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mm/damon/core: introduce nr_accesses_bp

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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: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
SeongJae Park 2023-09-15 02:52:48 +00:00 committed by Andrew Morton
parent 0926e8ff96
commit 80333828ea
3 changed files with 16 additions and 0 deletions
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5
include/linux/damon.h
View File

@ -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;

5
mm/damon/core-test.h
View File

@ -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){

6
mm/damon/core.c
View File

@ -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);
}