Merge tag 'docs-for-linus' of git://git.lwn.net/linux

Pull documentation update from Jon Corbet:
 "There is a nice new document from Neil on how pathname lookups work
  and some new CAN driver documentation.  Beyond that, we have
  kernel-doc fixes, a bit more work to support reproducible builds, and
  the usual collection of small fixes"

* tag 'docs-for-linus' of git://git.lwn.net/linux: (34 commits)
  Documentation: add new description of path-name lookup.
  Documentation/vm/slub.txt: document slabinfo-gnuplot.sh
  Doc: ABI/stable: Fix typo in ABI/stable
  doc: Clarify that nmi_watchdog param is for hardlockups
  Typo correction for description in gpio document.
  DocBook: Fix kernel-doc to be case-insensitive for private:
  kernel-docs.txt: update kernelnewbies reference
  Doc:kvm: Fix typo in Doc/virtual/kvm
  Documentation/Changes: Add bc in "Current Minimal Requirements" section
  Documentation/email-clients.txt: remove trailing whitespace
  DocBook: Use a fixed encoding for output
  MAINTAINERS: The docs tree has moved
  Docs/kernel-parameters: Add earlycon devicetree usage
  SubmittingPatches: make Subject examples match the de facto standard
  Documentation: gpio: mention that <function>-gpio has been deprecated
  Documentation: cgroups: just fix a few typos
  Documentation: Update kselftest.txt
  Documentation: DMA API: Be more explicit that nents is always the same
  Documentation: Update the default value of crashkernel low
  zram: update documentation
  ...

Documentation/kernel-parameters.txt

@@ -790,8 +790,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			is passed, kernel could allocate physical memory region
 			above 4G, that cause second kernel crash on system
 			that require some amount of low memory, e.g. swiotlb
-			requires at least 64M+32K low memory.  Kernel would
-			try to allocate 72M below 4G automatically.
+			requires at least 64M+32K low memory, also enough extra
+			low memory is needed to make sure DMA buffers for 32-bit
+			devices won't run out. Kernel would try to allocate at
+			at least 256M below 4G automatically.
 			This one let user to specify own low range under 4G
 			for second kernel instead.
 			0: to disable low allocation.
@@ -972,6 +974,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
 	earlycon=	[KNL] Output early console device and options.
 
+			When used with no options, the early console is
+			determined by the stdout-path property in device
+			tree's chosen node.
+
 		cdns,<addr>
 			Start an early, polled-mode console on a cadence serial
 			port at the specified address. The cadence serial port
@@ -2340,11 +2346,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 	nmi_watchdog=	[KNL,BUGS=X86] Debugging features for SMP kernels
 			Format: [panic,][nopanic,][num]
 			Valid num: 0 or 1
-			0 - turn nmi_watchdog off
-			1 - turn nmi_watchdog on
+			0 - turn hardlockup detector in nmi_watchdog off
+			1 - turn hardlockup detector in nmi_watchdog on
 			When panic is specified, panic when an NMI watchdog
 			timeout occurs (or 'nopanic' to override the opposite
-			default).
+			default). To disable both hard and soft lockup detectors,
+			please see 'nowatchdog'.
 			This is useful when you use a panic=... timeout and
 			need the box quickly up again.