Adopting addr_unit would make DAMON_MINREGION 'addr_unit * 4096'
bytes and cause data alignment issues[1].
Add damon_ctx->min_region to change DAMON_MIN_REGION from a global
macro value to per-context variable.
[1] https://lore.kernel.org/all/527714dd-0e33-43ab-bbbd-d89670ba79e7@huawei.com
Signed-off-by: Quanmin Yan <yanquanmin1@huawei.com>
---
include/linux/damon.h | 4 ++-
mm/damon/core.c | 68 ++++++++++++++++++++----------------
mm/damon/sysfs.c | 8 +++--
mm/damon/tests/core-kunit.h | 16 ++++-----
mm/damon/tests/vaddr-kunit.h | 2 +-
mm/damon/vaddr.c | 2 +-
6 files changed, 56 insertions(+), 44 deletions(-)
diff --git a/include/linux/damon.h b/include/linux/damon.h
index 6fa52f7495d9..bebd791f37f1 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -747,6 +747,7 @@ struct damon_attrs {
*
* @ops: Set of monitoring operations for given use cases.
* @addr_unit: Scale factor for core to ops address conversion.
+ * @min_region: Minimum Region Size.
* @adaptive_targets: Head of monitoring targets (&damon_target) list.
* @schemes: Head of schemes (&damos) list.
*/
@@ -789,6 +790,7 @@ struct damon_ctx {
struct damon_operations ops;
unsigned long addr_unit;
+ unsigned long min_region;
struct list_head adaptive_targets;
struct list_head schemes;
@@ -877,7 +879,7 @@ static inline void damon_insert_region(struct damon_region *r,
void damon_add_region(struct damon_region *r, struct damon_target *t);
void damon_destroy_region(struct damon_region *r, struct damon_target *t);
int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges,
- unsigned int nr_ranges);
+ unsigned int nr_ranges, unsigned long min_region);
void damon_update_region_access_rate(struct damon_region *r, bool accessed,
struct damon_attrs *attrs);
diff --git a/mm/damon/core.c b/mm/damon/core.c
index 8f8aa84953ac..980e271e42e9 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -208,7 +208,7 @@ static int damon_fill_regions_holes(struct damon_region *first,
* 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)
+ unsigned int nr_ranges, unsigned long min_region)
{
struct damon_region *r, *next;
unsigned int i;
@@ -245,16 +245,16 @@ int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges,
/* no region intersects with this range */
newr = damon_new_region(
ALIGN_DOWN(range->start,
- DAMON_MIN_REGION),
- ALIGN(range->end, DAMON_MIN_REGION));
+ min_region),
+ ALIGN(range->end, 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);
+ min_region);
+ last->ar.end = ALIGN(range->end, min_region);
/* fill possible holes in the range */
err = damon_fill_regions_holes(first, last, t);
@@ -545,6 +545,7 @@ struct damon_ctx *damon_new_ctx(void)
ctx->attrs.max_nr_regions = 1000;
ctx->addr_unit = 1;
+ ctx->min_region = DAMON_MIN_REGION;
INIT_LIST_HEAD(&ctx->adaptive_targets);
INIT_LIST_HEAD(&ctx->schemes);
@@ -1127,8 +1128,8 @@ static struct damon_target *damon_nth_target(int n, struct damon_ctx *ctx)
*
* If @src has no region, @dst keeps current regions.
*/
-static int damon_commit_target_regions(
- struct damon_target *dst, struct damon_target *src)
+static int damon_commit_target_regions(struct damon_target *dst,
+ struct damon_target *src, unsigned long src_min_region)
{
struct damon_region *src_region;
struct damon_addr_range *ranges;
@@ -1145,18 +1146,19 @@ static int damon_commit_target_regions(
i = 0;
damon_for_each_region(src_region, src)
ranges[i++] = src_region->ar;
- err = damon_set_regions(dst, ranges, i);
+ err = damon_set_regions(dst, ranges, i, src_min_region);
kfree(ranges);
return err;
}
static int damon_commit_target(
struct damon_target *dst, bool dst_has_pid,
- struct damon_target *src, bool src_has_pid)
+ struct damon_target *src, bool src_has_pid,
+ unsigned long src_min_region)
{
int err;
- err = damon_commit_target_regions(dst, src);
+ err = damon_commit_target_regions(dst, src, src_min_region);
if (err)
return err;
if (dst_has_pid)
@@ -1178,7 +1180,8 @@ static int damon_commit_targets(
if (src_target) {
err = damon_commit_target(
dst_target, damon_target_has_pid(dst),
- src_target, damon_target_has_pid(src));
+ src_target, damon_target_has_pid(src),
+ src->min_region);
if (err)
return err;
} else {
@@ -1201,7 +1204,8 @@ static int damon_commit_targets(
if (!new_target)
return -ENOMEM;
err = damon_commit_target(new_target, false,
- src_target, damon_target_has_pid(src));
+ src_target, damon_target_has_pid(src),
+ src->min_region);
if (err) {
damon_destroy_target(new_target, NULL);
return err;
@@ -1248,6 +1252,7 @@ int damon_commit_ctx(struct damon_ctx *dst, struct damon_ctx *src)
}
dst->ops = src->ops;
dst->addr_unit = src->addr_unit;
+ dst->min_region = max(DAMON_MIN_REGION / dst->addr_unit, 1);
return 0;
}
@@ -1280,8 +1285,8 @@ static unsigned long damon_region_sz_limit(struct damon_ctx *ctx)
if (ctx->attrs.min_nr_regions)
sz /= ctx->attrs.min_nr_regions;
- if (sz < DAMON_MIN_REGION)
- sz = DAMON_MIN_REGION;
+ if (sz < ctx->min_region)
+ sz = ctx->min_region;
return sz;
}
@@ -1641,8 +1646,9 @@ static bool damos_valid_target(struct damon_ctx *c, struct damon_target *t,
*
* Return: true if the region should be entirely skipped, false otherwise.
