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-rw-r--r--kernel/rcu/Makefile4
-rw-r--r--kernel/rcu/rcutorture.c20
-rw-r--r--kernel/rcu/tiny_plugin.h15
-rw-r--r--kernel/rcu/tree.c214
-rw-r--r--kernel/rcu/tree.h42
-rw-r--r--kernel/rcu/tree_plugin.h27
-rw-r--r--kernel/rcu/update.c1
7 files changed, 170 insertions, 153 deletions
diff --git a/kernel/rcu/Makefile b/kernel/rcu/Makefile
index 61a16569f..032b2c015 100644
--- a/kernel/rcu/Makefile
+++ b/kernel/rcu/Makefile
@@ -1,3 +1,7 @@
+# Any varying coverage in these files is non-deterministic
+# and is generally not a function of system call inputs.
+KCOV_INSTRUMENT := n
+
obj-y += update.o sync.o
obj-$(CONFIG_SRCU) += srcu.o
obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index d2988d047..250ea67c1 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -130,10 +130,8 @@ static struct rcu_torture __rcu *rcu_torture_current;
static unsigned long rcu_torture_current_version;
static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
static DEFINE_SPINLOCK(rcu_torture_lock);
-static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1],
- rcu_torture_count) = { 0 };
-static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1],
- rcu_torture_batch) = { 0 };
+static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) = { 0 };
+static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) = { 0 };
static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
static atomic_t n_rcu_torture_alloc;
static atomic_t n_rcu_torture_alloc_fail;
@@ -932,12 +930,14 @@ rcu_torture_writer(void *arg)
int nsynctypes = 0;
VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
- pr_alert("%s" TORTURE_FLAG
- " Grace periods expedited from boot/sysfs for %s,\n",
- torture_type, cur_ops->name);
- pr_alert("%s" TORTURE_FLAG
- " Testing of dynamic grace-period expediting diabled.\n",
- torture_type);
+ if (!can_expedite) {
+ pr_alert("%s" TORTURE_FLAG
+ " Grace periods expedited from boot/sysfs for %s,\n",
+ torture_type, cur_ops->name);
+ pr_alert("%s" TORTURE_FLAG
+ " Disabled dynamic grace-period expediting.\n",
+ torture_type);
+ }
/* Initialize synctype[] array. If none set, take default. */
if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
diff --git a/kernel/rcu/tiny_plugin.h b/kernel/rcu/tiny_plugin.h
index e492a5253..196f0302e 100644
--- a/kernel/rcu/tiny_plugin.h
+++ b/kernel/rcu/tiny_plugin.h
@@ -23,7 +23,7 @@
*/
#include <linux/kthread.h>
-#include <linux/module.h>
+#include <linux/init.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
@@ -122,18 +122,7 @@ free_out:
debugfs_remove_recursive(rcudir);
return 1;
}
-
-static void __exit rcutiny_trace_cleanup(void)
-{
- debugfs_remove_recursive(rcudir);
-}
-
-module_init(rcutiny_trace_init);
-module_exit(rcutiny_trace_cleanup);
-
-MODULE_AUTHOR("Paul E. McKenney");
-MODULE_DESCRIPTION("Read-Copy Update tracing for tiny implementation");
-MODULE_LICENSE("GPL");
+device_initcall(rcutiny_trace_init);
static void check_cpu_stall(struct rcu_ctrlblk *rcp)
{
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 9fd5b628a..9a535a86e 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -108,7 +108,6 @@ RCU_STATE_INITIALIZER(rcu_sched, 's', call_rcu_sched);
RCU_STATE_INITIALIZER(rcu_bh, 'b', call_rcu_bh);
static struct rcu_state *const rcu_state_p;
-static struct rcu_data __percpu *const rcu_data_p;
