forked from Minki/linux
ftrace: Separate hash allocation and assignment
When filtering, allocate a hash to insert the function records. After the filtering is complete, assign it to the ftrace_ops structure. This allows the ftrace_ops structure to have a much smaller array of hash buckets instead of wasting a lot of memory. A read only empty_hash is created to be the minimum size that any ftrace_ops can point to. When a new hash is created, it has the following steps: o Allocate a default hash. o Walk the function records assigning the filtered records to the hash o Allocate a new hash with the appropriate size buckets o Move the entries from the default hash to the new hash. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt
Steven Rostedt
parent
f45948e898
commit
33dc9b1267
@ -57,7 +57,8 @@
|
||||
/* hash bits for specific function selection */
|
||||
#define FTRACE_HASH_BITS 7
|
||||
#define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
|
||||
#define FTRACE_HASH_MAX_BITS 10
|
||||
#define FTRACE_HASH_DEFAULT_BITS 10
|
||||
#define FTRACE_HASH_MAX_BITS 12
|
||||
|
||||
/* ftrace_enabled is a method to turn ftrace on or off */
|
||||
int ftrace_enabled __read_mostly;
|
||||
@ -877,22 +878,22 @@ struct ftrace_hash {
|
||||
unsigned long count;
|
||||
};
|
||||
|
||||
static struct hlist_head notrace_buckets[1 << FTRACE_HASH_MAX_BITS];
|
||||
static struct ftrace_hash notrace_hash = {
|
||||
.size_bits = FTRACE_HASH_MAX_BITS,
|
||||
.buckets = notrace_buckets,
|
||||
};
|
||||
|
||||
static struct hlist_head filter_buckets[1 << FTRACE_HASH_MAX_BITS];
|
||||
static struct ftrace_hash filter_hash = {
|
||||
.size_bits = FTRACE_HASH_MAX_BITS,
|
||||
.buckets = filter_buckets,
|
||||
/*
|
||||
* We make these constant because no one should touch them,
|
||||
* but they are used as the default "empty hash", to avoid allocating
|
||||
* it all the time. These are in a read only section such that if
|
||||
* anyone does try to modify it, it will cause an exception.
|
||||
*/
|
||||
static const struct hlist_head empty_buckets[1];
|
||||
static const struct ftrace_hash empty_hash = {
|
||||
.buckets = (struct hlist_head *)empty_buckets,
|
||||
};
|
||||
#define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
|
||||
|
||||
struct ftrace_ops global_ops = {
|
||||
.func = ftrace_stub,
|
||||
.notrace_hash = ¬race_hash,
|
||||
.filter_hash = &filter_hash,
|
||||
.notrace_hash = EMPTY_HASH,
|
||||
.filter_hash = EMPTY_HASH,
|
||||
};
|
||||
|
||||
static struct dyn_ftrace *ftrace_new_addrs;
|
||||
@ -941,35 +942,50 @@ ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
|
||||
return NULL;
|
||||
}
|
||||
|
||||
static void __add_hash_entry(struct ftrace_hash *hash,
|
||||
struct ftrace_func_entry *entry)
|
||||
{
|
||||
struct hlist_head *hhd;
|
||||
unsigned long key;
|
||||
|
||||
if (hash->size_bits)
|
||||
key = hash_long(entry->ip, hash->size_bits);
|
||||
else
|
||||
key = 0;
|
||||
|
||||
hhd = &hash->buckets[key];
|
||||
hlist_add_head(&entry->hlist, hhd);
|
||||
hash->count++;
|
||||
}
|
||||
|
||||
static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
|
||||
{
|
||||
struct ftrace_func_entry *entry;
|
||||
struct hlist_head *hhd;
|
||||
unsigned long key;
|
||||
|
||||
entry = kmalloc(sizeof(*entry), GFP_KERNEL);
|
