* [PATCH tip/core/rcu 0/2] Enforce RCU grace-period transitivity
@ 2015-12-04 23:41 Paul E. McKenney
2015-12-04 23:42 ` [PATCH tip/core/rcu 1/2] rcu: Create transitive rnp->lock acquisition functions Paul E. McKenney
2015-12-04 23:42 ` [PATCH tip/core/rcu 2/2] rcu: Add transitivity to remaining rcu_node ->lock acquisitions Paul E. McKenney
0 siblings, 2 replies; 3+ messages in thread
From: Paul E. McKenney @ 2015-12-04 23:41 UTC (permalink / raw)
To: linux-kernel
Cc: mingo, jiangshanlai, dipankar, akpm, mathieu.desnoyers, josh,
tglx, peterz, rostedt, dhowells, edumazet, dvhart, fweisbec,
oleg, bobby.prani
Hello!
Within RCU, acquisitions of the rcu_node structure's ->lock field must
be followed by smp_mb__after_unlock_lock() in order to enforce RCU's
grace-period memory-ordering guarantees. In theory, acquisitions for
debug purposes need not have smp_mb__after_unlock_lock(), but in practice,
anything other than fully consistent enforcement of this rule is a recipe
for disaster. This series therefore adds smp_mb__after_unlock_lock()
for consistency:
1. Create wrapper functions to minimize the number of these
smp_mb__after_unlock_lock() calls, and apply these wrapper
functions throughout. Courtesy of Peter Zijlstra.
2. Catch up wrapper-function application to patches that were
in flight at the time #1 was created.
Thanx, Paul
------------------------------------------------------------------------
b/kernel/rcu/tree.c | 102 ++++++++++++++++-----------------------------
b/kernel/rcu/tree.h | 39 +++++++++++++++++
b/kernel/rcu/tree_plugin.h | 20 +++-----
b/kernel/rcu/tree_trace.c | 2
4 files changed, 85 insertions(+), 78 deletions(-)
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH tip/core/rcu 1/2] rcu: Create transitive rnp->lock acquisition functions
2015-12-04 23:41 [PATCH tip/core/rcu 0/2] Enforce RCU grace-period transitivity Paul E. McKenney
@ 2015-12-04 23:42 ` Paul E. McKenney
2015-12-04 23:42 ` [PATCH tip/core/rcu 2/2] rcu: Add transitivity to remaining rcu_node ->lock acquisitions Paul E. McKenney
1 sibling, 0 replies; 3+ messages in thread
From: Paul E. McKenney @ 2015-12-04 23:42 UTC (permalink / raw)
To: linux-kernel
Cc: mingo, jiangshanlai, dipankar, akpm, mathieu.desnoyers, josh,
tglx, peterz, rostedt, dhowells, edumazet, dvhart, fweisbec,
oleg, bobby.prani, Paul E. McKenney
From: Peter Zijlstra <peterz@infradead.org>
Providing RCU's memory-ordering guarantees requires that the rcu_node
tree's locking provide transitive memory ordering, which the Linux kernel's
spinlocks currently do not provide unless smp_mb__after_unlock_lock()
is used. Having a separate smp_mb__after_unlock_lock() after each and
every lock acquisition is error-prone, hard to read, and a bit annoying,
so this commit provides wrapper functions that pull in the
smp_mb__after_unlock_lock() invocations.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
kernel/rcu/tree.c | 78 ++++++++++++++++--------------------------------
kernel/rcu/tree.h | 39 ++++++++++++++++++++++++
kernel/rcu/tree_plugin.h | 18 ++++-------
3 files changed, 71 insertions(+), 64 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index f07343b54fe5..daf17e248757 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1534,10 +1534,8 @@ rcu_start_future_gp(struct rcu_node *rnp, struct rcu_data *rdp,
* hold it, acquire the root rcu_node structure's lock in order to
* start one (if needed).
