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rcu: Remove rsp parameter from rcu_node tree accessor macros
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There now is only one rcu_state structure in a given build of the Linux
kernel, so there is no need to pass it as a parameter to RCU's rcu_node
tree's accessor macros.  This commit therefore removes the rsp parameter
from those macros in kernel/rcu/rcu.h, and removes some now-unused rsp
local variables while in the area.

Signed-off-by: Paul E. McKenney <[email protected]>
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@paulmck
paulmck committed Aug 30, 2018
1 parent 63d4c8c commit aedf4ba
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Showing 5 changed files with 33 additions and 40 deletions.
28 changes: 11 additions & 17 deletions kernel/rcu/rcu.h
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Original file line number Diff line number Diff line change
Expand Up @@ -329,39 +329,33 @@ static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt)
}

/* Returns first leaf rcu_node of the specified RCU flavor. */
#define rcu_first_leaf_node(rsp) ((rsp)->level[rcu_num_lvls - 1])
#define rcu_first_leaf_node() (rcu_state.level[rcu_num_lvls - 1])

/* Is this rcu_node a leaf? */
#define rcu_is_leaf_node(rnp) ((rnp)->level == rcu_num_lvls - 1)

/* Is this rcu_node the last leaf? */
#define rcu_is_last_leaf_node(rsp, rnp) ((rnp) == &(rsp)->node[rcu_num_nodes - 1])
#define rcu_is_last_leaf_node(rnp) ((rnp) == &rcu_state.node[rcu_num_nodes - 1])

/*
* Do a full breadth-first scan of the rcu_node structures for the
* Do a full breadth-first scan of the {s,}rcu_node structures for the
* specified rcu_state structure.
*/
#define rcu_for_each_node_breadth_first(rsp, rnp) \
for ((rnp) = &(rsp)->node[0]; \
(rnp) < &(rsp)->node[rcu_num_nodes]; (rnp)++)

/*
* Do a breadth-first scan of the non-leaf rcu_node structures for the
* specified rcu_state structure. Note that if there is a singleton
* rcu_node tree with but one rcu_node structure, this loop is a no-op.
*/
#define rcu_for_each_nonleaf_node_breadth_first(rsp, rnp) \
for ((rnp) = &(rsp)->node[0]; !rcu_is_leaf_node(rsp, rnp); (rnp)++)
#define srcu_for_each_node_breadth_first(sp, rnp) \
for ((rnp) = &(sp)->node[0]; \
(rnp) < &(sp)->node[rcu_num_nodes]; (rnp)++)
#define rcu_for_each_node_breadth_first(rnp) \
srcu_for_each_node_breadth_first(&rcu_state, rnp)

/*
* Scan the leaves of the rcu_node hierarchy for the specified rcu_state
* structure. Note that if there is a singleton rcu_node tree with but
* one rcu_node structure, this loop -will- visit the rcu_node structure.
* It is still a leaf node, even if it is also the root node.
*/
#define rcu_for_each_leaf_node(rsp, rnp) \
for ((rnp) = rcu_first_leaf_node(rsp); \
(rnp) < &(rsp)->node[rcu_num_nodes]; (rnp)++)
#define rcu_for_each_leaf_node(rnp) \
for ((rnp) = rcu_first_leaf_node(); \
(rnp) < &rcu_state.node[rcu_num_nodes]; (rnp)++)

/*
* Iterate over all possible CPUs in a leaf RCU node.
Expand Down
4 changes: 2 additions & 2 deletions kernel/rcu/srcutree.c
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Original file line number Diff line number Diff line change
Expand Up @@ -105,7 +105,7 @@ static void init_srcu_struct_nodes(struct srcu_struct *sp, bool is_static)
rcu_init_levelspread(levelspread, num_rcu_lvl);

/* Each pass through this loop initializes one srcu_node structure. */
rcu_for_each_node_breadth_first(sp, snp) {
srcu_for_each_node_breadth_first(sp, snp) {
spin_lock_init(&ACCESS_PRIVATE(snp, lock));
WARN_ON_ONCE(ARRAY_SIZE(snp->srcu_have_cbs) !=
ARRAY_SIZE(snp->srcu_data_have_cbs));
Expand Down Expand Up @@ -561,7 +561,7 @@ static void srcu_gp_end(struct srcu_struct *sp)

