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, 21 insertions, 13 deletions

diff --git a/Documentation/kernel-per-CPU-kthreads.txt b/Documentation/kernel-per-CPU-kthreads.txt
index f3cd299..f4cbfe0 100644
--- a/Documentation/kernel-per-CPU-kthreads.txt
+++ b/Documentation/kernel-per-CPU-kthreads.txt
@@ -190,20 +190,24 @@ To reduce its OS jitter, do any of the following:
 		on each CPU, including cs_dbs_timer() and od_dbs_timer().
 		WARNING:  Please check your CPU specifications to
 		make sure that this is safe on your particular system.
-	d.	It is not possible to entirely get rid of OS jitter
-		from vmstat_update() on CONFIG_SMP=y systems, but you
-		can decrease its frequency by writing a large value
-		to /proc/sys/vm/stat_interval.	The default value is
-		HZ, for an interval of one second.  Of course, larger
-		values will make your virtual-memory statistics update
-		more slowly.  Of course, you can also run your workload
-		at a real-time priority, thus preempting vmstat_update(),
+	d.	As of v3.18, Christoph Lameter's on-demand vmstat workers
+		commit prevents OS jitter due to vmstat_update() on
+		CONFIG_SMP=y systems.  Before v3.18, is not possible
+		to entirely get rid of the OS jitter, but you can
+		decrease its frequency by writing a large value to
+		/proc/sys/vm/stat_interval.  The default value is HZ,
+		for an interval of one second.	Of course, larger values
+		will make your virtual-memory statistics update more
+		slowly.  Of course, you can also run your workload at
+		a real-time priority, thus preempting vmstat_update(),
 		but if your workload is CPU-bound, this is a bad idea.
 		However, there is an RFC patch from Christoph Lameter
 		(based on an earlier one from Gilad Ben-Yossef) that
 		reduces or even eliminates vmstat overhead for some
 		workloads at https://lkml.org/lkml/2013/9/4/379.
-	e.	If running on high-end powerpc servers, build with
+	e.	Boot with "elevator=noop" to avoid workqueue use by
+		the block layer.
+	f.	If running on high-end powerpc servers, build with
 		CONFIG_PPC_RTAS_DAEMON=n.  This prevents the RTAS
 		daemon from running on each CPU every second or so.
 		(This will require editing Kconfig files and will defeat
@@ -211,12 +215,12 @@ To reduce its OS jitter, do any of the following:
 		due to the rtas_event_scan() function.
 		WARNING:  Please check your CPU specifications to
 		make sure that this is safe on your particular system.
-	f.	If running on Cell Processor, build your kernel with
+	g.	If running on Cell Processor, build your kernel with
 		CBE_CPUFREQ_SPU_GOVERNOR=n to avoid OS jitter from
 		spu_gov_work().
 		WARNING:  Please check your CPU specifications to
 		make sure that this is safe on your particular system.
-	g.	If running on PowerMAC, build your kernel with
+	h.	If running on PowerMAC, build your kernel with
 		CONFIG_PMAC_RACKMETER=n to disable the CPU-meter,
 		avoiding OS jitter from rackmeter_do_timer().
 
@@ -258,8 +262,12 @@ Purpose: Detect software lockups on each CPU.
 To reduce its OS jitter, do at least one of the following:
 1.	Build with CONFIG_LOCKUP_DETECTOR=n, which will prevent these
 	kthreads from being created in the first place.
-2.	Echo a zero to /proc/sys/kernel/watchdog to disable the
+2.	Boot with "nosoftlockup=0", which will also prevent these kthreads
+	from being created.  Other related watchdog and softlockup boot
+	parameters may be found in Documentation/kernel-parameters.txt
+	and Documentation/watchdog/watchdog-parameters.txt.
+3.	Echo a zero to /proc/sys/kernel/watchdog to disable the
 	watchdog timer.
-3.	Echo a large number of /proc/sys/kernel/watchdog_thresh in
+4.	Echo a large number of /proc/sys/kernel/watchdog_thresh in
 	order to reduce the frequency of OS jitter due to the watchdog
 	timer down to a level that is acceptable for your workload.