Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:

 - the rest of MM

 - KASAN updates

 - procfs updates

 - exit, fork updates

 - printk updates

 - lib/ updates

 - radix-tree testsuite updates

 - checkpatch updates

 - kprobes updates

 - a few other misc bits

* emailed patches from Andrew Morton <[email protected]>: (162 commits)
  samples/kprobes: print out the symbol name for the hooks
  samples/kprobes: add a new module parameter
  kprobes: add the "tls" argument for j_do_fork
  init/main.c: simplify initcall_blacklisted()
  fs/efs/super.c: fix return value
  checkpatch: improve --git <commit-count> shortcut
  checkpatch: reduce number of `git log` calls with --git
  checkpatch: add support to check already applied git commits
  checkpatch: add --list-types to show message types to show or ignore
  checkpatch: advertise the --fix and --fix-inplace options more
  checkpatch: whine about ACCESS_ONCE
  checkpatch: add test for keywords not starting on tabstops
  checkpatch: improve CONSTANT_COMPARISON test for structure members
  checkpatch: add PREFER_IS_ENABLED test
  lib/GCD.c: use binary GCD algorithm instead of Euclidean
  radix-tree: free up the bottom bit of exceptional entries for reuse
  dax: move RADIX_DAX_ definitions to dax.c
  radix-tree: make radix_tree_descend() more useful
  radix-tree: introduce radix_tree_replace_clear_tags()
  radix-tree: tidy up __radix_tree_create()
  ...

Documentation/ABI/testing/sysfs-block-zram

@@ -166,3 +166,12 @@ Description:
 		The mm_stat file is read-only and represents device's mm
 		statistics (orig_data_size, compr_data_size, etc.) in a format
 		similar to block layer statistics file format.
+
+What:		/sys/block/zram<id>/debug_stat
+Date:		July 2016
+Contact:	Sergey Senozhatsky <[email protected]>
+Description:
+		The debug_stat file is read-only and represents various
+		device's debugging info useful for kernel developers. Its
+		format is not documented intentionally and may change
+		anytime without any notice.

Documentation/blockdev/zram.txt

@@ -59,27 +59,16 @@ num_devices parameter is optional and tells zram how many devices should be
 pre-created. Default: 1.
 
 2) Set max number of compression streams
-	Compression backend may use up to max_comp_streams compression streams,
-	thus allowing up to max_comp_streams concurrent compression operations.
-	By default, compression backend uses single compression stream.
+	Regardless the value passed to this attribute, ZRAM will always
+	allocate multiple compression streams - one per online CPUs - thus
+	allowing several concurrent compression operations. The number of
+	allocated compression streams goes down when some of the CPUs
+	become offline. There is no single-compression-stream mode anymore,
+	unless you are running a UP system or has only 1 CPU online.
 
-	Examples:
-	#show max compression streams number
+	To find out how many streams are currently available:
 	cat /sys/block/zram0/max_comp_streams
 
-	#set max compression streams number to 3
-	echo 3 > /sys/block/zram0/max_comp_streams
-
-Note:
-In order to enable compression backend's multi stream support max_comp_streams
-must be initially set to desired concurrency level before ZRAM device
-initialisation. Once the device initialised as a single stream compression
-backend (max_comp_streams equals to 1), you will see error if you try to change
-the value of max_comp_streams because single stream compression backend
-implemented as a special case by lock overhead issue and does not support
-dynamic max_comp_streams. Only multi stream backend supports dynamic
-max_comp_streams adjustment.
-
 3) Select compression algorithm
 	Using comp_algorithm device attribute one can see available and
 	currently selected (shown in square brackets) compression algorithms,
@@ -183,6 +172,7 @@ mem_limit         RW    the maximum amount of memory ZRAM can use to store
 pages_compacted   RO    the number of pages freed during compaction
                         (available only via zram<id>/mm_stat node)
 compact           WO    trigger memory compaction
+debug_stat        RO    this file is used for zram debugging purposes
 
 WARNING
 =======

Documentation/filesystems/proc.txt

@@ -225,6 +225,7 @@ Table 1-2: Contents of the status files (as of 4.1)
  TracerPid                   PID of process tracing this process (0 if not)
  Uid                         Real, effective, saved set, and  file system UIDs
  Gid                         Real, effective, saved set, and  file system GIDs
+ Umask                       file mode creation mask
  FDSize                      number of file descriptor slots currently allocated
  Groups                      supplementary group list
  NStgid                      descendant namespace thread group ID hierarchy

Documentation/vm/transhuge.txt

@@ -340,7 +340,7 @@ unaffected. libhugetlbfs will also work fine as usual.
 
 == Graceful fallback ==
 
-Code walking pagetables but unware about huge pmds can simply call
+Code walking pagetables but unaware about huge pmds can simply call
 split_huge_pmd(vma, pmd, addr) where the pmd is the one returned by
 pmd_offset. It's trivial to make the code transparent hugepage aware
 by just grepping for "pmd_offset" and adding split_huge_pmd where
@@ -414,7 +414,7 @@ tracking. The alternative is alter ->_mapcount in all subpages on each
 map/unmap of the whole compound page.
 
 We set PG_double_map when a PMD of the page got split for the first time,
-but still have PMD mapping. The addtional references go away with last
+but still have PMD mapping. The additional references go away with last
 compound_mapcount.
 
 split_huge_page internally has to distribute the refcounts in the head
@@ -432,10 +432,10 @@ page->_mapcount.
 We safe against physical memory scanners too: the only legitimate way
 scanner can get reference to a page is get_page_unless_zero().
 
-All tail pages has zero ->_refcount until atomic_add(). It prevent scanner
-from geting reference to tail page up to the point. After the atomic_add()
-we don't care about ->_refcount value.  We already known how many references
-with should uncharge from head page.
+All tail pages have zero ->_refcount until atomic_add(). This prevents the
+scanner from getting a reference to the tail page up to that point. After the
+atomic_add() we don't care about the ->_refcount value.  We already known how
+many references should be uncharged from the head page.
 
 For head page get_page_unless_zero() will succeed and we don't mind. It's
 clear where reference should go after split: it will stay on head page.

Documentation/vm/z3fold.txt

@@ -0,0 +1,26 @@
+z3fold
+------
+
+z3fold is a special purpose allocator for storing compressed pages.
+It is designed to store up to three compressed pages per physical page.
+It is a zbud derivative which allows for higher compression
+ratio keeping the simplicity and determinism of its predecessor.
+
+The main differences between z3fold and zbud are:
+* unlike zbud, z3fold allows for up to PAGE_SIZE allocations
+* z3fold can hold up to 3 compressed pages in its page
+* z3fold doesn't export any API itself and is thus intended to be used
+  via the zpool API.
+
+To keep the determinism and simplicity, z3fold, just like zbud, always
+stores an integral number of compressed pages per page, but it can store
+up to 3 pages unlike zbud which can store at most 2. Therefore the
+compression ratio goes to around 2.7x while zbud's one is around 1.7x.
+
+Unlike zbud (but like zsmalloc for that matter) z3fold_alloc() does not
+return a dereferenceable pointer. Instead, it returns an unsigned long
+handle which encodes actual location of the allocated object.
+
+Keeping effective compression ratio close to zsmalloc's, z3fold doesn't
+depend on MMU enabled and provides more predictable reclaim behavior
+which makes it a better fit for small and response-critical systems.