp_seq = READ_ONCE(rsp->gp_seq);
- rdp->rcu_onl_gp_flags = READ_ONCE(rsp->gp_flags);
- if (rnp->qsmask & mask) { /* RCU waiting on incoming CPU? */
- /* Report QS -after- changing ->qsmaskinitnext! */
- rcu_report_qs_rnp(mask, rnp, rnp->gp_seq, flags);
- } else {
- raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
- }
+ rdp = per_cpu_ptr(&rcu_data, cpu);
+ rnp = rdp->mynode;
+ mask = rdp->grpmask;
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
+ rnp->qsmaskinitnext |= mask;
+ oldmask = rnp->expmaskinitnext;
+ rnp->expmaskinitnext |= mask;
+ oldmask ^= rnp->expmaskinitnext;
+ nbits = bitmap_weight(&oldmask, BITS_PER_LONG);
+ /* Allow lockless access for expedited grace periods. */
+ smp_store_release(&rsp->ncpus, rsp->ncpus + nbits); /* ^^^ */
+ rcu_gpnum_ovf(rnp, rdp); /* Offline-induced counter wrap? */
+ rdp->rcu_onl_gp_seq = READ_ONCE(rsp->gp_seq);
+ rdp->rcu_onl_gp_flags = READ_ONCE(rsp->gp_flags);
+ if (rnp->qsmask & mask) { /* RCU waiting on incoming CPU? */
+ /* Report QS -after- changing ->qsmaskinitnext! */
+ rcu_report_qs_rnp(mask, rnp, rnp->gp_seq, flags);
+ } else {
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
smp_mb(); /* Ensure RCU read-side usage follows above initialization. */
}
@@ -3643,7 +3615,6 @@ static int __init rcu_spawn_gp_kthread(void)
unsigned long flags;
int kthread_prio_in = kthread_prio;
struct rcu_node *rnp;
- struct rcu_state *rsp;
struct sched_param sp;
struct task_struct *t;
@@ -3663,19 +3634,17 @@ static int __init rcu_spawn_gp_kthread(void)
kthread_prio, kthread_prio_in);
rcu_scheduler_fully_active = 1;
- for_each_rcu_flavor(rsp) {
- t = kthread_create(rcu_gp_kthread, NULL, "%s", rsp->name);
- BUG_ON(IS_ERR(t));
- rnp = rcu_get_root();
- raw_spin_lock_irqsave_rcu_node(rnp, flags);
- rsp->gp_kthread = t;
- if (kthread_prio) {
- sp.sched_priority = kthread_prio;
- sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
- }
- raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
- wake_up_process(t);
+ t = kthread_create(rcu_gp_kthread, NULL, "%s", rcu_state.name);
+ BUG_ON(IS_ERR(t));
+ rnp = rcu_get_root();
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
+ rcu_state.gp_kthread = t;
+ if (kthread_prio) {
+ sp.sched_priority = kthread_prio;
+ sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
}
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+ wake_up_process(t);
rcu_spawn_nocb_kthreads();
rcu_spawn_boost_kthreads();
return 0;
@@ -3781,7 +3750,6 @@ static void __init rcu_init_one(void)
per_cpu_ptr(&rcu_data, i)->mynode = rnp;
rcu_boot_init_percpu_data(i);
}
- list_add(&rsp->flavors, &rcu_struct_flavors);
}
/*
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 6f1b1a3fc23d..8abc15c42d84 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -360,7 +360,6 @@ struct rcu_state {
/* jiffies. */
const char *name; /* Name of structure. */
char abbr; /* Abbreviated name. */
- struct list_head flavors; /* List of RCU flavors. */
spinlock_t ofl_lock ____cacheline_internodealigned_in_smp;
/* Synchronize offline with */
@@ -417,12 +416,6 @@ static const char *tp_rcu_varname __used __tracepoint_string = rcu_name;
#define RCU_NAME rcu_name
#endif /* #else #ifdef CONFIG_TRACING */
-extern struct list_head rcu_struct_flavors;
-
-/* Sequence through rcu_state structures for each RCU flavor. */
-#define for_each_rcu_flavor(rsp) \
- list_for_each_entry((rsp), &rcu_struct_flavors, flavors)
-
/*
* RCU implementation internal declarations:
*/
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 59d66ee26310..878a1d2cd465 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1561,31 +1561,28 @@ static bool __maybe_unused rcu_try_advance_all_cbs(void)
struct rcu_data *rdp;
struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
struct rcu_node *rnp;
- struct rcu_state *rsp;
/* Exit early if we advanced recently. */
if (jiffies == rdtp->last_advance_all)
return false;
rdtp->last_advance_all = jiffies;
- for_each_rcu_flavor(rsp) {
- rdp = this_cpu_ptr(&rcu_data);
- rnp = rdp->mynode;
+ rdp = this_cpu_ptr(&rcu_data);
+ rnp = rdp->mynode;
- /*
- * Don't bother checking unless a grace period has
- * completed since we last checked and there are
- * callbacks not yet ready to invoke.
