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lockdep: BFS cleanup

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Some cleanups of the lockdep code after the BFS series:

 - Remove the last traces of the generation id
 - Fixup comment style
 - Move the bfs routines into lockdep.c
 - Cleanup the bfs routines

[ tom.leiming@gmail.com: Fix crash ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1246201486-7308-11-git-send-email-tom.leiming@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2009-07-16 15:44:29 +02:00
parent 12f3dfd022
commit af01296145
3 changed files with 175 additions and 213 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
include/linux/lockdep.h
View file

@ -58,7 +58,6 @@ struct lock_class {
struct lockdep_subclass_key *key;
unsigned int subclass;
unsigned int dep_gen_id;
/*
* IRQ/softirq usage tracking bits:
@ -150,9 +149,9 @@ struct lock_list {
struct stack_trace trace;
int distance;
/*The parent field is used to implement breadth-first search,and
*the bit 0 is reused to indicate if the lock has been accessed
*in BFS.
/*
* The parent field is used to implement breadth-first search, and the
* bit 0 is reused to indicate if the lock has been accessed in BFS.
*/
struct lock_list *parent;
};

274
kernel/lockdep.c
View file

@ -43,6 +43,7 @@
#include <linux/ftrace.h>
#include <linux/stringify.h>
#include <linux/bitops.h>
#include <asm/sections.h>
#include "lockdep_internals.h"
@ -118,7 +119,7 @@ static inline int debug_locks_off_graph_unlock(void)
static int lockdep_initialized;
unsigned long nr_list_entries;
struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
/*
* All data structures here are protected by the global debug_lock.
@ -390,19 +391,6 @@ unsigned int nr_process_chains;
unsigned int max_lockdep_depth;
unsigned int max_recursion_depth;
static unsigned int lockdep_dependency_gen_id;
static bool lockdep_dependency_visit(struct lock_class *source,
unsigned int depth)
{
if (!depth)
lockdep_dependency_gen_id++;
if (source->dep_gen_id == lockdep_dependency_gen_id)
return true;
source->dep_gen_id = lockdep_dependency_gen_id;
return false;
}
#ifdef CONFIG_DEBUG_LOCKDEP
/*
* We cannot printk in early bootup code. Not even early_printk()
@ -551,88 +539,6 @@ static void lockdep_print_held_locks(struct task_struct *curr)
}
}
static void print_lock_class_header(struct lock_class *class, int depth)
{
int bit;
printk("%*s->", depth, "");
print_lock_name(class);
printk(" ops: %lu", class->ops);
printk(" {\n");
for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
if (class->usage_mask & (1 << bit)) {
int len = depth;
len += printk("%*s %s", depth, "", usage_str[bit]);
len += printk(" at:\n");
print_stack_trace(class->usage_traces + bit, len);
}
}
printk("%*s }\n", depth, "");
printk("%*s ... key at: ",depth,"");
print_ip_sym((unsigned long)class->key);
}
/*
* printk the shortest lock dependencies from @start to @end in reverse order:
*/
static void __used
print_shortest_lock_dependencies(struct lock_list *leaf,
struct lock_list *root)
{
struct lock_list *entry = leaf;
int depth;
/*compute depth from generated tree by BFS*/
depth = get_lock_depth(leaf);
do {
print_lock_class_header(entry->class, depth);
printk("%*s ... acquired at:\n", depth, "");
print_stack_trace(&entry->trace, 2);
printk("\n");
if (depth == 0 && (entry != root)) {
printk("lockdep:%s bad BFS generated tree\n", __func__);
break;
}
entry = get_lock_parent(entry);
depth--;
} while (entry && (depth >= 0));
return;
}
/*
* printk all lock dependencies starting at <entry>:
*/
static void __used
print_lock_dependencies(struct lock_class *class, int depth)
{
struct lock_list *entry;
if (lockdep_dependency_visit(class, depth))
return;
if (DEBUG_LOCKS_WARN_ON(depth >= 20))
return;
print_lock_class_header(class, depth);
list_for_each_entry(entry, &class->locks_after, entry) {
if (DEBUG_LOCKS_WARN_ON(!entry->class))
return;
print_lock_dependencies(entry->class, depth + 1);
printk("%*s ... acquired at:\n",depth,"");
print_stack_trace(&entry->trace, 2);
printk("\n");
}
}
static void print_kernel_version(void)
{
printk("%s %.*s\n", init_utsname()->release,
@ -927,9 +833,101 @@ static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
return 1;
}
unsigned long bfs_accessed[BITS_TO_LONGS(MAX_LOCKDEP_ENTRIES)];
/*For good efficiency of modular, we use power of 2*/
#define MAX_CIRCULAR_QUEUE_SIZE 4096UL
#define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1)
/* The circular_queue and helpers is used to implement the
* breadth-first search(BFS)algorithem, by which we can build
* the shortest path from the next lock to be acquired to the
* previous held lock if there is a circular between them.
* */
struct circular_queue {
unsigned long element[MAX_CIRCULAR_QUEUE_SIZE];
unsigned int front, rear;
};