*/
- if (rnp != rnp_root) {
- raw_spin_lock(&rnp_root->lock);
- smp_mb__after_unlock_lock();
- }
+ if (rnp != rnp_root)
+ raw_spin_lock_rcu_node(rnp_root);
/*
* Get a new grace-period number. If there really is no grace
@@ -1786,11 +1784,10 @@ static void note_gp_changes(struct rcu_state *rsp, struct rcu_data *rdp)
if ((rdp->gpnum == READ_ONCE(rnp->gpnum) &&
rdp->completed == READ_ONCE(rnp->completed) &&
!unlikely(READ_ONCE(rdp->gpwrap))) || /* w/out lock. */
- !raw_spin_trylock(&rnp->lock)) { /* irqs already off, so later. */
+ !raw_spin_trylock_rcu_node(rnp)) { /* irqs already off, so later. */
local_irq_restore(flags);
return;
}
- smp_mb__after_unlock_lock();
needwake = __note_gp_changes(rsp, rnp, rdp);
raw_spin_unlock_irqrestore(&rnp->lock, flags);
if (needwake)
@@ -1814,8 +1811,7 @@ static int rcu_gp_init(struct rcu_state *rsp)
struct rcu_node *rnp = rcu_get_root(rsp);
WRITE_ONCE(rsp->gp_activity, jiffies);
- raw_spin_lock_irq(&rnp->lock);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irq_rcu_node(rnp);
if (!READ_ONCE(rsp->gp_flags)) {
/* Spurious wakeup, tell caller to go back to sleep. */
raw_spin_unlock_irq(&rnp->lock);
@@ -1847,8 +1843,7 @@ static int rcu_gp_init(struct rcu_state *rsp)
*/
rcu_for_each_leaf_node(rsp, rnp) {
rcu_gp_slow(rsp, gp_preinit_delay);
- raw_spin_lock_irq(&rnp->lock);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irq_rcu_node(rnp);
if (rnp->qsmaskinit == rnp->qsmaskinitnext &&
!rnp->wait_blkd_tasks) {
/* Nothing to do on this leaf rcu_node structure. */
@@ -1904,8 +1899,7 @@ static int rcu_gp_init(struct rcu_state *rsp)
*/
rcu_for_each_node_breadth_first(rsp, rnp) {
rcu_gp_slow(rsp, gp_init_delay);
- raw_spin_lock_irq(&rnp->lock);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irq_rcu_node(rnp);
rdp = this_cpu_ptr(rsp->rda);
rcu_preempt_check_blocked_tasks(rnp);
rnp->qsmask = rnp->qsmaskinit;
@@ -1973,8 +1967,7 @@ static void rcu_gp_fqs(struct rcu_state *rsp, bool first_time)
}
/* Clear flag to prevent immediate re-entry. */
if (READ_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) {
- raw_spin_lock_irq(&rnp->lock);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irq_rcu_node(rnp);
WRITE_ONCE(rsp->gp_flags,
READ_ONCE(rsp->gp_flags) & ~RCU_GP_FLAG_FQS);
raw_spin_unlock_irq(&rnp->lock);
@@ -1993,8 +1986,7 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
struct rcu_node *rnp = rcu_get_root(rsp);
WRITE_ONCE(rsp->gp_activity, jiffies);
- raw_spin_lock_irq(&rnp->lock);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irq_rcu_node(rnp);
gp_duration = jiffies - rsp->gp_start;
if (gp_duration > rsp->gp_max)
rsp->gp_max = gp_duration;
@@ -2019,8 +2011,7 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
* grace period is recorded in any of the rcu_node structures.
