Keep the HPET-based hardlockup detector disabled unless explicitly enabled via a command line argument. If such parameter is not given, the hardlockup detector will fallback to use the perf-based implementation.
The function hardlockup_panic_setup() is updated to return 0 in order to to allow __setup functions of specific hardlockup detectors (in this case hardlockup_detector_hpet_setup()) to inspect the nmi_watchdog boot parameter. Cc: Ashok Raj <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Tony Luck <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Jacob Pan <[email protected]> Cc: "Rafael J. Wysocki" <[email protected]> Cc: Don Zickus <[email protected]> Cc: Nicholas Piggin <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: Alexei Starovoitov <[email protected]> Cc: Babu Moger <[email protected]> Cc: Mathieu Desnoyers <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Philippe Ombredanne <[email protected]> Cc: Colin Ian King <[email protected]> Cc: Byungchul Park <[email protected]> Cc: "Paul E. McKenney" <[email protected]> Cc: "Luis R. Rodriguez" <[email protected]> Cc: Waiman Long <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Randy Dunlap <[email protected]> Cc: Davidlohr Bueso <[email protected]> Cc: Christoffer Dall <[email protected]> Cc: Marc Zyngier <[email protected]> Cc: Kai-Heng Feng <[email protected]> Cc: Konrad Rzeszutek Wilk <[email protected]> Cc: David Rientjes <[email protected]> Cc: "Ravi V. Shankar" <[email protected]> Cc: [email protected] Cc: [email protected] Signed-off-by: Ricardo Neri <[email protected]> -- checkpatch gives the following warning: CHECK: __setup appears un-documented -- check Documentation/admin-guide/kernel-parameters.rst +__setup("nmi_watchdog=", hardlockup_detector_hpet_setup); This is a false-positive as the option nmi_watchdog is already documented. The option is re-evaluated in this file as well. --- Documentation/admin-guide/kernel-parameters.txt | 5 ++++- kernel/watchdog.c | 2 +- kernel/watchdog_hld_hpet.c | 13 +++++++++++++ 3 files changed, 18 insertions(+), 2 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index f2040d4..a8833c7 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2577,7 +2577,7 @@ Format: [state][,regs][,debounce][,die] nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels - Format: [panic,][nopanic,][num] + Format: [panic,][nopanic,][num,][hpet] Valid num: 0 or 1 0 - turn hardlockup detector in nmi_watchdog off 1 - turn hardlockup detector in nmi_watchdog on @@ -2587,6 +2587,9 @@ please see 'nowatchdog'. This is useful when you use a panic=... timeout and need the box quickly up again. + When hpet is specified, the NMI watchdog will be driven + by an HPET timer, if available in the system. Otherwise, + the perf-based implementation will be used. These settings can be accessed at runtime via the nmi_watchdog and hardlockup_panic sysctls. diff --git a/kernel/watchdog.c b/kernel/watchdog.c index b94bbe3..b5ce6e4 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -84,7 +84,7 @@ static int __init hardlockup_panic_setup(char *str) nmi_watchdog_user_enabled = 0; else if (!strncmp(str, "1", 1)) nmi_watchdog_user_enabled = 1; - return 1; + return 0; } __setup("nmi_watchdog=", hardlockup_panic_setup); diff --git a/kernel/watchdog_hld_hpet.c b/kernel/watchdog_hld_hpet.c index ebb820d..12e5937 100644 --- a/kernel/watchdog_hld_hpet.c +++ b/kernel/watchdog_hld_hpet.c @@ -17,6 +17,7 @@ #define pr_fmt(fmt) "NMI hpet watchdog: " fmt static struct hpet_hld_data *hld_data; +static bool hardlockup_use_hpet; /** * get_count() - Get the current count of the HPET timer @@ -488,6 +489,15 @@ static void hardlockup_detector_hpet_stop(void) spin_unlock(&hld_data->lock); } +static int __init hardlockup_detector_hpet_setup(char *str) +{ + if (strstr(str, "hpet")) + hardlockup_use_hpet = true; + + return 0; +} +__setup("nmi_watchdog=", hardlockup_detector_hpet_setup); + /** * hardlockup_detector_hpet_init() - Initialize the hardlockup detector * @@ -502,6 +512,9 @@ static int __init hardlockup_detector_hpet_init(void) { int ret; + if (!hardlockup_use_hpet) + return -EINVAL; + if (!is_hpet_enabled()) return -ENODEV; -- 2.7.4
