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rcu: Remove for_each_rcu_flavor() flavor-traversal macro

Browse source 
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@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2018-07-04 15:35:00 -07:00
parent 564a9ae604
commit b97d23c51c
3 changed files with 91 additions and 145 deletions
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172
kernel/rcu/tree.c
View file

@ -85,8 +85,6 @@ struct rcu_state rcu_state = {
.ofl_lock = __SPIN_LOCK_UNLOCKED(rcu_state.ofl_lock), .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. */ /* Dump rcu_node combining tree at boot to verify correct setup. */
static bool dump_tree; static bool dump_tree;
module_param(dump_tree, bool, 0444); module_param(dump_tree, bool, 0444);
@ -568,31 +566,28 @@ void show_rcu_gp_kthreads(void)
int cpu; int cpu;
struct rcu_data *rdp; struct rcu_data *rdp;
struct rcu_node *rnp; struct rcu_node *rnp;
struct rcu_state *rsp;
for_each_rcu_flavor(rsp) { pr_info("%s: wait state: %d ->state: %#lx\n", rcu_state.name,
pr_info("%s: wait state: %d ->state: %#lx\n", rcu_state.gp_state, rcu_state.gp_kthread->state);
rsp->name, rsp->gp_state, rsp->gp_kthread->state); rcu_for_each_node_breadth_first(rnp) {
rcu_for_each_node_breadth_first(rnp) { if (ULONG_CMP_GE(rcu_state.gp_seq, rnp->gp_seq_needed))
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))
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; continue;
pr_info("\trcu_node %d:%d ->gp_seq %lu ->gp_seq_needed %lu\n", pr_info("\tcpu %d ->gp_seq_needed %lu\n",
rnp->grplo, rnp->grphi, rnp->gp_seq, cpu, rdp->gp_seq_needed);
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(rsp->gp_seq,
rdp->gp_seq_needed))
continue;
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); 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) static void rcu_eqs_enter(bool user)
{ {
struct rcu_state *rsp;
struct rcu_data *rdp; struct rcu_data *rdp;
struct rcu_dynticks *rdtp; struct rcu_dynticks *rdtp;
@ -655,10 +649,8 @@ static void rcu_eqs_enter(bool user)
lockdep_assert_irqs_disabled(); lockdep_assert_irqs_disabled();
trace_rcu_dyntick(TPS("Start"), rdtp->dynticks_nesting, 0, rdtp->dynticks); 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)); 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);
rdp = this_cpu_ptr(&rcu_data); do_nocb_deferred_wakeup(rdp);
do_nocb_deferred_wakeup(rdp);
}
rcu_prepare_for_idle(); rcu_prepare_for_idle();
rcu_preempt_deferred_qs(current); rcu_preempt_deferred_qs(current);
WRITE_ONCE(rdtp->dynticks_nesting, 0); /* Avoid irq-access tearing. */ WRITE_ONCE(rdtp->dynticks_nesting, 0); /* Avoid irq-access tearing. */
@ -1024,21 +1016,17 @@ bool rcu_lockdep_current_cpu_online(void)
{ {
struct rcu_data *rdp; struct rcu_data *rdp;
struct rcu_node *rnp; struct rcu_node *rnp;
struct rcu_state *rsp; bool ret = false;
if (in_nmi() || !rcu_scheduler_fully_active) if (in_nmi() || !rcu_scheduler_fully_active)
return true; return true;
preempt_disable(); preempt_disable();
for_each_rcu_flavor(rsp) { rdp = this_cpu_ptr(&rcu_data);
rdp = this_cpu_ptr(&rcu_data); rnp = rdp->mynode;
rnp = rdp->mynode; if (rdp->grpmask & rcu_rnp_online_cpus(rnp))
if (rdp->grpmask & rcu_rnp_online_cpus(rnp)) { ret = true;
preempt_enable();
return true;
}
}
preempt_enable(); preempt_enable();
return false; return ret;
} }
EXPORT_SYMBOL_GPL(rcu_lockdep_current_cpu_online); EXPORT_SYMBOL_GPL(rcu_lockdep_current_cpu_online);
@ -1516,10 +1504,7 @@ static void check_cpu_stall(struct rcu_data *rdp)
*/ */
void rcu_cpu_stall_reset(void) void rcu_cpu_stall_reset(void)
{ {
struct rcu_state *rsp; WRITE_ONCE(rcu_state.jiffies_stall, jiffies + ULONG_MAX / 2);
for_each_rcu_flavor(rsp)
WRITE_ONCE(rsp->jiffies_stall, jiffies + ULONG_MAX / 2);
} }
/* Trace-event wrapper function for trace_rcu_future_grace_period. */ /* Trace-event wrapper function for trace_rcu_future_grace_period. */
@ -3134,17 +3119,12 @@ static bool rcu_cpu_has_callbacks(bool *all_lazy)
bool al = true; bool al = true;
bool hc = false; bool hc = false;
struct rcu_data *rdp; struct rcu_data *rdp;
struct rcu_state *rsp;
for_each_rcu_flavor(rsp) { rdp = this_cpu_ptr(&rcu_data);
rdp = this_cpu_ptr(&rcu_data); if (!rcu_segcblist_empty(&rdp->cblist)) {
if (rcu_segcblist_empty(&rdp->cblist))
continue;
hc = true; hc = true;
if (rcu_segcblist_n_nonlazy_cbs(&rdp->cblist) || !all_lazy) { if (rcu_segcblist_n_nonlazy_cbs(&rdp->cblist))
al = false; al = false;
break;
}
} }
if (all_lazy) if (all_lazy)
*all_lazy = al; *all_lazy = al;
@ -3436,15 +3416,12 @@ int rcutree_online_cpu(unsigned int cpu)
unsigned long flags; unsigned long flags;
struct rcu_data *rdp; struct rcu_data *rdp;
struct rcu_node *rnp; struct rcu_node *rnp;
struct rcu_state *rsp;
for_each_rcu_flavor(rsp) { rdp = per_cpu_ptr(&rcu_data, cpu);
rdp = per_cpu_ptr(&rcu_data, cpu); rnp = rdp->mynode;
rnp = rdp->mynode; raw_spin_lock_irqsave_rcu_node(rnp, flags);
raw_spin_lock_irqsave_rcu_node(rnp, flags); rnp->ffmask |= rdp->grpmask;
rnp->ffmask |= rdp->grpmask; raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
if (IS_ENABLED(CONFIG_TREE_SRCU)) if (IS_ENABLED(CONFIG_TREE_SRCU))
srcu_online_cpu(cpu); srcu_online_cpu(cpu);
if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE) if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)
@ -3463,15 +3440,12 @@ int rcutree_offline_cpu(unsigned int cpu)
unsigned long flags; unsigned long flags;
struct rcu_data *rdp; struct rcu_data *rdp;
struct rcu_node *rnp; struct rcu_node *rnp;
struct rcu_state *rsp;
for_each_rcu_flavor(rsp) { rdp = per_cpu_ptr(&rcu_data, cpu);
rdp = per_cpu_ptr(&rcu_data, cpu); rnp = rdp->mynode;
rnp = rdp->mynode; raw_spin_lock_irqsave_rcu_node(rnp, flags);
raw_spin_lock_irqsave_rcu_node(rnp, flags); rnp->ffmask &= ~rdp->grpmask;
rnp->ffmask &= ~rdp->grpmask; raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
rcutree_affinity_setting(cpu, cpu); rcutree_affinity_setting(cpu, cpu);
if (IS_ENABLED(CONFIG_TREE_SRCU)) if (IS_ENABLED(CONFIG_TREE_SRCU))
@ -3500,34 +3474,32 @@ void rcu_cpu_starting(unsigned int cpu)
unsigned long oldmask; unsigned long oldmask;
struct rcu_data *rdp; struct rcu_data *rdp;
struct rcu_node *rnp; struct rcu_node *rnp;
struct rcu_state *rsp; struct rcu_state *rsp = &rcu_state;
if (per_cpu(rcu_cpu_started, cpu)) if (per_cpu(rcu_cpu_started, cpu))
return; return;
per_cpu(rcu_cpu_started, cpu) = 1; per_cpu(rcu_cpu_started, cpu) = 1;
for_each_rcu_flavor(rsp) { rdp = per_cpu_ptr(&rcu_data, cpu);
rdp = per_cpu_ptr(&rcu_data, cpu); rnp = rdp->mynode;
rnp = rdp->mynode; mask = rdp->grpmask;
mask = rdp->grpmask; raw_spin_lock_irqsave_rcu_node(rnp, flags);
raw_spin_lock_irqsave_rcu_node(rnp, flags); rnp->qsmaskinitnext |= mask;
rnp->qsmaskinitnext |= mask; oldmask = rnp->expmaskinitnext;
oldmask = rnp->expmaskinitnext; rnp->expmaskinitnext |= mask;
rnp->expmaskinitnext |= mask; oldmask ^= rnp->expmaskinitnext;
oldmask ^= rnp->expmaskinitnext; nbits = bitmap_weight(&oldmask, BITS_PER_LONG);
nbits = bitmap_weight(&oldmask, BITS_PER_LONG); /* Allow lockless access for expedited grace periods. */
/* Allow lockless access for expedited grace periods. */ smp_store_release(&rsp->ncpus, rsp->ncpus + nbits); /* ^^^ */
smp_store_release(&rsp->ncpus, rsp->ncpus + nbits); /* ^^^ */ rcu_gpnum_ovf(rnp, rdp); /* Offline-induced counter wrap? */
rcu_gpnum_ovf(rnp, rdp); /* Offline-induced counter wrap? */ rdp->rcu_onl_gp_seq = READ_ONCE(rsp->gp_seq);
rdp->rcu_onl_gp_seq = READ_ONCE(rsp->gp_seq); rdp->rcu_onl_gp_flags = READ_ONCE(rsp->gp_flags);
rdp->rcu_onl_gp_flags = READ_ONCE(rsp->gp_flags); if (rnp->qsmask & mask) { /* RCU waiting on incoming CPU? */
