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ftrace: Have the function probes call their own function

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Now that the function probes have their own ftrace_ops, there's no reason to
continue using the ftrace_func_hash to find which probe to call in the
function callback. The ops that is passed in to the function callback is
part of the probe_ops to call.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (VMware) 2017-04-04 21:31:28 -04:00
parent 1ec3a81a0c
commit eee8ded131
3 changed files with 101 additions and 129 deletions
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4
include/linux/ftrace.h
View File

@ -443,8 +443,8 @@ enum {
FTRACE_ITER_FILTER = (1 << 0),
FTRACE_ITER_NOTRACE = (1 << 1),
FTRACE_ITER_PRINTALL = (1 << 2),
FTRACE_ITER_DO_HASH = (1 << 3),
FTRACE_ITER_HASH = (1 << 4),
FTRACE_ITER_DO_PROBES = (1 << 3),
FTRACE_ITER_PROBE = (1 << 4),
FTRACE_ITER_ENABLED = (1 << 5),
};

225
kernel/trace/ftrace.c
View File

@ -1096,14 +1096,7 @@ static bool update_all_ops;
# error Dynamic ftrace depends on MCOUNT_RECORD
#endif
static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
struct ftrace_func_probe {
struct hlist_node node;
struct ftrace_probe_ops *ops;
unsigned long ip;
struct list_head free_list;
};
static LIST_HEAD(ftrace_func_probes);
struct ftrace_func_entry {
struct hlist_node hlist;
@ -1270,7 +1263,7 @@ static void
remove_hash_entry(struct ftrace_hash *hash,
struct ftrace_func_entry *entry)
{
hlist_del(&entry->hlist);
hlist_del_rcu(&entry->hlist);
hash->count--;
}
@ -3063,35 +3056,58 @@ struct ftrace_iterator {
loff_t func_pos;
struct ftrace_page *pg;
struct dyn_ftrace *func;
struct ftrace_func_probe *probe;
struct ftrace_probe_ops *probe;
struct ftrace_func_entry *probe_entry;
struct trace_parser parser;
struct ftrace_hash *hash;
struct ftrace_ops *ops;
int hidx;
int pidx;
int idx;
unsigned flags;
};
static void *
t_hash_next(struct seq_file *m, loff_t *pos)
t_probe_next(struct seq_file *m, loff_t *pos)
{
struct ftrace_iterator *iter = m->private;
struct ftrace_hash *hash;
struct list_head *next;
struct hlist_node *hnd = NULL;
struct hlist_head *hhd;
int size;
(*pos)++;
iter->pos = *pos;
if (iter->probe)
hnd = &iter->probe->node;
retry:
if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
if (list_empty(&ftrace_func_probes))
return NULL;
hhd = &ftrace_func_hash[iter->hidx];
if (!iter->probe) {
next = ftrace_func_probes.next;
iter->probe = list_entry(next, struct ftrace_probe_ops, list);
}
if (iter->probe_entry)
hnd = &iter->probe_entry->hlist;
hash = iter->probe->ops.func_hash->filter_hash;
size = 1 << hash->size_bits;
retry:
if (iter->pidx >= size) {
if (iter->probe->list.next == &ftrace_func_probes)
return NULL;
next = iter->probe->list.next;
iter->probe = list_entry(next, struct ftrace_probe_ops, list);
hash = iter->probe->ops.func_hash->filter_hash;
size = 1 << hash->size_bits;
iter->pidx = 0;
}
hhd = &hash->buckets[iter->pidx];
if (hlist_empty(hhd)) {
iter->hidx++;
iter->pidx++;
