From: Jim Cromie <jim.cromie@gmail.com>
To: jbaron@akamai.com, linux-kernel@vger.kernel.org,
akpm@linuxfoundation.org
Cc: gregkh@linuxfoundation.org, linux@rasmusvillemoes.dk,
Jim Cromie <jim.cromie@gmail.com>
Subject: [PATCH v4 05/16] dyndbg: fix overcounting of ram used by dyndbg
Date: Mon, 9 Dec 2019 19:27:31 -0700 [thread overview]
Message-ID: <20191210022742.822686-6-jim.cromie@gmail.com> (raw)
In-Reply-To: <20191210022742.822686-1-jim.cromie@gmail.com>
during dyndbg init, verbose logging prints its ram overhead. It
counted strlens of struct _ddebug's 4 string members, in all callsite
entries, which would be approximately correct if each had been
mallocd. But they are pointers into shared .rodata; for example, all
10 kobject callsites have identical filename, module values.
Its best not to count that memory at all, since we cannot know they
were linked in because of CONFIG_DYNAMIC_DEBUG=y, and we want to
report a number that reflects what ram is saved by deconfiguring it.
Also fix wording and size under-reporting of the __dyndbg section.
Heres my overhead, on a virtme-run VM on a fedora-31 laptop:
dynamic_debug:dynamic_debug_init: 260 modules, 2479 entries \
and 10400 bytes in ddebug tables, 138824 bytes in __dyndbg section
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
lib/dynamic_debug.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 0a4588fe342e..b5fb0aa0fbc3 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1008,7 +1008,6 @@ static int __init dynamic_debug_init(void)
char *cmdline;
int ret = 0;
int n = 0, entries = 0, modct = 0;
- int verbose_bytes = 0;
if (__start___dyndbg == __stop___dyndbg) {
pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
@@ -1019,9 +1018,6 @@ static int __init dynamic_debug_init(void)
iter_start = iter;
for (; iter < __stop___dyndbg; iter++) {
entries++;
- verbose_bytes += strlen(iter->modname) + strlen(iter->function)
- + strlen(iter->filename) + strlen(iter->format);
-
if (strcmp(modname, iter->modname)) {
modct++;
ret = ddebug_add_module(iter_start, n, modname);
@@ -1038,9 +1034,9 @@ static int __init dynamic_debug_init(void)
goto out_err;
ddebug_init_success = 1;
- vpr_info("%d modules, %d entries and %d bytes in ddebug tables, %d bytes in (readonly) verbose section\n",
+ vpr_info("%d modules, %d entries and %d bytes in ddebug tables, %d bytes in __dyndbg section\n",
modct, entries, (int)(modct * sizeof(struct ddebug_table)),
- verbose_bytes + (int)(__stop___dyndbg - __start___dyndbg));
+ (int)(entries * sizeof(struct _ddebug)));
/* apply ddebug_query boot param, dont unload tables on err */
if (ddebug_setup_string[0] != '\0') {
--
2.23.0
next prev parent reply other threads:[~2019-12-10 2:28 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-10 2:27 [PATCH v4 00/16] dynamic-debug cleanups, 2 new features Jim Cromie
2019-12-10 2:27 ` [PATCH v4 01/16] dyndbg-docs: eschew file /full/path query in docs Jim Cromie
2019-12-10 2:27 ` [PATCH v4 02/16] dyndbg: drop obsolete comment on ddebug_proc_open Jim Cromie
2019-12-10 2:27 ` [PATCH v4 03/16] dyndbg: raise verbosity needed to enable ddebug_proc_* logging Jim Cromie
2019-12-10 2:27 ` [PATCH v4 04/16] dyndbg: rename __verbose section to __dyndbg Jim Cromie
2019-12-10 2:27 ` Jim Cromie [this message]
2019-12-10 2:27 ` [PATCH v4 06/16] dyndbg: fix a BUG_ON in ddebug_describe_flags Jim Cromie
2019-12-10 19:58 ` Jason Baron
2019-12-13 1:35 ` jim.cromie
2019-12-10 2:27 ` [PATCH v4 07/16] dyndbg: refactor parse_linerange out of ddebug_parse_query Jim Cromie
2019-12-10 2:27 ` [PATCH v4 08/16] dyndbg: accept 'file foo.c:func1' and 'file foo.c:10-100' Jim Cromie
2019-12-10 2:27 ` [PATCH v4 09/16] dyndbg: refactor ddebug_read_flags out of ddebug_parse_flags Jim Cromie
2019-12-10 2:27 ` [PATCH v4 10/16] dyndbg: combine flags & mask into a struct, use that Jim Cromie
2019-12-10 2:27 ` [PATCH v4 11/16] dyndbg: add filter parameter to ddebug_parse_flags Jim Cromie
2019-12-10 2:27 ` [PATCH v4 12/16] dyndbg: extend ddebug_parse_flags to accept optional filter-flags Jim Cromie
2019-12-10 2:27 ` [PATCH v4 13/16] dyndbg: prefer declarative init in caller, to memset in callee Jim Cromie
2019-12-10 2:27 ` [PATCH v4 14/16] dyndbg: add user-flag, negating-flags, and filtering on flags Jim Cromie
2019-12-10 2:27 ` [PATCH v4 15/16] dyndbg: allow negating flag-chars in modflags Jim Cromie
2019-12-10 2:27 ` [PATCH v4 16/16] dyndbg: make ddebug_tables list LIFO for add/remove_module Jim Cromie
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