if (rnp->qsmask & mask) { /* RCU waiting on incoming CPU? */ /* Report QS -after- changing ->qsmaskinitnext! */
/* Report QS -after- changing ->qsmaskinitnext! */ rcu_report_qs_rnp(mask, rnp, rnp->gp_seq, flags);
rcu_report_qs_rnp(mask, rnp, rnp->gp_seq, flags); } else {
} else { raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
} }
smp_mb(); /* Ensure RCU read-side usage follows above initialization. */ smp_mb(); /* Ensure RCU read-side usage follows above initialization. */
} }
@ -3644,7 +3616,6 @@ static int __init rcu_spawn_gp_kthread(void)
unsigned long flags; unsigned long flags;
int kthread_prio_in = kthread_prio; int kthread_prio_in = kthread_prio;
struct rcu_node *rnp; struct rcu_node *rnp;
struct rcu_state *rsp;
struct sched_param sp; struct sched_param sp;
struct task_struct *t; struct task_struct *t;
@ -3664,19 +3635,17 @@ static int __init rcu_spawn_gp_kthread(void)
kthread_prio, kthread_prio_in); kthread_prio, kthread_prio_in);
rcu_scheduler_fully_active = 1; rcu_scheduler_fully_active = 1;
for_each_rcu_flavor(rsp) { t = kthread_create(rcu_gp_kthread, NULL, "%s", rcu_state.name);
t = kthread_create(rcu_gp_kthread, NULL, "%s", rsp->name); BUG_ON(IS_ERR(t));
BUG_ON(IS_ERR(t)); rnp = rcu_get_root();
rnp = rcu_get_root(); raw_spin_lock_irqsave_rcu_node(rnp, flags);
raw_spin_lock_irqsave_rcu_node(rnp, flags); rcu_state.gp_kthread = t;
rsp->gp_kthread = t; if (kthread_prio) {
if (kthread_prio) { sp.sched_priority = kthread_prio;
sp.sched_priority = kthread_prio; sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
}
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
wake_up_process(t);
} }
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
wake_up_process(t);
rcu_spawn_nocb_kthreads(); rcu_spawn_nocb_kthreads();
rcu_spawn_boost_kthreads(); rcu_spawn_boost_kthreads();
return 0; return 0;
@ -3782,7 +3751,6 @@ static void __init rcu_init_one(void)
per_cpu_ptr(&rcu_data, i)->mynode = rnp; per_cpu_ptr(&rcu_data, i)->mynode = rnp;
rcu_boot_init_percpu_data(i); rcu_boot_init_percpu_data(i);
} }
list_add(&rsp->flavors, &rcu_struct_flavors);
} }
/* /*

7
kernel/rcu/tree.h
View file

@ -360,7 +360,6 @@ struct rcu_state {
/* jiffies. */ /* jiffies. */
const char *name; /* Name of structure. */ const char *name; /* Name of structure. */
char abbr; /* Abbreviated name. */ char abbr; /* Abbreviated name. */
struct list_head flavors; /* List of RCU flavors. */
spinlock_t ofl_lock ____cacheline_internodealigned_in_smp; spinlock_t ofl_lock ____cacheline_internodealigned_in_smp;
/* Synchronize offline with */ /* Synchronize offline with */
@ -417,12 +416,6 @@ static const char *tp_rcu_varname __used __tracepoint_string = rcu_name;
#define RCU_NAME rcu_name #define RCU_NAME rcu_name
#endif /* #else #ifdef CONFIG_TRACING */ #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: * RCU implementation internal declarations:
*/ */

57
kernel/rcu/tree_plugin.h
View file

@ -1561,31 +1561,28 @@ static bool __maybe_unused rcu_try_advance_all_cbs(void)
struct rcu_data *rdp; struct rcu_data *rdp;
struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks); struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
struct rcu_node *rnp; struct rcu_node *rnp;
struct rcu_state *rsp;
/* Exit early if we advanced recently. */ /* Exit early if we advanced recently. */
if (jiffies == rdtp->last_advance_all) if (jiffies == rdtp->last_advance_all)
return false; return false;
rdtp->last_advance_all = jiffies; rdtp->last_advance_all = jiffies;
for_each_rcu_flavor(rsp) { rdp = this_cpu_ptr(&rcu_data);
rdp = this_cpu_ptr(&rcu_data); rnp = rdp->mynode;
rnp = rdp->mynode;
/* /*
* Don't bother checking unless a grace period has * Don't bother checking unless a grace period has
* completed since we last checked and there are * completed since we last checked and there are
* callbacks not yet ready to invoke. * callbacks not yet ready to invoke.
