Documentation/ABI/testing/sysfs-fs-f2fs

@@ -41,8 +41,7 @@ Description:	This parameter controls the number of prefree segments to be
 What:		/sys/fs/f2fs/<disk>/main_blkaddr
 Date:		November 2019
 Contact:	"Ramon Pantin" <pantin@google.com>
-Description:
-		 Shows first block address of MAIN area.
+Description:	Shows first block address of MAIN area.
 
 What:		/sys/fs/f2fs/<disk>/ipu_policy
 Date:		November 2013
@@ -493,3 +492,23 @@ Contact:	"Chao Yu" <yuchao0@huawei.com>
 Description:	When ATGC is on, it controls age threshold to bypass GCing young
 		candidates whose age is not beyond the threshold, by default it was
 		initialized as 604800 seconds (equals to 7 days).
+
+What:		/sys/fs/f2fs/<disk>/gc_reclaimed_segments
+Date:		July 2021
+Contact:	"Daeho Jeong" <daehojeong@google.com>
+Description:	Show how many segments have been reclaimed by GC during a specific
+		GC mode (0: GC normal, 1: GC idle CB, 2: GC idle greedy,
+		3: GC idle AT, 4: GC urgent high, 5: GC urgent low)
+		You can re-initialize this value to "0".
+
+What:		/sys/fs/f2fs/<disk>/gc_segment_mode
+Date:		July 2021
+Contact:	"Daeho Jeong" <daehojeong@google.com>
+Description:	You can control for which gc mode the "gc_reclaimed_segments" node shows.
+		Refer to the description of the modes in "gc_reclaimed_segments".
+
+What:		/sys/fs/f2fs/<disk>/seq_file_ra_mul
+Date:		July 2021
+Contact:	"Daeho Jeong" <daehojeong@google.com>
+Description:	You can	control the multiplier value of	bdi device readahead window size
+		between 2 (default) and 256 for POSIX_FADV_SEQUENTIAL advise option.

Documentation/ABI/testing/sysfs-kernel-dmabuf-buffers

+What:		/sys/kernel/dmabuf/buffers
+Date:		May 2021
+KernelVersion:	v5.13
+Contact:	Hridya Valsaraju <hridya@google.com>
+Description:	The /sys/kernel/dmabuf/buffers directory contains a
+		snapshot of the internal state of every DMA-BUF.
+		/sys/kernel/dmabuf/buffers/<inode_number> will contain the
+		statistics for the DMA-BUF with the unique inode number
+		<inode_number>
+Users:		kernel memory tuning/debugging tools
+
+What:		/sys/kernel/dmabuf/buffers/<inode_number>/exporter_name
+Date:		May 2021
+KernelVersion:	v5.13
+Contact:	Hridya Valsaraju <hridya@google.com>
+Description:	This file is read-only and contains the name of the exporter of
+		the DMA-BUF.
+
+What:		/sys/kernel/dmabuf/buffers/<inode_number>/size
+Date:		May 2021
+KernelVersion:	v5.13
+Contact:	Hridya Valsaraju <hridya@google.com>
+Description:	This file is read-only and specifies the size of the DMA-BUF in
+		bytes.

Documentation/ABI/testing/sysfs-kernel-iommu_groups

@@ -42,8 +42,12 @@ Description:	/sys/kernel/iommu_groups/<grp_id>/type shows the type of default
 		========  ======================================================
 		DMA       All the DMA transactions from the device in this group
 		          are translated by the iommu.
+		DMA-FQ    As above, but using batched invalidation to lazily
+		          remove translations after use. This may offer reduced
+			  overhead at the cost of reduced memory protection.
 		identity  All the DMA transactions from the device in this group
-		          are not translated by the iommu.
+		          are not translated by the iommu. Maximum performance
+			  but zero protection.
 		auto      Change to the type the device was booted with.
 		========  ======================================================
 

