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Date: Wed, 29 Aug 2018 15:38:42 -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 40/52] rcu: Remove rsp parameter from rcu_node tree accessor macros
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 <paulmck@...ux.vnet.ibm.com>
---
.../Data-Structures/Data-Structures.html | 23 +++++----------
kernel/rcu/rcu.h | 28 ++++++++-----------
kernel/rcu/srcutree.c | 4 +--
kernel/rcu/tree.c | 19 ++++++-------
kernel/rcu/tree_exp.h | 18 ++++++------
kernel/rcu/tree_plugin.h | 4 +--
6 files changed, 40 insertions(+), 56 deletions(-)
diff --git a/Documentation/RCU/Design/Data-Structures/Data-Structures.html b/Documentation/RCU/Design/Data-Structures/Data-Structures.html
index f5120a00f511..772c26a3865a 100644
--- a/Documentation/RCU/Design/Data-Structures/Data-Structures.html
+++ b/Documentation/RCU/Design/Data-Structures/Data-Structures.html
@@ -1372,8 +1372,7 @@ that is, if the CPU is currently idle.
Accessor Functions</a></h3>
<p>The following listing shows the
-<tt>rcu_get_root()</tt>, <tt>rcu_for_each_node_breadth_first</tt>,
-<tt>rcu_for_each_nonleaf_node_breadth_first()</tt>, and
+<tt>rcu_get_root()</tt>, <tt>rcu_for_each_node_breadth_first</tt> and
<tt>rcu_for_each_leaf_node()</tt> function and macros:
<pre>
@@ -1386,13 +1385,9 @@ Accessor Functions</a></h3>
7 for ((rnp) = &(rsp)->node[0]; \
8 (rnp) < &(rsp)->node[NUM_RCU_NODES]; (rnp)++)
9
- 10 #define rcu_for_each_nonleaf_node_breadth_first(rsp, rnp) \
- 11 for ((rnp) = &(rsp)->node[0]; \
- 12 (rnp) < (rsp)->level[NUM_RCU_LVLS - 1]; (rnp)++)
- 13
- 14 #define rcu_for_each_leaf_node(rsp, rnp) \
- 15 for ((rnp) = (rsp)->level[NUM_RCU_LVLS - 1]; \
- 16 (rnp) < &(rsp)->node[NUM_RCU_NODES]; (rnp)++)
+ 10 #define rcu_for_each_leaf_node(rsp, rnp) \
+ 11 for ((rnp) = (rsp)->level[NUM_RCU_LVLS - 1]; \
+ 12 (rnp) < &(rsp)->node[NUM_RCU_NODES]; (rnp)++)
</pre>
<p>The <tt>rcu_get_root()</tt> simply returns a pointer to the
@@ -1405,10 +1400,7 @@ macro takes advantage of the layout of the <tt>rcu_node</tt>
structures in the <tt>rcu_state</tt> structure's
<tt>->node[]</tt> array, performing a breadth-first traversal by
simply traversing the array in order.
-The <tt>rcu_for_each_nonleaf_node_breadth_first()</tt> macro operates
-similarly, but traverses only the first part of the array, thus excluding
-the leaf <tt>rcu_node</tt> structures.
-Finally, the <tt>rcu_for_each_leaf_node()</tt> macro traverses only
+Similarly, the <tt>rcu_for_each_leaf_node()</tt> macro traverses only
the last part of the array, thus traversing only the leaf
<tt>rcu_node</tt> structures.
@@ -1416,15 +1408,14 @@ the last part of the array, thus traversing only the leaf
<tr><th> </th></tr>
<tr><th align="left">Quick Quiz:</th></tr>
<tr><td>
- What do <tt>rcu_for_each_nonleaf_node_breadth_first()</tt> and
+ What does
<tt>rcu_for_each_leaf_node()</tt> do if the <tt>rcu_node</tt> tree
contains only a single node?
</td></tr>
<tr><th align="left">Answer:</th></tr>
<tr><td bgcolor="#ffffff"><font color="ffffff">
In the single-node case,
- <tt>rcu_for_each_nonleaf_node_breadth_first()</tt> is a no-op
- and <tt>rcu_for_each_leaf_node()</tt> traverses the single node.
+ <tt>rcu_for_each_leaf_node()</tt> traverses the single node.
</font></td></tr>
<tr><td> </td></tr>
</table>
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index 4d04683c31b2..2bb77fddc11f 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -329,29 +329,23 @@ 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
@@ -359,9 +353,9 @@ static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt)
* 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.
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index 6c9866a854b1..2042080cd38b 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -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));
@@ -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];
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index c3031b566851..35b705c1da40 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -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",
@@ -1275,7 +1275,7 @@ 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))
@@ -1335,7 +1335,7 @@ 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) {
@@ -1872,7 +1872,7 @@ 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 &&
@@ -1932,7 +1932,7 @@ 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);
@@ -2045,7 +2045,7 @@ 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);
@@ -2605,9 +2605,8 @@ 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);
@@ -3777,7 +3776,7 @@ 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++;
@@ -3877,7 +3876,7 @@ 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(" ");
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index b6f7bc34ac49..060bdb45cd95 100644
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -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);
@@ -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;
@@ -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;
@@ -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);
}
@@ -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;
@@ -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))
@@ -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))
@@ -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. */
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index e6ec25e47d00..b60d3df92ff5 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -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);
}
@@ -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);
}
--
2.17.1
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