The quilt patch titled
Subject: mm/damon/core: implement intervals auto-tuning
has been removed from the -mm tree. Its filename was
mm-damon-core-implement-intervals-auto-tuning.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: SeongJae Park <sj@xxxxxxxxxx>
Subject: mm/damon/core: implement intervals auto-tuning
Date: Mon, 3 Mar 2025 14:17:20 -0800
Implement the DAMON sampling and aggregation intervals auto-tuning
mechanism as briefly described on 'struct damon_intervals_goal'. The core
part for deciding the direction and amount of the changes is implemented
reusing the feedback loop function which is being used for DAMOS quotas
auto-tuning. Unlike the DAMOS quotas auto-tuning use case, limit the
maximum decreasing amount after the adjustment to 50% of the current
value, though. This is because the intervals have no good merits at rapid
reductions since it could unnecessarily increase the monitoring overhead.
Link: https://lkml.kernel.org/r/20250303221726.484227-3-sj@xxxxxxxxxx
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/damon.h | 16 ++++++++
mm/damon/core.c | 76 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 92 insertions(+)
--- a/include/linux/damon.h~mm-damon-core-implement-intervals-auto-tuning
+++ a/include/linux/damon.h
@@ -713,6 +713,17 @@ struct damon_attrs {
struct damon_intervals_goal intervals_goal;
unsigned long min_nr_regions;
unsigned long max_nr_regions;
+/* private: internal use only */
+ /*
+ * @aggr_interval to @sample_interval ratio.
+ * Core-external components call damon_set_attrs() with &damon_attrs
+ * that this field is unset. In the case, damon_set_attrs() sets this
+ * field of resulting &damon_attrs. Core-internal components such as
+ * kdamond_tune_intervals() calls damon_set_attrs() with &damon_attrs
+ * that this field is set. In the case, damon_set_attrs() just keep
+ * it.
+ */
+ unsigned long aggr_samples;
};
/**
@@ -761,6 +772,11 @@ struct damon_ctx {
* update
*/
unsigned long next_ops_update_sis;
+ /*
+ * number of sample intervals that should be passed before next
+ * intervals tuning
+ */
+ unsigned long next_intervals_tune_sis;
/* for waiting until the execution of the kdamond_fn is started */
struct completion kdamond_started;
/* for scheme quotas prioritization */
--- a/mm/damon/core.c~mm-damon-core-implement-intervals-auto-tuning
+++ a/mm/damon/core.c
@@ -664,6 +664,10 @@ int damon_set_attrs(struct damon_ctx *ct
if (attrs->sample_interval > attrs->aggr_interval)
return -EINVAL;
+ /* calls from core-external doesn't set this. */
+ if (!attrs->aggr_samples)
+ attrs->aggr_samples = attrs->aggr_interval / sample_interval;
+
ctx->next_aggregation_sis = ctx->passed_sample_intervals +
attrs->aggr_interval / sample_interval;
ctx->next_ops_update_sis = ctx->passed_sample_intervals +
@@ -1301,6 +1305,65 @@ static void kdamond_reset_aggregated(str
}
}
+static unsigned long damon_get_intervals_score(struct damon_ctx *c)
+{
+ struct damon_target *t;
+ struct damon_region *r;
+ unsigned long sz_region, max_access_events = 0, access_events = 0;
+ unsigned long target_access_events;
+ unsigned long goal_bp = c->attrs.intervals_goal.access_bp;
+
+ damon_for_each_target(t, c) {
+ damon_for_each_region(r, t) {
+ sz_region = damon_sz_region(r);
+ max_access_events += sz_region * c->attrs.aggr_samples;
+ access_events += sz_region * r->nr_accesses;
+ }
+ }
+ target_access_events = max_access_events * goal_bp / 10000;
+ return access_events * 10000 / target_access_events;
+}
+
+static unsigned long damon_feed_loop_next_input(unsigned long last_input,
+ unsigned long score);
+
+static unsigned long damon_get_intervals_adaptation_bp(struct damon_ctx *c)
+{
+ unsigned long score_bp, adaptation_bp;
+
+ score_bp = damon_get_intervals_score(c);
+ adaptation_bp = damon_feed_loop_next_input(100000000, score_bp) /
+ 10000;
+ /*
+ * adaptaion_bp ranges from 1 to 20,000. Avoid too rapid reduction of
+ * the intervals by rescaling [1,10,000] to [5000, 10,000].