static struct circular_queue lock_cq;
static unsigned long bfs_accessed[BITS_TO_LONGS(MAX_LOCKDEP_ENTRIES)];
unsigned int max_bfs_queue_depth;
static inline void __cq_init(struct circular_queue *cq)
{
cq->front = cq->rear = 0;
bitmap_zero(bfs_accessed, MAX_LOCKDEP_ENTRIES);
}
static inline int __cq_empty(struct circular_queue *cq)
{
return (cq->front == cq->rear);
}
static inline int __cq_full(struct circular_queue *cq)
{
return ((cq->rear + 1) & CQ_MASK) == cq->front;
}
static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem)
{
if (__cq_full(cq))
return -1;
cq->element[cq->rear] = elem;
cq->rear = (cq->rear + 1) & CQ_MASK;
return 0;
}
static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem)
{
if (__cq_empty(cq))
return -1;
*elem = cq->element[cq->front];
cq->front = (cq->front + 1) & CQ_MASK;
return 0;
}
static inline unsigned int __cq_get_elem_count(struct circular_queue *cq)
{
return (cq->rear - cq->front) & CQ_MASK;
}
static inline void mark_lock_accessed(struct lock_list *lock,
struct lock_list *parent)
{
unsigned long nr;
nr = lock - list_entries;
WARN_ON(nr >= nr_list_entries);
lock->parent = parent;
set_bit(nr, bfs_accessed);
}
static inline unsigned long lock_accessed(struct lock_list *lock)
{
unsigned long nr;
nr = lock - list_entries;
WARN_ON(nr >= nr_list_entries);
return test_bit(nr, bfs_accessed);
}
static inline struct lock_list *get_lock_parent(struct lock_list *child)
{
return child->parent;
}
static inline int get_lock_depth(struct lock_list *child)
{
int depth = 0;
struct lock_list *parent;
while ((parent = get_lock_parent(child))) {
child = parent;
depth++;
}
return depth;
}
static int __bfs(struct lock_list *source_entry,
void *data,
int (*match)(struct lock_list *entry, void *data),
@ -1202,14 +1200,6 @@ check_noncircular(struct lock_list *root, struct lock_class *target,
* without creating any illegal irq-safe -> irq-unsafe lock dependency.
*/
#define BFS_PROCESS_RET(ret) do { \
if (ret < 0) \
return print_bfs_bug(ret); \
if (ret == 1) \
return 1; \
} while (0)
static inline int usage_match(struct lock_list *entry, void *bit)
{
return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit);
@ -1263,6 +1253,60 @@ find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit,
return result;
}
static void print_lock_class_header(struct lock_class *class, int depth)
{
int bit;
printk("%*s->", depth, "");
print_lock_name(class);
printk(" ops: %lu", class->ops);
printk(" {\n");
for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
if (class->usage_mask & (1 << bit)) {
int len = depth;
len += printk("%*s %s", depth, "", usage_str[bit]);
len += printk(" at:\n");
print_stack_trace(class->usage_traces + bit, len);
}
}
printk("%*s }\n", depth, "");
printk("%*s ... key at: ",depth,"");
print_ip_sym((unsigned long)class->key);
}
/*
* printk the shortest lock dependencies from @start to @end in reverse order:
*/
static void __used
print_shortest_lock_dependencies(struct lock_list *leaf,
struct lock_list *root)
{
struct lock_list *entry = leaf;
int depth;
/*compute depth from generated tree by BFS*/
depth = get_lock_depth(leaf);
do {
print_lock_class_header(entry->class, depth);
printk("%*s ... acquired at:\n", depth, "");
print_stack_trace(&entry->trace, 2);
printk("\n");
if (depth == 0 && (entry != root)) {
printk("lockdep:%s bad BFS generated tree\n", __func__);
break;
}
entry = get_lock_parent(entry);
depth--;
} while (entry && (depth >= 0));
return;
}
static int
print_bad_irq_dependency(struct task_struct *curr,
@ -1349,12 +1393,18 @@ check_usage(struct task_struct *curr, struct held_lock *prev,
this.class = hlock_class(prev);
ret = find_usage_backwards(&this, bit_backwards, &target_entry);
BFS_PROCESS_RET(ret);
if (ret < 0)
return print_bfs_bug(ret);
if (ret == 1)
return ret;
that.parent = NULL;
that.class = hlock_class(next);
ret = find_usage_forwards(&that, bit_forwards, &target_entry1);
BFS_PROCESS_RET(ret);
if (ret < 0)
return print_bfs_bug(ret);
if (ret == 1)
return ret;
return print_bad_irq_dependency(curr, &this, &that,
target_entry, target_entry1,
@ -2038,7 +2088,10 @@ check_usage_forwards(struct task_struct *curr, struct held_lock *this,
root.parent = NULL;
root.class = hlock_class(this);
ret = find_usage_forwards(&root, bit, &target_entry);
BFS_PROCESS_RET(ret);
if (ret < 0)
return print_bfs_bug(ret);
if (ret == 1)
return ret;
return print_irq_inversion_bug(curr, &root, target_entry,
this, 1, irqclass);
@ -2059,7 +2112,10 @@ check_usage_backwards(struct task_struct *curr, struct held_lock *this,
root.parent = NULL;
root.class = hlock_class(this);
ret = find_usage_backwards(&root, bit, &target_entry);
BFS_PROCESS_RET(ret);
if (ret < 0)
return print_bfs_bug(ret);
if (ret == 1)
return ret;
return print_irq_inversion_bug(curr, &root, target_entry,
this, 1, irqclass);