Documentation/ABI/testing/sysfs-kernel-mm-numa

+What:		/sys/kernel/mm/numa/
+Date:		June 2021
+Contact:	Linux memory management mailing list <linux-mm@kvack.org>
+Description:	Interface for NUMA
+
+What:		/sys/kernel/mm/numa/demotion_enabled
+Date:		June 2021
+Contact:	Linux memory management mailing list <linux-mm@kvack.org>
+Description:	Enable/disable demoting pages during reclaim
+
+		Page migration during reclaim is intended for systems
+		with tiered memory configurations.  These systems have
+		multiple types of memory with varied performance
+		characteristics instead of plain NUMA systems where
+		the same kind of memory is found at varied distances.
+		Allowing page migration during reclaim enables these
+		systems to migrate pages from fast tiers to slow tiers
+		when the fast tier is under pressure.  This migration
+		is performed before swap.  It may move data to a NUMA
+		node that does not fall into the cpuset of the
+		allocating process which might be construed to violate
+		the guarantees of cpusets.  This should not be enabled
+		on systems which need strict cpuset location
+		guarantees.

Documentation/ABI/testing/sysfs-platform-dell-smbios

 What:		/sys/devices/platform/<platform>/tokens/*
 Date:		November 2017
 KernelVersion:	4.15
-Contact:	"Mario Limonciello" <mario.limonciello@dell.com>
+Contact:	Dell.Client.Kernel@dell.com
 Description:
 		A read-only description of Dell platform tokens
 		available on the machine.

Documentation/ABI/testing/sysfs-platform-dptf

@@ -111,3 +111,43 @@ Contact:	linux-acpi@vger.kernel.org
 Description:
 		(RW) The PCH FIVR (Fully Integrated Voltage Regulator) switching frequency in MHz,
 		when FIVR clock is 38.4MHz.
+
+What:		/sys/bus/platform/devices/INTC1045:00/pch_fivr_switch_frequency/fivr_switching_freq_mhz
+Date:		September, 2021
+KernelVersion:	v5.15
+Contact:	linux-acpi@vger.kernel.org
+Description:
+		(RO) Get the FIVR switching control frequency in MHz.
+
+What:		/sys/bus/platform/devices/INTC1045:00/pch_fivr_switch_frequency/fivr_switching_fault_status
+Date:		September, 2021
+KernelVersion:	v5.15
+Contact:	linux-acpi@vger.kernel.org
+Description:
+		(RO) Read the FIVR switching frequency control fault status.
+
+What:		/sys/bus/platform/devices/INTC1045:00/pch_fivr_switch_frequency/ssc_clock_info
+Date:		September, 2021
+KernelVersion:	v5.15
+Contact:	linux-acpi@vger.kernel.org
+Description:
+		(RO) Presents SSC (spread spectrum clock) information for EMI
+		(Electro magnetic interference) control. This is a bit mask.
+		Bits	Description
+		[7:0]	Sets clock spectrum spread percentage:
+			0x00=0.2% , 0x3F=10%
+			1 LSB = 0.1% increase in spread (for
+			settings 0x01 thru 0x1C)
+			1 LSB = 0.2% increase in spread (for
+			settings 0x1E thru 0x3F)
+		[8]	When set to 1, enables spread
+			spectrum clock
+		[9]	0: Triangle mode. FFC frequency
+			walks around the Fcenter in a linear
+			fashion
+			1: Random walk mode. FFC frequency
+			changes randomly within the SSC
+			(Spread spectrum clock) range
+		[10]	0: No white noise. 1: Add white noise
+			to spread waveform
+		[11]	When 1, future writes are ignored.

Documentation/ABI/testing/sysfs-platform-intel-wmi-thunderbolt

 What:		/sys/devices/platform/<platform>/force_power
 Date:		September 2017
 KernelVersion:	4.15
-Contact:	"Mario Limonciello" <mario.limonciello@dell.com>
+Contact:	"Mario Limonciello" <mario.limonciello@outlook.com>
 Description:
 		Modify the platform force power state, influencing
 		Thunderbolt controllers to turn on or off when no

Documentation/ABI/testing/sysfs-platform_profile

@@ -26,3 +26,10 @@ Contact:	Hans de Goede <hdegoede@redhat.com>
 Description:	Reading this file gives the current selected profile for this
 		device. Writing this file with one of the strings from
 		platform_profile_choices changes the profile to the new value.
+
+		This file can be monitored for changes by polling for POLLPRI,
+		POLLPRI will be signalled on any changes, independent of those
+		changes coming from a userspace write; or coming from another
+		source such as e.g. a hotkey triggered profile change handled
+		either directly by the embedded-controller or fully handled
+		inside the kernel.