*/
rcu_for_each_node_breadth_first(rsp, rnp) {
- raw_spin_lock_irq(&rnp->lock);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irq_rcu_node(rnp);
WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp));
WARN_ON_ONCE(rnp->qsmask);
WRITE_ONCE(rnp->completed, rsp->gpnum);
@@ -2035,8 +2026,7 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
rcu_gp_slow(rsp, gp_cleanup_delay);
}
rnp = rcu_get_root(rsp);
- raw_spin_lock_irq(&rnp->lock);
- smp_mb__after_unlock_lock(); /* Order GP before ->completed update. */
+ raw_spin_lock_irq_rcu_node(rnp); /* Order GP before ->completed update. */
rcu_nocb_gp_set(rnp, nocb);
/* Declare grace period done. */
@@ -2284,8 +2274,7 @@ rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp,
raw_spin_unlock_irqrestore(&rnp->lock, flags);
rnp_c = rnp;
rnp = rnp->parent;
- raw_spin_lock_irqsave(&rnp->lock, flags);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
oldmask = rnp_c->qsmask;
}
@@ -2332,8 +2321,7 @@ static void rcu_report_unblock_qs_rnp(struct rcu_state *rsp,
gps = rnp->gpnum;
mask = rnp->grpmask;
raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */
- raw_spin_lock(&rnp_p->lock); /* irqs already disabled. */
- smp_mb__after_unlock_lock();
+ raw_spin_lock_rcu_node(rnp_p); /* irqs already disabled. */
rcu_report_qs_rnp(mask, rsp, rnp_p, gps, flags);
}
@@ -2355,8 +2343,7 @@ rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp)
struct rcu_node *rnp;
rnp = rdp->mynode;
- raw_spin_lock_irqsave(&rnp->lock, flags);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
if ((rdp->cpu_no_qs.b.norm &&
rdp->rcu_qs_ctr_snap == __this_cpu_read(rcu_qs_ctr)) ||
rdp->gpnum != rnp->gpnum || rnp->completed == rnp->gpnum ||
@@ -2582,8 +2569,7 @@ static void rcu_cleanup_dead_rnp(struct rcu_node *rnp_leaf)
rnp = rnp->parent;
if (!rnp)
break;
- raw_spin_lock(&rnp->lock); /* irqs already disabled. */
- smp_mb__after_unlock_lock(); /* GP memory ordering. */
+ raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */
rnp->qsmaskinit &= ~mask;
rnp->qsmask &= ~mask;
if (rnp->qsmaskinit) {
@@ -2611,8 +2597,7 @@ static void rcu_cleanup_dying_idle_cpu(int cpu, struct rcu_state *rsp)
/* Remove outgoing CPU from mask in the leaf rcu_node structure. */
mask = rdp->grpmask;
- raw_spin_lock_irqsave(&rnp->lock, flags);
- smp_mb__after_unlock_lock(); /* Enforce GP memory-order guarantee. */
+ raw_spin_lock_irqsave_rcu_node(rnp, flags); /* Enforce GP memory-order guarantee. */
rnp->qsmaskinitnext &= ~mask;
raw_spin_unlock_irqrestore(&rnp->lock, flags);
}
@@ -2809,8 +2794,7 @@ static void force_qs_rnp(struct rcu_state *rsp,
rcu_for_each_leaf_node(rsp, rnp) {
cond_resched_rcu_qs();
mask = 0;
- raw_spin_lock_irqsave(&rnp->lock, flags);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (rnp->qsmask == 0) {
if (rcu_state_p == &rcu_sched_state ||
rsp != rcu_state_p ||
@@ -2881,8 +2865,7 @@ static void force_quiescent_state(struct rcu_state *rsp)
/* rnp_old == rcu_get_root(rsp), rnp == NULL. */
/* Reached the root of the rcu_node tree, acquire lock. */
- raw_spin_lock_irqsave(&rnp_old->lock, flags);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irqsave_rcu_node(rnp_old, flags);
raw_spin_unlock(&rnp_old->fqslock);
if (READ_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) {
rsp->n_force_qs_lh++;
@@ -3005,8 +2988,7 @@ static void __call_rcu_core(struct rcu_state *rsp, struct rcu_data *rdp,
if (!rcu_gp_in_progress(rsp)) {
struct rcu_node *rnp_root = rcu_get_root(rsp);
- raw_spin_lock(&rnp_root->lock);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_rcu_node(rnp_root);
needwake = rcu_start_gp(rsp);
raw_spin_unlock(&rnp_root->lock);
if (needwake)
@@ -3426,8 +3408,7 @@ static void sync_exp_reset_tree_hotplug(struct rcu_state *rsp)
* CPUs for the current rcu_node structure up the rcu_node tree.
