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author | Bart Van Assche <bvanassche@acm.org> | 2019-02-14 15:00:47 -0800 |
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committer | Ingo Molnar <mingo@kernel.org> | 2019-02-28 07:55:44 +0100 |
commit | ace35a7ac493d4284a57ad807579011bebba891c (patch) | |
tree | 98de82d8345d82e819eb5ba730098831ba7c6d03 /kernel/locking | |
parent | a0b0fd53e1e67639b303b15939b9c653dbe7a8c4 (diff) | |
download | linux-ace35a7ac493d4284a57ad807579011bebba891c.tar.gz linux-ace35a7ac493d4284a57ad807579011bebba891c.tar.bz2 linux-ace35a7ac493d4284a57ad807579011bebba891c.zip |
locking/lockdep: Reuse list entries that are no longer in use
Instead of abandoning elements of list_entries[] that are no longer in
use, make alloc_list_entry() reuse array elements that have been freed.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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>
Cc: johannes.berg@intel.com
Cc: tj@kernel.org
Link: https://lkml.kernel.org/r/20190214230058.196511-13-bvanassche@acm.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking')
-rw-r--r-- | kernel/locking/lockdep.c | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 8ecf355dd163..2c6d0b67e7b6 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -45,6 +45,7 @@ #include <linux/hash.h> #include <linux/ftrace.h> #include <linux/stringify.h> +#include <linux/bitmap.h> #include <linux/bitops.h> #include <linux/gfp.h> #include <linux/random.h> @@ -132,6 +133,7 @@ static inline int debug_locks_off_graph_unlock(void) unsigned long nr_list_entries; static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; +static DECLARE_BITMAP(list_entries_in_use, MAX_LOCKDEP_ENTRIES); /* * All data structures here are protected by the global debug_lock. @@ -907,7 +909,10 @@ out_set_class_cache: */ static struct lock_list *alloc_list_entry(void) { - if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { + int idx = find_first_zero_bit(list_entries_in_use, + ARRAY_SIZE(list_entries)); + + if (idx >= ARRAY_SIZE(list_entries)) { if (!debug_locks_off_graph_unlock()) return NULL; @@ -915,7 +920,9 @@ static struct lock_list *alloc_list_entry(void) dump_stack(); return NULL; } - return list_entries + nr_list_entries++; + nr_list_entries++; + __set_bit(idx, list_entries_in_use); + return list_entries + idx; } /* @@ -1019,7 +1026,7 @@ static inline void mark_lock_accessed(struct lock_list *lock, unsigned long nr; nr = lock - list_entries; - WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ + WARN_ON(nr >= ARRAY_SIZE(list_entries)); /* Out-of-bounds, input fail */ lock->parent = parent; lock->class->dep_gen_id = lockdep_dependency_gen_id; } @@ -1029,7 +1036,7 @@ static inline unsigned long lock_accessed(struct lock_list *lock) unsigned long nr; nr = lock - list_entries; - WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ + WARN_ON(nr >= ARRAY_SIZE(list_entries)); /* Out-of-bounds, input fail */ return lock->class->dep_gen_id == lockdep_dependency_gen_id; } @@ -4276,13 +4283,13 @@ static void zap_class(struct pending_free *pf, struct lock_class *class) * Remove all dependencies this lock is * involved in: */ - for (i = 0, entry = list_entries; i < nr_list_entries; i++, entry++) { + for_each_set_bit(i, list_entries_in_use, ARRAY_SIZE(list_entries)) { + entry = list_entries + i; if (entry->class != class && entry->links_to != class) continue; + __clear_bit(i, list_entries_in_use); + nr_list_entries--; list_del_rcu(&entry->entry); - /* Clear .class and .links_to to avoid double removal. */ - WRITE_ONCE(entry->class, NULL); - WRITE_ONCE(entry->links_to, NULL); } if (list_empty(&class->locks_after) && list_empty(&class->locks_before)) { @@ -4596,6 +4603,7 @@ void __init lockdep_init(void) (sizeof(lock_classes) + sizeof(classhash_table) + sizeof(list_entries) + + sizeof(list_entries_in_use) + sizeof(chainhash_table) + sizeof(delayed_free) #ifdef CONFIG_PROVE_LOCKING |