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-rw-r--r--kernel/acct.c17
-rw-r--r--kernel/cgroup.c46
-rw-r--r--kernel/fork.c2
-rw-r--r--kernel/kexec.c6
-rw-r--r--kernel/lockdep.c84
-rw-r--r--kernel/lockdep_internals.h72
-rw-r--r--kernel/lockdep_proc.c58
-rw-r--r--kernel/profile.c4
-rw-r--r--kernel/ptrace.c11
-rw-r--r--kernel/rcupdate.c19
-rw-r--r--kernel/rcutiny.c35
-rw-r--r--kernel/rcutiny_plugin.h39
-rw-r--r--kernel/rcutorture.c2
-rw-r--r--kernel/rcutree.c131
-rw-r--r--kernel/rcutree.h2
-rw-r--r--kernel/rcutree_plugin.h69
-rw-r--r--kernel/rcutree_trace.c4
-rw-r--r--kernel/sched.c2
-rw-r--r--kernel/softirq.c2
19 files changed, 406 insertions, 199 deletions
diff --git a/kernel/acct.c b/kernel/acct.c
index 24f8c81fc48..e4c0e1fee9b 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -353,17 +353,18 @@ restart:
void acct_exit_ns(struct pid_namespace *ns)
{
- struct bsd_acct_struct *acct;
+ struct bsd_acct_struct *acct = ns->bacct;
- spin_lock(&acct_lock);
- acct = ns->bacct;
- if (acct != NULL) {
- if (acct->file != NULL)
- acct_file_reopen(acct, NULL, NULL);
+ if (acct == NULL)
+ return;
- kfree(acct);
- }
+ del_timer_sync(&acct->timer);
+ spin_lock(&acct_lock);
+ if (acct->file != NULL)
+ acct_file_reopen(acct, NULL, NULL);
spin_unlock(&acct_lock);
+
+ kfree(acct);
}
/*
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 3a53c771e50..6d870f2d122 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4435,7 +4435,15 @@ __setup("cgroup_disable=", cgroup_disable);
*/
unsigned short css_id(struct cgroup_subsys_state *css)
{
- struct css_id *cssid = rcu_dereference(css->id);
+ struct css_id *cssid;
+
+ /*
+ * This css_id() can return correct value when somone has refcnt
+ * on this or this is under rcu_read_lock(). Once css->id is allocated,
+ * it's unchanged until freed.
+ */
+ cssid = rcu_dereference_check(css->id,
+ rcu_read_lock_held() || atomic_read(&css->refcnt));
if (cssid)
return cssid->id;
@@ -4445,7 +4453,10 @@ EXPORT_SYMBOL_GPL(css_id);
unsigned short css_depth(struct cgroup_subsys_state *css)
{
- struct css_id *cssid = rcu_dereference(css->id);
+ struct css_id *cssid;
+
+ cssid = rcu_dereference_check(css->id,
+ rcu_read_lock_held() || atomic_read(&css->refcnt));
if (cssid)
return cssid->depth;
@@ -4453,15 +4464,36 @@ unsigned short css_depth(struct cgroup_subsys_state *css)
}
EXPORT_SYMBOL_GPL(css_depth);
+/**
+ * css_is_ancestor - test "root" css is an ancestor of "child"
+ * @child: the css to be tested.
+ * @root: the css supporsed to be an ancestor of the child.
+ *
+ * Returns true if "root" is an ancestor of "child" in its hierarchy. Because
+ * this function reads css->id, this use rcu_dereference() and rcu_read_lock().
+ * But, considering usual usage, the csses should be valid objects after test.
+ * Assuming that the caller will do some action to the child if this returns
+ * returns true, the caller must take "child";s reference count.
+ * If "child" is valid object and this returns true, "root" is valid, too.
+ */
+
bool css_is_ancestor(struct cgroup_subsys_state *child,
const struct cgroup_subsys_state *root)
{
- struct css_id *child_id = rcu_dereference(child->id);
- struct css_id *root_id = rcu_dereference(root->id);
+ struct css_id *child_id;
+ struct css_id *root_id;
+ bool ret = true;
- if (!child_id || !root_id || (child_id->depth < root_id->depth))
- return false;
- return child_id->stack[root_id->depth] == root_id->id;
+ rcu_read_lock();
+ child_id = rcu_dereference(child->id);
+ root_id = rcu_dereference(root->id);
+ if (!child_id
+ || !root_id
+ || (child_id->depth < root_id->depth)
+ || (child_id->stack[root_id->depth] != root_id->id))
+ ret = false;
+ rcu_read_unlock();
+ return ret;
}
static void __free_css_id_cb(struct rcu_head *head)
diff --git a/kernel/fork.c b/kernel/fork.c
index 44b0791b0a2..4c14942a0ee 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1114,8 +1114,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
p->bts = NULL;
- p->stack_start = stack_start;
-
/* Perform scheduler related setup. Assign this task to a CPU. */
sched_fork(p, clone_flags);
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 87ebe8adc47..474a84715ea 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -1134,11 +1134,9 @@ int crash_shrink_memory(unsigned long new_size)
free_reserved_phys_range(end, crashk_res.end);
- if (start == end) {
- crashk_res.end = end;
+ if (start == end)
release_resource(&crashk_res);
- } else
- crashk_res.end = end - 1;
+ crashk_res.end = end - 1;
unlock:
mutex_unlock(&kexec_mutex);
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 2594e1ce41c..4349e979341 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -431,20 +431,7 @@ static struct stack_trace lockdep_init_trace = {
/*
* Various lockdep statistics:
*/
-atomic_t chain_lookup_hits;
-atomic_t chain_lookup_misses;
-atomic_t hardirqs_on_events;
-atomic_t hardirqs_off_events;
-atomic_t redundant_hardirqs_on;
-atomic_t redundant_hardirqs_off;
-atomic_t softirqs_on_events;
-atomic_t softirqs_off_events;
-atomic_t redundant_softirqs_on;
-atomic_t redundant_softirqs_off;
-atomic_t nr_unused_locks;
-atomic_t nr_cyclic_checks;
-atomic_t nr_find_usage_forwards_checks;
-atomic_t nr_find_usage_backwards_checks;
+DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats);
#endif
/*
@@ -748,7 +735,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
return NULL;
}
class = lock_classes + nr_lock_classes++;
- debug_atomic_inc(&nr_unused_locks);
+ debug_atomic_inc(nr_unused_locks);
class->key = key;
class->name = lock->name;
class->subclass = subclass;
@@ -818,7 +805,8 @@ static struct lock_list *alloc_list_entry(void)
* Add a new dependency to the head of the list:
*/
static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
- struct list_head *head, unsigned long ip, int distance)
+ struct list_head *head, unsigned long ip,
+ int distance, struct stack_trace *trace)
{
struct lock_list *entry;
/*
@@ -829,11 +817,9 @@ static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
if (!entry)
return 0;
- if (!save_trace(&entry->trace))
- return 0;
-
entry->class = this;
entry->distance = distance;
+ entry->trace = *trace;
/*
* Since we never remove from the dependency list, the list can
* be walked lockless by other CPUs, it's only allocation
@@ -1205,7 +1191,7 @@ check_noncircular(struct lock_list *root, struct lock_class *target,
{
int result;
- debug_atomic_inc(&nr_cyclic_checks);
+ debug_atomic_inc(nr_cyclic_checks);
result = __bfs_forwards(root, target, class_equal, target_entry);
@@ -1242,7 +1228,7 @@ find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit,
{
int result;
- debug_atomic_inc(&nr_find_usage_forwards_checks);
+ debug_atomic_inc(nr_find_usage_forwards_checks);
result = __bfs_forwards(root, (void *)bit, usage_match, target_entry);
@@ -1265,7 +1251,7 @@ find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit,
{
int result;
- debug_atomic_inc(&nr_find_usage_backwards_checks);
+ debug_atomic_inc(nr_find_usage_backwards_checks);
result = __bfs_backwards(root, (void *)bit, usage_match, target_entry);
@@ -1635,12 +1621,20 @@ check_deadlock(struct task_struct *curr, struct held_lock *next,
*/
static int
check_prev_add(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next, int distance)
+ struct held_lock *next, int distance, int trylock_loop)
{
struct lock_list *entry;
int ret;
struct lock_list this;
struct lock_list *uninitialized_var(target_entry);
+ /*
+ * Static variable, serialized by the graph_lock().