- */
- if ((rcu_seq_completed_gp(rdp->gp_seq,
- rcu_seq_current(&rnp->gp_seq)) ||
- unlikely(READ_ONCE(rdp->gpwrap))) &&
- rcu_segcblist_pend_cbs(&rdp->cblist))
- note_gp_changes(rdp);
-
- if (rcu_segcblist_ready_cbs(&rdp->cblist))
- cbs_ready = true;
- }
+ /*
+ * Don't bother checking unless a grace period has
+ * completed since we last checked and there are
+ * callbacks not yet ready to invoke.
+ */
+ if ((rcu_seq_completed_gp(rdp->gp_seq,
+ rcu_seq_current(&rnp->gp_seq)) ||
+ unlikely(READ_ONCE(rdp->gpwrap))) &&
+ rcu_segcblist_pend_cbs(&rdp->cblist))
+ note_gp_changes(rdp);
+
+ if (rcu_segcblist_ready_cbs(&rdp->cblist))
+ cbs_ready = true;
return cbs_ready;
}
@@ -1648,7 +1645,6 @@ static void rcu_prepare_for_idle(void)
struct rcu_data *rdp;
struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
struct rcu_node *rnp;
- struct rcu_state *rsp;
int tne;
lockdep_assert_irqs_disabled();
@@ -1686,10 +1682,8 @@ static void rcu_prepare_for_idle(void)
if (rdtp->last_accelerate == jiffies)
return;
rdtp->last_accelerate = jiffies;
- for_each_rcu_flavor(rsp) {
- rdp = this_cpu_ptr(&rcu_data);
- if (!rcu_segcblist_pend_cbs(&rdp->cblist))
- continue;
+ rdp = this_cpu_ptr(&rcu_data);
+ if (rcu_segcblist_pend_cbs(&rdp->cblist)) {
rnp = rdp->mynode;
raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */
needwake = rcu_accelerate_cbs(rnp, rdp);
@@ -1824,10 +1818,7 @@ static void zero_cpu_stall_ticks(struct rcu_data *rdp)
/* Increment ->ticks_this_gp for all flavors of RCU. */
static void increment_cpu_stall_ticks(void)
{
- struct rcu_state *rsp;
-
- for_each_rcu_flavor(rsp)
- raw_cpu_inc(rcu_data.ticks_this_gp);
+ raw_cpu_inc(rcu_data.ticks_this_gp);
}
#ifdef CONFIG_RCU_NOCB_CPU
@@ -2384,7 +2375,6 @@ void __init rcu_init_nohz(void)
{
int cpu;
bool need_rcu_nocb_mask = false;
- struct rcu_state *rsp;
#if defined(CONFIG_NO_HZ_FULL)
if (tick_nohz_full_running && cpumask_weight(tick_nohz_full_mask))
@@ -2418,11 +2408,9 @@ void __init rcu_init_nohz(void)
if (rcu_nocb_poll)
pr_info("\tPoll for callbacks from no-CBs CPUs.\n");
- for_each_rcu_flavor(rsp) {
- for_each_cpu(cpu, rcu_nocb_mask)
- init_nocb_callback_list(per_cpu_ptr(&rcu_data, cpu));
- rcu_organize_nocb_kthreads();
- }
+ for_each_cpu(cpu, rcu_nocb_mask)
+ init_nocb_callback_list(per_cpu_ptr(&rcu_data, cpu));
+ rcu_organize_nocb_kthreads();
}
/* Initialize per-rcu_data variables for no-CBs CPUs. */
@@ -2489,11 +2477,8 @@ static void rcu_spawn_one_nocb_kthread(int cpu)
*/
static void rcu_spawn_all_nocb_kthreads(int cpu)
{
- struct rcu_state *rsp;
-
if (rcu_scheduler_fully_active)
- for_each_rcu_flavor(rsp)
- rcu_spawn_one_nocb_kthread(cpu);
+ rcu_spawn_one_nocb_kthread(cpu);
}
/*
--
2.17.1
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