hnd = NULL;
goto retry;
}
@ -3101,7 +3117,7 @@ t_hash_next(struct seq_file *m, loff_t *pos)
else {
hnd = hnd->next;
if (!hnd) {
iter->hidx++;
iter->pidx++;
goto retry;
}
}
@ -3109,26 +3125,28 @@ t_hash_next(struct seq_file *m, loff_t *pos)
if (WARN_ON_ONCE(!hnd))
return NULL;
iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
return iter;
}
static void *t_hash_start(struct seq_file *m, loff_t *pos)
static void *t_probe_start(struct seq_file *m, loff_t *pos)
{
struct ftrace_iterator *iter = m->private;
void *p = NULL;
loff_t l;
if (!(iter->flags & FTRACE_ITER_DO_HASH))
if (!(iter->flags & FTRACE_ITER_DO_PROBES))
return NULL;
if (iter->func_pos > *pos)
return NULL;
iter->hidx = 0;
iter->probe = NULL;
iter->probe_entry = NULL;
iter->pidx = 0;
for (l = 0; l <= (*pos - iter->func_pos); ) {
p = t_hash_next(m, &l);
p = t_probe_next(m, &l);
if (!p)
break;
}
@ -3136,24 +3154,27 @@ static void *t_hash_start(struct seq_file *m, loff_t *pos)
return NULL;
/* Only set this if we have an item */
iter->flags |= FTRACE_ITER_HASH;
iter->flags |= FTRACE_ITER_PROBE;
return iter;
}
static int
t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
{
struct ftrace_func_probe *rec;
struct ftrace_probe_ops *probe;
struct ftrace_func_entry *probe_entry;
rec = iter->probe;
if (WARN_ON_ONCE(!rec))
probe = iter->probe;
probe_entry = iter->probe_entry;
if (WARN_ON_ONCE(!probe || !probe_entry))
return -EIO;
if (rec->ops->print)
return rec->ops->print(m, rec->ip, rec->ops, NULL);
if (probe->print)
return probe->print(m, probe_entry->ip, probe, NULL);
seq_printf(m, "%ps:%ps\n", (void *)rec->ip, (void *)rec->ops->func);
seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip, (void *)probe->func);
return 0;
}
@ -3205,19 +3226,19 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
if (unlikely(ftrace_disabled))
return NULL;
if (iter->flags & FTRACE_ITER_HASH)
return t_hash_next(m, pos);
if (iter->flags & FTRACE_ITER_PROBE)
return t_probe_next(m, pos);
if (iter->flags & FTRACE_ITER_PRINTALL) {
/* next must increment pos, and t_hash_start does not */
/* next must increment pos, and t_probe_start does not */
(*pos)++;
return t_hash_start(m, &l);
return t_probe_start(m, &l);
}
ret = t_func_next(m, pos);
if (!ret)
return t_hash_start(m, &l);
return t_probe_start(m, &l);
return ret;
}
@ -3226,7 +3247,7 @@ static void reset_iter_read(struct ftrace_iterator *iter)
{
iter->pos = 0;
iter->func_pos = 0;
iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE);
}
static void *t_start(struct seq_file *m, loff_t *pos)
@ -3255,15 +3276,15 @@ static void *t_start(struct seq_file *m, loff_t *pos)
ftrace_hash_empty(iter->hash)) {
iter->func_pos = 1; /* Account for the message */
if (*pos > 0)
return t_hash_start(m, pos);
return t_probe_start(m, pos);
iter->flags |= FTRACE_ITER_PRINTALL;
/* reset in case of seek/pread */
iter->flags &= ~FTRACE_ITER_HASH;
iter->flags &= ~FTRACE_ITER_PROBE;
return iter;
}
if (iter->flags & FTRACE_ITER_HASH)
return t_hash_start(m, pos);
if (iter->flags & FTRACE_ITER_PROBE)
return t_probe_start(m, pos);