||||
if (!entry)
|
||||
return -ENOMEM;
|
||||
|
||||
if (hash->size_bits)
|
||||
key = hash_long(ip, hash->size_bits);
|
||||
else
|
||||
key = 0;
|
||||
|
||||
entry->ip = ip;
|
||||
hhd = &hash->buckets[key];
|
||||
hlist_add_head(&entry->hlist, hhd);
|
||||
hash->count++;
|
||||
__add_hash_entry(hash, entry);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void
|
||||
free_hash_entry(struct ftrace_hash *hash,
|
||||
struct ftrace_func_entry *entry)
|
||||
{
|
||||
hlist_del(&entry->hlist);
|
||||
kfree(entry);
|
||||
hash->count--;
|
||||
}
|
||||
|
||||
static void
|
||||
remove_hash_entry(struct ftrace_hash *hash,
|
||||
struct ftrace_func_entry *entry)
|
||||
{
|
||||
hlist_del(&entry->hlist);
|
||||
kfree(entry);
|
||||
hash->count--;
|
||||
}
|
||||
|
||||
@ -981,14 +997,156 @@ static void ftrace_hash_clear(struct ftrace_hash *hash)
|
||||
int size = 1 << hash->size_bits;
|
||||
int i;
|
||||
|
||||
if (!hash->count)
|
||||
return;
|
||||
|
||||
for (i = 0; i < size; i++) {
|
||||
hhd = &hash->buckets[i];
|
||||
hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist)
|
||||
remove_hash_entry(hash, entry);
|
||||
free_hash_entry(hash, entry);
|
||||
}
|
||||
FTRACE_WARN_ON(hash->count);
|
||||
}
|
||||
|
||||
static void free_ftrace_hash(struct ftrace_hash *hash)
|
||||
{
|
||||
if (!hash || hash == EMPTY_HASH)
|
||||
return;
|
||||
ftrace_hash_clear(hash);
|
||||
kfree(hash->buckets);
|
||||
kfree(hash);
|
||||
}
|
||||
|
||||
static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
|
||||
{
|
||||
struct ftrace_hash *hash;
|
||||
int size;
|
||||
|
||||
hash = kzalloc(sizeof(*hash), GFP_KERNEL);
|
||||
if (!hash)
|
||||
return NULL;
|
||||
|
||||
size = 1 << size_bits;
|
||||
hash->buckets = kzalloc(sizeof(*hash->buckets) * size, GFP_KERNEL);
|
||||
|
||||
if (!hash->buckets) {
|
||||
kfree(hash);
|
||||
return NULL;
|
||||
}
|
||||
|
||||
hash->size_bits = size_bits;
|
||||
|
||||
return hash;
|
||||
}
|
||||
|
||||
static struct ftrace_hash *
|
||||
alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
|
||||
{
|
||||
struct ftrace_func_entry *entry;
|
||||
struct ftrace_hash *new_hash;
|
||||
struct hlist_node *tp;
|
||||
int size;
|
||||
int ret;
|
||||
int i;
|
||||
|
||||
new_hash = alloc_ftrace_hash(size_bits);
|
||||
if (!new_hash)
|
||||
return NULL;
|
||||
|
||||
/* Empty hash? */
|
||||
if (!hash || !hash->count)
|
||||
return new_hash;
|
||||
|
||||
size = 1 << hash->size_bits;
|
||||
for (i = 0; i < size; i++) {
|
||||
hlist_for_each_entry(entry, tp, &hash->buckets[i], hlist) {
|
||||
ret = add_hash_entry(new_hash, entry->ip);
|
||||
if (ret < 0)
|
||||
goto free_hash;
|
||||
}
|
||||
}
|
||||
|
||||
FTRACE_WARN_ON(new_hash->count != hash->count);
|
||||
|
||||
return new_hash;
|
||||
|
||||
free_hash:
|
||||
free_ftrace_hash(new_hash);
|
||||
return NULL;
|
||||
}
|
||||
|
||||
static int
|
||||
ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src)
|
||||
{
|
||||
struct ftrace_func_entry *entry;
|
||||
struct hlist_node *tp, *tn;
|
||||
struct hlist_head *hhd;
|
||||
struct ftrace_hash *hash = *dst;
|
||||
unsigned long key;
|
||||
int size = src->count;
|
||||
int bits = 0;
|
||||
int i;
|
||||
|
||||
/*
|
||||
* If the new source is empty, just free dst and assign it
|
||||
* the empty_hash.