+ */
+ if (adaptation_bp <= 10000)
+ adaptation_bp = 5000 + adaptation_bp / 2;
+ return adaptation_bp;
+}
+
+static void kdamond_tune_intervals(struct damon_ctx *c)
+{
+ unsigned long adaptation_bp;
+ struct damon_attrs new_attrs;
+ struct damon_intervals_goal *goal;
+
+ adaptation_bp = damon_get_intervals_adaptation_bp(c);
+ if (adaptation_bp == 10000)
+ return;
+
+ new_attrs = c->attrs;
+ goal = &c->attrs.intervals_goal;
+ new_attrs.sample_interval = min(goal->max_sample_us,
+ c->attrs.sample_interval * adaptation_bp / 10000);
+ new_attrs.sample_interval = max(goal->min_sample_us,
+ new_attrs.sample_interval);
+ new_attrs.aggr_interval = new_attrs.sample_interval *
+ c->attrs.aggr_samples;
+ damon_set_attrs(c, &new_attrs);
+}
+
static void damon_split_region_at(struct damon_target *t,
struct damon_region *r, unsigned long sz_r);
@@ -2209,6 +2272,8 @@ static void kdamond_init_intervals_sis(s
ctx->next_aggregation_sis = ctx->attrs.aggr_interval / sample_interval;
ctx->next_ops_update_sis = ctx->attrs.ops_update_interval /
sample_interval;
+ ctx->next_intervals_tune_sis = ctx->next_aggregation_sis *
+ ctx->attrs.intervals_goal.aggrs;
damon_for_each_scheme(scheme, ctx) {
apply_interval = scheme->apply_interval_us ?
@@ -2293,6 +2358,17 @@ static int kdamond_fn(void *data)
sample_interval = ctx->attrs.sample_interval ?
ctx->attrs.sample_interval : 1;
if (ctx->passed_sample_intervals >= next_aggregation_sis) {
+ if (ctx->attrs.intervals_goal.aggrs &&
+ ctx->passed_sample_intervals >=
+ ctx->next_intervals_tune_sis) {
+ ctx->next_intervals_tune_sis +=
+ ctx->attrs.aggr_samples *
+ ctx->attrs.intervals_goal.aggrs;
+ kdamond_tune_intervals(ctx);
+ sample_interval = ctx->attrs.sample_interval ?
+ ctx->attrs.sample_interval : 1;
+
+ }
ctx->next_aggregation_sis = next_aggregation_sis +
ctx->attrs.aggr_interval / sample_interval;
_
Patches currently in -mm which might be from sj@xxxxxxxxxx are
mm-damon-sysfs-schemes-let-damon_sysfs_scheme_set_filters-be-used-for-different-named-directories.patch
mm-damon-sysfs-schemes-implement-core_filters-and-ops_filters-directories.patch
mm-damon-sysfs-schemes-commit-filters-in-coreops_filters-directories.patch
mm-damon-core-expose-damos_filter_for_ops-to-damon-kernel-api-callers.patch
mm-damon-sysfs-schemes-record-filters-of-which-layer-should-be-added-to-the-given-filters-directory.patch
mm-damon-sysfs-schemes-return-error-when-for-attempts-to-install-filters-on-wrong-sysfs-directory.patch
docs-abi-damon-document-coreops_filters-directories.patch
docs-admin-guide-mm-damon-usage-update-for-coreops_filters-directories.patch
mm-damon-sysfs-validate-user-inputs-from-damon_sysfs_commit_input.patch
mm-damon-core-invoke-kdamond_call-after-merging-is-done-if-possible.patch
mm-damon-core-make-damon_set_attrs-be-safe-to-be-called-from-damon_call.patch
mm-damon-sysfs-handle-commit-command-using-damon_call.patch
mm-damon-sysfs-remove-damon_sysfs_cmd_request-code-from-damon_sysfs_handle_cmd.patch
mm-damon-sysfs-remove-damon_sysfs_cmd_request_callback-and-its-callers.patch
mm-damon-sysfs-remove-damon_sysfs_cmd_request-and-its-readers.patch
mm-damon-sysfs-schemes-remove-obsolete-comment-for-damon_sysfs_schemes_clear_regions.patch
mm-damon-remove-damon_callback-private.patch
mm-damon-remove-before_start-of-damon_callback.patch
mm-damon-remove-damon_callback-after_sampling.patch
mm-damon-remove-damon_callback-before_damos_apply.patch
mm-damon-remove-damon_operations-reset_aggregated.patch
mm-damon-sysfs-schemes-avoid-wformat-security-warning-on-damon_sysfs_access_pattern_add_range_dir.patch
mm-madvise-use-is_memory_failure-from-madvise_do_behavior.patch
mm-madvise-split-out-populate-behavior-check-logic.patch
mm-madvise-deduplicate-madvise_do_behavior-skip-case-handlings.patch
mm-madvise-remove-len-parameter-of-madvise_do_behavior.patch