*/ */
if ((rcu_seq_completed_gp(rdp->gp_seq, if ((rcu_seq_completed_gp(rdp->gp_seq,
rcu_seq_current(&rnp->gp_seq)) || rcu_seq_current(&rnp->gp_seq)) ||
unlikely(READ_ONCE(rdp->gpwrap))) && unlikely(READ_ONCE(rdp->gpwrap))) &&
rcu_segcblist_pend_cbs(&rdp->cblist)) rcu_segcblist_pend_cbs(&rdp->cblist))
note_gp_changes(rdp); note_gp_changes(rdp);
if (rcu_segcblist_ready_cbs(&rdp->cblist)) if (rcu_segcblist_ready_cbs(&rdp->cblist))
cbs_ready = true; cbs_ready = true;
}
return cbs_ready; return cbs_ready;
} }
@ -1648,7 +1645,6 @@ static void rcu_prepare_for_idle(void)
struct rcu_data *rdp; struct rcu_data *rdp;
struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks); struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
struct rcu_node *rnp; struct rcu_node *rnp;
struct rcu_state *rsp;
int tne; int tne;
lockdep_assert_irqs_disabled(); lockdep_assert_irqs_disabled();
@ -1686,10 +1682,8 @@ static void rcu_prepare_for_idle(void)
if (rdtp->last_accelerate == jiffies) if (rdtp->last_accelerate == jiffies)
return; return;
rdtp->last_accelerate = jiffies; rdtp->last_accelerate = jiffies;
for_each_rcu_flavor(rsp) { rdp = this_cpu_ptr(&rcu_data);
rdp = this_cpu_ptr(&rcu_data); if (rcu_segcblist_pend_cbs(&rdp->cblist)) {
if (!rcu_segcblist_pend_cbs(&rdp->cblist))
continue;
rnp = rdp->mynode; rnp = rdp->mynode;
raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */ raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */
needwake = rcu_accelerate_cbs(rnp, rdp); 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. */ /* Increment ->ticks_this_gp for all flavors of RCU. */
static void increment_cpu_stall_ticks(void) static void increment_cpu_stall_ticks(void)
{ {
struct rcu_state *rsp; raw_cpu_inc(rcu_data.ticks_this_gp);
for_each_rcu_flavor(rsp)
raw_cpu_inc(rcu_data.ticks_this_gp);
} }
#ifdef CONFIG_RCU_NOCB_CPU #ifdef CONFIG_RCU_NOCB_CPU
@ -2384,7 +2375,6 @@ void __init rcu_init_nohz(void)
{ {
int cpu; int cpu;
bool need_rcu_nocb_mask = false; bool need_rcu_nocb_mask = false;
struct rcu_state *rsp;
#if defined(CONFIG_NO_HZ_FULL) #if defined(CONFIG_NO_HZ_FULL)
if (tick_nohz_full_running && cpumask_weight(tick_nohz_full_mask)) 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) if (rcu_nocb_poll)
pr_info("\tPoll for callbacks from no-CBs CPUs.\n"); pr_info("\tPoll for callbacks from no-CBs CPUs.\n");
for_each_rcu_flavor(rsp) { for_each_cpu(cpu, rcu_nocb_mask)
for_each_cpu(cpu, rcu_nocb_mask) init_nocb_callback_list(per_cpu_ptr(&rcu_data, cpu));
init_nocb_callback_list(per_cpu_ptr(&rcu_data, cpu)); rcu_organize_nocb_kthreads();
rcu_organize_nocb_kthreads();
}
} }
/* Initialize per-rcu_data variables for no-CBs CPUs. */ /* 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) static void rcu_spawn_all_nocb_kthreads(int cpu)
{ {
struct rcu_state *rsp;
if (rcu_scheduler_fully_active) if (rcu_scheduler_fully_active)
for_each_rcu_flavor(rsp) rcu_spawn_one_nocb_kthread(cpu);
rcu_spawn_one_nocb_kthread(cpu);
} }
/* /*