[PATCH] introduce a default off mode for kmemleak
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From: Jason Baron on 13 Jul 2010 16:40 Hi, Kmemleak can be very useful in figuring out where a kernel leak is suspected, but I've run into issues it which makes it hard to enable by default - reports false positives, oom kills on low memory systems (512 MB). Although these can be addressed, there is still the memory footprint, and runtime overhead, so I think it might make sense to create mode where it is disabled by default, but can still be enabled on the command line via: kmemleak=on. thanks, -Jason Introduce a new DEBUG_KMEMLEAK_DEFAULT_OFF config parameter that allows kmemleak to be disabled by default, but enabled on the command line via: kmemleak=on. Although a reboot is required to turn it on, its still useful to not require a re-compile. Signed-off-by: Jason Baron <jbaron(a)redhat.com> --- lib/Kconfig.debug | 7 +++++++ mm/kmemleak.c | 26 +++++++++++++++++++++++++- 2 files changed, 32 insertions(+), 1 deletions(-) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index e722e9d..95ab402 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -400,6 +400,13 @@ config DEBUG_KMEMLEAK_TEST If unsure, say N. +config DEBUG_KMEMLEAK_DEFAULT_OFF + bool "Default kmemleak to off" + depends on DEBUG_KMEMLEAK + help + Say Y here to disable kmemleak by default. It can then be enabled + on the command line via kmemleak=on. + config DEBUG_PREEMPT bool "Debug preemptible kernel" depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 2c0d032..1006267 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -211,6 +211,11 @@ static signed long jiffies_scan_wait; static int kmemleak_stack_scan = 1; /* protects the memory scanning, parameters and debug/kmemleak file access */ static DEFINE_MUTEX(scan_mutex); +#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF +/* setting kmemleak=on, will set this var, skipping the disable */ +static int kmemleak_skip_disable; +#endif + /* * Early object allocation/freeing logging. Kmemleak is initialized after the @@ -1600,10 +1605,22 @@ static int kmemleak_boot_config(char *str) { if (!str) return -EINVAL; + if (strcmp(str, "off") == 0) +#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF + return -EINVAL; +#else kmemleak_disable(); - else if (strcmp(str, "on") != 0) +#endif + else if (strcmp(str, "on") == 0) +#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF + kmemleak_skip_disable = 1; +#else + return -EINVAL; +#endif + else return -EINVAL; + return 0; } early_param("kmemleak", kmemleak_boot_config); @@ -1616,6 +1633,13 @@ void __init kmemleak_init(void) int i; unsigned long flags; +#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF + if (!kmemleak_skip_disable) { + kmemleak_disable(); + return; + } +#endif + jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE); jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000); -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |