linux-kernel - [PATCH v2 04/24] dyndbg: refine debug verbosity; 1 is basic, 2 more chatty

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Date:   Sat, 13 Jun 2020 09:57:18 -0600
From:   Jim Cromie <jim.cromie@...il.com>
To:     jbaron@...mai.com, linux-kernel@...r.kernel.org,
        akpm@...uxfoundation.org, gregkh@...uxfoundation.org
Cc:     linux@...musvillemoes.dk, Jim Cromie <jim.cromie@...il.com>
Subject: [PATCH v2 04/24] dyndbg: refine debug verbosity; 1 is basic, 2 more chatty

The verbose/debug logging done for `cat $MNT/dynamic_debug/control` is
voluminous (2 per control file entry + 2 per PAGE).  Moreover, it just
prints pointer and sequence, which is not useful to a dyndbg user.
So just drop them.

Also require verbose>=2 for several other debug printks that are a bit
too chatty for typical needs;

ddebug_change() prints changes, once per modified callsite.  Since
queries like "+p" will enable ~2300 callsites in a typical laptop, a
user probably doesnt need to see them often.  ddebug_exec_queries()
still summarizes with verbose=1.

ddebug_(add|remove)_module() also print 1 line per action on a module,
not needed by typical modprobe user.

This leaves verbose=1 better focussed on the >control parsing process.
---
 lib/dynamic_debug.c | 21 ++++++++-------------
 1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 2989a590ce9a..c97872cffc8e 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -105,12 +105,15 @@ static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,
 	return buf;
 }
 
-#define vpr_info(fmt, ...)					\
+#define vnpr_info(lvl, fmt, ...)				\
 do {								\
-	if (verbose)						\
+	if (verbose >= lvl)					\
 		pr_info(fmt, ##__VA_ARGS__);			\
 } while (0)
 
+#define vpr_info(fmt, ...)	vnpr_info(1, fmt, ##__VA_ARGS__)
+#define v2pr_info(fmt, ...)	vnpr_info(2, fmt, ##__VA_ARGS__)
+
 static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
 {
 	/* trim any trailing newlines */
@@ -198,7 +201,7 @@ static int ddebug_change(const struct ddebug_query *query,
 				static_branch_enable(&dp->key.dd_key_true);
 #endif
 			dp->flags = newflags;
-			vpr_info("changed %s:%d [%s]%s =%s\n",
+			v2pr_info("changed %s:%d [%s]%s =%s\n",
 				 trim_prefix(dp->filename), dp->lineno,
 				 dt->mod_name, dp->function,
 				 ddebug_describe_flags(dp, flagbuf,
@@ -771,8 +774,6 @@ static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
 	struct _ddebug *dp;
 	int n = *pos;
 
-	vpr_info("called m=%p *pos=%lld\n", m, (unsigned long long)*pos);
-
 	mutex_lock(&ddebug_lock);
 
 	if (!n)
@@ -795,9 +796,6 @@ static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
 	struct ddebug_iter *iter = m->private;
 	struct _ddebug *dp;
 
-	vpr_info("called m=%p p=%p *pos=%lld\n",
-		 m, p, (unsigned long long)*pos);
-
 	if (p == SEQ_START_TOKEN)
 		dp = ddebug_iter_first(iter);
 	else
@@ -818,8 +816,6 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
 	struct _ddebug *dp = p;
 	char flagsbuf[10];
 
-	vpr_info("called m=%p p=%p\n", m, p);
-
 	if (p == SEQ_START_TOKEN) {
 		seq_puts(m,
 			 "# filename:lineno [module]function flags format\n");
@@ -842,7 +838,6 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
  */
 static void ddebug_proc_stop(struct seq_file *m, void *p)
 {
-	vpr_info("called m=%p p=%p\n", m, p);
 	mutex_unlock(&ddebug_lock);
 }
 
@@ -905,7 +900,7 @@ int ddebug_add_module(struct _ddebug *tab, unsigned int n,
 	list_add_tail(&dt->link, &ddebug_tables);
 	mutex_unlock(&ddebug_lock);
 
-	vpr_info("%u debug prints in module %s\n", n, dt->mod_name);
+	v2pr_info("%u debug prints in module %s\n", n, dt->mod_name);
 	return 0;
 }
 
@@ -964,7 +959,7 @@ int ddebug_remove_module(const char *mod_name)
 	struct ddebug_table *dt, *nextdt;
 	int ret = -ENOENT;
 
-	vpr_info("removing module \"%s\"\n", mod_name);
+	v2pr_info("removing module \"%s\"\n", mod_name);
 
 	mutex_lock(&ddebug_lock);
 	list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
-- 
2.26.2