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Date: Fri, 16 Oct 2015 11:05:15 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: Dmitry Safonov <0x7f454c46@...il.com>
Cc: mingo@...hat.com, corbet@....net, linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/5] ftrace: introduce ftrace_glob structure
On Tue, 29 Sep 2015 19:46:14 +0300
Dmitry Safonov <0x7f454c46@...il.com> wrote:
> ftrace_match parameters are very related and I reduce the number of local
> variables & parameters with it.
> This is also preparation for module globbing as it would introduce more
> realated variables & parameters.
>
> Signed-off-by: Dmitry Safonov <0x7f454c46@...il.com>
> ---
> kernel/trace/ftrace.c | 84 ++++++++++++++++++++++++++++-----------------------
> 1 file changed, 46 insertions(+), 38 deletions(-)
>
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index a56f028..6ffc1a2 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -3420,27 +3420,35 @@ ftrace_notrace_open(struct inode *inode, struct file *file)
> inode, file);
> }
>
> -static int ftrace_match(char *str, char *regex, int len, int type)
> +/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
> +struct ftrace_glob {
> + char *search;
> + unsigned len;
> + int type;
> +};
> +
> +static int ftrace_match(char *str, struct ftrace_glob *g)
> {
> int matched = 0;
> int slen;
>
> - switch (type) {
> + switch (g->type) {
> case MATCH_FULL:
> - if (strcmp(str, regex) == 0)
> + if (strcmp(str, g->search) == 0)
> matched = 1;
> break;
> case MATCH_FRONT_ONLY:
> - if (strncmp(str, regex, len) == 0)
> + if (strncmp(str, g->search, g->len) == 0)
> matched = 1;
> break;
> case MATCH_MIDDLE_ONLY:
> - if (strstr(str, regex))
> + if (strstr(str, g->search))
> matched = 1;
> break;
> case MATCH_END_ONLY:
> slen = strlen(str);
> - if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
> + if (slen >= g->len && memcmp(str + slen - g->len,
> + g->search, g->len) == 0)
I'm going to modify this a little to:
if (slen >= g->len &&
memcmp(str + slen - g->len, g->search, g->len) == 0)
As it's a bit easier to read.
> matched = 1;
> break;
> }
> @@ -3472,8 +3480,8 @@ enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
> }
>
> static int
> -ftrace_match_record(struct dyn_ftrace *rec, char *mod,
> - char *regex, int len, int type)
> +ftrace_match_record(struct dyn_ftrace *rec,
> + char *mod, struct ftrace_glob *func_g)
> {
> char str[KSYM_SYMBOL_LEN];
> char *modname;
> @@ -3486,28 +3494,27 @@ ftrace_match_record(struct dyn_ftrace *rec, char *mod,
> return 0;
>
> /* blank search means to match all funcs in the mod */
> - if (!len)
> + if (!func_g->len)
> return 1;
> }
>
> - return ftrace_match(str, regex, len, type);
> + return ftrace_match(str, func_g);
> }
>
> static int
> -match_records(struct ftrace_hash *hash, char *buff, int len, char *mod)
> +match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
> {
> - unsigned search_len = 0;
> struct ftrace_page *pg;
> struct dyn_ftrace *rec;
> - int type = MATCH_FULL;
> - char *search = buff;
> + struct ftrace_glob func_g = { .type = MATCH_FULL };
> int found = 0;
> int ret;
> int clear_filter;
>
> if (len) {
> - type = filter_parse_regex(buff, len, &search, &clear_filter);
> - search_len = strlen(search);
> + func_g.type = filter_parse_regex(func, len,
> + &func_g.search, &clear_filter);
I'm reformatting this too.