+ *
+ * We use this static variable to save the stack trace in case
+ * we call into this function multiple times due to encountering
+ * trylocks in the held lock stack.
+ */
+ static struct stack_trace trace;
/*
* Prove that the new <prev> -> <next> dependency would not
@@ -1688,20 +1682,23 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
}
}
+ if (!trylock_loop && !save_trace(&trace))
+ return 0;
+
/*
* Ok, all validations passed, add the new lock
* to the previous lock's dependency list:
*/
ret = add_lock_to_list(hlock_class(prev), hlock_class(next),
&hlock_class(prev)->locks_after,
- next->acquire_ip, distance);
+ next->acquire_ip, distance, &trace);
if (!ret)
return 0;
ret = add_lock_to_list(hlock_class(next), hlock_class(prev),
&hlock_class(next)->locks_before,
- next->acquire_ip, distance);
+ next->acquire_ip, distance, &trace);
if (!ret)
return 0;
@@ -1731,6 +1728,7 @@ static int
check_prevs_add(struct task_struct *curr, struct held_lock *next)
{
int depth = curr->lockdep_depth;
+ int trylock_loop = 0;
struct held_lock *hlock;
/*
@@ -1756,7 +1754,8 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next)
* added:
*/
if (hlock->read != 2) {
- if (!check_prev_add(curr, hlock, next, distance))
+ if (!check_prev_add(curr, hlock, next,
+ distance, trylock_loop))
return 0;
/*
* Stop after the first non-trylock entry,
@@ -1779,6 +1778,7 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next)
if (curr->held_locks[depth].irq_context !=
curr->held_locks[depth-1].irq_context)
break;
+ trylock_loop = 1;
}
return 1;
out_bug:
@@ -1825,7 +1825,7 @@ static inline int lookup_chain_cache(struct task_struct *curr,
list_for_each_entry(chain, hash_head, entry) {
if (chain->chain_key == chain_key) {
cache_hit:
- debug_atomic_inc(&chain_lookup_hits);
+ debug_atomic_inc(chain_lookup_hits);
if (very_verbose(class))
printk("\nhash chain already cached, key: "
"%016Lx tail class: [%p] %s\n",
@@ -1890,7 +1890,7 @@ cache_hit:
chain_hlocks[chain->base + j] = class - lock_classes;
}
list_add_tail_rcu(&chain->entry, hash_head);
- debug_atomic_inc(&chain_lookup_misses);
+ debug_atomic_inc(chain_lookup_misses);
inc_chains();
return 1;
@@ -2311,7 +2311,12 @@ void trace_hardirqs_on_caller(unsigned long ip)
return;
if (unlikely(curr->hardirqs_enabled)) {
- debug_atomic_inc(&redundant_hardirqs_on);
+ /*
+ * Neither irq nor preemption are disabled here
+ * so this is racy by nature but loosing one hit
+ * in a stat is not a big deal.
+ */
+ __debug_atomic_inc(redundant_hardirqs_on);
return;
}
/* we'll do an OFF -> ON transition: */
@@ -2338,7 +2343,7 @@ void trace_hardirqs_on_caller(unsigned long ip)
curr->hardirq_enable_ip = ip;
curr->hardirq_enable_event = ++curr->irq_events;
- debug_atomic_inc(&hardirqs_on_events);
+ debug_atomic_inc(hardirqs_on_events);
}
EXPORT_SYMBOL(trace_hardirqs_on_caller);
@@ -2370,9 +2375,9 @@ void trace_hardirqs_off_caller(unsigned long ip)
curr->hardirqs_enabled = 0;
curr->hardirq_disable_ip = ip;
curr->hardirq_disable_event = ++curr->irq_events;
- debug_atomic_inc(&hardirqs_off_events);
+ debug_atomic_inc(hardirqs_off_events);
} else
- debug_atomic_inc(&redundant_hardirqs_off);
+ debug_atomic_inc(redundant_hardirqs_off);
}
EXPORT_SYMBOL(trace_hardirqs_off_caller);
@@ -2396,7 +2401,7 @@ void trace_softirqs_on(unsigned long ip)
return;
if (curr->softirqs_enabled) {
- debug_atomic_inc(&redundant_softirqs_on);
+ debug_atomic_inc(redundant_softirqs_on);
return;
}
@@ -2406,7 +2411,7 @@ void trace_softirqs_on(unsigned long ip)
curr->softirqs_enabled = 1;
curr->softirq_enable_ip = ip;
curr->softirq_enable_event = ++curr->irq_events;
- debug_atomic_inc(&softirqs_on_events);
+ debug_atomic_inc(softirqs_on_events);
/*
* We are going to turn softirqs on, so set the
* usage bit for all held locks, if hardirqs are
@@ -2436,10 +2441,10 @@ void trace_softirqs_off(unsigned long ip)
curr->softirqs_enabled = 0;
curr->softirq_disable_ip = ip;
curr->softirq_disable_event = ++curr->irq_events;
- debug_atomic_inc(&softirqs_off_events);
+ debug_atomic_inc(softirqs_off_events);
DEBUG_LOCKS_WARN_ON(!softirq_count());
} else
- debug_atomic_inc(&redundant_softirqs_off);
+ debug_atomic_inc(redundant_softirqs_off);
}
static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags)
@@ -2644,7 +2649,7 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
return 0;
break;
case LOCK_USED:
- debug_atomic_dec(&nr_unused_locks);
+ debug_atomic_dec(nr_unused_locks);
break;
default:
if (!debug_locks_off_graph_unlock())
@@ -2750,7 +2755,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
if (!class)
return 0;
}
- debug_atomic_inc((atomic_t *)&class->ops);
+ atomic_inc((atomic_t *)&class->ops);
if (very_verbose(class)) {
printk("\nacquire class [%p] %s", class->key, class->name);
if (class->name_version > 1)
@@ -3801,8 +3806,11 @@ void lockdep_rcu_dereference(const char *file, const int line)
{
struct task_struct *curr = current;
+#ifndef CONFIG_PROVE_RCU_REPEATEDLY
if (!debug_locks_off())
return;
+#endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */
+ /* Note: the following can be executed concurrently, so be careful. */
printk("\n===================================================\n");
printk( "[ INFO: suspicious rcu_dereference_check() usage. ]\n");
printk( "---------------------------------------------------\n");
diff --git a/kernel/lockdep_internals.h b/kernel/lockdep_internals.h
index a2ee95ad131..4f560cfedc8 100644
--- a/kernel/lockdep_internals.h
+++ b/kernel/lockdep_internals.h
@@ -110,30 +110,60 @@ lockdep_count_backward_deps(struct lock_class *class)
#endif
#ifdef CONFIG_DEBUG_LOCKDEP
+
+#include <asm/local.h>
/*
- * Various lockdep statistics:
+ * Various lockdep statistics.
