trace doc: convert trace/events-kmem.txt to rst format

This converts the plain text documentation to reStructuredText format and
add it into Sphinx TOC tree. No essential content change.

Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Changbin Du <changbin.du@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/trace/events-kmem.rst

@@ -1,19 +1,23 @@
+============================
 Subsystem Trace Points: kmem
+============================
 
 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
-  o Page allocation
-  o Per-CPU Allocator Activity
-  o External Fragmentation
+  - Slab allocation of small objects of unknown type (kmalloc)
+  - Slab allocation of small objects of known type
+  - Page allocation
+  - Per-CPU Allocator Activity
+  - External Fragmentation
 
 This document describes what each of the tracepoints is and why they
 might be useful.
 
 1. Slab allocation of small objects of unknown type
 ===================================================
+::
+
   kmalloc		call_site=%lx ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s
   kmalloc_node	call_site=%lx ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s node=%d
   kfree		call_site=%lx ptr=%p
@@ -27,6 +31,8 @@ the allocation sites were.
 
 2. Slab allocation of small objects of known type
 =================================================
+::
+
   kmem_cache_alloc	call_site=%lx ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s
   kmem_cache_alloc_node	call_site=%lx ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s node=%d
   kmem_cache_free		call_site=%lx ptr=%p
@@ -38,6 +44,8 @@ but the call_site can usually be used to extrapolate that information.
 
 3. Page allocation
 ==================
+::
+
   mm_page_alloc		  page=%p pfn=%lu order=%d migratetype=%d gfp_flags=%s
   mm_page_alloc_zone_locked page=%p pfn=%lu order=%u migratetype=%d cpu=%d percpu_refill=%d
   mm_page_free		  page=%p pfn=%lu order=%d
@@ -65,6 +73,8 @@ contention on the zone->lru_lock.
 
 4. Per-CPU Allocator Activity
 =============================
+::
+
   mm_page_alloc_zone_locked	page=%p pfn=%lu order=%u migratetype=%d cpu=%d percpu_refill=%d
   mm_page_pcpu_drain		page=%p pfn=%lu order=%d cpu=%d migratetype=%d
 
@@ -92,6 +102,8 @@ can be allocated and freed on the same CPU through some algorithm change.
 
 5. External Fragmentation
 =========================
+::
+
   mm_page_alloc_extfrag		page=%p pfn=%lu alloc_order=%d fallback_order=%d pageblock_order=%d alloc_migratetype=%d fallback_migratetype=%d fragmenting=%d change_ownership=%d
 
 External fragmentation affects whether a high-order allocation will be

Documentation/trace/index.rst

@@ -13,3 +13,4 @@ Linux Tracing Technologies
    uprobetracer
    tracepoints
    events
+   events-kmem