/* Initiate callback invocation as needed. */
idx = rcu_seq_ctr(gpseq) % ARRAY_SIZE(snp->srcu_have_cbs);
rcu_for_each_node_breadth_first(sp, snp) {
srcu_for_each_node_breadth_first(sp, snp) {
spin_lock_irq_rcu_node(snp);
cbs = false;
last_lvl = snp >= sp->level[rcu_num_lvls - 1];
Expand Down
19 changes: 9 additions & 10 deletions kernel/rcu/tree.c
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Original file line number Diff line number Diff line change
Expand Up @@ -573,7 +573,7 @@ void show_rcu_gp_kthreads(void)
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(rsp, rnp) {
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",
Expand Down Expand Up @@ -1276,7 +1276,7 @@ static void rcu_dump_cpu_stacks(void)
unsigned long flags;
struct rcu_node *rnp;

rcu_for_each_leaf_node(&rcu_state, rnp) {
rcu_for_each_leaf_node(rnp) {
raw_spin_lock_irqsave_rcu_node(rnp, flags);
for_each_leaf_node_possible_cpu(rnp, cpu)
if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu))
Expand Down Expand Up @@ -1336,7 +1336,7 @@ static void print_other_cpu_stall(unsigned long gp_seq)
*/
pr_err("INFO: %s detected stalls on CPUs/tasks:", rsp->name);
print_cpu_stall_info_begin();
rcu_for_each_leaf_node(rsp, rnp) {
rcu_for_each_leaf_node(rnp) {
raw_spin_lock_irqsave_rcu_node(rnp, flags);
ndetected += rcu_print_task_stall(rnp);
if (rnp->qsmask != 0) {
Expand Down Expand Up @@ -1873,7 +1873,7 @@ static bool rcu_gp_init(void)
* will handle subsequent offline CPUs.
*/
rsp->gp_state = RCU_GP_ONOFF;
rcu_for_each_leaf_node(rsp, rnp) {
rcu_for_each_leaf_node(rnp) {
spin_lock(&rsp->ofl_lock);
raw_spin_lock_irq_rcu_node(rnp);
if (rnp->qsmaskinit == rnp->qsmaskinitnext &&
Expand Down Expand Up @@ -1933,7 +1933,7 @@ static bool rcu_gp_init(void)
* process finishes, because this kthread handles both.
*/
rsp->gp_state = RCU_GP_INIT;
rcu_for_each_node_breadth_first(rsp, rnp) {
rcu_for_each_node_breadth_first(rnp) {
rcu_gp_slow(gp_init_delay);
raw_spin_lock_irqsave_rcu_node(rnp, flags);
rdp = this_cpu_ptr(&rcu_data);
Expand Down Expand Up @@ -2046,7 +2046,7 @@ static void rcu_gp_cleanup(void)
*/
new_gp_seq = rsp->gp_seq;
rcu_seq_end(&new_gp_seq);
rcu_for_each_node_breadth_first(rsp, rnp) {
rcu_for_each_node_breadth_first(rnp) {
raw_spin_lock_irq_rcu_node(rnp);
if (WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)))
dump_blkd_tasks(rnp, 10);
Expand Down Expand Up @@ -2606,9 +2606,8 @@ static void force_qs_rnp(int (*f)(struct rcu_data *rsp))
unsigned long flags;
unsigned long mask;
struct rcu_node *rnp;
struct rcu_state *rsp = &rcu_state;

rcu_for_each_leaf_node(rsp, rnp) {
rcu_for_each_leaf_node(rnp) {
cond_resched_tasks_rcu_qs();
mask = 0;
raw_spin_lock_irqsave_rcu_node(rnp, flags);
Expand Down Expand Up @@ -3778,7 +3777,7 @@ static void __init rcu_init_one(void)

init_swait_queue_head(&rsp->gp_wq);
init_swait_queue_head(&rsp->expedited_wq);
rnp = rcu_first_leaf_node(rsp);
rnp = rcu_first_leaf_node();
for_each_possible_cpu(i) {
while (i > rnp->grphi)
rnp++;
Expand Down Expand Up @@ -3878,7 +3877,7 @@ static void __init rcu_dump_rcu_node_tree(void)

pr_info("rcu_node tree layout dump\n");
pr_info(" ");
rcu_for_each_node_breadth_first(&rcu_state, rnp) {
rcu_for_each_node_breadth_first(rnp) {
if (rnp->level != level) {
pr_cont("\n");
pr_info(" ");
Expand Down
18 changes: 9 additions & 9 deletions kernel/rcu/tree_exp.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -97,7 +97,7 @@ static void sync_exp_reset_tree_hotplug(void)
* Each pass through the following loop propagates newly onlined
* CPUs for the current rcu_node structure up the rcu_node tree.
*/
rcu_for_each_leaf_node(&rcu_state, rnp) {
rcu_for_each_leaf_node(rnp) {
raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (rnp->expmaskinit == rnp->expmaskinitnext) {
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
Expand Down Expand Up @@ -141,7 +141,7 @@ static void __maybe_unused sync_exp_reset_tree(void)
struct rcu_node *rnp;

sync_exp_reset_tree_hotplug();
rcu_for_each_node_breadth_first(&rcu_state, rnp) {
rcu_for_each_node_breadth_first(rnp) {
raw_spin_lock_irqsave_rcu_node(rnp, flags);
WARN_ON_ONCE(rnp->expmask);
rnp->expmask = rnp->expmaskinit;
Expand Down Expand Up @@ -438,14 +438,14 @@ static void sync_rcu_exp_select_cpus(smp_call_func_t func)
trace_rcu_exp_grace_period(rcu_state.name, rcu_exp_gp_seq_endval(), TPS("select"));