+ * We want them per cpu as they are often accessed in fast path
+ * and we want to avoid too much cache bouncing.
*/
-extern atomic_t chain_lookup_hits;
-extern atomic_t chain_lookup_misses;
-extern atomic_t hardirqs_on_events;
-extern atomic_t hardirqs_off_events;
-extern atomic_t redundant_hardirqs_on;
-extern atomic_t redundant_hardirqs_off;
-extern atomic_t softirqs_on_events;
-extern atomic_t softirqs_off_events;
-extern atomic_t redundant_softirqs_on;
-extern atomic_t redundant_softirqs_off;
-extern atomic_t nr_unused_locks;
-extern atomic_t nr_cyclic_checks;
-extern atomic_t nr_cyclic_check_recursions;
-extern atomic_t nr_find_usage_forwards_checks;
-extern atomic_t nr_find_usage_forwards_recursions;
-extern atomic_t nr_find_usage_backwards_checks;
-extern atomic_t nr_find_usage_backwards_recursions;
-# define debug_atomic_inc(ptr) atomic_inc(ptr)
-# define debug_atomic_dec(ptr) atomic_dec(ptr)
-# define debug_atomic_read(ptr) atomic_read(ptr)
+struct lockdep_stats {
+ int chain_lookup_hits;
+ int chain_lookup_misses;
+ int hardirqs_on_events;
+ int hardirqs_off_events;
+ int redundant_hardirqs_on;
+ int redundant_hardirqs_off;
+ int softirqs_on_events;
+ int softirqs_off_events;
+ int redundant_softirqs_on;
+ int redundant_softirqs_off;
+ int nr_unused_locks;
+ int nr_cyclic_checks;
+ int nr_cyclic_check_recursions;
+ int nr_find_usage_forwards_checks;
+ int nr_find_usage_forwards_recursions;
+ int nr_find_usage_backwards_checks;
+ int nr_find_usage_backwards_recursions;
+};
+
+DECLARE_PER_CPU(struct lockdep_stats, lockdep_stats);
+
+#define __debug_atomic_inc(ptr) \
+ this_cpu_inc(lockdep_stats.ptr);
+
+#define debug_atomic_inc(ptr) { \
+ WARN_ON_ONCE(!irqs_disabled()); \
+ __this_cpu_inc(lockdep_stats.ptr); \
+}
+
+#define debug_atomic_dec(ptr) { \
+ WARN_ON_ONCE(!irqs_disabled()); \
+ __this_cpu_dec(lockdep_stats.ptr); \
+}
+
+#define debug_atomic_read(ptr) ({ \
+ struct lockdep_stats *__cpu_lockdep_stats; \
+ unsigned long long __total = 0; \
+ int __cpu; \
+ for_each_possible_cpu(__cpu) { \
+ __cpu_lockdep_stats = &per_cpu(lockdep_stats, __cpu); \
+ __total += __cpu_lockdep_stats->ptr; \
+ } \
+ __total; \
+})
#else
+# define __debug_atomic_inc(ptr) do { } while (0)
# define debug_atomic_inc(ptr) do { } while (0)
# define debug_atomic_dec(ptr) do { } while (0)
# define debug_atomic_read(ptr) 0
diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c
index d4aba4f3584..59b76c8ce9d 100644
--- a/kernel/lockdep_proc.c
+++ b/kernel/lockdep_proc.c
@@ -184,34 +184,34 @@ static const struct file_operations proc_lockdep_chains_operations = {
static void lockdep_stats_debug_show(struct seq_file *m)
{
#ifdef CONFIG_DEBUG_LOCKDEP
- unsigned int hi1 = debug_atomic_read(&hardirqs_on_events),
- hi2 = debug_atomic_read(&hardirqs_off_events),
- hr1 = debug_atomic_read(&redundant_hardirqs_on),
- hr2 = debug_atomic_read(&redundant_hardirqs_off),
- si1 = debug_atomic_read(&softirqs_on_events),
- si2 = debug_atomic_read(&softirqs_off_events),
- sr1 = debug_atomic_read(&redundant_softirqs_on),
- sr2 = debug_atomic_read(&redundant_softirqs_off);
-
- seq_printf(m, " chain lookup misses: %11u\n",
- debug_atomic_read(&chain_lookup_misses));
- seq_printf(m, " chain lookup hits: %11u\n",
- debug_atomic_read(&chain_lookup_hits));
- seq_printf(m, " cyclic checks: %11u\n",
- debug_atomic_read(&nr_cyclic_checks));
- seq_printf(m, " find-mask forwards checks: %11u\n",
- debug_atomic_read(&nr_find_usage_forwards_checks));
- seq_printf(m, " find-mask backwards checks: %11u\n",
- debug_atomic_read(&nr_find_usage_backwards_checks));
-
- seq_printf(m, " hardirq on events: %11u\n", hi1);
- seq_printf(m, " hardirq off events: %11u\n", hi2);
- seq_printf(m, " redundant hardirq ons: %11u\n", hr1);
- seq_printf(m, " redundant hardirq offs: %11u\n", hr2);
- seq_printf(m, " softirq on events: %11u\n", si1);
- seq_printf(m, " softirq off events: %11u\n", si2);
- seq_printf(m, " redundant softirq ons: %11u\n", sr1);
- seq_printf(m, " redundant softirq offs: %11u\n", sr2);
+ unsigned long long hi1 = debug_atomic_read(hardirqs_on_events),
+ hi2 = debug_atomic_read(hardirqs_off_events),
+ hr1 = debug_atomic_read(redundant_hardirqs_on),
+ hr2 = debug_atomic_read(redundant_hardirqs_off),
+ si1 = debug_atomic_read(softirqs_on_events),
+ si2 = debug_atomic_read(softirqs_off_events),