LIST_HEAD(rcu_struct_flavors);
/* Dump rcu_node combining tree at boot to verify correct setup. */
@@ -1083,13 +1082,12 @@ static int dyntick_save_progress_counter(struct rcu_data *rdp,
rcu_sysidle_check_cpu(rdp, isidle, maxj);
if ((rdp->dynticks_snap & 0x1) == 0) {
trace_rcu_fqs(rdp->rsp->name, rdp->gpnum, rdp->cpu, TPS("dti"));
- return 1;
- } else {
if (ULONG_CMP_LT(READ_ONCE(rdp->gpnum) + ULONG_MAX / 4,
rdp->mynode->gpnum))
WRITE_ONCE(rdp->gpwrap, true);
- return 0;
+ return 1;
}
+ return 0;
}
/*
@@ -1173,15 +1171,16 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp,
smp_mb(); /* ->cond_resched_completed before *rcrmp. */
WRITE_ONCE(*rcrmp,
READ_ONCE(*rcrmp) + rdp->rsp->flavor_mask);
- resched_cpu(rdp->cpu); /* Force CPU into scheduler. */
- rdp->rsp->jiffies_resched += 5; /* Enable beating. */
- } else if (ULONG_CMP_GE(jiffies, rdp->rsp->jiffies_resched)) {
- /* Time to beat on that CPU again! */
- resched_cpu(rdp->cpu); /* Force CPU into scheduler. */
- rdp->rsp->jiffies_resched += 5; /* Re-enable beating. */
}
+ rdp->rsp->jiffies_resched += 5; /* Re-enable beating. */
}
+ /* And if it has been a really long time, kick the CPU as well. */
+ if (ULONG_CMP_GE(jiffies,
+ rdp->rsp->gp_start + 2 * jiffies_till_sched_qs) ||
+ ULONG_CMP_GE(jiffies, rdp->rsp->gp_start + jiffies_till_sched_qs))
+ resched_cpu(rdp->cpu); /* Force CPU into scheduler. */
+
return 0;
}
@@ -1246,7 +1245,7 @@ static void rcu_dump_cpu_stacks(struct rcu_state *rsp)
if (rnp->qsmask & (1UL << cpu))
dump_cpu_task(rnp->grplo + cpu);
}
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
}
@@ -1266,12 +1265,12 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum)
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);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
return;
}
WRITE_ONCE(rsp->jiffies_stall,
jiffies + 3 * rcu_jiffies_till_stall_check() + 3);
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
/*
* OK, time to rat on our buddy...
@@ -1292,7 +1291,7 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum)
ndetected++;
}
}
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
print_cpu_stall_info_end();
@@ -1357,7 +1356,7 @@ static void print_cpu_stall(struct rcu_state *rsp)
if (ULONG_CMP_GE(jiffies, READ_ONCE(rsp->jiffies_stall)))
WRITE_ONCE(rsp->jiffies_stall,
jiffies + 3 * rcu_jiffies_till_stall_check() + 3);
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
/*
* Attempt to revive the RCU machinery by forcing a context switch.
@@ -1595,7 +1594,7 @@ rcu_start_future_gp(struct rcu_node *rnp, struct rcu_data *rdp,
}
unlock_out:
if (rnp != rnp_root)
- raw_spin_unlock(&rnp_root->lock);
+ raw_spin_unlock_rcu_node(rnp_root);
out:
if (c_out != NULL)
*c_out = c;
@@ -1814,7 +1813,7 @@ static void note_gp_changes(struct rcu_state *rsp, struct rcu_data *rdp)
return;
}
needwake = __note_gp_changes(rsp, rnp, rdp);
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
if (needwake)
rcu_gp_kthread_wake(rsp);
}
@@ -1839,7 +1838,7 @@ static bool rcu_gp_init(struct rcu_state *rsp)
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);
+ raw_spin_unlock_irq_rcu_node(rnp);
return false;
}
WRITE_ONCE(rsp->gp_flags, 0); /* Clear all flags: New grace period. */
@@ -1849,7 +1848,7 @@ static bool rcu_gp_init(struct rcu_state *rsp)
* Grace period already in progress, don't start another.
* Not supposed to be able to happen.
