[RFC PATCH 1/9] mm/damon/core: introduce damos->ops_filters

[SeongJae Park <sj@kernel.org>]

DAMOS filters can be categorized into two groups depending on which
layer they are handled, namely core layer and ops layer.  Also their
evaluation sequence is decided by the categorization.  Currently, all
filters are maintained in single list in mix.  It makes the filters
evaluation loop inefficient since it should do the categorization in the
loop for every iteration.  Introduce another list that will be used for
having all operations layer-handled DAMOS filters.

Note that this change simply adds the list and does not change any DAMON
code to use it in real.  It will be done by following changes.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 include/linux/damon.h | 8 ++++++++
 mm/damon/core.c       | 1 +
 2 files changed, 9 insertions(+)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 795ca09b1107..add82fdc1117 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -448,6 +448,7 @@ struct damos_access_pattern {
  * @wmarks:		Watermarks for automated (in)activation of this scheme.
  * @target_nid:		Destination node if @action is "migrate_{hot,cold}".
  * @filters:		Additional set of &struct damos_filter for &action.
+ * @ops_filters:	ops layer handling &struct damos_filter objects list.
  * @last_applied:	Last @action applied ops-managing entity.
  * @stat:		Statistics of this scheme.
  * @list:		List head for siblings.
@@ -503,6 +504,7 @@ struct damos {
 		int target_nid;
 	};
 	struct list_head filters;
+	struct list_head ops_filters;
 	void *last_applied;
 	struct damos_stat stat;
 	struct list_head list;
@@ -810,6 +812,12 @@ static inline unsigned long damon_sz_region(struct damon_region *r)
 #define damos_for_each_filter_safe(f, next, scheme) \
 	list_for_each_entry_safe(f, next, &(scheme)->filters, list)
 
+#define damos_for_each_ops_filter(f, scheme) \
+	list_for_each_entry(f, &(scheme)->ops_filters, list)
+
+#define damos_for_each_ops_filter_safe(f, next, scheme) \
+	list_for_each_entry_safe(f, next, &(scheme)->ops_filters, list)
+
 #ifdef CONFIG_DAMON
 
 struct damon_region *damon_new_region(unsigned long start, unsigned long end);
diff --git a/mm/damon/core.c b/mm/damon/core.c
index 38f545fea585..bcb7e42098dc 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -374,6 +374,7 @@ struct damos *damon_new_scheme(struct damos_access_pattern *pattern,
 	 */
 	scheme->next_apply_sis = 0;
 	INIT_LIST_HEAD(&scheme->filters);
+	INIT_LIST_HEAD(&scheme->ops_filters);
 	scheme->stat = (struct damos_stat){};
 	INIT_LIST_HEAD(&scheme->list);
 
-- 
2.39.5