+ sr1 = debug_atomic_read(redundant_softirqs_on),
+ sr2 = debug_atomic_read(redundant_softirqs_off);
+
+ seq_printf(m, " chain lookup misses: %11llu\n",
+ debug_atomic_read(chain_lookup_misses));
+ seq_printf(m, " chain lookup hits: %11llu\n",
+ debug_atomic_read(chain_lookup_hits));
+ seq_printf(m, " cyclic checks: %11llu\n",
+ debug_atomic_read(nr_cyclic_checks));
+ seq_printf(m, " find-mask forwards checks: %11llu\n",
+ debug_atomic_read(nr_find_usage_forwards_checks));
+ seq_printf(m, " find-mask backwards checks: %11llu\n",
+ debug_atomic_read(nr_find_usage_backwards_checks));
+
+ seq_printf(m, " hardirq on events: %11llu\n", hi1);
+ seq_printf(m, " hardirq off events: %11llu\n", hi2);
+ seq_printf(m, " redundant hardirq ons: %11llu\n", hr1);
+ seq_printf(m, " redundant hardirq offs: %11llu\n", hr2);
+ seq_printf(m, " softirq on events: %11llu\n", si1);
+ seq_printf(m, " softirq off events: %11llu\n", si2);
+ seq_printf(m, " redundant softirq ons: %11llu\n", sr1);
+ seq_printf(m, " redundant softirq offs: %11llu\n", sr2);
#endif
}
@@ -263,7 +263,7 @@ static int lockdep_stats_show(struct seq_file *m, void *v)
#endif
}
#ifdef CONFIG_DEBUG_LOCKDEP
- DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused);
+ DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
#endif
seq_printf(m, " lock-classes: %11lu [max: %lu]\n",
nr_lock_classes, MAX_LOCKDEP_KEYS);
diff --git a/kernel/profile.c b/kernel/profile.c
index a55d3a367ae..dfadc5b729f 100644
--- a/kernel/profile.c
+++ b/kernel/profile.c
@@ -127,8 +127,10 @@ int __ref profile_init(void)
return 0;
prof_buffer = vmalloc(buffer_bytes);
- if (prof_buffer)
+ if (prof_buffer) {
+ memset(prof_buffer, 0, buffer_bytes);
return 0;
+ }
free_cpumask_var(prof_cpu_mask);
return -ENOMEM;
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 42ad8ae729a..2f0f50b450a 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -14,7 +14,6 @@
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
-#include <linux/smp_lock.h>
#include <linux/ptrace.h>
#include <linux/security.h>
#include <linux/signal.h>
@@ -666,10 +665,6 @@ SYSCALL_DEFINE4(ptrace, long, request, long, pid, long, addr, long, data)
struct task_struct *child;
long ret;
- /*
- * This lock_kernel fixes a subtle race with suid exec
- */
- lock_kernel();
if (request == PTRACE_TRACEME) {
ret = ptrace_traceme();
if (!ret)
@@ -703,7 +698,6 @@ SYSCALL_DEFINE4(ptrace, long, request, long, pid, long, addr, long, data)
out_put_task_struct:
put_task_struct(child);
out:
- unlock_kernel();
return ret;
}
@@ -813,10 +807,6 @@ asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
struct task_struct *child;
long ret;
- /*
- * This lock_kernel fixes a subtle race with suid exec
- */
- lock_kernel();
if (request == PTRACE_TRACEME) {
ret = ptrace_traceme();
goto out;
@@ -846,7 +836,6 @@ asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
out_put_task_struct:
put_task_struct(child);
out:
- unlock_kernel();
return ret;
}
#endif /* CONFIG_COMPAT */
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index 49d808e833b..72a8dc9567f 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -44,7 +44,6 @@
#include <linux/cpu.h>
#include <linux/mutex.h>
#include <linux/module.h>
-#include <linux/kernel_stat.h>
#include <linux/hardirq.h>
#ifdef CONFIG_DEBUG_LOCK_ALLOC
@@ -64,9 +63,6 @@ struct lockdep_map rcu_sched_lock_map =
EXPORT_SYMBOL_GPL(rcu_sched_lock_map);
#endif
-int rcu_scheduler_active __read_mostly;
-EXPORT_SYMBOL_GPL(rcu_scheduler_active);
-
#ifdef CONFIG_DEBUG_LOCK_ALLOC
int debug_lockdep_rcu_enabled(void)
@@ -97,21 +93,6 @@ EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held);
#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
/*
- * This function is invoked towards the end of the scheduler's initialization
- * process. Before this is called, the idle task might contain
- * RCU read-side critical sections (during which time, this idle
- * task is booting the system). After this function is called, the
- * idle tasks are prohibited from containing RCU read-side critical
- * sections.
- */
-void rcu_scheduler_starting(void)
-{
- WARN_ON(num_online_cpus() != 1);
- WARN_ON(nr_context_switches() > 0);
- rcu_scheduler_active = 1;
-}
-
-/*
* Awaken the corresponding synchronize_rcu() instance now that a
* grace period has elapsed.