/*
* Unfortunately, we need to restart at ftrace_pages_start
@ -3279,7 +3300,7 @@ static void *t_start(struct seq_file *m, loff_t *pos)
}
if (!p)
return t_hash_start(m, pos);
return t_probe_start(m, pos);
return iter;
}
@ -3310,8 +3331,8 @@ static int t_show(struct seq_file *m, void *v)
struct ftrace_iterator *iter = m->private;
struct dyn_ftrace *rec;
if (iter->flags & FTRACE_ITER_HASH)
return t_hash_show(m, iter);
if (iter->flags & FTRACE_ITER_PROBE)
return t_probe_show(m, iter);
if (iter->flags & FTRACE_ITER_PRINTALL) {
if (iter->flags & FTRACE_ITER_NOTRACE)
@ -3490,7 +3511,7 @@ ftrace_filter_open(struct inode *inode, struct file *file)
struct ftrace_ops *ops = inode->i_private;
return ftrace_regex_open(ops,
FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
inode, file);
}
@ -3765,16 +3786,9 @@ core_initcall(ftrace_mod_cmd_init);
static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *pt_regs)
{
struct ftrace_func_probe *entry;
struct hlist_head *hhd;
unsigned long key;
struct ftrace_probe_ops *probe_ops;
key = hash_long(ip, FTRACE_HASH_BITS);
hhd = &ftrace_func_hash[key];
if (hlist_empty(hhd))
return;
probe_ops = container_of(op, struct ftrace_probe_ops, ops);
/*
* Disable preemption for these calls to prevent a RCU grace
@ -3782,20 +3796,10 @@ static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
* on the hash. rcu_read_lock is too dangerous here.
*/
preempt_disable_notrace();
hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
if (entry->ip == ip)
entry->ops->func(ip, parent_ip, entry->ops, NULL);
}
probe_ops->func(ip, parent_ip, probe_ops, NULL);
preempt_enable_notrace();
}
static void ftrace_free_entry(struct ftrace_func_probe *entry)
{
if (entry->ops->free)
entry->ops->free(entry->ops, entry->ip, NULL);
kfree(entry);
}
struct ftrace_func_map {
struct ftrace_func_entry entry;
void *data;
@ -3942,13 +3946,9 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
void *data)
{
struct ftrace_func_entry *entry;
struct ftrace_func_probe *probe;
struct ftrace_hash **orig_hash;
struct ftrace_hash *old_hash;
struct ftrace_hash *hash;
struct hlist_head hl;
struct hlist_node *n;
unsigned long key;
int count = 0;
int size;
int ret;
@ -3961,6 +3961,7 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
if (!(ops->ops.flags & FTRACE_OPS_FL_INITIALIZED)) {
ops->ops.func = function_trace_probe_call;
ftrace_ops_init(&ops->ops);
INIT_LIST_HEAD(&ops->list);
}
mutex_lock(&ops->ops.func_hash->regex_lock);
@ -3978,31 +3979,21 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
if (ret < 0)
goto out;
INIT_HLIST_HEAD(&hl);
size = 1 << hash->size_bits;
for (i = 0; i < size; i++) {
hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
if (ftrace_lookup_ip(old_hash, entry->ip))
continue;
probe = kmalloc(sizeof(*probe), GFP_KERNEL);
if (!probe) {
count = -ENOMEM;
goto err_free;
}
probe->ops = ops;
probe->ip = entry->ip;
/*
* The caller might want to do something special
* for each function we find. We call the callback
* to give the caller an opportunity to do so.
