mm/damon/design.rst

75 address regions is just wasteful.  However, because DAMON can deal with some
76 level of noise using the adaptive regions adjustment mechanism, tracking every
82 distinct regions that cover every mapped area of the address space.  The two
83 gaps between the three regions are the two biggest unmapped areas in the given
93     (small mmap()-ed regions and munmap()-ed regions)
126 ``update interval``, ``minimum number of regions``, and ``maximum number of
127 regions``.
167 overhead is controllable by setting the number of regions.  DAMON allows users
168 to set the minimum and the maximum number of regions for the trade-off.
174 Adaptive Regions Adjustment
177 Even somehow the initial monitoring target regions are well constructed to
184 adjacent regions and merges those if the frequency difference is small.  Then,
186 splits each region into two or three regions if the total number of regions
187 will not exceed the user-specified maximum number of regions after the split.
229     paging out memory regions that are not accessed for more than two minutes
233     using THP for memory regions that are larger than 2 MiB and showing a high
238 workloads or the system using DAMON, finding memory regions of special
240 operation changes for the regions.  The changes could be made by modifying or
255 level.  For such specifications, DAMON starts monitoring, finds regions having
257 to the regions as soon as found.
265 The management action that the users desire to apply to the regions of their
268 collecting statistics of the regions.
280 characteristics.  Hence, DAMOS resets the age of regions when an action is
294 regions that the scheme is having an interest in.
312 can use for applying the action, and/or a maximum bytes of memory regions that
322 cannot be applied to all regions of interest due to the quotas, DAMOS
323 prioritizes regions and applies the action to only regions having high enough
327 rarely accessed (colder) memory regions would be prioritized for page-out
328 scheme action.  In contrast, the colder regions would be deprioritized for huge
333 to calculate the priority using the access pattern properties of the regions.
370 Non-access pattern-based target memory regions filtering.  If users run
398 memory regions is filtered by an operations set layer-handled filter, it is