*/
diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c
index 9f6d9ff2572..38729d3cd23 100644
--- a/kernel/rcutiny.c
+++ b/kernel/rcutiny.c
@@ -44,9 +44,9 @@ struct rcu_ctrlblk {
};
/* Definition for rcupdate control block. */
-static struct rcu_ctrlblk rcu_ctrlblk = {
- .donetail = &rcu_ctrlblk.rcucblist,
- .curtail = &rcu_ctrlblk.rcucblist,
+static struct rcu_ctrlblk rcu_sched_ctrlblk = {
+ .donetail = &rcu_sched_ctrlblk.rcucblist,
+ .curtail = &rcu_sched_ctrlblk.rcucblist,
};
static struct rcu_ctrlblk rcu_bh_ctrlblk = {
@@ -54,6 +54,11 @@ static struct rcu_ctrlblk rcu_bh_ctrlblk = {
.curtail = &rcu_bh_ctrlblk.rcucblist,
};
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+int rcu_scheduler_active __read_mostly;
+EXPORT_SYMBOL_GPL(rcu_scheduler_active);
+#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
+
#ifdef CONFIG_NO_HZ
static long rcu_dynticks_nesting = 1;
@@ -108,7 +113,8 @@ static int rcu_qsctr_help(struct rcu_ctrlblk *rcp)
*/
void rcu_sched_qs(int cpu)
{
- if (rcu_qsctr_help(&rcu_ctrlblk) + rcu_qsctr_help(&rcu_bh_ctrlblk))
+ if (rcu_qsctr_help(&rcu_sched_ctrlblk) +
+ rcu_qsctr_help(&rcu_bh_ctrlblk))
raise_softirq(RCU_SOFTIRQ);
}
@@ -173,7 +179,7 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp)
*/
static void rcu_process_callbacks(struct softirq_action *unused)
{
- __rcu_process_callbacks(&rcu_ctrlblk);
+ __rcu_process_callbacks(&rcu_sched_ctrlblk);
__rcu_process_callbacks(&rcu_bh_ctrlblk);
}
@@ -187,7 +193,8 @@ static void rcu_process_callbacks(struct softirq_action *unused)
*
* Cool, huh? (Due to Josh Triplett.)
*
- * But we want to make this a static inline later.
+ * But we want to make this a static inline later. The cond_resched()
+ * currently makes this problematic.
*/
void synchronize_sched(void)
{
@@ -195,12 +202,6 @@ void synchronize_sched(void)
}
EXPORT_SYMBOL_GPL(synchronize_sched);
-void synchronize_rcu_bh(void)
-{
- synchronize_sched();
-}
-EXPORT_SYMBOL_GPL(synchronize_rcu_bh);
-
/*
* Helper function for call_rcu() and call_rcu_bh().
*/
@@ -226,7 +227,7 @@ static void __call_rcu(struct rcu_head *head,
*/
void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
{
- __call_rcu(head, func, &rcu_ctrlblk);
+ __call_rcu(head, func, &rcu_sched_ctrlblk);
}
EXPORT_SYMBOL_GPL(call_rcu);
@@ -244,11 +245,13 @@ void rcu_barrier(void)
{
struct rcu_synchronize rcu;
+ init_rcu_head_on_stack(&rcu.head);
init_completion(&rcu.completion);
/* Will wake me after RCU finished. */
call_rcu(&rcu.head, wakeme_after_rcu);
/* Wait for it. */
wait_for_completion(&rcu.completion);
+ destroy_rcu_head_on_stack(&rcu.head);
}
EXPORT_SYMBOL_GPL(rcu_barrier);
@@ -256,11 +259,13 @@ void rcu_barrier_bh(void)
{
struct rcu_synchronize rcu;
+ init_rcu_head_on_stack(&rcu.head);
init_completion(&rcu.completion);
/* Will wake me after RCU finished. */
call_rcu_bh(&rcu.head, wakeme_after_rcu);
/* Wait for it. */
wait_for_completion(&rcu.completion);
+ destroy_rcu_head_on_stack(&rcu.head);
}
EXPORT_SYMBOL_GPL(rcu_barrier_bh);
@@ -268,11 +273,13 @@ void rcu_barrier_sched(void)
{
struct rcu_synchronize rcu;
+ init_rcu_head_on_stack(&rcu.head);
init_completion(&rcu.completion);
/* Will wake me after RCU finished. */
call_rcu_sched(&rcu.head, wakeme_after_rcu);
/* Wait for it. */
wait_for_completion(&rcu.completion);
+ destroy_rcu_head_on_stack(&rcu.head);
}
EXPORT_SYMBOL_GPL(rcu_barrier_sched);
@@ -280,3 +287,5 @@ void __init rcu_init(void)
{
open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
}
+
+#include "rcutiny_plugin.h"
diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h
new file mode 100644
index 00000000000..d223a92bc74
--- /dev/null
+++ b/kernel/rcutiny_plugin.h
@@ -0,0 +1,39 @@
+/*
+ * Read-Copy Update mechanism for mutual exclusion (tree-based version)
+ * Internal non-public definitions that provide either classic
+ * or preemptable semantics.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright IBM Corporation, 2009
+ *
+ * Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+ */
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+
+#include <linux/kernel_stat.h>
+
+/*
+ * During boot, we forgive RCU lockdep issues. After this function is
+ * invoked, we start taking RCU lockdep issues seriously.
+ */
+void rcu_scheduler_starting(void)
+{
+ WARN_ON(nr_context_switches() > 0);
+ rcu_scheduler_active = 1;
+}
+
+#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 58df55bf83e..077defb3457 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -464,9 +464,11 @@ static void rcu_bh_torture_synchronize(void)
{
struct rcu_bh_torture_synchronize rcu;
+ init_rcu_head_on_stack(&rcu.head);
init_completion(&rcu.completion);
call_rcu_bh(&rcu.head, rcu_bh_torture_wakeme_after_cb);
wait_for_completion(&rcu.completion);
+ destroy_rcu_head_on_stack(&rcu.head);
}
static struct rcu_torture_ops rcu_bh_ops = {
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 3ec8160fc75..d4437345706 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -46,6 +46,7 @@
#include <linux/cpu.h>
#include <linux/mutex.h>
#include <linux/time.h>
+#include <linux/kernel_stat.h>
#include "rcutree.h"
@@ -53,8 +54,8 @@
static struct lock_class_key rcu_node_class[NUM_RCU_LVLS];
-#define RCU_STATE_INITIALIZER(name) { \
- .level = { &name.node[0] }, \
+#define RCU_STATE_INITIALIZER(structname) { \
+ .level = { &structname.node[0] }, \
.levelcnt = { \
NUM_RCU_LVL_0, /* root of hierarchy. */ \
NUM_RCU_LVL_1, \
@@ -65,13 +66,14 @@ static struct lock_class_key rcu_node_class[NUM_RCU_LVLS];
.signaled = RCU_GP_IDLE, \
.gpnum = -300, \
.completed = -300, \
- .onofflock = __RAW_SPIN_LOCK_UNLOCKED(&name.onofflock), \
+ .onofflock = __RAW_SPIN_LOCK_UNLOCKED(&structname.onofflock), \
.orphan_cbs_list = NULL, \
- .orphan_cbs_tail = &name.orphan_cbs_list, \
+ .orphan_cbs_tail = &structname.orphan_cbs_list, \
.orphan_qlen = 0, \
- .fqslock = __RAW_SPIN_LOCK_UNLOCKED(&name.fqslock), \
+ .fqslock = __RAW_SPIN_LOCK_UNLOCKED(&structname.fqslock), \
.n_force_qs = 0, \
.n_force_qs_ngp = 0, \
+ .name = #structname, \
}
struct rcu_state rcu_sched_state = RCU_STATE_INITIALIZER(rcu_sched_state);
@@ -80,6 +82,9 @@ DEFINE_PER_CPU(struct rcu_data, rcu_sched_data);
struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh_state);
DEFINE_PER_CPU(struct rcu_data, rcu_bh_data);
+int rcu_scheduler_active __read_mostly;
+EXPORT_SYMBOL_GPL(rcu_scheduler_active);
+
/*
* Return true if an RCU grace period is in progress. The ACCESS_ONCE()s
* permit this function to be invoked without holding the root rcu_node
@@ -97,25 +102,32 @@ static int rcu_gp_in_progress(struct rcu_state *rsp)
*/
void rcu_sched_qs(int cpu)
{
- struct rcu_data *rdp;
+ struct rcu_data *rdp = &per_cpu(rcu_sched_data, cpu);
- rdp = &per_cpu(rcu_sched_data, cpu);
rdp->passed_quiesc_completed = rdp->gpnum - 1;
barrier();
rdp->passed_quiesc = 1;
- rcu_preempt_note_context_switch(cpu);
}
void rcu_bh_qs(int cpu)
{
- struct rcu_data *rdp;
+ struct rcu_data *rdp = &per_cpu(rcu_bh_data, cpu);
- rdp = &per_cpu(rcu_bh_data, cpu);
rdp->passed_quiesc_completed = rdp->gpnum - 1;
barrier();
rdp->passed_quiesc = 1;
}
+/*
+ * Note a context switch. This is a quiescent state for RCU-sched,
+ * and requires special handling for preemptible RCU.
