Merge branch 'perf/nmi' into perf/core

Conflicts:
	kernel/Makefile

Merge reason: Add the now complete topic, fix the conflict.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 20 insertions, 15 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index e722e9d62221..e2cd7fbf31c0 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -152,28 +152,33 @@ config DEBUG_SHIRQ
           Drivers ought to be able to handle interrupts coming in at those
           points; some don't and need to be caught.
 
-config DETECT_SOFTLOCKUP
-        bool "Detect Soft Lockups"
+config LOCKUP_DETECTOR
+        bool "Detect Hard and Soft Lockups"
         depends on DEBUG_KERNEL && !S390
-        default y
         help
-          Say Y here to enable the kernel to detect "soft lockups",
-          which are bugs that cause the kernel to loop in kernel
+          Say Y here to enable the kernel to act as a watchdog to detect
+          hard and soft lockups.
+
+          Softlockups are bugs that cause the kernel to loop in kernel
           mode for more than 60 seconds, without giving other tasks a
-          chance to run.
+          chance to run.  The current stack trace is displayed upon
+          detection and the system will stay locked up.
 
-          When a soft-lockup is detected, the kernel will print the
-          current stack trace (which you should report), but the
-          system will stay locked up. This feature has negligible
-          overhead.
+          Hardlockups are bugs that cause the CPU to loop in kernel mode
+          for more than 60 seconds, without letting other interrupts have a
+          chance to run.  The current stack trace is displayed upon detection
+          and the system will stay locked up.
+
+          The overhead should be minimal.  A periodic hrtimer runs to
+          generate interrupts and kick the watchdog task every 10-12 seconds.
+          An NMI is generated every 60 seconds or so to check for hardlockups.
 
-          (Note that "hard lockups" are separate type of bugs that
-           can be detected via the NMI-watchdog, on platforms that
-           support it.)
+config HARDLOCKUP_DETECTOR
+        def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI
 
 config BOOTPARAM_SOFTLOCKUP_PANIC
         bool "Panic (Reboot) On Soft Lockups"
-        depends on DETECT_SOFTLOCKUP
+        depends on LOCKUP_DETECTOR
         help
           Say Y here to enable the kernel to panic on "soft lockups",
           which are bugs that cause the kernel to loop in kernel
@@ -190,7 +195,7 @@ config BOOTPARAM_SOFTLOCKUP_PANIC
 
 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
         int
-        depends on DETECT_SOFTLOCKUP
+        depends on LOCKUP_DETECTOR
         range 0 1
         default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
         default 1 if BOOTPARAM_SOFTLOCKUP_PANIC