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Commit 3cdd868e authored by Changbin Du's avatar Changbin Du Committed by Jonathan Corbet
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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: default avatarChangbin Du <changbin.du@intel.com>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 73d98127

Documentation/trace/events-kmem.txt→Documentation/trace/events-kmem.rst

+31 −19
Original line number Diff line number Diff line 
============================

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

+1 −0
Original line number Diff line number Diff line
@@ -13,3 +13,4 @@ Linux Tracing Technologies 
   uprobetracer

   tracepoints

   events

   events-kmem