Documentation/ABI/testing/sysfs-power

@@ -295,7 +295,7 @@ Description:
 
 What:		/sys/power/resume_offset
 Date:		April 2018
-Contact:	Mario Limonciello <mario.limonciello@dell.com>
+Contact:	Mario Limonciello <mario.limonciello@outlook.com>
 Description:
 		This file is used for telling the kernel an offset into a disk
 		to use when hibernating the system such as with a swap file.

Documentation/PCI/endpoint/pci-endpoint-cfs.rst

@@ -43,6 +43,7 @@ entries corresponding to EPF driver will be created by the EPF core.
 		.. <EPF Driver1>/
 			... <EPF Device 11>/
 			... <EPF Device 21>/
+			... <EPF Device 31>/
 		.. <EPF Driver2>/
 			... <EPF Device 12>/
 			... <EPF Device 22>/
@@ -68,6 +69,7 @@ created)
 				... subsys_vendor_id
 				... subsys_id
 				... interrupt_pin
+			        ... <Symlink EPF Device 31>/
                                 ... primary/
 			                ... <Symlink EPC Device1>/
                                 ... secondary/
@@ -79,6 +81,13 @@ interface should be added in 'primary' directory and symlink of endpoint
 controller connected to secondary interface should be added in 'secondary'
 directory.
 
+The <EPF Device> directory can have a list of symbolic links
+(<Symlink EPF Device 31>) to other <EPF Device>. These symbolic links should
+be created by the user to represent the virtual functions that are bound to
+the physical function. In the above directory structure <EPF Device 11> is a
+physical function and <EPF Device 31> is a virtual function. An EPF device once
+it's linked to another EPF device, cannot be linked to a EPC device.
+
 EPC Device
 ==========
 
@@ -98,7 +107,8 @@ entries corresponding to EPC device will be created by the EPC core.
 
 The <EPC Device> directory will have a list of symbolic links to
 <EPF Device>. These symbolic links should be created by the user to
-represent the functions present in the endpoint device.
+represent the functions present in the endpoint device. Only <EPF Device>
+that represents a physical function can be linked to a EPC device.
 
 The <EPC Device> directory will also have a *start* field. Once
 "1" is written to this field, the endpoint device will be ready to

Documentation/PCI/pci.rst

@@ -103,6 +103,7 @@ need pass only as many optional fields as necessary:
   - subvendor and subdevice fields default to PCI_ANY_ID (FFFFFFFF)
   - class and classmask fields default to 0
   - driver_data defaults to 0UL.
+  - override_only field defaults to 0.
 
 Note that driver_data must match the value used by any of the pci_device_id
 entries defined in the driver. This makes the driver_data field mandatory

Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst

@@ -112,6 +112,35 @@ on PowerPC.
 The ``smp_mb__after_unlock_lock()`` invocations prevent this
 ``WARN_ON()`` from triggering.
 
++-----------------------------------------------------------------------+
+| **Quick Quiz**:                                                       |
++-----------------------------------------------------------------------+
+| But the chain of rcu_node-structure lock acquisitions guarantees      |
+| that new readers will see all of the updater's pre-grace-period       |
+| accesses and also guarantees that the updater's post-grace-period     |
+| accesses will see all of the old reader's accesses.  So why do we     |
+| need all of those calls to smp_mb__after_unlock_lock()?               |
++-----------------------------------------------------------------------+
+| **Answer**:                                                           |
++-----------------------------------------------------------------------+
+| Because we must provide ordering for RCU's polling grace-period       |
+| primitives, for example, get_state_synchronize_rcu() and              |
+| poll_state_synchronize_rcu().  Consider this code::                   |
+|                                                                       |
+|  CPU 0                                     CPU 1                      |
+|  ----                                      ----                       |
+|  WRITE_ONCE(X, 1)                          WRITE_ONCE(Y, 1)           |
+|  g = get_state_synchronize_rcu()           smp_mb()                   |
+|  while (!poll_state_synchronize_rcu(g))    r1 = READ_ONCE(X)          |
+|          continue;                                                    |
+|  r0 = READ_ONCE(Y)                                                    |
+|                                                                       |
+| RCU guarantees that the outcome r0 == 0 && r1 == 0 will not           |
+| happen, even if CPU 1 is in an RCU extended quiescent state           |
+| (idle or offline) and thus won't interact directly with the RCU       |
+| core processing at all.                                               |
++-----------------------------------------------------------------------+
+
 This approach must be extended to include idle CPUs, which need
 RCU's grace-period memory ordering guarantee to extend to any
 RCU read-side critical sections preceding and following the current