> + func_g.len = strlen(func_g.search);
> }
>
> mutex_lock(&ftrace_lock);
> @@ -3516,7 +3523,7 @@ match_records(struct ftrace_hash *hash, char *buff, int len, char *mod)
> goto out_unlock;
>
> do_for_each_ftrace_rec(pg, rec) {
> - if (ftrace_match_record(rec, mod, search, search_len, type)) {
> + if (ftrace_match_record(rec, mod, &func_g)) {
> ret = enter_record(hash, rec, clear_filter);
> if (ret < 0) {
> found = ret;
> @@ -3682,14 +3689,15 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
> struct ftrace_hash *hash;
> struct ftrace_page *pg;
> struct dyn_ftrace *rec;
> - int type, len, not;
> + int not;
> unsigned long key;
> int count = 0;
> - char *search;
> int ret;
> + struct ftrace_glob func_g;
I'm moving this up to keep the "upside down x-mas tree" effect.
>
> - type = filter_parse_regex(glob, strlen(glob), &search, ¬);
> - len = strlen(search);
> + func_g.type = filter_parse_regex(glob, strlen(glob),
> + &func_g.search, ¬);
> + func_g.len = strlen(func_g.search);
>
> /* we do not support '!' for function probes */
> if (WARN_ON(not))
> @@ -3716,7 +3724,7 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
>
> do_for_each_ftrace_rec(pg, rec) {
>
> - if (!ftrace_match_record(rec, NULL, search, len, type))
> + if (!ftrace_match_record(rec, NULL, &func_g))
> continue;
>
> entry = kmalloc(sizeof(*entry), GFP_KERNEL);
> @@ -3795,18 +3803,18 @@ __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
> struct ftrace_hash *hash;
> struct hlist_node *tmp;
> char str[KSYM_SYMBOL_LEN];
> - int type = MATCH_FULL;
> - int i, len = 0;
> - char *search;
> - int ret;
> + int i, ret;
> + struct ftrace_glob func_g;
Same here.
>
> if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
> - glob = NULL;
> + func_g.search = NULL;
> else if (glob) {
> int not;
>
> - type = filter_parse_regex(glob, strlen(glob), &search, ¬);
> - len = strlen(search);
> + func_g.type = filter_parse_regex(glob, strlen(glob),
> + &func_g.search, ¬);
And this I'm formatting a bit differently, making the &func_g.search
equal to "glob".
> + func_g.len = strlen(func_g.search);
> + func_g.search = glob;
>
> /* we do not support '!' for function probes */
> if (WARN_ON(not))
> @@ -3835,10 +3843,10 @@ __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
> continue;
>
> /* do this last, since it is the most expensive */
> - if (glob) {
> + if (func_g.search) {
> kallsyms_lookup(entry->ip, NULL, NULL,
> NULL, str);
> - if (!ftrace_match(str, glob, len, type))
> + if (!ftrace_match(str, &func_g))
> continue;
> }
>
> @@ -3867,7 +3875,7 @@ __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
> ftrace_free_entry(entry);
> }
> mutex_unlock(&ftrace_lock);
> -
> +
> out_unlock:
> mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
> free_ftrace_hash(hash);
> @@ -4585,19 +4593,19 @@ ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
> {
> struct dyn_ftrace *rec;
> struct ftrace_page *pg;
> - int search_len;
> int fail = 1;
> - int type, not;
> - char *search;
> + int not;
> bool exists;
> int i;
> + struct ftrace_glob func_g;
Again, I'm moving that up.
>
> /* decode regex */
> - type = filter_parse_regex(buffer, strlen(buffer), &search, ¬);
> + func_g.type = filter_parse_regex(buffer, strlen(buffer),
> + &func_g.search, ¬);
Format change.
OK, patch looks good, but I'm going to do the formatting changes. I'm
not changing the code itself, except for the few places I moved the
declaration of func_g up to keep the declarations in
upside-down-x-mass-tree format.
Thanks,
-- Steve
> if (!not && *idx >= size)
> return -EBUSY;
>
> - search_len = strlen(search);
> + func_g.len = strlen(func_g.search);
>
> mutex_lock(&ftrace_lock);
>
> @@ -4608,7 +4616,7 @@ ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
>
> do_for_each_ftrace_rec(pg, rec) {
>
> - if (ftrace_match_record(rec, NULL, search, search_len, type)) {
> + if (ftrace_match_record(rec, NULL, &func_g)) {
> /* if it is in the array */
> exists = false;
> for (i = 0; i < *idx; i++) {
--
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