lockdep: add lock_class information to lock_chain and output it

This patch records array of lock_class into lock_chain, and export
lock_chain information via /proc/lockdep_chains.

It is based on x86/master branch of git-x86 tree, and has been tested
on x86_64 platform.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Huang, Ying 2008-06-20 16:39:21 +08:00 committed by Ingo Molnar
parent 2429e4ee78
commit 443cd507ce
4 changed files with 135 additions and 3 deletions

View file

@ -182,6 +182,9 @@ struct lock_list {
* We record lock dependency chains, so that we can cache them:
*/
struct lock_chain {
u8 irq_context;
u8 depth;
u16 base;
struct list_head entry;
u64 chain_key;
};

View file

@ -1458,7 +1458,14 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next)
}
unsigned long nr_lock_chains;
static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
atomic_t nr_chain_hlocks;
static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];
struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i)
{
return lock_classes + chain_hlocks[chain->base + i];
}
/*
* Look up a dependency chain. If the key is not present yet then
@ -1466,10 +1473,15 @@ static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
* validated. If the key is already hashed, return 0.
* (On return with 1 graph_lock is held.)
*/
static inline int lookup_chain_cache(u64 chain_key, struct lock_class *class)
static inline int lookup_chain_cache(struct task_struct *curr,
struct held_lock *hlock,
u64 chain_key)
{
struct lock_class *class = hlock->class;
struct list_head *hash_head = chainhashentry(chain_key);
struct lock_chain *chain;
struct held_lock *hlock_curr, *hlock_next;
int i, j, n;
if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
return 0;
@ -1517,6 +1529,26 @@ static inline int lookup_chain_cache(u64 chain_key, struct lock_class *class)
}
chain = lock_chains + nr_lock_chains++;
chain->chain_key = chain_key;
chain->irq_context = hlock->irq_context;
/* Find the first held_lock of current chain */
hlock_next = hlock;
for (i = curr->lockdep_depth - 1; i >= 0; i--) {
hlock_curr = curr->held_locks + i;
if (hlock_curr->irq_context != hlock_next->irq_context)
break;
hlock_next = hlock;
}
i++;
chain->depth = curr->lockdep_depth + 1 - i;
n = atomic_add_return(chain->depth, &nr_chain_hlocks);
if (unlikely(n < MAX_LOCKDEP_CHAIN_HLOCKS)) {
chain->base = n - chain->depth;
for (j = 0; j < chain->depth - 1; j++, i++) {
int lock_id = curr->held_locks[i].class - lock_classes;
chain_hlocks[chain->base + j] = lock_id;
}
chain_hlocks[chain->base + j] = class - lock_classes;
}
list_add_tail_rcu(&chain->entry, hash_head);
debug_atomic_inc(&chain_lookup_misses);
inc_chains();
@ -1538,7 +1570,7 @@ static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
* graph_lock for us)
*/
if (!hlock->trylock && (hlock->check == 2) &&
lookup_chain_cache(chain_key, hlock->class)) {
lookup_chain_cache(curr, hlock, chain_key)) {
/*
* Check whether last held lock:
*

View file

@ -23,6 +23,8 @@
#define MAX_LOCKDEP_CHAINS_BITS 14
#define MAX_LOCKDEP_CHAINS (1UL << MAX_LOCKDEP_CHAINS_BITS)
#define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS*5)
/*
* Stack-trace: tightly packed array of stack backtrace
* addresses. Protected by the hash_lock.
@ -30,15 +32,19 @@
#define MAX_STACK_TRACE_ENTRIES 262144UL
extern struct list_head all_lock_classes;
extern struct lock_chain lock_chains[];
extern void
get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4);
extern const char * __get_key_name(struct lockdep_subclass_key *key, char *str);
struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i);
extern unsigned long nr_lock_classes;
extern unsigned long nr_list_entries;
extern unsigned long nr_lock_chains;
extern atomic_t nr_chain_hlocks;
extern unsigned long nr_stack_trace_entries;
extern unsigned int nr_hardirq_chains;

View file

@ -178,6 +178,93 @@ static const struct file_operations proc_lockdep_operations = {
.release = seq_release,
};
static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
{
struct lock_chain *chain;
(*pos)++;
if (v == SEQ_START_TOKEN)
chain = m->private;
else {
chain = v;
if (*pos < nr_lock_chains)
chain = lock_chains + *pos;
else
chain = NULL;
}
return chain;
}
static void *lc_start(struct seq_file *m, loff_t *pos)
{
if (*pos == 0)
return SEQ_START_TOKEN;
if (*pos < nr_lock_chains)
return lock_chains + *pos;
return NULL;
}
static void lc_stop(struct seq_file *m, void *v)
{
}
static int lc_show(struct seq_file *m, void *v)
{
struct lock_chain *chain = v;
struct lock_class *class;
int i;
if (v == SEQ_START_TOKEN) {
seq_printf(m, "all lock chains:\n");
return 0;
}
seq_printf(m, "irq_context: %d\n", chain->irq_context);
for (i = 0; i < chain->depth; i++) {
class = lock_chain_get_class(chain, i);
seq_printf(m, "[%p] ", class->key);
print_name(m, class);
seq_puts(m, "\n");
}
seq_puts(m, "\n");
return 0;
}
static const struct seq_operations lockdep_chains_ops = {
.start = lc_start,
.next = lc_next,
.stop = lc_stop,
.show = lc_show,
};
static int lockdep_chains_open(struct inode *inode, struct file *file)
{
int res = seq_open(file, &lockdep_chains_ops);
if (!res) {
struct seq_file *m = file->private_data;
if (nr_lock_chains)
m->private = lock_chains;
else
m->private = NULL;
}
return res;
}
static const struct file_operations proc_lockdep_chains_operations = {
.open = lockdep_chains_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static void lockdep_stats_debug_show(struct seq_file *m)
{
#ifdef CONFIG_DEBUG_LOCKDEP
@ -294,6 +381,8 @@ static int lockdep_stats_show(struct seq_file *m, void *v)
#ifdef CONFIG_PROVE_LOCKING
seq_printf(m, " dependency chains: %11lu [max: %lu]\n",
nr_lock_chains, MAX_LOCKDEP_CHAINS);
seq_printf(m, " dependency chain hlocks: %11d [max: %lu]\n",
atomic_read(&nr_chain_hlocks), MAX_LOCKDEP_CHAIN_HLOCKS);
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
@ -661,6 +750,8 @@ static const struct file_operations proc_lock_stat_operations = {
static int __init lockdep_proc_init(void)
{
proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
proc_create("lockdep_chains", S_IRUSR, NULL,
&proc_lockdep_chains_operations);
proc_create("lockdep_stats", S_IRUSR, NULL,
&proc_lockdep_stats_operations);