Documentation/RCU/Design/Requirements/Requirements.rst

@@ -362,9 +362,8 @@ do_something_gp() uses rcu_dereference() to fetch from ``gp``:
       12 }
 
 The rcu_dereference() uses volatile casts and (for DEC Alpha) memory
-barriers in the Linux kernel. Should a `high-quality implementation of
-C11 ``memory_order_consume``
-[PDF] <http://www.rdrop.com/users/paulmck/RCU/consume.2015.07.13a.pdf>`__
+barriers in the Linux kernel. Should a |high-quality implementation of
+C11 memory_order_consume [PDF]|_
 ever appear, then rcu_dereference() could be implemented as a
 ``memory_order_consume`` load. Regardless of the exact implementation, a
 pointer fetched by rcu_dereference() may not be used outside of the
@@ -374,6 +373,9 @@ element has been passed from RCU to some other synchronization
 mechanism, most commonly locking or `reference
 counting <https://www.kernel.org/doc/Documentation/RCU/rcuref.txt>`__.
 
+.. |high-quality implementation of C11 memory_order_consume [PDF]| replace:: high-quality implementation of C11 ``memory_order_consume`` [PDF]
+.. _high-quality implementation of C11 memory_order_consume [PDF]: http://www.rdrop.com/users/paulmck/RCU/consume.2015.07.13a.pdf
+
 In short, updaters use rcu_assign_pointer() and readers use
 rcu_dereference(), and these two RCU API elements work together to
 ensure that readers have a consistent view of newly added data elements.

Documentation/RCU/checklist.rst

@@ -37,7 +37,7 @@ over a rather long period of time, but improvements are always welcome!
 
 1.	Does the update code have proper mutual exclusion?
 
-	RCU does allow -readers- to run (almost) naked, but -writers- must
+	RCU does allow *readers* to run (almost) naked, but *writers* must
 	still use some sort of mutual exclusion, such as:
 
 	a.	locking,
@@ -73,7 +73,7 @@ over a rather long period of time, but improvements are always welcome!
 	critical section is every bit as bad as letting them leak out
 	from under a lock.  Unless, of course, you have arranged some
 	other means of protection, such as a lock or a reference count
-	-before- letting them out of the RCU read-side critical section.
+	*before* letting them out of the RCU read-side critical section.
 
 3.	Does the update code tolerate concurrent accesses?
 
@@ -101,7 +101,7 @@ over a rather long period of time, but improvements are always welcome!
 	c.	Make updates appear atomic to readers.	For example,
 		pointer updates to properly aligned fields will
 		appear atomic, as will individual atomic primitives.
-		Sequences of operations performed under a lock will -not-
+		Sequences of operations performed under a lock will *not*
 		appear to be atomic to RCU readers, nor will sequences
 		of multiple atomic primitives.
 
@@ -333,7 +333,7 @@ over a rather long period of time, but improvements are always welcome!
 	for example) may be omitted.
 
 10.	Conversely, if you are in an RCU read-side critical section,
-	and you don't hold the appropriate update-side lock, you -must-
+	and you don't hold the appropriate update-side lock, you *must*
 	use the "_rcu()" variants of the list macros.  Failing to do so
 	will break Alpha, cause aggressive compilers to generate bad code,
 	and confuse people trying to read your code.
@@ -359,12 +359,12 @@ over a rather long period of time, but improvements are always welcome!
 	callback pending, then that RCU callback will execute on some
 	surviving CPU.	(If this was not the case, a self-spawning RCU
 	callback would prevent the victim CPU from ever going offline.)
-	Furthermore, CPUs designated by rcu_nocbs= might well -always-
+	Furthermore, CPUs designated by rcu_nocbs= might well *always*
 	have their RCU callbacks executed on some other CPUs, in fact,
 	for some  real-time workloads, this is the whole point of using
 	the rcu_nocbs= kernel boot parameter.
 
