Commit 80333828 authored by SeongJae Park's avatar SeongJae Park Committed by Andrew Morton
Browse files

mm/damon/core: introduce nr_accesses_bp 

Add yet another representation of the access rate of each region, namely
nr_accesses_bp.  It is just same to the nr_accesses but represents the
value in basis point (1 in 10,000), and updated at once in every
aggregation interval.  That is, moving_accesses_bp is just nr_accesses *
10000.  This may seems useless at the moment.  However, it will be useful
for representing less than one nr_accesses value that will be needed to
make moving sum-based nr_accesses.

Link: https://lkml.kernel.org/r/20230915025251.72816-6-sj@kernel.org


Signed-off-by: default avatarSeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 0926e8ff

include/linux/damon.h

+5 −0
Original line number Diff line number Diff line
@@ -40,6 +40,7 @@ struct damon_addr_range { 
 * @ar:			The address range of the region.

 * @sampling_addr:	Address of the sample for the next access check.

 * @nr_accesses:	Access frequency of this region.

 * @nr_accesses_bp:	@nr_accesses in basis point (0.01%).

 * @list:		List head for siblings.

 * @age:		Age of this region.

 *
@@ -49,6 +50,9 @@ struct damon_addr_range { 
 * not be done with direct access but with the helper function,

 * damon_update_region_access_rate().

 *

 * @nr_accesses_bp is another representation of @nr_accesses in basis point

 * (1 in 10,000) that updated every aggregation interval.

 *

 * @age is initially zero, increased for each aggregation interval, and reset

 * to zero again if the access frequency is significantly changed.  If two

 * regions are merged into a new region, both @nr_accesses and @age of the new
@@ -58,6 +62,7 @@ struct damon_region { 
	struct damon_addr_range ar;

	unsigned long sampling_addr;

	unsigned int nr_accesses;

	unsigned int nr_accesses_bp;

	struct list_head list;



	unsigned int age;

mm/damon/core-test.h

+5 −0
Original line number Diff line number Diff line
@@ -94,6 +94,7 @@ static void damon_test_aggregate(struct kunit *test) 
		for (ir = 0; ir < 3; ir++) {

			r = damon_new_region(saddr[it][ir], eaddr[it][ir]);

			r->nr_accesses = accesses[it][ir];

			r->nr_accesses_bp = accesses[it][ir] * 10000;

			damon_add_region(r, t);

		}

		it++;
@@ -147,9 +148,11 @@ static void damon_test_merge_two(struct kunit *test) 
	t = damon_new_target();

	r = damon_new_region(0, 100);

	r->nr_accesses = 10;

	r->nr_accesses_bp = 100000;

	damon_add_region(r, t);

	r2 = damon_new_region(100, 300);

	r2->nr_accesses = 20;

	r2->nr_accesses_bp = 200000;

	damon_add_region(r2, t);



	damon_merge_two_regions(t, r, r2);
@@ -196,6 +199,7 @@ static void damon_test_merge_regions_of(struct kunit *test) 
	for (i = 0; i < ARRAY_SIZE(sa); i++) {

		r = damon_new_region(sa[i], ea[i]);

		r->nr_accesses = nrs[i];

		r->nr_accesses_bp = nrs[i] * 10000;

		damon_add_region(r, t);

	}
@@ -297,6 +301,7 @@ static void damon_test_update_monitoring_result(struct kunit *test) 
	struct damon_region *r = damon_new_region(3, 7);



	r->nr_accesses = 15;

	r->nr_accesses_bp = 150000;

	r->age = 20;



	new_attrs = (struct damon_attrs){

mm/damon/core.c

+6 −0
Original line number Diff line number Diff line
@@ -128,6 +128,7 @@ struct damon_region *damon_new_region(unsigned long start, unsigned long end) 
	region->ar.start = start;

	region->ar.end = end;

	region->nr_accesses = 0;

	region->nr_accesses_bp = 0;

	INIT_LIST_HEAD(&region->list);



	region->age = 0;
@@ -508,6 +509,7 @@ static void damon_update_monitoring_result(struct damon_region *r, 
{

	r->nr_accesses = damon_nr_accesses_for_new_attrs(r->nr_accesses,

			old_attrs, new_attrs);

	r->nr_accesses_bp = r->nr_accesses * 10000;

	r->age = damon_age_for_new_attrs(r->age, old_attrs, new_attrs);

}
@@ -1115,6 +1117,7 @@ static void damon_merge_two_regions(struct damon_target *t, 


	l->nr_accesses = (l->nr_accesses * sz_l + r->nr_accesses * sz_r) /

			(sz_l + sz_r);

	l->nr_accesses_bp = l->nr_accesses * 10000;

	l->age = (l->age * sz_l + r->age * sz_r) / (sz_l + sz_r);

	l->ar.end = r->ar.end;

	damon_destroy_region(r, t);
@@ -1138,6 +1141,8 @@ static void damon_merge_regions_of(struct damon_target *t, unsigned int thres, 
		else

			r->age++;



		r->nr_accesses_bp = r->nr_accesses * 10000;



		if (prev && prev->ar.end == r->ar.start &&

		    abs(prev->nr_accesses - r->nr_accesses) <= thres &&

		    damon_sz_region(prev) + damon_sz_region(r) <= sz_limit)
@@ -1186,6 +1191,7 @@ static void damon_split_region_at(struct damon_target *t, 


	new->age = r->age;

	new->last_nr_accesses = r->last_nr_accesses;

	new->nr_accesses_bp = r->nr_accesses_bp;



	damon_insert_region(new, r, damon_next_region(r), t);

}