*/
- raw_spin_unlock_irq(&rnp->lock);
+ raw_spin_unlock_irq_rcu_node(rnp);
return false;
}
@@ -1858,7 +1857,7 @@ static bool rcu_gp_init(struct rcu_state *rsp)
/* Record GP times before starting GP, hence smp_store_release(). */
smp_store_release(&rsp->gpnum, rsp->gpnum + 1);
trace_rcu_grace_period(rsp->name, rsp->gpnum, TPS("start"));
- raw_spin_unlock_irq(&rnp->lock);
+ raw_spin_unlock_irq_rcu_node(rnp);
/*
* Apply per-leaf buffered online and offline operations to the
@@ -1872,7 +1871,7 @@ static bool rcu_gp_init(struct rcu_state *rsp)
if (rnp->qsmaskinit == rnp->qsmaskinitnext &&
!rnp->wait_blkd_tasks) {
/* Nothing to do on this leaf rcu_node structure. */
- raw_spin_unlock_irq(&rnp->lock);
+ raw_spin_unlock_irq_rcu_node(rnp);
continue;
}
@@ -1906,7 +1905,7 @@ static bool rcu_gp_init(struct rcu_state *rsp)
rcu_cleanup_dead_rnp(rnp);
}
- raw_spin_unlock_irq(&rnp->lock);
+ raw_spin_unlock_irq_rcu_node(rnp);
}
/*
@@ -1937,7 +1936,7 @@ static bool rcu_gp_init(struct rcu_state *rsp)
trace_rcu_grace_period_init(rsp->name, rnp->gpnum,
rnp->level, rnp->grplo,
rnp->grphi, rnp->qsmask);
- raw_spin_unlock_irq(&rnp->lock);
+ raw_spin_unlock_irq_rcu_node(rnp);
cond_resched_rcu_qs();
WRITE_ONCE(rsp->gp_activity, jiffies);
}
@@ -1995,7 +1994,7 @@ static void rcu_gp_fqs(struct rcu_state *rsp, bool first_time)
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);
+ raw_spin_unlock_irq_rcu_node(rnp);
}
}
@@ -2025,7 +2024,7 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
* safe for us to drop the lock in order to mark the grace
* period as completed in all of the rcu_node structures.
*/
- raw_spin_unlock_irq(&rnp->lock);
+ raw_spin_unlock_irq_rcu_node(rnp);
/*
* Propagate new ->completed value to rcu_node structures so
@@ -2047,7 +2046,7 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
/* smp_mb() provided by prior unlock-lock pair. */
nocb += rcu_future_gp_cleanup(rsp, rnp);
sq = rcu_nocb_gp_get(rnp);
- raw_spin_unlock_irq(&rnp->lock);
+ raw_spin_unlock_irq_rcu_node(rnp);
rcu_nocb_gp_cleanup(sq);
cond_resched_rcu_qs();
WRITE_ONCE(rsp->gp_activity, jiffies);
@@ -2070,7 +2069,7 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
READ_ONCE(rsp->gpnum),
TPS("newreq"));
}
- raw_spin_unlock_irq(&rnp->lock);
+ raw_spin_unlock_irq_rcu_node(rnp);
}
/*
@@ -2236,18 +2235,20 @@ static bool rcu_start_gp(struct rcu_state *rsp)
}
/*
- * Report a full set of quiescent states to the specified rcu_state
- * data structure. This involves cleaning up after the prior grace
- * period and letting rcu_start_gp() start up the next grace period
- * if one is needed. Note that the caller must hold rnp->lock, which
- * is released before return.
+ * Report a full set of quiescent states to the specified rcu_state data
+ * structure. Invoke rcu_gp_kthread_wake() to awaken the grace-period
+ * kthread if another grace period is required. Whether we wake
+ * the grace-period kthread or it awakens itself for the next round
+ * of quiescent-state forcing, that kthread will clean up after the
+ * just-completed grace period. Note that the caller must hold rnp->lock,
+ * which is released before return.
*/
static void rcu_report_qs_rsp(struct rcu_state *rsp, unsigned long flags)
__releases(rcu_get_root(rsp)->lock)
{
WARN_ON_ONCE(!rcu_gp_in_progress(rsp));
WRITE_ONCE(rsp->gp_flags, READ_ONCE(rsp->gp_flags) | RCU_GP_FLAG_FQS);
- raw_spin_unlock_irqrestore(&rcu_get_root(rsp)->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rcu_get_root(rsp), flags);
swake_up(&rsp->gp_wq); /* Memory barrier implied by swake_up() path. */
}
@@ -2277,7 +2278,7 @@ rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp,
* Our bit has already been cleared, or the
* relevant grace period is already over, so done.