-13.	Unlike other forms of RCU, it -is- permissible to block in an
+13.	Unlike other forms of RCU, it *is* permissible to block in an
 	SRCU read-side critical section (demarked by srcu_read_lock()
 	and srcu_read_unlock()), hence the "SRCU": "sleepable RCU".
 	Please note that if you don't need to sleep in read-side critical
@@ -411,16 +411,16 @@ over a rather long period of time, but improvements are always welcome!
 14.	The whole point of call_rcu(), synchronize_rcu(), and friends
 	is to wait until all pre-existing readers have finished before
 	carrying out some otherwise-destructive operation.  It is
-	therefore critically important to -first- remove any path
+	therefore critically important to *first* remove any path
 	that readers can follow that could be affected by the
-	destructive operation, and -only- -then- invoke call_rcu(),
+	destructive operation, and *only then* invoke call_rcu(),
 	synchronize_rcu(), or friends.
 
 	Because these primitives only wait for pre-existing readers, it
 	is the caller's responsibility to guarantee that any subsequent
 	readers will execute safely.
 
-15.	The various RCU read-side primitives do -not- necessarily contain
+15.	The various RCU read-side primitives do *not* necessarily contain
 	memory barriers.  You should therefore plan for the CPU
 	and the compiler to freely reorder code into and out of RCU
 	read-side critical sections.  It is the responsibility of the
@@ -459,8 +459,8 @@ over a rather long period of time, but improvements are always welcome!
 	pass in a function defined within a loadable module, then it in
 	necessary to wait for all pending callbacks to be invoked after
 	the last invocation and before unloading that module.  Note that
-	it is absolutely -not- sufficient to wait for a grace period!
-	The current (say) synchronize_rcu() implementation is -not-
+	it is absolutely *not* sufficient to wait for a grace period!
+	The current (say) synchronize_rcu() implementation is *not*
 	guaranteed to wait for callbacks registered on other CPUs.
 	Or even on the current CPU if that CPU recently went offline
 	and came back online.
@@ -470,7 +470,7 @@ over a rather long period of time, but improvements are always welcome!
 	-	call_rcu() -> rcu_barrier()
 	-	call_srcu() -> srcu_barrier()
 
-	However, these barrier functions are absolutely -not- guaranteed
+	However, these barrier functions are absolutely *not* guaranteed
 	to wait for a grace period.  In fact, if there are no call_rcu()
 	callbacks waiting anywhere in the system, rcu_barrier() is within
 	its rights to return immediately.

Documentation/RCU/rcu_dereference.rst

@@ -43,7 +43,7 @@ Follow these rules to keep your RCU code working properly:
 	-	Set bits and clear bits down in the must-be-zero low-order
 		bits of that pointer.  This clearly means that the pointer
 		must have alignment constraints, for example, this does
-		-not- work in general for char* pointers.
+		*not* work in general for char* pointers.
 
 	-	XOR bits to translate pointers, as is done in some
 		classic buddy-allocator algorithms.
@@ -174,7 +174,7 @@ Follow these rules to keep your RCU code working properly:
 		Please see the "CONTROL DEPENDENCIES" section of
 		Documentation/memory-barriers.txt for more details.
 
-	-	The pointers are not equal -and- the compiler does
+	-	The pointers are not equal *and* the compiler does
 		not have enough information to deduce the value of the
 		pointer.  Note that the volatile cast in rcu_dereference()
 		will normally prevent the compiler from knowing too much.
@@ -360,7 +360,7 @@ in turn destroying the ordering between this load and the loads of the
 return values.  This can result in "p->b" returning pre-initialization
 garbage values.
 