+ */
+void rcu_note_context_switch(int cpu)
+{
+ rcu_sched_qs(cpu);
+ rcu_preempt_note_context_switch(cpu);
+}
+
#ifdef CONFIG_NO_HZ
DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = {
.dynticks_nesting = 1,
@@ -438,6 +450,8 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
+int rcu_cpu_stall_panicking __read_mostly;
+
static void record_gp_stall_check_time(struct rcu_state *rsp)
{
rsp->gp_start = jiffies;
@@ -470,7 +484,8 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
/* OK, time to rat on our buddy... */
- printk(KERN_ERR "INFO: RCU detected CPU stalls:");
+ printk(KERN_ERR "INFO: %s detected stalls on CPUs/tasks: {",
+ rsp->name);
rcu_for_each_leaf_node(rsp, rnp) {
raw_spin_lock_irqsave(&rnp->lock, flags);
rcu_print_task_stall(rnp);
@@ -481,7 +496,7 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
if (rnp->qsmask & (1UL << cpu))
printk(" %d", rnp->grplo + cpu);
}
- printk(" (detected by %d, t=%ld jiffies)\n",
+ printk("} (detected by %d, t=%ld jiffies)\n",
smp_processor_id(), (long)(jiffies - rsp->gp_start));
trigger_all_cpu_backtrace();
@@ -497,8 +512,8 @@ static void print_cpu_stall(struct rcu_state *rsp)
unsigned long flags;
struct rcu_node *rnp = rcu_get_root(rsp);
- printk(KERN_ERR "INFO: RCU detected CPU %d stall (t=%lu jiffies)\n",
- smp_processor_id(), jiffies - rsp->gp_start);
+ printk(KERN_ERR "INFO: %s detected stall on CPU %d (t=%lu jiffies)\n",
+ rsp->name, smp_processor_id(), jiffies - rsp->gp_start);
trigger_all_cpu_backtrace();
raw_spin_lock_irqsave(&rnp->lock, flags);
@@ -515,6 +530,8 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp)
long delta;
struct rcu_node *rnp;
+ if (rcu_cpu_stall_panicking)
+ return;
delta = jiffies - rsp->jiffies_stall;
rnp = rdp->mynode;
if ((rnp->qsmask & rdp->grpmask) && delta >= 0) {
@@ -529,6 +546,21 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp)
}
}
+static int rcu_panic(struct notifier_block *this, unsigned long ev, void *ptr)
+{
+ rcu_cpu_stall_panicking = 1;
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block rcu_panic_block = {
+ .notifier_call = rcu_panic,
+};
+
+static void __init check_cpu_stall_init(void)
+{
+ atomic_notifier_chain_register(&panic_notifier_list, &rcu_panic_block);
+}
+
#else /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
static void record_gp_stall_check_time(struct rcu_state *rsp)
@@ -539,6 +571,10 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp)
{
}
+static void __init check_cpu_stall_init(void)
+{
+}
+
#endif /* #else #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
/*
@@ -1125,8 +1161,6 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp)
*/
void rcu_check_callbacks(int cpu, int user)
{
- if (!rcu_pending(cpu))
- return; /* if nothing for RCU to do. */
if (user ||
(idle_cpu(cpu) && rcu_scheduler_active &&
!in_softirq() && hardirq_count() <= (1 << HARDIRQ_SHIFT))) {
@@ -1158,7 +1192,8 @@ void rcu_check_callbacks(int cpu, int user)
rcu_bh_qs(cpu);
}
rcu_preempt_check_callbacks(cpu);
- raise_softirq(RCU_SOFTIRQ);
+ if (rcu_pending(cpu))
+ raise_softirq(RCU_SOFTIRQ);
}
#ifdef CONFIG_SMP
@@ -1236,11 +1271,11 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
break; /* grace period idle or initializing, ignore. */
case RCU_SAVE_DYNTICK:
-
- raw_spin_unlock(&rnp->lock); /* irqs remain disabled */
if (RCU_SIGNAL_INIT != RCU_SAVE_DYNTICK)
break; /* So gcc recognizes the dead code. */
+ raw_spin_unlock(&rnp->lock); /* irqs remain disabled */
+
/* Record dyntick-idle state. */
force_qs_rnp(rsp, dyntick_save_progress_counter);
raw_spin_lock(&rnp->lock); /* irqs already disabled */
@@ -1449,11 +1484,13 @@ void synchronize_sched(void)
if (rcu_blocking_is_gp())
return;
+ init_rcu_head_on_stack(&rcu.head);
init_completion(&rcu.completion);
/* Will wake me after RCU finished. */
call_rcu_sched(&rcu.head, wakeme_after_rcu);
/* Wait for it. */
wait_for_completion(&rcu.completion);
+ destroy_rcu_head_on_stack(&rcu.head);
}
EXPORT_SYMBOL_GPL(synchronize_sched);
@@ -1473,11 +1510,13 @@ void synchronize_rcu_bh(void)
if (rcu_blocking_is_gp())
return;
+ init_rcu_head_on_stack(&rcu.head);
init_completion(&rcu.completion);
/* Will wake me after RCU finished. */
call_rcu_bh(&rcu.head, wakeme_after_rcu);
/* Wait for it. */
wait_for_completion(&rcu.completion);
+ destroy_rcu_head_on_stack(&rcu.head);
}
EXPORT_SYMBOL_GPL(synchronize_rcu_bh);
@@ -1498,8 +1537,20 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp)
check_cpu_stall(rsp, rdp);
/* Is the RCU core waiting for a quiescent state from this CPU? */
- if (rdp->qs_pending) {
+ if (rdp->qs_pending && !rdp->passed_quiesc) {
+
+ /*
+ * If force_quiescent_state() coming soon and this CPU
+ * needs a quiescent state, and this is either RCU-sched
+ * or RCU-bh, force a local reschedule.
