Messages in this thread Patch in this message | | | Subject | [PATCH -v2] lockdep: add lock_class information to lock_chain and output it | From | "Huang, Ying" <> | Date | Mon, 23 Jun 2008 11:20:54 +0800 |
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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.
ChangeLog:
v2:
- Enclosing proc file system related code into CONFIG_PROVE_LOCKING.
- Fix nr_chain_hlocks update code.
Signed-off-by: Huang Ying <ying.huang@intel.com>
--- include/linux/lockdep.h | 3 + kernel/lockdep.c | 44 +++++++++++++++++++- kernel/lockdep_internals.h | 6 ++ kernel/lockdep_proc.c | 95 +++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 145 insertions(+), 3 deletions(-)
--- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -1463,7 +1463,14 @@ out_bug: } unsigned long nr_lock_chains; -static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; +struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; +int 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 @@ -1471,10 +1478,15 @@ static struct lock_chain lock_chains[MAX * 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, cn; if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) return 0; @@ -1522,6 +1534,32 @@ cache_hit: } 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; + cn = nr_chain_hlocks; + while (cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS) { + n = cmpxchg(&nr_chain_hlocks, cn, cn + chain->depth); + if (n == cn) + break; + cn = n; + } + if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { + chain->base = cn; + 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(); @@ -1543,7 +1581,7 @@ static int validate_chain(struct task_st * 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: * --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -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; }; --- a/kernel/lockdep_proc.c +++ b/kernel/lockdep_proc.c @@ -178,6 +178,95 @@ static const struct file_operations proc .release = seq_release, }; +#ifdef CONFIG_PROVE_LOCKING +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, +}; +#endif /* CONFIG_PROVE_LOCKING */ + static void lockdep_stats_debug_show(struct seq_file *m) { #ifdef CONFIG_DEBUG_LOCKDEP @@ -294,6 +383,8 @@ static int lockdep_stats_show(struct seq #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", + nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS); #endif #ifdef CONFIG_TRACE_IRQFLAGS @@ -661,6 +752,10 @@ static const struct file_operations proc static int __init lockdep_proc_init(void) { proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations); +#ifdef CONFIG_PROVE_LOCKING + proc_create("lockdep_chains", S_IRUSR, NULL, + &proc_lockdep_chains_operations); +#endif proc_create("lockdep_stats", S_IRUSR, NULL, &proc_lockdep_stats_operations); --- a/kernel/lockdep_internals.h +++ b/kernel/lockdep_internals.h @@ -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 int nr_chain_hlocks; extern unsigned long nr_stack_trace_entries; extern unsigned int nr_hardirq_chains;
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