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-rw-r--r--mm/damon/core.c70
1 files changed, 60 insertions, 10 deletions
diff --git a/mm/damon/core.c b/mm/damon/core.c
index 3a05e71509b9..36f6f1d21ff0 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -2,7 +2,7 @@
/*
* Data Access Monitor
*
- * Author: SeongJae Park <sjpark@amazon.de>
+ * Author: SeongJae Park <sj@kernel.org>
*/
#define pr_fmt(fmt) "damon: " fmt
@@ -1043,26 +1043,76 @@ static void damon_do_apply_schemes(struct damon_ctx *c,
}
}
-/* Shouldn't be called if quota->ms and quota->sz are zero */
+/*
+ * damon_feed_loop_next_input() - get next input to achieve a target score.
+ * @last_input The last input.
+ * @score Current score that made with @last_input.
+ *
+ * Calculate next input to achieve the target score, based on the last input
+ * and current score. Assuming the input and the score are positively
+ * proportional, calculate how much compensation should be added to or
+ * subtracted from the last input as a proportion of the last input. Avoid
+ * next input always being zero by setting it non-zero always. In short form
+ * (assuming support of float and signed calculations), the algorithm is as
+ * below.
+ *
+ * next_input = max(last_input * ((goal - current) / goal + 1), 1)
+ *
+ * For simple implementation, we assume the target score is always 10,000. The
+ * caller should adjust @score for this.
+ *
+ * Returns next input that assumed to achieve the target score.
+ */
+static unsigned long damon_feed_loop_next_input(unsigned long last_input,
+ unsigned long score)
+{
+ const unsigned long goal = 10000;
+ unsigned long score_goal_diff = max(goal, score) - min(goal, score);
+ unsigned long score_goal_diff_bp = score_goal_diff * 10000 / goal;
+ unsigned long compensation = last_input * score_goal_diff_bp / 10000;
+ /* Set minimum input as 10000 to avoid compensation be zero */
+ const unsigned long min_input = 10000;
+
+ if (goal > score)
+ return last_input + compensation;
+ if (last_input > compensation + min_input)
+ return last_input - compensation;
+ return min_input;
+}
+
+/* Shouldn't be called if quota->ms, quota->sz, and quota->get_score unset */
static void damos_set_effective_quota(struct damos_quota *quota)
{
unsigned long throughput;
unsigned long esz;
- if (!quota->ms) {
+ if (!quota->ms && !quota->get_score) {
quota->esz = quota->sz;
return;
}
- if (quota->total_charged_ns)
- throughput = quota->total_charged_sz * 1000000 /
- quota->total_charged_ns;
- else
- throughput = PAGE_SIZE * 1024;
- esz = throughput * quota->ms;
+ if (quota->get_score) {
+ quota->esz_bp = damon_feed_loop_next_input(
+ max(quota->esz_bp, 10000UL),
+ quota->get_score(quota->get_score_arg));
+ esz = quota->esz_bp / 10000;
+ }
+
+ if (quota->ms) {
+ if (quota->total_charged_ns)
+ throughput = quota->total_charged_sz * 1000000 /
+ quota->total_charged_ns;
+ else
+ throughput = PAGE_SIZE * 1024;
+ if (quota->get_score)
+ esz = min(throughput * quota->ms, esz);
+ else
+ esz = throughput * quota->ms;
+ }
if (quota->sz && quota->sz < esz)
esz = quota->sz;
+
quota->esz = esz;
}
@@ -1074,7 +1124,7 @@ static void damos_adjust_quota(struct damon_ctx *c, struct damos *s)
unsigned long cumulated_sz;
unsigned int score, max_score = 0;
- if (!quota->ms && !quota->sz)
+ if (!quota->ms && !quota->sz && !quota->get_score)
return;
/* New charge window starts */