From b2b712bedf699a8c6f27cfc4a5ce6ec8c09ae1af Mon Sep 17 00:00:00 2001 From: Jim Cromie Date: Sun, 19 Jul 2020 17:10:46 -0600 Subject: [PATCH] dyndbg: fix overcounting of ram used by dyndbg 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 Acked-by: Signed-off-by: Jim Cromie Link: https://lore.kernel.org/r/20200719231058.1586423-7-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman --- 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 66c0bdf06ce78..9b24455079889 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -1017,7 +1017,6 @@ 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) { if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) { @@ -1033,9 +1032,6 @@ 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); @@ -1052,9 +1048,9 @@ 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') { -- 2.39.5