|
||||
*/
|
||||
if (!src->count) {
|
||||
free_ftrace_hash(*dst);
|
||||
*dst = EMPTY_HASH;
|
||||
return 0;
|
||||
}
|
||||
|
||||
ftrace_hash_clear(hash);
|
||||
|
||||
/*
|
||||
* Make the hash size about 1/2 the # found
|
||||
*/
|
||||
for (size /= 2; size; size >>= 1)
|
||||
bits++;
|
||||
|
||||
/* Don't allocate too much */
|
||||
if (bits > FTRACE_HASH_MAX_BITS)
|
||||
bits = FTRACE_HASH_MAX_BITS;
|
||||
|
||||
/* We can't modify the empty_hash */
|
||||
if (hash == EMPTY_HASH) {
|
||||
/* Create a new hash */
|
||||
*dst = alloc_ftrace_hash(bits);
|
||||
if (!*dst) {
|
||||
*dst = EMPTY_HASH;
|
||||
return -ENOMEM;
|
||||
}
|
||||
hash = *dst;
|
||||
} else {
|
||||
size = 1 << bits;
|
||||
|
||||
/* Use the old hash, but create new buckets */
|
||||
hhd = kzalloc(sizeof(*hhd) * size, GFP_KERNEL);
|
||||
if (!hhd)
|
||||
return -ENOMEM;
|
||||
|
||||
kfree(hash->buckets);
|
||||
hash->buckets = hhd;
|
||||
hash->size_bits = bits;
|
||||
}
|
||||
|
||||
size = 1 << src->size_bits;
|
||||
for (i = 0; i < size; i++) {
|
||||
hhd = &src->buckets[i];
|
||||
hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist) {
|
||||
if (bits > 0)
|
||||
key = hash_long(entry->ip, bits);
|
||||
else
|
||||
key = 0;
|
||||
remove_hash_entry(src, entry);
|
||||
__add_hash_entry(hash, entry);
|
||||
}
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* This is a double for. Do not use 'break' to break out of the loop,
|
||||
* you must use a goto.
|
||||
@ -1443,6 +1601,7 @@ struct ftrace_iterator {
|
||||
struct ftrace_func_probe *probe;
|
||||
struct trace_parser parser;
|
||||
struct ftrace_hash *hash;
|
||||
struct ftrace_ops *ops;
|
||||
int hidx;
|
||||
int idx;
|
||||
unsigned flags;
|
||||
@ -1742,22 +1901,37 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
|
||||
else
|
||||
hash = ops->filter_hash;
|
||||
|
||||
iter->hash = hash;
|
||||
iter->ops = ops;
|
||||
iter->flags = flag;
|
||||
|
||||
if (file->f_mode & FMODE_WRITE) {
|
||||
mutex_lock(&ftrace_lock);
|
||||
iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
|
||||
mutex_unlock(&ftrace_lock);
|
||||
|
||||
if (!iter->hash) {
|
||||
trace_parser_put(&iter->parser);
|
||||
kfree(iter);
|
||||
return -ENOMEM;
|
||||
}
|
||||
}
|
||||
|
||||
mutex_lock(&ftrace_regex_lock);
|
||||
|
||||
if ((file->f_mode & FMODE_WRITE) &&
|
||||
(file->f_flags & O_TRUNC))
|
||||
ftrace_filter_reset(hash);
|
||||
ftrace_filter_reset(iter->hash);
|
||||
|
||||
if (file->f_mode & FMODE_READ) {
|
||||
iter->pg = ftrace_pages_start;
|
||||
iter->flags = flag;
|
||||
|
||||
ret = seq_open(file, &show_ftrace_seq_ops);
|
||||
if (!ret) {
|
||||
struct seq_file *m = file->private_data;
|
||||
m->private = iter;
|
||||
} else {
|
||||
/* Failed */
|
||||
free_ftrace_hash(iter->hash);
|
||||
trace_parser_put(&iter->parser);
|
||||
kfree(iter);
|
||||
}
|
||||
@ -1835,7 +2009,7 @@ enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
|
||||
if (!entry)
|
||||
return 0;
|
||||
|
||||
remove_hash_entry(hash, entry);
|
||||
free_hash_entry(hash, entry);
|
||||
} else {
|
||||
/* Do nothing if it exists */
|
||||
if (entry)
|
||||
@ -2259,19 +2433,13 @@ int unregister_ftrace_command(struct ftrace_func_command *cmd)
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int ftrace_process_regex(char *buff, int len, int enable)
