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Diffstat (limited to 'Documentation/mm/damon/design.rst')
| -rw-r--r-- | Documentation/mm/damon/design.rst | 26 |
1 files changed, 22 insertions, 4 deletions
diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst index a20383d01a95..1f7e0586b5fa 100644 --- a/Documentation/mm/damon/design.rst +++ b/Documentation/mm/damon/design.rst @@ -154,6 +154,8 @@ The monitoring overhead of this mechanism will arbitrarily increase as the size of the target workload grows. +.. _damon_design_region_based_sampling: + Region Based Sampling ~~~~~~~~~~~~~~~~~~~~~ @@ -163,9 +165,10 @@ assumption (pages in a region have the same access frequencies) is kept, only one page in the region is required to be checked. Thus, for each ``sampling interval``, DAMON randomly picks one page in each region, waits for one ``sampling interval``, checks whether the page is accessed meanwhile, and -increases the access frequency of the region if so. Therefore, the monitoring -overhead is controllable by setting the number of regions. DAMON allows users -to set the minimum and the maximum number of regions for the trade-off. +increases the access frequency counter of the region if so. The counter is +called ``nr_regions`` of the region. Therefore, the monitoring overhead is +controllable by setting the number of regions. DAMON allows users to set the +minimum and the maximum number of regions for the trade-off. This scheme, however, cannot preserve the quality of the output if the assumption is not guaranteed. @@ -190,6 +193,8 @@ In this way, DAMON provides its best-effort quality and minimal overhead while keeping the bounds users set for their trade-off. +.. _damon_design_age_tracking: + Age Tracking ~~~~~~~~~~~~ @@ -254,7 +259,8 @@ works, DAMON provides a feature called Data Access Monitoring-based Operation Schemes (DAMOS). It lets users specify their desired schemes at a high level. For such specifications, DAMON starts monitoring, finds regions having the access pattern of interest, and applies the user-desired operation actions -to the regions as soon as found. +to the regions, for every user-specified time interval called +``apply_interval``. .. _damon_design_damos_action: @@ -471,3 +477,15 @@ 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. |