Merge Linus master into drm-next

The merge is clean, but the arm build fails afterwards,
due to API changes in the regulator tree.

I've included the patch into the merge to fix the build.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 74 insertions, 9 deletions

diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index 83ab256..c831001 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -77,12 +77,14 @@ show up in /proc/sys/kernel:
 - shmmax                      [ sysv ipc ]
 - shmmni
 - softlockup_all_cpu_backtrace
+- soft_watchdog
 - stop-a                      [ SPARC only ]
 - sysrq                       ==> Documentation/sysrq.txt
 - sysctl_writes_strict
 - tainted
 - threads-max
 - unknown_nmi_panic
+- watchdog
 - watchdog_thresh
 - version
 
@@ -417,16 +419,23 @@ successful IPC object allocation.
 
 nmi_watchdog:
 
-Enables/Disables the NMI watchdog on x86 systems. When the value is
-non-zero the NMI watchdog is enabled and will continuously test all
-online cpus to determine whether or not they are still functioning
-properly. Currently, passing "nmi_watchdog=" parameter at boot time is
-required for this function to work.
+This parameter can be used to control the NMI watchdog
+(i.e. the hard lockup detector) on x86 systems.
 
-If LAPIC NMI watchdog method is in use (nmi_watchdog=2 kernel
-parameter), the NMI watchdog shares registers with oprofile. By
-disabling the NMI watchdog, oprofile may have more registers to
-utilize.
+   0 - disable the hard lockup detector
+   1 - enable the hard lockup detector
+
+The hard lockup detector monitors each CPU for its ability to respond to
+timer interrupts. The mechanism utilizes CPU performance counter registers
+that are programmed to generate Non-Maskable Interrupts (NMIs) periodically
+while a CPU is busy. Hence, the alternative name 'NMI watchdog'.
+
+The NMI watchdog is disabled by default if the kernel is running as a guest
+in a KVM virtual machine. This default can be overridden by adding
+
+   nmi_watchdog=1
+
+to the guest kernel command line (see Documentation/kernel-parameters.txt).
 
 ==============================================================
 
@@ -816,6 +825,22 @@ NMI.
 
 ==============================================================
 
+soft_watchdog
+
+This parameter can be used to control the soft lockup detector.
+
+   0 - disable the soft lockup detector
+   1 - enable the soft lockup detector
+
+The soft lockup detector monitors CPUs for threads that are hogging the CPUs
+without rescheduling voluntarily, and thus prevent the 'watchdog/N' threads
+from running. The mechanism depends on the CPUs ability to respond to timer
+interrupts which are needed for the 'watchdog/N' threads to be woken up by
+the watchdog timer function, otherwise the NMI watchdog - if enabled - can
+detect a hard lockup condition.
+
+==============================================================
+
 tainted:
 
 Non-zero if the kernel has been tainted.  Numeric values, which
@@ -847,6 +872,27 @@ can be ORed together:
 
 ==============================================================
 
+threads-max
+
+This value controls the maximum number of threads that can be created
+using fork().
+
+During initialization the kernel sets this value such that even if the
+maximum number of threads is created, the thread structures occupy only
+a part (1/8th) of the available RAM pages.
+
+The minimum value that can be written to threads-max is 20.
+The maximum value that can be written to threads-max is given by the
+constant FUTEX_TID_MASK (0x3fffffff).
+If a value outside of this range is written to threads-max an error
+EINVAL occurs.
+
+The value written is checked against the available RAM pages. If the
+thread structures would occupy too much (more than 1/8th) of the
+available RAM pages threads-max is reduced accordingly.
+
+==============================================================
+
 unknown_nmi_panic:
 
 The value in this file affects behavior of handling NMI. When the
@@ -858,6 +904,25 @@ example.  If a system hangs up, try pressing the NMI switch.
 
 ==============================================================
 
+watchdog:
+
+This parameter can be used to disable or enable the soft lockup detector
+_and_ the NMI watchdog (i.e. the hard lockup detector) at the same time.
+
+   0 - disable both lockup detectors
+   1 - enable both lockup detectors
+
+The soft lockup detector and the NMI watchdog can also be disabled or
+enabled individually, using the soft_watchdog and nmi_watchdog parameters.
+If the watchdog parameter is read, for example by executing
+
+   cat /proc/sys/kernel/watchdog
+
+the output of this command (0 or 1) shows the logical OR of soft_watchdog
+and nmi_watchdog.
+
+==============================================================
+
 watchdog_thresh:
 
 This value can be used to control the frequency of hrtimer and NMI