*/
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
return;
}
WARN_ON_ONCE(oldmask); /* Any child must be all zeroed! */
@@ -2289,7 +2290,7 @@ rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp,
if (rnp->qsmask != 0 || rcu_preempt_blocked_readers_cgp(rnp)) {
/* Other bits still set at this level, so done. */
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
return;
}
mask = rnp->grpmask;
@@ -2299,7 +2300,7 @@ rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp,
break;
}
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
rnp_c = rnp;
rnp = rnp->parent;
raw_spin_lock_irqsave_rcu_node(rnp, flags);
@@ -2331,7 +2332,7 @@ static void rcu_report_unblock_qs_rnp(struct rcu_state *rsp,
if (rcu_state_p == &rcu_sched_state || rsp != rcu_state_p ||
rnp->qsmask != 0 || rcu_preempt_blocked_readers_cgp(rnp)) {
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
return; /* Still need more quiescent states! */
}
@@ -2348,19 +2349,14 @@ static void rcu_report_unblock_qs_rnp(struct rcu_state *rsp,
/* Report up the rest of the hierarchy, tracking current ->gpnum. */
gps = rnp->gpnum;
mask = rnp->grpmask;
- raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */
+ raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled. */
raw_spin_lock_rcu_node(rnp_p); /* irqs already disabled. */
rcu_report_qs_rnp(mask, rsp, rnp_p, gps, flags);
}
/*
* Record a quiescent state for the specified CPU to that CPU's rcu_data
- * structure. This must be either called from the specified CPU, or
- * called when the specified CPU is known to be offline (and when it is
- * also known that no other CPU is concurrently trying to help the offline
- * CPU). The lastcomp argument is used to make sure we are still in the
- * grace period of interest. We don't want to end the current grace period
- * based on quiescent states detected in an earlier grace period!
+ * structure. This must be called from the specified CPU.
*/
static void
rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp)
@@ -2385,14 +2381,14 @@ rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp)
*/
rdp->cpu_no_qs.b.norm = true; /* need qs for new gp. */
rdp->rcu_qs_ctr_snap = __this_cpu_read(rcu_qs_ctr);
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
return;
}
mask = rdp->grpmask;
if ((rnp->qsmask & mask) == 0) {
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
} else {
- rdp->core_needs_qs = 0;
+ rdp->core_needs_qs = false;
/*
* This GP can't end until cpu checks in, so all of our
@@ -2601,36 +2597,15 @@ static void rcu_cleanup_dead_rnp(struct rcu_node *rnp_leaf)
rnp->qsmaskinit &= ~mask;
rnp->qsmask &= ~mask;
if (rnp->qsmaskinit) {
- raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */
+ raw_spin_unlock_rcu_node(rnp);
+ /* irqs remain disabled. */
return;
}
- raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */
+ raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled. */
}
}
/*
- * The CPU is exiting the idle loop into the arch_cpu_idle_dead()
- * function. We now remove it from the rcu_node tree's ->qsmaskinit
- * bit masks.