+ */
rdp->n_rp_qs_pending++;
+ if (!rdp->preemptable &&
+ ULONG_CMP_LT(ACCESS_ONCE(rsp->jiffies_force_qs) - 1,
+ jiffies))
+ set_need_resched();
+ } else if (rdp->qs_pending && rdp->passed_quiesc) {
+ rdp->n_rp_report_qs++;
return 1;
}
@@ -1767,6 +1818,21 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
}
/*
+ * This function is invoked towards the end of the scheduler's initialization
+ * process. Before this is called, the idle task might contain
+ * RCU read-side critical sections (during which time, this idle
+ * task is booting the system). After this function is called, the
+ * idle tasks are prohibited from containing RCU read-side critical
+ * sections. This function also enables RCU lockdep checking.
+ */
+void rcu_scheduler_starting(void)
+{
+ WARN_ON(num_online_cpus() != 1);
+ WARN_ON(nr_context_switches() > 0);
+ rcu_scheduler_active = 1;
+}
+
+/*
* Compute the per-level fanout, either using the exact fanout specified
* or balancing the tree, depending on CONFIG_RCU_FANOUT_EXACT.
*/
@@ -1849,6 +1915,14 @@ static void __init rcu_init_one(struct rcu_state *rsp)
INIT_LIST_HEAD(&rnp->blocked_tasks[3]);
}
}
+
+ rnp = rsp->level[NUM_RCU_LVLS - 1];
+ for_each_possible_cpu(i) {
+ while (i > rnp->grphi)
+ rnp++;
+ rsp->rda[i]->mynode = rnp;
+ rcu_boot_init_percpu_data(i, rsp);
+ }
}
/*
@@ -1859,19 +1933,11 @@ static void __init rcu_init_one(struct rcu_state *rsp)
#define RCU_INIT_FLAVOR(rsp, rcu_data) \
do { \
int i; \
- int j; \
- struct rcu_node *rnp; \
\
- rcu_init_one(rsp); \
- rnp = (rsp)->level[NUM_RCU_LVLS - 1]; \
- j = 0; \
for_each_possible_cpu(i) { \
- if (i > rnp[j].grphi) \
- j++; \
- per_cpu(rcu_data, i).mynode = &rnp[j]; \
(rsp)->rda[i] = &per_cpu(rcu_data, i); \
- rcu_boot_init_percpu_data(i, rsp); \
} \
+ rcu_init_one(rsp); \
} while (0)
void __init rcu_init(void)
@@ -1879,12 +1945,6 @@ void __init rcu_init(void)
int cpu;
rcu_bootup_announce();
-#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
- printk(KERN_INFO "RCU-based detection of stalled CPUs is enabled.\n");
-#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
-#if NUM_RCU_LVL_4 != 0
- printk(KERN_INFO "Experimental four-level hierarchy is enabled.\n");
-#endif /* #if NUM_RCU_LVL_4 != 0 */
RCU_INIT_FLAVOR(&rcu_sched_state, rcu_sched_data);
RCU_INIT_FLAVOR(&rcu_bh_state, rcu_bh_data);
__rcu_init_preempt();
@@ -1898,6 +1958,7 @@ void __init rcu_init(void)
cpu_notifier(rcu_cpu_notify, 0);
for_each_online_cpu(cpu)
rcu_cpu_notify(NULL, CPU_UP_PREPARE, (void *)(long)cpu);
+ check_cpu_stall_init();
}
#include "rcutree_plugin.h"
diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index 4a525a30e08..14c040b18ed 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -223,6 +223,7 @@ struct rcu_data {
/* 5) __rcu_pending() statistics. */
unsigned long n_rcu_pending; /* rcu_pending() calls since boot. */
unsigned long n_rp_qs_pending;
+ unsigned long n_rp_report_qs;
unsigned long n_rp_cb_ready;
unsigned long n_rp_cpu_needs_gp;
unsigned long n_rp_gp_completed;
@@ -326,6 +327,7 @@ struct rcu_state {
unsigned long jiffies_stall; /* Time at which to check */
/* for CPU stalls. */
#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
+ char *name; /* Name of structure. */
};
/* Return values for rcu_preempt_offline_tasks(). */
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 79b53bda894..0e4f420245d 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -26,6 +26,45 @@
#include <linux/delay.h>
+/*
+ * Check the RCU kernel configuration parameters and print informative
+ * messages about anything out of the ordinary. If you like #ifdef, you
+ * will love this function.
+ */
+static void __init rcu_bootup_announce_oddness(void)
+{
+#ifdef CONFIG_RCU_TRACE
+ printk(KERN_INFO "\tRCU debugfs-based tracing is enabled.\n");
+#endif
+#if (defined(CONFIG_64BIT) && CONFIG_RCU_FANOUT != 64) || (!defined(CONFIG_64BIT) && CONFIG_RCU_FANOUT != 32)
+ printk(KERN_INFO "\tCONFIG_RCU_FANOUT set to non-default value of %d\n",
+ CONFIG_RCU_FANOUT);
+#endif
+#ifdef CONFIG_RCU_FANOUT_EXACT
+ printk(KERN_INFO "\tHierarchical RCU autobalancing is disabled.\n");
+#endif
+#ifdef CONFIG_RCU_FAST_NO_HZ
+ printk(KERN_INFO
+ "\tRCU dyntick-idle grace-period acceleration is enabled.\n");
+#endif
+#ifdef CONFIG_PROVE_RCU
+ printk(KERN_INFO "\tRCU lockdep checking is enabled.\n");
+#endif
+#ifdef CONFIG_RCU_TORTURE_TEST_RUNNABLE
+ printk(KERN_INFO "\tRCU torture testing starts during boot.\n");
+#endif
+#ifndef CONFIG_RCU_CPU_STALL_DETECTOR
+ printk(KERN_INFO
+ "\tRCU-based detection of stalled CPUs is disabled.\n");
+#endif
+#ifndef CONFIG_RCU_CPU_STALL_VERBOSE
+ printk(KERN_INFO "\tVerbose stalled-CPUs detection is disabled.\n");
+#endif
+#if NUM_RCU_LVL_4 != 0
+ printk(KERN_INFO "\tExperimental four-level hierarchy is enabled.\n");
+#endif
+}
+
#ifdef CONFIG_TREE_PREEMPT_RCU
struct rcu_state rcu_preempt_state = RCU_STATE_INITIALIZER(rcu_preempt_state);
@@ -38,8 +77,8 @@ static int rcu_preempted_readers_exp(struct rcu_node *rnp);
*/
static void __init rcu_bootup_announce(void)
{
- printk(KERN_INFO
- "Experimental preemptable hierarchical RCU implementation.\n");
+ printk(KERN_INFO "Preemptable hierarchical RCU implementation.\n");
+ rcu_bootup_announce_oddness();
}
/*
@@ -75,13 +114,19 @@ EXPORT_SYMBOL_GPL(rcu_force_quiescent_state);
* that this just means that the task currently running on the CPU is
* not in a quiescent state. There might be any number of tasks blocked
* while in an RCU read-side critical section.