*/
rcu_for_each_leaf_node(rsp, rnp) {
- raw_spin_lock_irqsave(&rnp->lock, flags);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (rnp->expmaskinit == rnp->expmaskinitnext) {
raw_spin_unlock_irqrestore(&rnp->lock, flags);
continue; /* No new CPUs, nothing to do. */
@@ -3447,8 +3428,7 @@ static void sync_exp_reset_tree_hotplug(struct rcu_state *rsp)
rnp_up = rnp->parent;
done = false;
while (rnp_up) {
- raw_spin_lock_irqsave(&rnp_up->lock, flags);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irqsave_rcu_node(rnp_up, flags);
if (rnp_up->expmaskinit)
done = true;
rnp_up->expmaskinit |= mask;
@@ -3472,8 +3452,7 @@ static void __maybe_unused sync_exp_reset_tree(struct rcu_state *rsp)
sync_exp_reset_tree_hotplug(rsp);
rcu_for_each_node_breadth_first(rsp, rnp) {
- raw_spin_lock_irqsave(&rnp->lock, flags);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
WARN_ON_ONCE(rnp->expmask);
rnp->expmask = rnp->expmaskinit;
raw_spin_unlock_irqrestore(&rnp->lock, flags);
@@ -3531,8 +3510,7 @@ static void __rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
mask = rnp->grpmask;
raw_spin_unlock(&rnp->lock); /* irqs remain disabled */
rnp = rnp->parent;
- raw_spin_lock(&rnp->lock); /* irqs already disabled */
- smp_mb__after_unlock_lock();
+ raw_spin_lock_rcu_node(rnp); /* irqs already disabled */
WARN_ON_ONCE(!(rnp->expmask & mask));
rnp->expmask &= ~mask;
}
@@ -3549,8 +3527,7 @@ static void __maybe_unused rcu_report_exp_rnp(struct rcu_state *rsp,
{
unsigned long flags;
- raw_spin_lock_irqsave(&rnp->lock, flags);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
__rcu_report_exp_rnp(rsp, rnp, wake, flags);
}
@@ -3564,8 +3541,7 @@ static void rcu_report_exp_cpu_mult(struct rcu_state *rsp, struct rcu_node *rnp,
{
unsigned long flags;
- raw_spin_lock_irqsave(&rnp->lock, flags);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (!(rnp->expmask & mask)) {
raw_spin_unlock_irqrestore(&rnp->lock, flags);
return;
@@ -3708,8 +3684,7 @@ static void sync_rcu_exp_select_cpus(struct rcu_state *rsp,
sync_exp_reset_tree(rsp);
rcu_for_each_leaf_node(rsp, rnp) {
- raw_spin_lock_irqsave(&rnp->lock, flags);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
/* Each pass checks a CPU for identity, offline, and idle. */
mask_ofl_test = 0;
@@ -4198,8 +4173,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
*/
rnp = rdp->mynode;
mask = rdp->grpmask;
- raw_spin_lock(&rnp->lock); /* irqs already disabled. */
- smp_mb__after_unlock_lock();
+ raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */
rnp->qsmaskinitnext |= mask;
rnp->expmaskinitnext |= mask;
if (!rdp->beenonline)
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 9fb4e238d4dc..f32bebb6bc90 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -664,3 +664,42 @@ static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll)
#else /* #ifdef CONFIG_PPC */
#define smp_mb__after_unlock_lock() do { } while (0)
#endif /* #else #ifdef CONFIG_PPC */
+
+/*
+ * Wrappers for the rcu_node::lock acquire.
