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| author | Bart Van Assche <bvanassche@acm.org> | 2019-07-22 20:24:43 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2019-07-25 15:43:28 +0200 |
| commit | 8c779229d0f4fe83ead90bdcbbf08b02989aa200 (patch) | |
| tree | 2a9d6239c74f3889ec46a4ea0037d32d8dd41505 /kernel/locking | |
| parent | locking/lockdep: Reduce space occupied by stack traces (diff) | |
| download | linux-8c779229d0f4fe83ead90bdcbbf08b02989aa200.tar.xz linux-8c779229d0f4fe83ead90bdcbbf08b02989aa200.zip | |
locking/lockdep: Report more stack trace statistics
Report the number of stack traces and the number of stack trace hash
chains. These two numbers are useful because these allow to estimate
the number of stack trace hash collisions.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Link: https://lkml.kernel.org/r/20190722182443.216015-5-bvanassche@acm.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking')
| -rw-r--r-- | kernel/locking/lockdep.c | 29 | ||||
| -rw-r--r-- | kernel/locking/lockdep_internals.h | 4 | ||||
| -rw-r--r-- | kernel/locking/lockdep_proc.c | 6 |
3 files changed, 39 insertions, 0 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 1a96869cb2f0..3c3902c40a0e 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -516,6 +516,35 @@ static struct lock_trace *save_trace(void) return trace; } + +/* Return the number of stack traces in the stack_trace[] array. */ +u64 lockdep_stack_trace_count(void) +{ + struct lock_trace *trace; + u64 c = 0; + int i; + + for (i = 0; i < ARRAY_SIZE(stack_trace_hash); i++) { + hlist_for_each_entry(trace, &stack_trace_hash[i], hash_entry) { + c++; + } + } + + return c; +} + +/* Return the number of stack hash chains that have at least one stack trace. */ +u64 lockdep_stack_hash_count(void) +{ + u64 c = 0; + int i; + + for (i = 0; i < ARRAY_SIZE(stack_trace_hash); i++) + if (!hlist_empty(&stack_trace_hash[i])) + c++; + + return c; +} #endif unsigned int nr_hardirq_chains; diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h index 93a008bf77db..18d85aebbb57 100644 --- a/kernel/locking/lockdep_internals.h +++ b/kernel/locking/lockdep_internals.h @@ -140,6 +140,10 @@ extern unsigned int max_bfs_queue_depth; #ifdef CONFIG_PROVE_LOCKING extern unsigned long lockdep_count_forward_deps(struct lock_class *); extern unsigned long lockdep_count_backward_deps(struct lock_class *); +#ifdef CONFIG_TRACE_IRQFLAGS +u64 lockdep_stack_trace_count(void); +u64 lockdep_stack_hash_count(void); +#endif #else static inline unsigned long lockdep_count_forward_deps(struct lock_class *class) diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c index ed9842425cac..dadb7b7fba37 100644 --- a/kernel/locking/lockdep_proc.c +++ b/kernel/locking/lockdep_proc.c @@ -285,6 +285,12 @@ static int lockdep_stats_show(struct seq_file *m, void *v) nr_process_chains); seq_printf(m, " stack-trace entries: %11lu [max: %lu]\n", nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES); +#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) + seq_printf(m, " number of stack traces: %llu\n", + lockdep_stack_trace_count()); + seq_printf(m, " number of stack hash chains: %llu\n", + lockdep_stack_hash_count()); +#endif seq_printf(m, " combined max dependencies: %11u\n", (nr_hardirq_chains + 1) * (nr_softirq_chains + 1) * |