From eee8ded131f15e0f5b1897c9c4a7687fabd28822 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Tue, 4 Apr 2017 21:31:28 -0400 Subject: ftrace: Have the function probes call their own function 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) --- kernel/trace/ftrace.c | 225 ++++++++++++++++++++++---------------------------- 1 file changed, 98 insertions(+), 127 deletions(-) (limited to 'kernel/trace/ftrace.c') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index cf6b7263199a..493c7ff7e860 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -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; - - key = hash_long(ip, FTRACE_HASH_BITS); + struct ftrace_probe_ops *probe_ops; - 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); - - for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) { - struct hlist_head *hhd = &ftrace_func_hash[i]; + INIT_HLIST_HEAD(&hhd); - hlist_for_each_entry_safe(entry, tmp, hhd, node) { - - /* break up if statements for readability */ - if (entry->ops != ops) - continue; + size = 1 << hash->size_bits; + for (i = 0; i < size; i++) { + hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) { - /* 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); -- cgit v1.2.3