*/
if (ops->init && ops->init(ops, entry->ip, data) < 0) {
kfree(probe);
goto err_free;
if (ops->init) {
ret = ops->init(ops, entry->ip, data);
if (ret < 0)
goto out;
}
hlist_add_head(&probe->node, &hl);
count++;
}
}
@ -4012,17 +4003,15 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
ret = ftrace_hash_move_and_update_ops(&ops->ops, orig_hash,
hash, 1);
if (ret < 0)
goto err_free_unlock;
goto out_unlock;
hlist_for_each_entry_safe(probe, n, &hl, node) {
hlist_del(&probe->node);
key = hash_long(probe->ip, FTRACE_HASH_BITS);
hlist_add_head_rcu(&probe->node, &ftrace_func_hash[key]);
}
if (list_empty(&ops->list))
list_add(&ops->list, &ftrace_func_probes);
if (!(ops->ops.flags & FTRACE_OPS_FL_ENABLED))
ret = ftrace_startup(&ops->ops, 0);
out_unlock:
mutex_unlock(&ftrace_lock);
if (!ret)
@ -4032,34 +4021,22 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
free_ftrace_hash(hash);
return ret;
err_free_unlock:
mutex_unlock(&ftrace_lock);
err_free:
hlist_for_each_entry_safe(probe, n, &hl, node) {
hlist_del(&probe->node);
if (ops->free)
ops->free(ops, probe->ip, NULL);
kfree(probe);
}
goto out;
}
int
unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
{
struct ftrace_ops_hash old_hash_ops;
struct ftrace_func_entry *rec_entry;
struct ftrace_func_probe *entry;
struct ftrace_func_probe *p;
struct ftrace_func_entry *entry;
struct ftrace_glob func_g;
struct ftrace_hash **orig_hash;
struct ftrace_hash *old_hash;
struct list_head free_list;
struct ftrace_hash *hash = NULL;
struct hlist_node *tmp;
struct hlist_head hhd;
char str[KSYM_SYMBOL_LEN];
int i, ret;
int size;
if (!(ops->ops.flags & FTRACE_OPS_FL_INITIALIZED))
return -EINVAL;
@ -4097,18 +4074,12 @@ unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
if (!hash)
goto out_unlock;
INIT_LIST_HEAD(&free_list);
INIT_HLIST_HEAD(&hhd);
for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
struct hlist_head *hhd = &ftrace_func_hash[i];
size = 1 << hash->size_bits;
for (i = 0; i < size; i++) {
hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
hlist_for_each_entry_safe(entry, tmp, hhd, node) {
/* break up if statements for readability */
if (entry->ops != ops)
continue;
/* do this last, since it is the most expensive */
if (func_g.search) {
kallsyms_lookup(entry->ip, NULL, NULL,
NULL, str);
@ -4116,26 +4087,24 @@ unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
continue;
}
rec_entry = ftrace_lookup_ip(hash, entry->ip);
/* It is possible more than one entry had this ip */
if (rec_entry)
free_hash_entry(hash, rec_entry);
hlist_del_rcu(&entry->node);
list_add(&entry->free_list, &free_list);
remove_hash_entry(hash, entry);
hlist_add_head(&entry->hlist, &hhd);
}
}
/* Nothing found? */
if (list_empty(&free_list)) {
if (hlist_empty(&hhd)) {
ret = -EINVAL;
goto out_unlock;
}
mutex_lock(&ftrace_lock);
if (ftrace_hash_empty(hash))
if (ftrace_hash_empty(hash)) {
ftrace_shutdown(&ops->ops, 0);
list_del_init(&ops->list);
}
ret = ftrace_hash_move_and_update_ops(&ops->ops, orig_hash,
hash, 1);
@ -4146,9 +4115,11 @@ unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
&old_hash_ops);
synchronize_sched();
list_for_each_entry_safe(entry, p, &free_list, free_list) {
list_del(&entry->free_list);
ftrace_free_entry(entry);
hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
hlist_del(&entry->hlist);
if (ops->free)
ops->free(ops, entry->ip, NULL);
kfree(entry);
}
mutex_unlock(&ftrace_lock);

1
kernel/trace/trace.h
View File

@ -933,6 +933,7 @@ static inline void ftrace_pid_follow_fork(struct trace_array *tr, bool enable) {
struct ftrace_probe_ops {
struct ftrace_ops ops;
struct list_head list;
void (*func)(unsigned long ip,
unsigned long parent_ip,
struct ftrace_probe_ops *ops,