+ mm-damon-core-introduce-damon_operations-prep_probes.patch added to mm-new branch

+ mm-damon-core-introduce-damon_operations-prep_probes.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm/damon/core: introduce damon_operations->prep_probes()
has been added to the -mm mm-new branch.  Its filename is
     mm-damon-core-introduce-damon_operations-prep_probes.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-damon-core-introduce-damon_operations-prep_probes.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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------------------------------------------------------
From: SJ Park <sj@kernel.org>
Subject: mm/damon/core: introduce damon_operations->prep_probes()
Date: Tue, 1 Sep 2026 06:24:54 -0700

damon_prep needs to be executed by the underlying DAMON operation set. 
Extend the operation set callback list for the execution of damon_prep
actions.  If the underlying operation set implements the callback, DAMON
core executes it in the monitoring preparation time.

Link: https://lore.kernel.org/20260901132506.99243-8-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/damon.h |    5 +++++
 mm/damon/core.c       |   20 +++++++++++++++++++-
 2 files changed, 24 insertions(+), 1 deletion(-)

--- a/include/linux/damon.h~mm-damon-core-introduce-damon_operations-prep_probes
+++ a/include/linux/damon.h
@@ -630,6 +630,7 @@ enum damon_ops_id {
  * @update:			Update operations-related data structures.
  * @prepare_access_checks:	Prepare next access check of target regions.
  * @check_accesses:		Check the accesses to target regions.
+ * @prep_probes:		Prepare applying probes for each region.
  * @apply_probes:		Apply probes for each region.
  * @get_scheme_score:		Get the score of a region for a scheme.
  * @apply_scheme:		Apply a DAMON-based operation scheme.
@@ -657,6 +658,9 @@ enum damon_ops_id {
  * last preparation and update the number of observed accesses of each region.
  * It should also return max number of observed accesses that made as a result
  * of its update.  The value will be used for regions adjustment threshold.
+ * @prep_probes should execute required &struct damon_prep for next &struct
+ * damon_probe applications to each region.  It should also set
+ * &damon_region->sampling_addr of each region if ``set_samples`` is true.
  * @apply_probes should apply the data attribute probes to each region and
  * accordingly update the probe hits counter of the region.  It should also
  * set &damon_region->sampling_addr of each region if ``set_samples`` is true.
@@ -679,6 +683,7 @@ struct damon_operations {
 	void (*update)(struct damon_ctx *context);
 	void (*prepare_access_checks)(struct damon_ctx *context);
 	unsigned int (*check_accesses)(struct damon_ctx *context);
+	void (*prep_probes)(struct damon_ctx *context, bool set_samples);
 	unsigned int (*apply_probes)(struct damon_ctx *context,
 			bool set_samples, bool return_max_wsum);
 	int (*get_scheme_score)(struct damon_ctx *context,
--- a/mm/damon/core.c~mm-damon-core-introduce-damon_operations-prep_probes
+++ a/mm/damon/core.c
@@ -157,6 +157,18 @@ static struct damon_prep *damon_nth_prep
 	return NULL;
 }
 
+static bool damon_has_prep(struct damon_ctx *c)
+{
+	struct damon_prep *prep;
+	struct damon_probe *probe;
+
+	damon_for_each_probe(probe, c) {
+		damon_for_each_prep(prep, probe)
+			return true;
+	}
+	return false;
+}
+
 struct damon_filter *damon_new_filter(enum damon_filter_type type,
 		bool matching, bool allow)
 {
@@ -3894,14 +3906,19 @@ static int kdamond_fn(void *data)
 		unsigned long next_ops_update_sis = ctx->next_ops_update_sis;
 		unsigned long sample_interval = ctx->attrs.sample_interval;
 		bool access_check_disabled = damon_has_probe_weights(ctx);
+		bool do_prep;
 		unsigned int max_merge_score = 0, max_wsum;
 		bool get_max_wsum;
 
 		if (kdamond_wait_activation(ctx))
 			break;
 
+		do_prep = ctx->ops.prep_probes && damon_has_prep(ctx);
+
 		if (!access_check_disabled && ctx->ops.prepare_access_checks)
 			ctx->ops.prepare_access_checks(ctx);
+		if (do_prep)
+			ctx->ops.prep_probes(ctx, access_check_disabled);
 
 		kdamond_usleep(sample_interval);
 		ctx->passed_sample_intervals++;
@@ -3916,7 +3933,8 @@ static int kdamond_fn(void *data)
 			else
 				get_max_wsum = false;
 			max_wsum = ctx->ops.apply_probes(ctx,
-					access_check_disabled, get_max_wsum);
+					access_check_disabled && !do_prep,
+					get_max_wsum);
 			if (get_max_wsum)
 				max_merge_score = max_wsum;
 		}
_

Patches currently in -mm which might be from sj@kernel.org are

mm-damon-core-skip-applying-scheme-if-region-split-for-quota-fails.patch
mm-damon-paddr-respect-folio-end-for-damos_stat.patch
mm-damon-paddr-respect-folio-end-for-damos-actions-except-stat.patch
mm-damon-vaddr-respect-folio-end-for-damos_stat.patch
mm-damon-vaddr-respect-folio-end-for-damos_migrate_hotcold.patch
mm-damon-core-handle-extreme-memory-state-in-damon_get_node_mem_bp.patch
mm-damon-core-handle-extreme-memory-state-in-get_node_memcg_used_bp.patch
mm-damon-core-handle-extreme-memory-state-in-get_in_active_mem_bp.patch
mm-damon-core-introduce-damon_filter_type_pgidle_unset.patch
mm-damon-paddr-support-pgidle_unset-probe-filter-type.patch
mm-damon-sysfs-support-pgidle_unset-probe-filter-type.patch
docs-mm-damon-design-document-pgidle_unset-probe-filter-type.patch
mm-damon-core-introduce-damon_prep-struct.patch
mm-damon-core-commit-preps.patch
mm-damon-core-introduce-damon_operations-prep_probes.patch
mm-damon-paddr-support-damon_prep.patch
mm-damon-sysfs-implement-preps-directory.patch
mm-damon-sysfs-implement-preps-nr_preps-file.patch
mm-damon-sysfs-create-directories-for-nr_preps-writes.patch
mm-damon-sysfs-implement-prep_action-file.patch
mm-damon-sysfs-pass-preps-to-damon-core.patch
selftests-damon-sysfssh-test-probe-prep-sysfs-files.patch
docs-mm-damon-design-document-probe-preps.patch
docs-admin-guide-mm-damon-usage-document-probe-preps-sysfs-files.patch
docs-abi-damon-document-probe-prep-sysfs-files.patch