+ *
+ * Because the rcu_nodes form a tree, the tree traversal locking will observe
+ * different lock values, this in turn means that an UNLOCK of one level
+ * followed by a LOCK of another level does not imply a full memory barrier;
+ * and most importantly transitivity is lost.
+ *
+ * In order to restore full ordering between tree levels, augment the regular
+ * lock acquire functions with smp_mb__after_unlock_lock().
+ */
+static inline void raw_spin_lock_rcu_node(struct rcu_node *rnp)
+{
+ raw_spin_lock(&rnp->lock);
+ smp_mb__after_unlock_lock();
+}
+
+static inline void raw_spin_lock_irq_rcu_node(struct rcu_node *rnp)
+{
+ raw_spin_lock_irq(&rnp->lock);
+ smp_mb__after_unlock_lock();
+}
+
+#define raw_spin_lock_irqsave_rcu_node(rnp, flags) \
+do { \
+ typecheck(unsigned long, flags); \
+ raw_spin_lock_irqsave(&(rnp)->lock, flags); \
+ smp_mb__after_unlock_lock(); \
+} while (0)
+
+static inline bool raw_spin_trylock_rcu_node(struct rcu_node *rnp)
+{
+ bool locked = raw_spin_trylock(&rnp->lock);
+
+ if (locked)
+ smp_mb__after_unlock_lock();
+ return locked;
+}
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 630c19772630..fa0e3b96a9ed 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -301,8 +301,7 @@ static void rcu_preempt_note_context_switch(void)
/* Possibly blocking in an RCU read-side critical section. */
rdp = this_cpu_ptr(rcu_state_p->rda);
rnp = rdp->mynode;
- raw_spin_lock_irqsave(&rnp->lock, flags);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
t->rcu_read_unlock_special.b.blocked = true;
t->rcu_blocked_node = rnp;
@@ -457,8 +456,7 @@ void rcu_read_unlock_special(struct task_struct *t)
*/
for (;;) {
rnp = t->rcu_blocked_node;
- raw_spin_lock(&rnp->lock); /* irqs already disabled. */
- smp_mb__after_unlock_lock();
+ raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */
if (rnp == t->rcu_blocked_node)
break;
WARN_ON_ONCE(1);
@@ -989,8 +987,7 @@ static int rcu_boost(struct rcu_node *rnp)
READ_ONCE(rnp->boost_tasks) == NULL)
return 0; /* Nothing left to boost. */
- raw_spin_lock_irqsave(&rnp->lock, flags);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
/*
* Recheck under the lock: all tasks in need of boosting
@@ -1176,8 +1173,7 @@ static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
"rcub/%d", rnp_index);
if (IS_ERR(t))
return PTR_ERR(t);
- raw_spin_lock_irqsave(&rnp->lock, flags);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
rnp->boost_kthread_task = t;
raw_spin_unlock_irqrestore(&rnp->lock, flags);
sp.sched_priority = kthread_prio;
@@ -1567,8 +1563,7 @@ static void rcu_prepare_for_idle(void)
if (!*rdp->nxttail[RCU_DONE_TAIL])
continue;
rnp = rdp->mynode;
- raw_spin_lock(&rnp->lock); /* irqs already disabled. */
- smp_mb__after_unlock_lock();
+ raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */
needwake = rcu_accelerate_cbs(rsp, rnp, rdp);
raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */
if (needwake)
@@ -2068,8 +2063,7 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp)
bool needwake;
struct rcu_node *rnp = rdp->mynode;
- raw_spin_lock_irqsave(&rnp->lock, flags);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
needwake = rcu_start_future_gp(rnp, rdp, &c);
raw_spin_unlock_irqrestore(&rnp->lock, flags);
if (needwake)
--
2.5.2
