lockdep: add lock_class information to lock_chain and output it
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>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index a796f1f..7553a28 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -1459,7 +1459,7 @@
unsigned long nr_lock_chains;
struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
-atomic_t nr_chain_hlocks;
+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)
@@ -1481,7 +1481,7 @@
struct list_head *hash_head = chainhashentry(chain_key);
struct lock_chain *chain;
struct held_lock *hlock_curr, *hlock_next;
- int i, j, n;
+ int i, j, n, cn;
if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
return 0;
@@ -1540,9 +1540,15 @@
}
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;
+ 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;
diff --git a/kernel/lockdep_internals.h b/kernel/lockdep_internals.h
index db09b17..c3600a0 100644
--- a/kernel/lockdep_internals.h
+++ b/kernel/lockdep_internals.h
@@ -44,7 +44,7 @@
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 int 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 14d052c..9b0e940 100644
--- a/kernel/lockdep_proc.c
+++ b/kernel/lockdep_proc.c
@@ -178,6 +178,7 @@
.release = seq_release,
};
+#ifdef CONFIG_PROVE_LOCKING
static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
{
struct lock_chain *chain;
@@ -264,6 +265,7 @@
.llseek = seq_lseek,
.release = seq_release,
};
+#endif /* CONFIG_PROVE_LOCKING */
static void lockdep_stats_debug_show(struct seq_file *m)
{
@@ -382,7 +384,7 @@
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);
+ nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS);
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
@@ -750,8 +752,10 @@
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);
