DAMON virtual address space operation set (vaddr) is not supporting
prep_probes.  Add the support.

Signed-off-by: SJ Park <sj@kernel.org>
---
 mm/damon/vaddr.c | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index af9e1b82454cc..20f4784f17817 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -483,6 +483,45 @@ static unsigned int damon_va_check_accesses(struct damon_ctx *ctx)
 	return max_nr_accesses;
 }
 
+static void damon_va_prep_probe_region(struct damon_ctx *ctx,
+		struct mm_struct *mm, struct damon_region *r,
+		struct damon_probe *probe)
+{
+	struct damon_prep *p;
+
+	damon_for_each_prep(p, probe) {
+		switch (p->action) {
+		case DAMON_PREP_SET_PGIDLE:
+			damon_va_mkold(mm, r->sampling_addr);
+			break;
+		default:
+			break;
+		}
+	}
+}
+
+static void damon_va_prep_probes(struct damon_ctx *ctx, bool set_samples)
+{
+	struct damon_target *t;
+	struct mm_struct *mm;
+	struct damon_region *r;
+	struct damon_probe *p;
+
+	damon_for_each_target(t, ctx) {
+		mm = damon_get_mm(t);
+		if (!mm)
+			continue;
+		damon_for_each_region(r, t) {
+			if (set_samples)
+				r->sampling_addr = damon_rand(ctx, r->ar.start,
+						r->ar.end);
+			damon_for_each_probe(p, ctx)
+				damon_va_prep_probe_region(ctx, mm, r, p);
+		}
+		mmput(mm);
+	}
+}
+
 static bool damos_va_filter_young_match(struct damos_filter *filter,
 		struct folio *folio, struct vm_area_struct *vma,
 		unsigned long addr, pte_t *ptep, pmd_t *pmdp)
@@ -911,6 +950,7 @@ static int __init damon_va_initcall(void)
 		.update = damon_va_update,
 		.prepare_access_checks = damon_va_prepare_access_checks,
 		.check_accesses = damon_va_check_accesses,
+		.prep_probes = damon_va_prep_probes,
 		.target_valid = damon_va_target_valid,
 		.cleanup_target = damon_va_cleanup_target,
 		.apply_scheme = damon_va_apply_scheme,
-- 
2.47.3