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH tip/core/rcu 2/2] rcu: Add transitivity to remaining rcu_node ->lock acquisitions
2015-12-04 23:41 [PATCH tip/core/rcu 0/2] Enforce RCU grace-period transitivity Paul E. McKenney
2015-12-04 23:42 ` [PATCH tip/core/rcu 1/2] rcu: Create transitive rnp->lock acquisition functions Paul E. McKenney
@ 2015-12-04 23:42 ` Paul E. McKenney
1 sibling, 0 replies; 3+ messages in thread
From: Paul E. McKenney @ 2015-12-04 23:42 UTC (permalink / raw)
To: linux-kernel
Cc: mingo, jiangshanlai, dipankar, akpm, mathieu.desnoyers, josh,
tglx, peterz, rostedt, dhowells, edumazet, dvhart, fweisbec,
oleg, bobby.prani, Paul E. McKenney
The rule is that all acquisitions of the rcu_node structure's ->lock
must provide transitivity: The lock is not acquired that frequently,
and sorting out exactly which required it and which did not would be
a maintenance nightmare. This commit therefore supplies the needed
transitivity to the remaining ->lock acquisitions.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
kernel/rcu/tree.c | 24 ++++++++++++------------
kernel/rcu/tree_plugin.h | 2 +-
kernel/rcu/tree_trace.c | 2 +-
3 files changed, 14 insertions(+), 14 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index daf17e248757..81aa1cdc6bc9 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1214,7 +1214,7 @@ static void rcu_dump_cpu_stacks(struct rcu_state *rsp)
struct rcu_node *rnp;
rcu_for_each_leaf_node(rsp, rnp) {
- raw_spin_lock_irqsave(&rnp->lock, flags);
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (rnp->qsmask != 0) {
for (cpu = 0; cpu <= rnp->grphi - rnp->grplo; cpu++)
if (rnp->qsmask & (1UL << cpu))
@@ -1237,7 +1237,7 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum)
/* Only let one CPU complain about others per time interval. */
- raw_spin_lock_irqsave(&rnp->lock, flags);
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
delta = jiffies - READ_ONCE(rsp->jiffies_stall);
if (delta < RCU_STALL_RAT_DELAY || !rcu_gp_in_progress(rsp)) {
raw_spin_unlock_irqrestore(&rnp->lock, flags);
@@ -1256,7 +1256,7 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum)
rsp->name);
print_cpu_stall_info_begin();
rcu_for_each_leaf_node(rsp, rnp) {
- raw_spin_lock_irqsave(&rnp->lock, flags);
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
ndetected += rcu_print_task_stall(rnp);
if (rnp->qsmask != 0) {
for (cpu = 0; cpu <= rnp->grphi - rnp->grplo; cpu++)
@@ -1327,7 +1327,7 @@ static void print_cpu_stall(struct rcu_state *rsp)
rcu_dump_cpu_stacks(rsp);
- raw_spin_lock_irqsave(&rnp->lock, flags);
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (ULONG_CMP_GE(jiffies, READ_ONCE(rsp->jiffies_stall)))
WRITE_ONCE(rsp->jiffies_stall,
jiffies + 3 * rcu_jiffies_till_stall_check() + 3);
@@ -2897,7 +2897,7 @@ __rcu_process_callbacks(struct rcu_state *rsp)
/* Does this CPU require a not-yet-started grace period? */
local_irq_save(flags);
if (cpu_needs_another_gp(rsp, rdp)) {
- raw_spin_lock(&rcu_get_root(rsp)->lock); /* irqs disabled. */
+ raw_spin_lock_rcu_node(rcu_get_root(rsp)); /* irqs disabled. */
needwake = rcu_start_gp(rsp);
raw_spin_unlock_irqrestore(&rcu_get_root(rsp)->lock, flags);
if (needwake)
@@ -3718,7 +3718,7 @@ retry_ipi:
mask_ofl_ipi &= ~mask;
} else {
/* Failed, raced with offline. */
- raw_spin_lock_irqsave(&rnp->lock, flags);