- */
-static void rcu_cleanup_dying_idle_cpu(int cpu, struct rcu_state *rsp)
-{
- unsigned long flags;
- unsigned long mask;
- struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu);
- struct rcu_node *rnp = rdp->mynode; /* Outgoing CPU's rdp & rnp. */
-
- if (!IS_ENABLED(CONFIG_HOTPLUG_CPU))
- return;
-
- /* Remove outgoing CPU from mask in the leaf rcu_node structure. */
- mask = rdp->grpmask;
- raw_spin_lock_irqsave_rcu_node(rnp, flags); /* Enforce GP memory-order guarantee. */
- rnp->qsmaskinitnext &= ~mask;
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
-}
-
-/*
* The CPU has been completely removed, and some other CPU is reporting
* this fact from process context. Do the remainder of the cleanup,
* including orphaning the outgoing CPU's RCU callbacks, and also
@@ -2861,7 +2836,7 @@ static void force_qs_rnp(struct rcu_state *rsp,
rcu_report_qs_rnp(mask, rsp, rnp, rnp->gpnum, flags);
} else {
/* Nothing to do here, so just drop the lock. */
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
}
}
@@ -2897,11 +2872,11 @@ static void force_quiescent_state(struct rcu_state *rsp)
raw_spin_unlock(&rnp_old->fqslock);
if (READ_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) {
rsp->n_force_qs_lh++;
- raw_spin_unlock_irqrestore(&rnp_old->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp_old, flags);
return; /* Someone beat us to it. */
}
WRITE_ONCE(rsp->gp_flags, READ_ONCE(rsp->gp_flags) | RCU_GP_FLAG_FQS);
- raw_spin_unlock_irqrestore(&rnp_old->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp_old, flags);
swake_up(&rsp->gp_wq); /* Memory barrier implied by swake_up() path. */
}
@@ -2927,7 +2902,7 @@ __rcu_process_callbacks(struct rcu_state *rsp)
if (cpu_needs_another_gp(rsp, rdp)) {
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);
+ raw_spin_unlock_irqrestore_rcu_node(rcu_get_root(rsp), flags);
if (needwake)
rcu_gp_kthread_wake(rsp);
} else {
@@ -3018,7 +2993,7 @@ static void __call_rcu_core(struct rcu_state *rsp, struct rcu_data *rdp,
raw_spin_lock_rcu_node(rnp_root);
needwake = rcu_start_gp(rsp);
- raw_spin_unlock(&rnp_root->lock);
+ raw_spin_unlock_rcu_node(rnp_root);
if (needwake)
rcu_gp_kthread_wake(rsp);
} else {
@@ -3438,14 +3413,14 @@ static void sync_exp_reset_tree_hotplug(struct rcu_state *rsp)
rcu_for_each_leaf_node(rsp, rnp) {
raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (rnp->expmaskinit == rnp->expmaskinitnext) {
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
continue; /* No new CPUs, nothing to do. */
}
/* Update this node's mask, track old value for propagation. */
oldmask = rnp->expmaskinit;
rnp->expmaskinit = rnp->expmaskinitnext;
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
/* If was already nonzero, nothing to propagate. */
if (oldmask)
@@ -3460,7 +3435,7 @@ static void sync_exp_reset_tree_hotplug(struct rcu_state *rsp)
if (rnp_up->expmaskinit)
done = true;
rnp_up->expmaskinit |= mask;
- raw_spin_unlock_irqrestore(&rnp_up->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp_up, flags);
if (done)
break;
mask = rnp_up->grpmask;
@@ -3483,7 +3458,7 @@ static void __maybe_unused sync_exp_reset_tree(struct rcu_state *rsp)
raw_spin_lock_irqsave_rcu_node(rnp, flags);
WARN_ON_ONCE(rnp->expmask);
rnp->expmask = rnp->expmaskinit;
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
}
@@ -3524,11 +3499,11 @@ static void __rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
if (!rnp->expmask)
rcu_initiate_boost(rnp, flags);
else
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
break;
}
if (rnp->parent == NULL) {
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
if (wake) {
smp_mb(); /* EGP done before wake_up(). */
swake_up(&rsp->expedited_wq);
@@ -3536,7 +3511,7 @@ static void __rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
break;
}
mask = rnp->grpmask;
- raw_spin_unlock(&rnp->lock); /* irqs remain disabled */
+ raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled */
rnp = rnp->parent;
raw_spin_lock_rcu_node(rnp); /* irqs already disabled */
WARN_ON_ONCE(!(rnp->expmask & mask));
@@ -3571,7 +3546,7 @@ static void rcu_report_exp_cpu_mult(struct rcu_state *rsp, struct rcu_node *rnp,
raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (!(rnp->expmask & mask)) {
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
return;
}
rnp->expmask &= ~mask;
@@ -3732,7 +3707,7 @@ static void sync_rcu_exp_select_cpus(struct rcu_state *rsp,
*/
if (rcu_preempt_has_tasks(rnp))
rnp->exp_tasks = rnp->blkd_tasks.next;
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
/* IPI the remaining CPUs for expedited quiescent state. */
mask = 1;
@@ -3749,7 +3724,7 @@ retry_ipi:
raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (cpu_online(cpu) &&
(rnp->expmask & mask)) {
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
schedule_timeout_uninterruptible(1);
if (cpu_online(cpu) &&
(rnp->expmask & mask))
@@ -3758,7 +3733,7 @@ retry_ipi:
}
if (!(rnp->expmask & mask))
mask_ofl_ipi &= ~mask;
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
/* Report quiescent states for those that went offline. */
mask_ofl_test |= mask_ofl_ipi;
@@ -4165,7 +4140,7 @@ static void rcu_init_new_rnp(struct rcu_node *rnp_leaf)
return;
raw_spin_lock_rcu_node(rnp); /* Interrupts already disabled. */
rnp->qsmaskinit |= mask;
- raw_spin_unlock(&rnp->lock); /* Interrupts remain disabled. */
+ raw_spin_unlock_rcu_node(rnp); /* Interrupts remain disabled. */
}
}
@@ -4189,7 +4164,7 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)
rdp->rsp = rsp;
mutex_init(&rdp->exp_funnel_mutex);
rcu_boot_init_nocb_percpu_data(rdp);
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
/*
@@ -4217,7 +4192,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
rcu_sysidle_init_percpu_data(rdp->dynticks);
atomic_set(&rdp->dynticks->dynticks,
(atomic_read(&rdp->dynticks->dynticks) & ~0x1) + 1);
- raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */
+ raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled. */
/*
* Add CPU to leaf rcu_node pending-online bitmask. Any needed
@@ -4238,7 +4213,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
rdp->rcu_qs_ctr_snap = per_cpu(rcu_qs_ctr, cpu);
rdp->core_needs_qs = false;
trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("cpuonl"));
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
static void rcu_prepare_cpu(int cpu)
@@ -4249,6 +4224,46 @@ static void rcu_prepare_cpu(int cpu)
rcu_init_percpu_data(cpu, rsp);
}
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * The CPU is exiting the idle loop into the arch_cpu_idle_dead()
+ * function. We now remove it from the rcu_node tree's ->qsmaskinit
+ * bit masks.
+ * The CPU is exiting the idle loop into the arch_cpu_idle_dead()
+ * function. We now remove it from the rcu_node tree's ->qsmaskinit
+ * bit masks.
+ */
+static void rcu_cleanup_dying_idle_cpu(int cpu, struct rcu_state *rsp)
+{
+ unsigned long flags;
+ unsigned long mask;
+ struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu);
+ struct rcu_node *rnp = rdp->mynode; /* Outgoing CPU's rdp & rnp. */
+
+ if (!IS_ENABLED(CONFIG_HOTPLUG_CPU))
+ return;
+
+ /* Remove outgoing CPU from mask in the leaf rcu_node structure. */
+ mask = rdp->grpmask;
+ raw_spin_lock_irqsave_rcu_node(rnp, flags); /* Enforce GP memory-order guarantee. */
+ rnp->qsmaskinitnext &= ~mask;
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+}
+
+void rcu_report_dead(unsigned int cpu)
+{
+ struct rcu_state *rsp;
+
+ /* QS for any half-done expedited RCU-sched GP. */
+ preempt_disable();
+ rcu_report_exp_rdp(&rcu_sched_state,
+ this_cpu_ptr(rcu_sched_state.rda), true);
+ preempt_enable();
+ for_each_rcu_flavor(rsp)
+ rcu_cleanup_dying_idle_cpu(cpu, rsp);
+}
+#endif
+
/*
* Handle CPU online/offline notification events.
*/
@@ -4280,17 +4295,6 @@ int rcu_cpu_notify(struct notifier_block *self,
for_each_rcu_flavor(rsp)
rcu_cleanup_dying_cpu(rsp);
break;
- case CPU_DYING_IDLE:
- /* QS for any half-done expedited RCU-sched GP. */
- preempt_disable();
- rcu_report_exp_rdp(&rcu_sched_state,
- this_cpu_ptr(rcu_sched_state.rda), true);
- preempt_enable();
-
- for_each_rcu_flavor(rsp) {
- rcu_cleanup_dying_idle_cpu(cpu, rsp);
- }
- break;
case CPU_DEAD:
case CPU_DEAD_FROZEN:
case CPU_UP_CANCELED:
@@ -4360,7 +4364,7 @@ static int __init rcu_spawn_gp_kthread(void)
sp.sched_priority = kthread_prio;
sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
}
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
wake_up_process(t);
}
rcu_spawn_nocb_kthreads();
@@ -4451,8 +4455,8 @@ static void __init rcu_init_one(struct rcu_state *rsp)
cpustride *= levelspread[i];
rnp = rsp->level[i];
for (j = 0; j < levelcnt[i]; j++, rnp++) {
- raw_spin_lock_init(&rnp->lock);
- lockdep_set_class_and_name(&rnp->lock,
+ raw_spin_lock_init(&ACCESS_PRIVATE(rnp, lock));
+ lockdep_set_class_and_name(&ACCESS_PRIVATE(rnp, lock),
&rcu_node_class[i], buf[i]);
raw_spin_lock_init(&rnp->fqslock);
lockdep_set_class_and_name(&rnp->fqslock,
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index bbd235d0e..df668c0f9 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -150,8 +150,9 @@ struct rcu_dynticks {
* Definition for node within the RCU grace-period-detection hierarchy.
*/
struct rcu_node {
- raw_spinlock_t lock; /* Root rcu_node's lock protects some */
- /* rcu_state fields as well as following. */
+ raw_spinlock_t __private lock; /* Root rcu_node's lock protects */
+ /* some rcu_state fields as well as */
+ /* following. */
unsigned long gpnum; /* Current grace period for this node. */
/* This will either be equal to or one */
/* behind the root rcu_node's gpnum. */
@@ -682,7 +683,7 @@ static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll)
#endif /* #else #ifdef CONFIG_PPC */
/*
- * Wrappers for the rcu_node::lock acquire.
+ * Wrappers for the rcu_node::lock acquire and release.
*
* 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
@@ -691,29 +692,48 @@ static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll)
*
* In order to restore full ordering between tree levels, augment the regular
* lock acquire functions with smp_mb__after_unlock_lock().
+ *
+ * As ->lock of struct rcu_node is a __private field, therefore one should use
+ * these wrappers rather than directly call raw_spin_{lock,unlock}* on ->lock.
*/
static inline void raw_spin_lock_rcu_node(struct rcu_node *rnp)
{
- raw_spin_lock(&rnp->lock);
+ raw_spin_lock(&ACCESS_PRIVATE(rnp, lock));
smp_mb__after_unlock_lock();
}
+static inline void raw_spin_unlock_rcu_node(struct rcu_node *rnp)
+{
+ raw_spin_unlock(&ACCESS_PRIVATE(rnp, lock));
+}
+
static inline void raw_spin_lock_irq_rcu_node(struct rcu_node *rnp)
{
- raw_spin_lock_irq(&rnp->lock);
+ raw_spin_lock_irq(&ACCESS_PRIVATE(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(); \
+static inline void raw_spin_unlock_irq_rcu_node(struct rcu_node *rnp)
+{
+ raw_spin_unlock_irq(&ACCESS_PRIVATE(rnp, lock));
+}
+
+#define raw_spin_lock_irqsave_rcu_node(rnp, flags) \
+do { \
+ typecheck(unsigned long, flags); \
+ raw_spin_lock_irqsave(&ACCESS_PRIVATE(rnp, lock), flags); \
+ smp_mb__after_unlock_lock(); \
+} while (0)
+
+#define raw_spin_unlock_irqrestore_rcu_node(rnp, flags) \
+do { \
+ typecheck(unsigned long, flags); \
+ raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(rnp, lock), flags); \
} while (0)
static inline bool raw_spin_trylock_rcu_node(struct rcu_node *rnp)
{
- bool locked = raw_spin_trylock(&rnp->lock);
+ bool locked = raw_spin_trylock(&ACCESS_PRIVATE(rnp, lock));
if (locked)
smp_mb__after_unlock_lock();
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 080bd202d..efdf7b61c 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -235,7 +235,7 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp)
rnp->gp_tasks = &t->rcu_node_entry;
if (!rnp->exp_tasks && (blkd_state & RCU_EXP_BLKD))
rnp->exp_tasks = &t->rcu_node_entry;
- raw_spin_unlock(&rnp->lock); /* rrupts remain disabled. */
+ raw_spin_unlock_rcu_node(rnp); /* interrupts remain disabled. */
/*
* Report the quiescent state for the expedited GP. This expedited
@@ -489,7 +489,7 @@ void rcu_read_unlock_special(struct task_struct *t)
!!rnp->gp_tasks);
rcu_report_unblock_qs_rnp(rcu_state_p, rnp, flags);
} else {
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
/* Unboost if we were boosted. */
@@ -518,14 +518,14 @@ static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp)
raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (!rcu_preempt_blocked_readers_cgp(rnp)) {
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
return;
}
t = list_entry(rnp->gp_tasks->prev,
struct task_struct, rcu_node_entry);
list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry)
sched_show_task(t);
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
/*
@@ -807,7 +807,6 @@ void exit_rcu(void)
#else /* #ifdef CONFIG_PREEMPT_RCU */
static struct rcu_state *const rcu_state_p = &rcu_sched_state;
-static struct rcu_data __percpu *const rcu_data_p = &rcu_sched_data;
/*
* Tell them what RCU they are running.