+ *
+ * Unlike the other rcu_*_qs() functions, callers to this function
+ * must disable irqs in order to protect the assignment to
+ * ->rcu_read_unlock_special.
*/
static void rcu_preempt_qs(int cpu)
{
struct rcu_data *rdp = &per_cpu(rcu_preempt_data, cpu);
+
rdp->passed_quiesc_completed = rdp->gpnum - 1;
barrier();
rdp->passed_quiesc = 1;
+ current->rcu_read_unlock_special &= ~RCU_READ_UNLOCK_NEED_QS;
}
/*
@@ -144,9 +189,8 @@ static void rcu_preempt_note_context_switch(int cpu)
* grace period, then the fact that the task has been enqueued
* means that we continue to block the current grace period.
*/
- rcu_preempt_qs(cpu);
local_irq_save(flags);
- t->rcu_read_unlock_special &= ~RCU_READ_UNLOCK_NEED_QS;
+ rcu_preempt_qs(cpu);
local_irq_restore(flags);
}
@@ -236,7 +280,6 @@ static void rcu_read_unlock_special(struct task_struct *t)
*/
special = t->rcu_read_unlock_special;
if (special & RCU_READ_UNLOCK_NEED_QS) {
- t->rcu_read_unlock_special &= ~RCU_READ_UNLOCK_NEED_QS;
rcu_preempt_qs(smp_processor_id());
}
@@ -473,7 +516,6 @@ static void rcu_preempt_check_callbacks(int cpu)
struct task_struct *t = current;
if (t->rcu_read_lock_nesting == 0) {
- t->rcu_read_unlock_special &= ~RCU_READ_UNLOCK_NEED_QS;
rcu_preempt_qs(cpu);
return;
}
@@ -515,11 +557,13 @@ void synchronize_rcu(void)
if (!rcu_scheduler_active)
return;
+ init_rcu_head_on_stack(&rcu.head);
init_completion(&rcu.completion);
/* Will wake me after RCU finished. */
call_rcu(&rcu.head, wakeme_after_rcu);
/* Wait for it. */
wait_for_completion(&rcu.completion);
+ destroy_rcu_head_on_stack(&rcu.head);
}
EXPORT_SYMBOL_GPL(synchronize_rcu);
@@ -754,6 +798,7 @@ void exit_rcu(void)
static void __init rcu_bootup_announce(void)
{
printk(KERN_INFO "Hierarchical RCU implementation.\n");
+ rcu_bootup_announce_oddness();
}
/*
@@ -1008,6 +1053,8 @@ static DEFINE_PER_CPU(unsigned long, rcu_dyntick_holdoff);
int rcu_needs_cpu(int cpu)
{
int c = 0;
+ int snap;
+ int snap_nmi;
int thatcpu;
/* Check for being in the holdoff period. */
@@ -1015,12 +1062,18 @@ int rcu_needs_cpu(int cpu)
return rcu_needs_cpu_quick_check(cpu);
/* Don't bother unless we are the last non-dyntick-idle CPU. */
- for_each_cpu_not(thatcpu, nohz_cpu_mask)
- if (thatcpu != cpu) {
+ for_each_online_cpu(thatcpu) {
+ if (thatcpu == cpu)
+ continue;
+ snap = per_cpu(rcu_dynticks, thatcpu).dynticks;
+ snap_nmi = per_cpu(rcu_dynticks, thatcpu).dynticks_nmi;
+ smp_mb(); /* Order sampling of snap with end of grace period. */
+ if (((snap & 0x1) != 0) || ((snap_nmi & 0x1) != 0)) {
per_cpu(rcu_dyntick_drain, cpu) = 0;
per_cpu(rcu_dyntick_holdoff, cpu) = jiffies - 1;
return rcu_needs_cpu_quick_check(cpu);
}
+ }
/* Check and update the rcu_dyntick_drain sequencing. */
if (per_cpu(rcu_dyntick_drain, cpu) <= 0) {
diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c
index d45db2e35d2..36c95b45738 100644
--- a/kernel/rcutree_trace.c
+++ b/kernel/rcutree_trace.c
@@ -241,11 +241,13 @@ static const struct file_operations rcugp_fops = {
static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
{
seq_printf(m, "%3d%cnp=%ld "
- "qsp=%ld cbr=%ld cng=%ld gpc=%ld gps=%ld nf=%ld nn=%ld\n",
+ "qsp=%ld rpq=%ld cbr=%ld cng=%ld "
+ "gpc=%ld gps=%ld nf=%ld nn=%ld\n",
rdp->cpu,
cpu_is_offline(rdp->cpu) ? '!' : ' ',
rdp->n_rcu_pending,
rdp->n_rp_qs_pending,
+ rdp->n_rp_report_qs,
rdp->n_rp_cb_ready,
rdp->n_rp_cpu_needs_gp,
rdp->n_rp_gp_completed,
diff --git a/kernel/sched.c b/kernel/sched.c
index 3c2a54f70ff..d8a213ccdc3 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3706,7 +3706,7 @@ need_resched:
preempt_disable();
cpu = smp_processor_id();
rq = cpu_rq(cpu);
- rcu_sched_qs(cpu);
+ rcu_note_context_switch(cpu);
prev = rq->curr;
switch_count = &prev->nivcsw;
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 7c1a67ef027..0db913a5c60 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -716,7 +716,7 @@ static int run_ksoftirqd(void * __bind_cpu)
preempt_enable_no_resched();
cond_resched();
preempt_disable();
- rcu_sched_qs((long)__bind_cpu);
+ rcu_note_context_switch((long)__bind_cpu);
}
preempt_enable();
set_current_state(TASK_INTERRUPTIBLE);
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-03 09:25:07 +0000