Docs/mm/damon/design: place execution model and data structures at the beginning

The execution model and data structures section at the end of the design
document is briefly explaining how DAMON works overall.  Knowing that
first may help better drawing the overall picture.  It may also help
better understanding following detailed sections.  Move it to the
beginning of the document.

Link: https://lkml.kernel.org/r/20231213190338.54146-4-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Documentation/mm/damon/design.rst

@@ -5,6 +5,18 @@ Design
 ======
 
 
+.. _damon_design_execution_model_and_data_structures:
+
+Execution Model and Data Structures
+===================================
+
+The monitoring-related information including the monitoring request
+specification and DAMON-based operation schemes are stored in a data structure
+called DAMON ``context``.  DAMON executes each context with a kernel thread
+called ``kdamond``.  Multiple kdamonds could run in parallel, for different
+types of monitoring.
+
+
 Overall Architecture
 ====================
 
@@ -490,15 +502,3 @@ modules for proactive reclamation and LRU lists manipulation are provided.  For
 more detail, please read the usage documents for those
 (:doc:`/admin-guide/mm/damon/reclaim` and
 :doc:`/admin-guide/mm/damon/lru_sort`).
-
-
-.. _damon_design_execution_model_and_data_structures:
-
-Execution Model and Data Structures
-===================================
-
-The monitoring-related information including the monitoring request
-specification and DAMON-based operation schemes are stored in a data structure
-called DAMON ``context``.  DAMON executes each context with a kernel thread
-called ``kdamond``.  Multiple kdamonds could run in parallel, for different
-types of monitoring.