mm tracing: cleanup Documentation/trace/events-kmem.txt

Clean up typos/grammos/spellos in events-kmem.txt.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/trace/events-kmem.txt

 			Subsystem Trace Points: kmem
 
-The tracing system kmem captures events related to object and page allocation
-within the kernel. Broadly speaking there are four major subheadings.
+The kmem tracing system captures events related to object and page allocation
+within the kernel. Broadly speaking there are five major subheadings.
 
   o Slab allocation of small objects of unknown type (kmalloc)
   o Slab allocation of small objects of known type
@@ -9,7 +9,7 @@ within the kernel. Broadly speaking there are four major subheadings.
   o Per-CPU Allocator Activity
   o External Fragmentation
 
-This document will describe what each of the tracepoints are and why they
+This document describes what each of the tracepoints is and why they
 might be useful.
 
 1. Slab allocation of small objects of unknown type
@@ -34,7 +34,7 @@ kmem_cache_free		call_site=%lx ptr=%p
 These events are similar in usage to the kmalloc-related events except that
 it is likely easier to pin the event down to a specific cache. At the time
 of writing, no information is available on what slab is being allocated from,
-but the call_site can usually be used to extrapolate that information
+but the call_site can usually be used to extrapolate that information.
 
 3. Page allocation
 ==================
@@ -80,9 +80,9 @@ event indicating whether it is for a percpu_refill or not.
 When the per-CPU list is too full, a number of pages are freed, each one
 which triggers a mm_page_pcpu_drain event.
 
-The individual nature of the events are so that pages can be tracked
+The individual nature of the events is so that pages can be tracked
 between allocation and freeing. A number of drain or refill pages that occur
-consecutively imply the zone->lock being taken once. Large amounts of PCP
+consecutively imply the zone->lock being taken once. Large amounts of per-CPU
 refills and drains could imply an imbalance between CPUs where too much work
 is being concentrated in one place. It could also indicate that the per-CPU
 lists should be a larger size. Finally, large amounts of refills on one CPU
@@ -102,6 +102,6 @@ is important.
 
 Large numbers of this event implies that memory is fragmenting and
 high-order allocations will start failing at some time in the future. One
-means of reducing the occurange of this event is to increase the size of
+means of reducing the occurrence of this event is to increase the size of
 min_free_kbytes in increments of 3*pageblock_size*nr_online_nodes where
 pageblock_size is usually the size of the default hugepage size.