Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
 "The usual shower of hotfixes.

  Chris's memcg patches aren't actually fixes - they're mature but a few
  niggling review issues were late to arrive.

  The ocfs2 fixes are quite old - those took some time to get reviewer
  attention.

  Subsystems affected by this patch series: ocfs2, hotfixes, mm/memcg,
  mm/slab-generic"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm, sl[aou]b: guarantee natural alignment for kmalloc(power-of-two)
  mm, sl[ou]b: improve memory accounting
  mm, memcg: make scan aggression always exclude protection
  mm, memcg: make memory.emin the baseline for utilisation determination
  mm, memcg: proportional memory.{low,min} reclaim
  mm/vmpressure.c: fix a signedness bug in vmpressure_register_event()
  mm/page_alloc.c: fix a crash in free_pages_prepare()
  mm/z3fold.c: claim page in the beginning of free
  kernel/sysctl.c: do not override max_threads provided by userspace
  memcg: only record foreign writebacks with dirty pages when memcg is not disabled
  mm: fix -Wmissing-prototypes warnings
  writeback: fix use-after-free in finish_writeback_work()
  mm/memremap: drop unused SECTION_SIZE and SECTION_MASK
  panic: ensure preemption is disabled during panic()
  fs: ocfs2: fix a possible null-pointer dereference in ocfs2_info_scan_inode_alloc()
  fs: ocfs2: fix a possible null-pointer dereference in ocfs2_write_end_nolock()
  fs: ocfs2: fix possible null-pointer dereferences in ocfs2_xa_prepare_entry()
  ocfs2: clear zero in unaligned direct IO

2 files changed, 18 insertions, 6 deletions

diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 0fa8c0e615c2..5361ebec3361 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -615,8 +615,8 @@ on an IO device and is an example of this type.
 Protections
 -----------
 
-A cgroup is protected to be allocated upto the configured amount of
-the resource if the usages of all its ancestors are under their
+A cgroup is protected upto the configured amount of the resource
+as long as the usages of all its ancestors are under their
 protected levels.  Protections can be hard guarantees or best effort
 soft boundaries.  Protections can also be over-committed in which case
 only upto the amount available to the parent is protected among
@@ -1096,7 +1096,10 @@ PAGE_SIZE multiple when read back.
 	is within its effective min boundary, the cgroup's memory
 	won't be reclaimed under any conditions. If there is no
 	unprotected reclaimable memory available, OOM killer
-	is invoked.
+	is invoked. Above the effective min boundary (or
+	effective low boundary if it is higher), pages are reclaimed
+	proportionally to the overage, reducing reclaim pressure for
+	smaller overages.
 
        Effective min boundary is limited by memory.min values of
 	all ancestor cgroups. If there is memory.min overcommitment
@@ -1118,7 +1121,10 @@ PAGE_SIZE multiple when read back.
 	Best-effort memory protection.  If the memory usage of a
 	cgroup is within its effective low boundary, the cgroup's
 	memory won't be reclaimed unless memory can be reclaimed
-	from unprotected cgroups.
+	from unprotected cgroups.  Above the effective low boundary (or
+	effective min boundary if it is higher), pages are reclaimed
+	proportionally to the overage, reducing reclaim pressure for
+	smaller overages.
 
 	Effective low boundary is limited by memory.low values of
 	all ancestor cgroups. If there is memory.low overcommitment
@@ -2482,8 +2488,10 @@ system performance due to overreclaim, to the point where the feature
 becomes self-defeating.
 
 The memory.low boundary on the other hand is a top-down allocated
-reserve.  A cgroup enjoys reclaim protection when it's within its low,
-which makes delegation of subtrees possible.
+reserve.  A cgroup enjoys reclaim protection when it's within its
+effective low, which makes delegation of subtrees possible. It also
+enjoys having reclaim pressure proportional to its overage when
+above its effective low.
 
 The original high boundary, the hard limit, is defined as a strict
 limit that can not budge, even if the OOM killer has to be called.
diff --git a/Documentation/core-api/memory-allocation.rst b/Documentation/core-api/memory-allocation.rst
index 7744aa3bf2e0..939e3dfc86e9 100644
--- a/Documentation/core-api/memory-allocation.rst
+++ b/Documentation/core-api/memory-allocation.rst
@@ -98,6 +98,10 @@ limited. The actual limit depends on the hardware and the kernel
 configuration, but it is a good practice to use `kmalloc` for objects
 smaller than page size.
 
+The address of a chunk allocated with `kmalloc` is aligned to at least
+ARCH_KMALLOC_MINALIGN bytes.  For sizes which are a power of two, the
+alignment is also guaranteed to be at least the respective size.
+
 For large allocations you can use :c:func:`vmalloc` and
 :c:func:`vzalloc`, or directly request pages from the page
 allocator. The memory allocated by `vmalloc` and related functions is