|
||||
static int ftrace_process_regex(struct ftrace_hash *hash,
|
||||
char *buff, int len, int enable)
|
||||
{
|
||||
char *func, *command, *next = buff;
|
||||
struct ftrace_ops *ops = &global_ops;
|
||||
struct ftrace_func_command *p;
|
||||
struct ftrace_hash *hash;
|
||||
int ret;
|
||||
|
||||
if (enable)
|
||||
hash = ops->filter_hash;
|
||||
else
|
||||
hash = ops->notrace_hash;
|
||||
|
||||
func = strsep(&next, ":");
|
||||
|
||||
if (!next) {
|
||||
@ -2328,7 +2496,7 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
|
||||
|
||||
if (read >= 0 && trace_parser_loaded(parser) &&
|
||||
!trace_parser_cont(parser)) {
|
||||
ret = ftrace_process_regex(parser->buffer,
|
||||
ret = ftrace_process_regex(iter->hash, parser->buffer,
|
||||
parser->idx, enable);
|
||||
trace_parser_clear(parser);
|
||||
if (ret)
|
||||
@ -2356,26 +2524,40 @@ ftrace_notrace_write(struct file *file, const char __user *ubuf,
|
||||
return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
|
||||
}
|
||||
|
||||
static void
|
||||
static int
|
||||
ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
|
||||
int reset, int enable)
|
||||
{
|
||||
struct ftrace_hash **orig_hash;
|
||||
struct ftrace_hash *hash;
|
||||
int ret;
|
||||
|
||||
if (unlikely(ftrace_disabled))
|
||||
return;
|
||||
return -ENODEV;
|
||||
|
||||
if (enable)
|
||||
hash = ops->filter_hash;
|
||||
orig_hash = &ops->filter_hash;
|
||||
else
|
||||
hash = ops->notrace_hash;
|
||||
orig_hash = &ops->notrace_hash;
|
||||
|
||||
hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
|
||||
if (!hash)
|
||||
return -ENOMEM;
|
||||
|
||||
mutex_lock(&ftrace_regex_lock);
|
||||
if (reset)
|
||||
ftrace_filter_reset(hash);
|
||||
if (buf)
|
||||
ftrace_match_records(hash, buf, len);
|
||||
|
||||
mutex_lock(&ftrace_lock);
|
||||
ret = ftrace_hash_move(orig_hash, hash);
|
||||
mutex_unlock(&ftrace_lock);
|
||||
|
||||
mutex_unlock(&ftrace_regex_lock);
|
||||
|
||||
free_ftrace_hash(hash);
|
||||
return ret;
|
||||
}
|
||||
|
||||
/**
|
||||
@ -2484,7 +2666,9 @@ ftrace_regex_release(struct inode *inode, struct file *file)
|
||||
{
|
||||
struct seq_file *m = (struct seq_file *)file->private_data;
|
||||
struct ftrace_iterator *iter;
|
||||
struct ftrace_hash **orig_hash;
|
||||
struct trace_parser *parser;
|
||||
int ret;
|
||||
|
||||
mutex_lock(&ftrace_regex_lock);
|
||||
if (file->f_mode & FMODE_READ) {
|
||||
@ -2501,14 +2685,21 @@ ftrace_regex_release(struct inode *inode, struct file *file)
|
||||
}
|
||||
|
||||
trace_parser_put(parser);
|
||||
kfree(iter);
|
||||
|
||||
if (file->f_mode & FMODE_WRITE) {
|
||||
if (iter->flags & FTRACE_ITER_NOTRACE)
|
||||
orig_hash = &iter->ops->notrace_hash;
|
||||
else
|
||||
orig_hash = &iter->ops->filter_hash;
|
||||
|
||||
mutex_lock(&ftrace_lock);
|
||||
if (ftrace_start_up && ftrace_enabled)
|
||||
ret = ftrace_hash_move(orig_hash, iter->hash);
|
||||
if (!ret && ftrace_start_up && ftrace_enabled)
|
||||
ftrace_run_update_code(FTRACE_ENABLE_CALLS);
|
||||
mutex_unlock(&ftrace_lock);
|
||||
}
|
||||
free_ftrace_hash(iter->hash);
|
||||
kfree(iter);
|
||||
|
||||
mutex_unlock(&ftrace_regex_lock);
|
||||
return 0;
|
||||
|
||||
Loading…
Reference in New Issue
Block a user