mm/damon/vaddr: move 'damon_set_regions()' to core

This commit moves 'damon_set_regions()' from vaddr to core, as it is aimed
to be used by not only 'vaddr' but also other parts of DAMON.

Link: https://lkml.kernel.org/r/20220429160606.127307-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 73 insertions, 0 deletions

diff --git a/mm/damon/core.c b/mm/damon/core.c
index b6daaff37bec..7d25dc582fe3 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -157,6 +157,79 @@ void damon_destroy_region(struct damon_region *r, struct damon_target *t)
 	damon_free_region(r);
 }
 
+/*
+ * Check whether a region is intersecting an address range
+ *
+ * Returns true if it is.
+ */
+static bool damon_intersect(struct damon_region *r,
+		struct damon_addr_range *re)
+{
+	return !(r->ar.end <= re->start || re->end <= r->ar.start);
+}
+
+/*
+ * damon_set_regions() - Set regions of a target for given address ranges.
+ * @t:		the given target.
+ * @ranges:	array of new monitoring target ranges.
+ * @nr_ranges:	length of @ranges.
+ *
+ * This function adds new regions to, or modify existing regions of a
+ * monitoring target to fit in specific ranges.
+ *
+ * Return: 0 if success, or negative error code otherwise.
+ */
+int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges,
+		unsigned int nr_ranges)
+{
+	struct damon_region *r, *next;
+	unsigned int i;
+
+	/* Remove regions which are not in the new ranges */
+	damon_for_each_region_safe(r, next, t) {
+		for (i = 0; i < nr_ranges; i++) {
+			if (damon_intersect(r, &ranges[i]))
+				break;
+		}
+		if (i == nr_ranges)
+			damon_destroy_region(r, t);
+	}
+
+	/* Add new regions or resize existing regions to fit in the ranges */
+	for (i = 0; i < nr_ranges; i++) {
+		struct damon_region *first = NULL, *last, *newr;
+		struct damon_addr_range *range;
+
+		range = &ranges[i];
+		/* Get the first/last regions intersecting with the range */
+		damon_for_each_region(r, t) {
+			if (damon_intersect(r, range)) {
+				if (!first)
+					first = r;
+				last = r;
+			}
+			if (r->ar.start >= range->end)
+				break;
+		}
+		if (!first) {
+			/* no region intersects with this range */
+			newr = damon_new_region(
+					ALIGN_DOWN(range->start,
+						DAMON_MIN_REGION),
+					ALIGN(range->end, DAMON_MIN_REGION));
+			if (!newr)
+				return -ENOMEM;
+			damon_insert_region(newr, damon_prev_region(r), r, t);
+		} else {
+			/* resize intersecting regions to fit in this range */
+			first->ar.start = ALIGN_DOWN(range->start,
+					DAMON_MIN_REGION);
+			last->ar.end = ALIGN(range->end, DAMON_MIN_REGION);
+		}
+	}
+	return 0;
+}
+
 struct damos *damon_new_scheme(
 		unsigned long min_sz_region, unsigned long max_sz_region,
 		unsigned int min_nr_accesses, unsigned int max_nr_accesses,