97
kernel/lockdep_internals.h
View file

@ -91,6 +91,8 @@ extern unsigned int nr_process_chains;
extern unsigned int max_lockdep_depth;
extern unsigned int max_recursion_depth;
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 *);
@ -136,98 +138,3 @@ extern atomic_t nr_find_usage_backwards_recursions;
# define debug_atomic_dec(ptr) do { } while (0)
# define debug_atomic_read(ptr) 0
#endif
extern unsigned int max_bfs_queue_depth;
extern unsigned long nr_list_entries;
extern struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
extern unsigned long bfs_accessed[];
/*For good efficiency of modular, we use power of 2*/
#define MAX_CIRCULAR_QUE_SIZE 4096UL
/* The circular_queue and helpers is used to implement the
* breadth-first search(BFS)algorithem, by which we can build
* the shortest path from the next lock to be acquired to the
* previous held lock if there is a circular between them.
* */
struct circular_queue{
unsigned long element[MAX_CIRCULAR_QUE_SIZE];
unsigned int front, rear;
};
static inline void __cq_init(struct circular_queue *cq)
{
cq->front = cq->rear = 0;
bitmap_zero(bfs_accessed, MAX_LOCKDEP_ENTRIES);
}
static inline int __cq_empty(struct circular_queue *cq)
{
return (cq->front == cq->rear);
}
static inline int __cq_full(struct circular_queue *cq)
{
return ((cq->rear + 1)&(MAX_CIRCULAR_QUE_SIZE-1)) == cq->front;
}
static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem)
{
if (__cq_full(cq))
return -1;
cq->element[cq->rear] = elem;
cq->rear = (cq->rear + 1)&(MAX_CIRCULAR_QUE_SIZE-1);
return 0;
}
static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem)
{
if (__cq_empty(cq))
return -1;
*elem = cq->element[cq->front];
cq->front = (cq->front + 1)&(MAX_CIRCULAR_QUE_SIZE-1);
return 0;
}
static inline unsigned int __cq_get_elem_count(struct circular_queue *cq)
{
return (cq->rear - cq->front)&(MAX_CIRCULAR_QUE_SIZE-1);
}
static inline void mark_lock_accessed(struct lock_list *lock,
struct lock_list *parent)
{
unsigned long nr;
nr = lock - list_entries;
WARN_ON(nr >= nr_list_entries);
lock->parent = parent;
set_bit(nr, bfs_accessed);
}
static inline unsigned long lock_accessed(struct lock_list *lock)
{
unsigned long nr;
nr = lock - list_entries;
WARN_ON(nr >= nr_list_entries);
return test_bit(nr, bfs_accessed);
}
static inline struct lock_list *get_lock_parent(struct lock_list *child)
{
return child->parent;
}
static inline int get_lock_depth(struct lock_list *child)
{
int depth = 0;
struct lock_list *parent;
while ((parent = get_lock_parent(child))) {
child = parent;
depth++;
}
return depth;
}