-In short, rcu_dereference() is -not- optional when you are going to
+In short, rcu_dereference() is *not* optional when you are going to
 dereference the resulting pointer.
 
 

Documentation/RCU/stallwarn.rst

@@ -32,7 +32,7 @@ warnings:
 
 -	Booting Linux using a console connection that is too slow to
 	keep up with the boot-time console-message rate.  For example,
-	a 115Kbaud serial console can be -way- too slow to keep up
+	a 115Kbaud serial console can be *way* too slow to keep up
 	with boot-time message rates, and will frequently result in
 	RCU CPU stall warning messages.  Especially if you have added
 	debug printk()s.
@@ -105,7 +105,7 @@ warnings:
 	leading the realization that the CPU had failed.
 
 The RCU, RCU-sched, and RCU-tasks implementations have CPU stall warning.
-Note that SRCU does -not- have CPU stall warnings.  Please note that
+Note that SRCU does *not* have CPU stall warnings.  Please note that
 RCU only detects CPU stalls when there is a grace period in progress.
 No grace period, no CPU stall warnings.
 
@@ -145,7 +145,7 @@ CONFIG_RCU_CPU_STALL_TIMEOUT
 	this parameter is checked only at the beginning of a cycle.
 	So if you are 10 seconds into a 40-second stall, setting this
 	sysfs parameter to (say) five will shorten the timeout for the
-	-next- stall, or the following warning for the current stall
+	*next* stall, or the following warning for the current stall
 	(assuming the stall lasts long enough).  It will not affect the
 	timing of the next warning for the current stall.
 
@@ -189,8 +189,8 @@ rcupdate.rcu_task_stall_timeout
 Interpreting RCU's CPU Stall-Detector "Splats"
 ==============================================
 
-For non-RCU-tasks flavors of RCU, when a CPU detects that it is stalling,
-it will print a message similar to the following::
+For non-RCU-tasks flavors of RCU, when a CPU detects that some other
+CPU is stalling, it will print a message similar to the following::
 
 	INFO: rcu_sched detected stalls on CPUs/tasks:
 	2-...: (3 GPs behind) idle=06c/0/0 softirq=1453/1455 fqs=0
@@ -202,8 +202,10 @@ causing stalls, and that the stall was affecting RCU-sched.  This message
 will normally be followed by stack dumps for each CPU.  Please note that
 PREEMPT_RCU builds can be stalled by tasks as well as by CPUs, and that
 the tasks will be indicated by PID, for example, "P3421".  It is even
-possible for an rcu_state stall to be caused by both CPUs -and- tasks,
+possible for an rcu_state stall to be caused by both CPUs *and* tasks,
 in which case the offending CPUs and tasks will all be called out in the list.
+In some cases, CPUs will detect themselves stalling, which will result
+in a self-detected stall.
 
 CPU 2's "(3 GPs behind)" indicates that this CPU has not interacted with
 the RCU core for the past three grace periods.  In contrast, CPU 16's "(0
@@ -224,7 +226,7 @@ is the number that had executed since boot at the time that this CPU
 last noted the beginning of a grace period, which might be the current
 (stalled) grace period, or it might be some earlier grace period (for
 example, if the CPU might have been in dyntick-idle mode for an extended
-time period.  The number after the "/" is the number that have executed
+time period).  The number after the "/" is the number that have executed
 since boot until the current time.  If this latter number stays constant
 across repeated stall-warning messages, it is possible that RCU's softirq
 handlers are no longer able to execute on this CPU.  This can happen if
@@ -283,7 +285,8 @@ If the relevant grace-period kthread has been unable to run prior to
 the stall warning, as was the case in the "All QSes seen" line above,
 the following additional line is printed::
 
-	kthread starved for 23807 jiffies! g7075 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x1 ->cpu=5
+	rcu_sched kthread starved for 23807 jiffies! g7075 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x1 ->cpu=5
+	Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior.
 
 Starving the grace-period kthreads of CPU time can of course result
 in RCU CPU stall warnings even when all CPUs and tasks have passed
@@ -313,15 +316,21 @@ is the current ``TIMER_SOFTIRQ`` count on cpu 4.  If this value does not
 change on successive RCU CPU stall warnings, there is further reason to
 suspect a timer problem.
 
