commit 443cd507ce7f78c6f8742b72736585c031d5a921 Author: Huang, Ying Date: Fri Jun 20 16:39:21 2008 +0800 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 Cc: Peter Zijlstra Signed-off-by: Ingo Molnar diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 4c4d236..b26fbc7 100644 --- 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; }; diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 81a4e4a..a796f1f 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -1458,7 +1458,14 @@ out_bug: } unsigned long nr_lock_chains; -static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; +struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; +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 @@ -1466,9 +1473,14 @@ static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; * validated. If the key is already hashed, return 0. */ -static inline int lookup_chain_cache(u64 chain_key) +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 @@ 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; + 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, * (If lookup_chain_cache() returns with 1 it acquires * hash_lock for us) */ - if (!trylock && (check == 2) && lookup_chain_cache(chain_key)) { + if (!trylock && (check == 2) && lookup_chain_cache(curr, hlock, chain_key)) { /* * Check whether last held lock: * diff --git a/kernel/lockdep_internals.h b/kernel/lockdep_internals.h index 8ce09bc..db09b17 100644 --- 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 atomic_t nr_chain_hlocks; extern unsigned long nr_stack_trace_entries; extern unsigned int nr_hardirq_chains; diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c index 688c5f1..14d052c 100644 --- a/kernel/lockdep_proc.c +++ b/kernel/lockdep_proc.c @@ -178,6 +178,110 @@ static const struct file_operations proc_lockdep_operations = { .release = seq_release, }; +static void print_name(struct seq_file *m, struct lock_class *class) +{ + char str[128]; + const char *name = class->name; + + if (!name) { + name = __get_key_name(class->key, str); + seq_printf(m, "%s", name); + } else{ + seq_printf(m, "%s", name); + if (class->name_version > 1) + seq_printf(m, "#%d", class->name_version); + if (class->subclass) + seq_printf(m, "/%d", class->subclass); + } +} + +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 @@ -294,5 +381,7 @@ static int lockdep_stats_show(struct seq_file *m, void *v) 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); #ifdef CONFIG_TRACE_IRQFLAGS @@ -661,6 +750,9 @@ static const struct file_operations proc_lock_stat_operations = { entry = create_proc_entry("lockdep", S_IRUSR, NULL); if (entry) entry->proc_fops = &proc_lockdep_operations; + entry = create_proc_entry("lockdep_chains", S_IRUSR, NULL); + if (entry) + entry->proc_fops = &proc_lockdep_chains_operations; entry = create_proc_entry("lockdep_stats", S_IRUSR, NULL); if (entry)