diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst index 7360e5ac0d06..8b9727d91434 100644 --- a/Documentation/mm/damon/design.rst +++ b/Documentation/mm/damon/design.rst @@ -569,11 +569,21 @@ number of filters for each scheme. Each filter specifies - whether it is to allow (include) or reject (exclude) applying the scheme's action to the memory (``allow``). -When multiple filters are installed, each filter is evaluated in the installed -order. If a part of memory is matched to one of the filter, next filters are -ignored. If the memory passes through the filters evaluation stage because it -is not matched to any of the filters, applying the scheme's action to it is -allowed, same to the behavior when no filter exists. +For efficient handling of filters, some types of filters are handled by the +core layer, while others are handled by operations set. In the latter case, +hence, support of the filter types depends on the DAMON operations set. In +case of the core layer-handled filters, the memory regions that excluded by the +filter are not counted as the scheme has tried to the region. In contrast, if +a memory regions is filtered by an operations set layer-handled filter, it is +counted as the scheme has tried. This difference affects the statistics. + +When multiple filters are installed, the group of filters that handled by the +core layer are evaluated first. After that, the group of filters that handled +by the operations layer are evaluated. Filters in each of the groups are +evaluated in the installed order. If a part of memory is matched to one of the +filter, next filters are ignored. If the memory passes through the filters +evaluation stage because it is not matched to any of the filters, applying the +scheme's action to it is allowed, same to the behavior when no filter exists. For example, let's assume 1) a filter for allowing anonymous pages and 2) another filter for rejecting young pages are installed in the order. If a page @@ -590,14 +600,6 @@ filter-allowed or filters evaluation stage passed. It means that installing allow-filters at the end of the list makes no practical change but only filters-checking overhead. -For efficient handling of filters, some types of filters are handled by the -core layer, while others are handled by operations set. In the latter case, -hence, support of the filter types depends on the DAMON operations set. In -case of the core layer-handled filters, the memory regions that excluded by the -filter are not counted as the scheme has tried to the region. In contrast, if -a memory regions is filtered by an operations set layer-handled filter, it is -counted as the scheme has tried. This difference affects the statistics. - Below ``type`` of filters are currently supported. - anon