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

include/linux/memcontrol.h

@@ -356,6 +356,19 @@ static inline bool mem_cgroup_disabled(void)
 	return !cgroup_subsys_enabled(memory_cgrp_subsys);
 }
 
+static inline unsigned long mem_cgroup_protection(struct mem_cgroup *memcg,
+						  bool in_low_reclaim)
+{
+	if (mem_cgroup_disabled())
+		return 0;
+
+	if (in_low_reclaim)
+		return READ_ONCE(memcg->memory.emin);
+
+	return max(READ_ONCE(memcg->memory.emin),
+		   READ_ONCE(memcg->memory.elow));
+}
+
 enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root,
 						struct mem_cgroup *memcg);
 
@@ -537,6 +550,8 @@ void mem_cgroup_handle_over_high(void);
 
 unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg);
 
+unsigned long mem_cgroup_size(struct mem_cgroup *memcg);
+
 void mem_cgroup_print_oom_context(struct mem_cgroup *memcg,
 				struct task_struct *p);
 
@@ -829,6 +844,12 @@ static inline void memcg_memory_event_mm(struct mm_struct *mm,
 {
 }
 
+static inline unsigned long mem_cgroup_protection(struct mem_cgroup *memcg,
+						  bool in_low_reclaim)
+{
+	return 0;
+}
+
 static inline enum mem_cgroup_protection mem_cgroup_protected(
 	struct mem_cgroup *root, struct mem_cgroup *memcg)
 {
@@ -968,6 +989,11 @@ static inline unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg)
 	return 0;
 }
 
+static inline unsigned long mem_cgroup_size(struct mem_cgroup *memcg)
+{
+	return 0;
+}
+
 static inline void
 mem_cgroup_print_oom_context(struct mem_cgroup *memcg, struct task_struct *p)
 {
@@ -1264,6 +1290,9 @@ void mem_cgroup_track_foreign_dirty_slowpath(struct page *page,
 static inline void mem_cgroup_track_foreign_dirty(struct page *page,
 						  struct bdi_writeback *wb)
 {
+	if (mem_cgroup_disabled())
+		return;
+
 	if (unlikely(&page->mem_cgroup->css != wb->memcg_css))
 		mem_cgroup_track_foreign_dirty_slowpath(page, wb);
 }

include/linux/slab.h

@@ -493,6 +493,10 @@ static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
  * kmalloc is the normal method of allocating memory
  * for objects smaller than page size in the kernel.
  *
+ * The allocated object address is aligned to at least ARCH_KMALLOC_MINALIGN
+ * bytes. For @size of power of two bytes, the alignment is also guaranteed
+ * to be at least to the size.
+ *
  * The @flags argument may be one of the GFP flags defined at
  * include/linux/gfp.h and described at
  * :ref:`Documentation/core-api/mm-api.rst <mm-api-gfp-flags>`