@@ -991,7 +990,7 @@ static int rcu_boost(struct rcu_node *rnp)
* might exit their RCU read-side critical sections on their own.
*/
if (rnp->exp_tasks == NULL && rnp->boost_tasks == NULL) {
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
return 0;
}
@@ -1028,7 +1027,7 @@ static int rcu_boost(struct rcu_node *rnp)
*/
t = container_of(tb, struct task_struct, rcu_node_entry);
rt_mutex_init_proxy_locked(&rnp->boost_mtx, t);
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
/* Lock only for side effect: boosts task t's priority. */
rt_mutex_lock(&rnp->boost_mtx);
rt_mutex_unlock(&rnp->boost_mtx); /* Then keep lockdep happy. */
@@ -1088,7 +1087,7 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
if (!rcu_preempt_blocked_readers_cgp(rnp) && rnp->exp_tasks == NULL) {
rnp->n_balk_exp_gp_tasks++;
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
return;
}
if (rnp->exp_tasks != NULL ||
@@ -1098,13 +1097,13 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
ULONG_CMP_GE(jiffies, rnp->boost_time))) {
if (rnp->exp_tasks == NULL)
rnp->boost_tasks = rnp->gp_tasks;
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
t = rnp->boost_kthread_task;
if (t)
rcu_wake_cond(t, rnp->boost_kthread_status);
} else {
rcu_initiate_boost_trace(rnp);
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
}
@@ -1172,7 +1171,7 @@ static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
return PTR_ERR(t);
raw_spin_lock_irqsave_rcu_node(rnp, flags);
rnp->boost_kthread_task = t;
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
sp.sched_priority = kthread_prio;
sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
wake_up_process(t); /* get to TASK_INTERRUPTIBLE quickly. */
@@ -1308,7 +1307,7 @@ static void rcu_prepare_kthreads(int cpu)
static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
__releases(rnp->lock)
{
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
static void invoke_rcu_callbacks_kthread(void)
@@ -1559,7 +1558,7 @@ static void rcu_prepare_for_idle(void)
rnp = rdp->mynode;
raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */
needwake = rcu_accelerate_cbs(rsp, rnp, rdp);
- raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */
+ raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled. */
if (needwake)
rcu_gp_kthread_wake(rsp);
}
@@ -2064,7 +2063,7 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp)
raw_spin_lock_irqsave_rcu_node(rnp, flags);
needwake = rcu_start_future_gp(rnp, rdp, &c);
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
if (needwake)
rcu_gp_kthread_wake(rdp->rsp);
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 76b94e194..ca828b41c 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -128,6 +128,7 @@ bool rcu_gp_is_normal(void)
{
return READ_ONCE(rcu_normal);
}
+EXPORT_SYMBOL_GPL(rcu_gp_is_normal);
static atomic_t rcu_expedited_nesting =
ATOMIC_INIT(IS_ENABLED(CONFIG_RCU_EXPEDITE_BOOT) ? 1 : 0);