/* Schedule work for each leaf rcu_node structure. */
rcu_for_each_leaf_node(&rcu_state, rnp) {
rcu_for_each_leaf_node(rnp) {
rnp->exp_need_flush = false;
if (!READ_ONCE(rnp->expmask))
continue; /* Avoid early boot non-existent wq. */
rnp->rew.rew_func = func;
if (!READ_ONCE(rcu_par_gp_wq) ||
rcu_scheduler_active != RCU_SCHEDULER_RUNNING ||
rcu_is_last_leaf_node(&rcu_state, rnp)) {
rcu_is_last_leaf_node(rnp)) {
/* No workqueues yet or last leaf, do direct call. */
sync_rcu_exp_select_node_cpus(&rnp->rew.rew_work);
continue;
Expand All @@ -462,7 +462,7 @@ static void sync_rcu_exp_select_cpus(smp_call_func_t func)
}

/* Wait for workqueue jobs (if any) to complete. */
rcu_for_each_leaf_node(&rcu_state, rnp)
rcu_for_each_leaf_node(rnp)
if (rnp->exp_need_flush)
flush_work(&rnp->rew.rew_work);
}
Expand Down Expand Up @@ -496,7 +496,7 @@ static void synchronize_sched_expedited_wait(void)
pr_err("INFO: %s detected expedited stalls on CPUs/tasks: {",
rcu_state.name);
ndetected = 0;
rcu_for_each_leaf_node(&rcu_state, rnp) {
rcu_for_each_leaf_node(rnp) {
ndetected += rcu_print_task_exp_stall(rnp);
for_each_leaf_node_possible_cpu(rnp, cpu) {
struct rcu_data *rdp;
Expand All @@ -517,7 +517,7 @@ static void synchronize_sched_expedited_wait(void)
rnp_root->expmask, ".T"[!!rnp_root->exp_tasks]);
if (ndetected) {
pr_err("blocking rcu_node structures:");
rcu_for_each_node_breadth_first(&rcu_state, rnp) {
rcu_for_each_node_breadth_first(rnp) {
if (rnp == rnp_root)
continue; /* printed unconditionally */
if (sync_rcu_preempt_exp_done_unlocked(rnp))
Expand All @@ -529,7 +529,7 @@ static void synchronize_sched_expedited_wait(void)
}
pr_cont("\n");
}
rcu_for_each_leaf_node(&rcu_state, rnp) {
rcu_for_each_leaf_node(rnp) {
for_each_leaf_node_possible_cpu(rnp, cpu) {
mask = leaf_node_cpu_bit(rnp, cpu);
if (!(rnp->expmask & mask))
Expand Down Expand Up @@ -561,7 +561,7 @@ static void rcu_exp_wait_wake(unsigned long s)
*/
mutex_lock(&rcu_state.exp_wake_mutex);

rcu_for_each_node_breadth_first(&rcu_state, rnp) {
rcu_for_each_node_breadth_first(rnp) {
if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s)) {
spin_lock(&rnp->exp_lock);
/* Recheck, avoid hang in case someone just arrived. */
Expand Down
4 changes: 2 additions & 2 deletions kernel/rcu/tree_plugin.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -687,7 +687,7 @@ static void rcu_print_detail_task_stall(void)
struct rcu_node *rnp = rcu_get_root();

rcu_print_detail_task_stall_rnp(rnp);
rcu_for_each_leaf_node(&rcu_state, rnp)
rcu_for_each_leaf_node(rnp)
rcu_print_detail_task_stall_rnp(rnp);
}

Expand Down Expand Up @@ -1427,7 +1427,7 @@ static void __init rcu_spawn_boost_kthreads(void)
for_each_possible_cpu(cpu)
per_cpu(rcu_cpu_has_work, cpu) = 0;
BUG_ON(smpboot_register_percpu_thread(&rcu_cpu_thread_spec));
rcu_for_each_leaf_node(&rcu_state, rnp)
rcu_for_each_leaf_node(rnp)
(void)rcu_spawn_one_boost_kthread(rnp);
}

Expand Down

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