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authorWaiman Long <longman@redhat.com>2020-02-06 10:24:05 -0500
committerIngo Molnar <mingo@kernel.org>2020-02-11 13:10:49 +0100
commit1d44bcb4fdb650b2a57c9ff593a4d246a10ad801 (patch)
tree70c71d94edb4c03863c5679c659a6eed69170f3e /kernel
parentb9875e9882295749a14b31e16dd504ae904cf070 (diff)
locking/lockdep: Track number of zapped classes
The whole point of the lockdep dynamic key patch is to allow unused locks to be removed from the lockdep data buffers so that existing buffer space can be reused. However, there is no way to find out how many unused locks are zapped and so we don't know if the zapping process is working properly. Add a new nr_zapped_classes counter to track that and show it in /proc/lockdep_stats. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20200206152408.24165-4-longman@redhat.com
Diffstat (limited to 'kernel')
-rw-r--r--kernel/locking/lockdep.c2
-rw-r--r--kernel/locking/lockdep_internals.h1
-rw-r--r--kernel/locking/lockdep_proc.c6
3 files changed, 9 insertions, 0 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 35449f5b79fb..28222d03345f 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -147,6 +147,7 @@ static DECLARE_BITMAP(list_entries_in_use, MAX_LOCKDEP_ENTRIES);
#define KEYHASH_SIZE (1UL << KEYHASH_BITS)
static struct hlist_head lock_keys_hash[KEYHASH_SIZE];
unsigned long nr_lock_classes;
+unsigned long nr_zapped_classes;
#ifndef CONFIG_DEBUG_LOCKDEP
static
#endif
@@ -4880,6 +4881,7 @@ static void zap_class(struct pending_free *pf, struct lock_class *class)
}
remove_class_from_lock_chains(pf, class);
+ nr_zapped_classes++;
}
static void reinit_class(struct lock_class *class)
diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h
index a525368b8cf6..76db80446a32 100644
--- a/kernel/locking/lockdep_internals.h
+++ b/kernel/locking/lockdep_internals.h
@@ -130,6 +130,7 @@ extern const char *__get_key_name(const struct lockdep_subclass_key *key,
struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i);
extern unsigned long nr_lock_classes;
+extern unsigned long nr_zapped_classes;
extern unsigned long nr_list_entries;
long lockdep_next_lockchain(long i);
unsigned long lock_chain_count(void);
diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c
index c2224381c149..99e2f3f6adca 100644
--- a/kernel/locking/lockdep_proc.c
+++ b/kernel/locking/lockdep_proc.c
@@ -343,6 +343,12 @@ static int lockdep_stats_show(struct seq_file *m, void *v)
seq_printf(m, " debug_locks: %11u\n",
debug_locks);
+ /*
+ * Zappped classes and lockdep data buffers reuse statistics.
+ */
+ seq_puts(m, "\n");
+ seq_printf(m, " zapped classes: %11lu\n",
+ nr_zapped_classes);
return 0;
}