+These messages are usually followed by stack dumps of the CPUs and tasks
+involved in the stall.  These stack traces can help you locate the cause
+of the stall, keeping in mind that the CPU detecting the stall will have
+an interrupt frame that is mainly devoted to detecting the stall.
+
 
 Multiple Warnings From One Stall
 ================================
 
-If a stall lasts long enough, multiple stall-warning messages will be
-printed for it.  The second and subsequent messages are printed at
+If a stall lasts long enough, multiple stall-warning messages will
+be printed for it.  The second and subsequent messages are printed at
 longer intervals, so that the time between (say) the first and second
 message will be about three times the interval between the beginning
-of the stall and the first message.
+of the stall and the first message.  It can be helpful to compare the
+stack dumps for the different messages for the same stalled grace period.
 
 
 Stall Warnings for Expedited Grace Periods

Documentation/admin-guide/README.rst

@@ -259,7 +259,7 @@ Configuring the kernel
 Compiling the kernel
 --------------------
 
- - Make sure you have at least gcc 4.9 available.
+ - Make sure you have at least gcc 5.1 available.
    For more information, refer to :ref:`Documentation/process/changes.rst <changes>`.
 
    Please note that you can still run a.out user programs with this kernel.

Documentation/admin-guide/acpi/ssdt-overlays.rst

@@ -30,22 +30,21 @@ following ASL code can be used::
         {
             Device (STAC)
             {
-                Name (_ADR, Zero)
                 Name (_HID, "BMA222E")
+                Name (RBUF, ResourceTemplate ()
+                {
+                    I2cSerialBus (0x0018, ControllerInitiated, 0x00061A80,
+                                AddressingMode7Bit, "\\_SB.I2C6", 0x00,
+                                ResourceConsumer, ,)
+                    GpioInt (Edge, ActiveHigh, Exclusive, PullDown, 0x0000,
+                            "\\_SB.GPO2", 0x00, ResourceConsumer, , )
+                    { // Pin list
+                        0
+                    }
+                })
 
                 Method (_CRS, 0, Serialized)
                 {
-                    Name (RBUF, ResourceTemplate ()
-                    {
-                        I2cSerialBus (0x0018, ControllerInitiated, 0x00061A80,
-                                    AddressingMode7Bit, "\\_SB.I2C6", 0x00,
-                                    ResourceConsumer, ,)
-                        GpioInt (Edge, ActiveHigh, Exclusive, PullDown, 0x0000,
-                                "\\_SB.GPO2", 0x00, ResourceConsumer, , )
-                        { // Pin list
-                            0
-                        }
-                    })
                     Return (RBUF)
                 }
             }
@@ -75,7 +74,7 @@ This option allows loading of user defined SSDTs from initrd and it is useful
 when the system does not support EFI or when there is not enough EFI storage.
 
 It works in a similar way with initrd based ACPI tables override/upgrade: SSDT
-aml code must be placed in the first, uncompressed, initrd under the
+AML code must be placed in the first, uncompressed, initrd under the
 "kernel/firmware/acpi" path. Multiple files can be used and this will translate
 in loading multiple tables. Only SSDT and OEM tables are allowed. See
 initrd_table_override.txt for more details.
@@ -103,12 +102,14 @@ This is the preferred method, when EFI is supported on the platform, because it
 allows a persistent, OS independent way of storing the user defined SSDTs. There
 is also work underway to implement EFI support for loading user defined SSDTs
 and using this method will make it easier to convert to the EFI loading
-mechanism when that will arrive.
+mechanism when that will arrive. To enable it, the
+CONFIG_EFI_CUSTOM_SSDT_OVERLAYS shoyld be chosen to y.
 
-In order to load SSDTs from an EFI variable the efivar_ssdt kernel command line
-parameter can be used. The argument for the option is the variable name to
-use. If there are multiple variables with the same name but with different
-vendor GUIDs, all of them will be loaded.
+In order to load SSDTs from an EFI variable the ``"efivar_ssdt=..."`` kernel
+command line parameter can be used (the name has a limitation of 16 characters).
+The argument for the option is the variable name to use. If there are multiple
+variables with the same name but with different vendor GUIDs, all of them will
+be loaded.
 
