Documentation/features/vm: Add feature description and arch support status file for 'THP'

Cc: <linux-api@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Cc: <linux-kernel@vger.kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Documentation/features/vm/THP/arch-support.txt

+#
+# Feature name:          THP
+#         Kconfig:       HAVE_ARCH_TRANSPARENT_HUGEPAGE
+#         description:   arch supports transparent hugepages
+#
+    -----------------------
+    |         arch |status|
+    -----------------------
+    |       alpha: | TODO |
+    |         arc: |  ..  |
+    |         arm: |  ok  |
+    |       arm64: |  ok  |
+    |       avr32: |  ..  |
+    |    blackfin: |  ..  |
+    |         c6x: |  ..  |
+    |        cris: |  ..  |
+    |         frv: |  ..  |
+    |       h8300: |  ..  |
+    |     hexagon: |  ..  |
+    |        ia64: | TODO |
+    |        m32r: |  ..  |
+    |        m68k: |  ..  |
+    |       metag: |  ..  |
+    |  microblaze: |  ..  |
+    |        mips: |  ok  |
+    |     mn10300: |  ..  |
+    |       nios2: |  ..  |
+    |    openrisc: |  ..  |
+    |      parisc: | TODO |
+    |     powerpc: |  ok  |
+    |        s390: |  ok  |
+    |       score: |  ..  |
+    |          sh: |  ..  |
+    |       sparc: |  ok  |
+    |        tile: | TODO |
+    |          um: |  ..  |
+    |   unicore32: |  ..  |
+    |         x86: |  ok  |
+    |      xtensa: |  ..  |
+    -----------------------