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (cpu_online(cpu) &&
(rnp->expmask & mask)) {
raw_spin_unlock_irqrestore(&rnp->lock,
@@ -3727,8 +3727,8 @@ retry_ipi:
if (cpu_online(cpu) &&
(rnp->expmask & mask))
goto retry_ipi;
- raw_spin_lock_irqsave(&rnp->lock,
- flags);
+ raw_spin_lock_irqsave_rcu_node(rnp,
+ flags);
}
if (!(rnp->expmask & mask))
mask_ofl_ipi &= ~mask;
@@ -4110,7 +4110,7 @@ static void rcu_init_new_rnp(struct rcu_node *rnp_leaf)
rnp = rnp->parent;
if (rnp == NULL)
return;
- raw_spin_lock(&rnp->lock); /* Interrupts already disabled. */
+ raw_spin_lock_rcu_node(rnp); /* Interrupts already disabled. */
rnp->qsmaskinit |= mask;
raw_spin_unlock(&rnp->lock); /* Interrupts remain disabled. */
}
@@ -4127,7 +4127,7 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)
struct rcu_node *rnp = rcu_get_root(rsp);
/* Set up local state, ensuring consistent view of global state. */
- raw_spin_lock_irqsave(&rnp->lock, flags);
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
rdp->grpmask = 1UL << (cpu - rdp->mynode->grplo);
rdp->dynticks = &per_cpu(rcu_dynticks, cpu);
WARN_ON_ONCE(rdp->dynticks->dynticks_nesting != DYNTICK_TASK_EXIT_IDLE);
@@ -4154,7 +4154,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
struct rcu_node *rnp = rcu_get_root(rsp);
/* Set up local state, ensuring consistent view of global state. */
- raw_spin_lock_irqsave(&rnp->lock, flags);
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
rdp->qlen_last_fqs_check = 0;
rdp->n_force_qs_snap = rsp->n_force_qs;
rdp->blimit = blimit;
@@ -4301,7 +4301,7 @@ static int __init rcu_spawn_gp_kthread(void)
t = kthread_create(rcu_gp_kthread, rsp, "%s", rsp->name);
BUG_ON(IS_ERR(t));
rnp = rcu_get_root(rsp);
- raw_spin_lock_irqsave(&rnp->lock, flags);
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
rsp->gp_kthread = t;
if (kthread_prio) {
sp.sched_priority = kthread_prio;
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index fa0e3b96a9ed..57ba873d2f18 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -525,7 +525,7 @@ static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp)
unsigned long flags;
struct task_struct *t;
- raw_spin_lock_irqsave(&rnp->lock, flags);
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (!rcu_preempt_blocked_readers_cgp(rnp)) {
raw_spin_unlock_irqrestore(&rnp->lock, flags);
return;
diff --git a/kernel/rcu/tree_trace.c b/kernel/rcu/tree_trace.c
index ef7093cc9b5c..8efaba870d96 100644
--- a/kernel/rcu/tree_trace.c
+++ b/kernel/rcu/tree_trace.c
@@ -319,7 +319,7 @@ static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp)
unsigned long gpmax;
struct rcu_node *rnp = &rsp->node[0];
- raw_spin_lock_irqsave(&rnp->lock, flags);
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
completed = READ_ONCE(rsp->completed);
gpnum = READ_ONCE(rsp->gpnum);
if (completed == gpnum)
--
2.5.2
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2015-12-04 23:41 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-12-04 23:41 [PATCH tip/core/rcu 0/2] Enforce RCU grace-period transitivity Paul E. McKenney
2015-12-04 23:42 ` [PATCH tip/core/rcu 1/2] rcu: Create transitive rnp->lock acquisition functions Paul E. McKenney
2015-12-04 23:42 ` [PATCH tip/core/rcu 2/2] rcu: Add transitivity to remaining rcu_node ->lock acquisitions Paul E. McKenney
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