 In order to store the AML code in an EFI variable the efivarfs filesystem can be
 used. It is enabled and mounted by default in /sys/firmware/efi/efivars in all
@@ -127,7 +128,7 @@ variable with the content from a given file::
 
     #!/bin/sh -e
 
-    while ! [ -z "$1" ]; do
+    while [ -n "$1" ]; do
             case "$1" in
             "-f") filename="$2"; shift;;
             "-g") guid="$2"; shift;;
@@ -167,14 +168,14 @@ variable with the content from a given file::
 Loading ACPI SSDTs from configfs
 ================================
 
-This option allows loading of user defined SSDTs from userspace via the configfs
+This option allows loading of user defined SSDTs from user space via the configfs
 interface. The CONFIG_ACPI_CONFIGFS option must be select and configfs must be
 mounted. In the following examples, we assume that configfs has been mounted in
-/config.
+/sys/kernel/config.
 
-New tables can be loading by creating new directories in /config/acpi/table/ and
-writing the SSDT aml code in the aml attribute::
+New tables can be loading by creating new directories in /sys/kernel/config/acpi/table
+and writing the SSDT AML code in the aml attribute::
 
-    cd /config/acpi/table
+    cd /sys/kernel/config/acpi/table
     mkdir my_ssdt
     cat ~/ssdt.aml > my_ssdt/aml

Documentation/admin-guide/binderfs.rst

@@ -72,3 +72,16 @@ that the `rm() <rm_>`_ tool can be used to delete them. Note that the
 ``binder-control`` device cannot be deleted since this would make the binderfs
 instance unusable.  The ``binder-control`` device will be deleted when the
 binderfs instance is unmounted and all references to it have been dropped.
+
+Binder features
+---------------
+
+Assuming an instance of binderfs has been mounted at ``/dev/binderfs``, the
+features supported by the binder driver can be located under
+``/dev/binderfs/features/``. The presence of individual files can be tested
+to determine whether a particular feature is supported by the driver.
+
+Example::
+
+        cat /dev/binderfs/features/oneway_spam_detection
+        1

Documentation/admin-guide/bootconfig.rst

@@ -178,7 +178,7 @@ update the boot loader and the kernel image itself as long as the boot
 loader passes the correct initrd file size. If by any chance, the boot
 loader passes a longer size, the kernel fails to find the bootconfig data.
 
-To do this operation, Linux kernel provides "bootconfig" command under
+To do this operation, Linux kernel provides ``bootconfig`` command under
 tools/bootconfig, which allows admin to apply or delete the config file
 to/from initrd image. You can build it by the following command::
 
@@ -196,6 +196,43 @@ To remove the config from the image, you can use -d option as below::
 Then add "bootconfig" on the normal kernel command line to tell the
 kernel to look for the bootconfig at the end of the initrd file.
 
+
+Kernel parameters via Boot Config
+=================================
+
+In addition to the kernel command line, the boot config can be used for
+passing the kernel parameters. All the key-value pairs under ``kernel``
+key will be passed to kernel cmdline directly. Moreover, the key-value
+pairs under ``init`` will be passed to init process via the cmdline.
+The parameters are concatinated with user-given kernel cmdline string
+as the following order, so that the command line parameter can override
+bootconfig parameters (this depends on how the subsystem handles parameters
+but in general, earlier parameter will be overwritten by later one.)::
+
+ [bootconfig params][cmdline params] -- [bootconfig init params][cmdline init params]
+
+Here is an example of the bootconfig file for kernel/init parameters.::
+
+ kernel {
+   root = 01234567-89ab-cdef-0123-456789abcd
+ }
+ init {
+  splash
+ }
+
+This will be copied into the kernel cmdline string as the following::
+
+ root="01234567-89ab-cdef-0123-456789abcd" -- splash
+
+If user gives some other command line like,::
+
+ ro bootconfig -- quiet
+
+The final kernel cmdline will be the following::
+
+ root="01234567-89ab-cdef-0123-456789abcd" ro bootconfig -- splash quiet
+
+
 Config File Limitation
 ======================