[RFC PATCH 14/14] mm/damon/core: remove damon_callback

[SeongJae Park <sj@kernel.org>]

All damon_callback usages are replicated by damon_call() and
damos_walk().  Remove damon_callback.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 include/linux/damon.h | 31 +------------------------------
 mm/damon/core.c       | 26 +++++++-------------------
 2 files changed, 8 insertions(+), 49 deletions(-)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 52b307db63de..5e5cabbf8190 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -628,34 +628,6 @@ struct damon_operations {
 	void (*cleanup)(struct damon_ctx *context);
 };
 
-/**
- * struct damon_callback - Monitoring events notification callbacks.
- *
- * @after_wmarks_check:	Called after each schemes' watermarks check.
- * @after_aggregation:	Called after each aggregation.
- * @before_terminate:	Called before terminating the monitoring.
- *
- * The monitoring thread (&damon_ctx.kdamond) calls @before_terminate just
- * before finishing the monitoring.
- *
- * The monitoring thread calls @after_wmarks_check after each DAMON-based
- * operation schemes' watermarks check.  If users need to make changes to the
- * attributes of the monitoring context while it's deactivated due to the
- * watermarks, this is the good place to do.
- *
- * The monitoring thread calls @after_aggregation for each of the aggregation
- * intervals.  Therefore, users can safely access the monitoring results
- * without additional protection.  For the reason, users are recommended to use
- * these callback for the accesses to the results.
- *
- * If any callback returns non-zero, monitoring stops.
- */
-struct damon_callback {
-	int (*after_wmarks_check)(struct damon_ctx *context);
-	int (*after_aggregation)(struct damon_ctx *context);
-	void (*before_terminate)(struct damon_ctx *context);
-};
-
 /*
  * struct damon_call_control - Control damon_call().
  *
@@ -726,7 +698,7 @@ struct damon_intervals_goal {
  * ``mmap()`` calls from the application, in case of virtual memory monitoring)
  * and applies the changes for each @ops_update_interval.  All time intervals
  * are in micro-seconds.  Please refer to &struct damon_operations and &struct
- * damon_callback for more detail.
+ * damon_call_control for more detail.
  */
 struct damon_attrs {
 	unsigned long sample_interval;
@@ -816,7 +788,6 @@ struct damon_ctx {
 	struct mutex kdamond_lock;
 
 	struct damon_operations ops;
-	struct damon_callback callback;
 
 	struct list_head adaptive_targets;
 	struct list_head schemes;
diff --git a/mm/damon/core.c b/mm/damon/core.c
index 719373bcfaad..ebf483fc0b76 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -680,9 +680,7 @@ static bool damon_valid_intervals_goal(struct damon_attrs *attrs)
  * @attrs:		monitoring attributes
  *
  * This function should be called while the kdamond is not running, an access
- * check results aggregation is not ongoing (e.g., from &struct
- * damon_callback->after_aggregation or &struct
- * damon_callback->after_wmarks_check callbacks), or from damon_call().
+ * check results aggregation is not ongoing (e.g., from damon_call().
  *
  * Every time interval is in micro-seconds.
  *
@@ -778,7 +776,7 @@ static void damos_commit_quota_goal(
  * DAMON contexts, instead of manual in-place updates.
  *
  * This function should be called from parameters-update safe context, like
- * DAMON callbacks.
+ * damon_call().
  */
 int damos_commit_quota_goals(struct damos_quota *dst, struct damos_quota *src)
 {
@@ -1137,7 +1135,7 @@ static int damon_commit_targets(
  * in-place updates.
  *
  * This function should be called from parameters-update safe context, like
- * DAMON callbacks.
+ * damon_call().
  */
 int damon_commit_ctx(struct damon_ctx *dst, struct damon_ctx *src)
 {
@@ -2444,9 +2442,6 @@ static int kdamond_wait_activation(struct damon_ctx *ctx)
 
 		kdamond_usleep(min_wait_time);
 
-		if (ctx->callback.after_wmarks_check &&
-				ctx->callback.after_wmarks_check(ctx))
-			break;
 		kdamond_call(ctx, false);
 		damos_walk_cancel(ctx);
 	}
@@ -2503,10 +2498,9 @@ static int kdamond_fn(void *data)
 	while (!kdamond_need_stop(ctx)) {
 		/*
 		 * ctx->attrs and ctx->next_{aggregation,ops_update}_sis could
-		 * be changed from after_wmarks_check() or after_aggregation()
-		 * callbacks.  Read the values here, and use those for this
-		 * iteration.  That is, damon_set_attrs() updated new values
-		 * are respected from next iteration.
+		 * be changed from kdamond_call().  Read the values here, and
+		 * use those for this iteration.  That is, damon_set_attrs()
+		 * updated new values are respected from next iteration.
 		 */
 		unsigned long next_aggregation_sis = ctx->next_aggregation_sis;
 		unsigned long next_ops_update_sis = ctx->next_ops_update_sis;
@@ -2524,14 +2518,10 @@ static int kdamond_fn(void *data)
 		if (ctx->ops.check_accesses)
 			max_nr_accesses = ctx->ops.check_accesses(ctx);
 
-		if (ctx->passed_sample_intervals >= next_aggregation_sis) {
+		if (ctx->passed_sample_intervals >= next_aggregation_sis)
 			kdamond_merge_regions(ctx,
 					max_nr_accesses / 10,
 					sz_limit);
-			if (ctx->callback.after_aggregation &&
-					ctx->callback.after_aggregation(ctx))
-				break;
-		}
 
 		/*
 		 * do kdamond_call() and kdamond_apply_schemes() after
@@ -2597,8 +2587,6 @@ static int kdamond_fn(void *data)
 			damon_destroy_region(r, t);
 	}
 
-	if (ctx->callback.before_terminate)
-		ctx->callback.before_terminate(ctx);
 	if (ctx->ops.cleanup)
 		ctx->ops.cleanup(ctx);
 	kfree(ctx->regions_score_histogram);
-- 
2.39.5