*/
-static bool damos_skip_charged_region(struct damon_target *t,
- struct damon_region **rp, struct damos *s)
+static bool damos_skip_charged_region(
+ struct damon_target *t, struct damon_region **rp,
+ struct damos *s, unsigned long min_region)
{
struct damon_region *r = *rp;
struct damos_quota *quota = &s->quota;
@@ -1664,11 +1670,11 @@ static bool damos_skip_charged_region(struct damon_target *t,
if (quota->charge_addr_from && r->ar.start <
quota->charge_addr_from) {
sz_to_skip = ALIGN_DOWN(quota->charge_addr_from -
- r->ar.start, DAMON_MIN_REGION);
+ r->ar.start, min_region);
if (!sz_to_skip) {
- if (damon_sz_region(r) <= DAMON_MIN_REGION)
+ if (damon_sz_region(r) <= min_region)
return true;
- sz_to_skip = DAMON_MIN_REGION;
+ sz_to_skip = min_region;
}
damon_split_region_at(t, r, sz_to_skip);
r = damon_next_region(r);
@@ -1693,7 +1699,8 @@ static void damos_update_stat(struct damos *s,
}
static bool damos_filter_match(struct damon_ctx *ctx, struct damon_target *t,
- struct damon_region *r, struct damos_filter *filter)
+ struct damon_region *r, struct damos_filter *filter,
+ unsigned long min_region)
{
bool matched = false;
struct damon_target *ti;
@@ -1710,8 +1717,8 @@ static bool damos_filter_match(struct damon_ctx *ctx, struct damon_target *t,
matched = target_idx == filter->target_idx;
break;
case DAMOS_FILTER_TYPE_ADDR:
- start = ALIGN_DOWN(filter->addr_range.start, DAMON_MIN_REGION);
- end = ALIGN_DOWN(filter->addr_range.end, DAMON_MIN_REGION);
+ start = ALIGN_DOWN(filter->addr_range.start, min_region);
+ end = ALIGN_DOWN(filter->addr_range.end, min_region);
/* inside the range */
if (start <= r->ar.start && r->ar.end <= end) {
@@ -1747,7 +1754,7 @@ static bool damos_filter_out(struct damon_ctx *ctx, struct damon_target *t,
s->core_filters_allowed = false;
damos_for_each_filter(filter, s) {
- if (damos_filter_match(ctx, t, r, filter)) {
+ if (damos_filter_match(ctx, t, r, filter, ctx->min_region)) {
if (filter->allow)
s->core_filters_allowed = true;
return !filter->allow;
@@ -1882,7 +1889,7 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
if (c->ops.apply_scheme) {
if (quota->esz && quota->charged_sz + sz > quota->esz) {
sz = ALIGN_DOWN(quota->esz - quota->charged_sz,
- DAMON_MIN_REGION);
+ c->min_region);
if (!sz)
goto update_stat;
damon_split_region_at(t, r, sz);
@@ -1930,7 +1937,7 @@ static void damon_do_apply_schemes(struct damon_ctx *c,
if (quota->esz && quota->charged_sz >= quota->esz)
continue;
- if (damos_skip_charged_region(t, &r, s))
+ if (damos_skip_charged_region(t, &r, s, c->min_region))
continue;
if (!damos_valid_target(c, t, r, s))
@@ -2324,7 +2331,8 @@ static void damon_split_region_at(struct damon_target *t,
}
/* Split every region in the given target into 'nr_subs' regions */
-static void damon_split_regions_of(struct damon_target *t, int nr_subs)
+static void damon_split_regions_of(struct damon_target *t,
+ int nr_subs, unsigned long min_region)
{
struct damon_region *r, *next;
unsigned long sz_region, sz_sub = 0;
@@ -2334,13 +2342,13 @@ static void damon_split_regions_of(struct damon_target *t, int nr_subs)
sz_region = damon_sz_region(r);
for (i = 0; i < nr_subs - 1 &&
- sz_region > 2 * DAMON_MIN_REGION; i++) {
+ sz_region > 2 * min_region; i++) {
/*
* Randomly select size of left sub-region to be at
* least 10 percent and at most 90% of original region
*/
sz_sub = ALIGN_DOWN(damon_rand(1, 10) *
- sz_region / 10, DAMON_MIN_REGION);
+ sz_region / 10, min_region);
/* Do not allow blank region */
if (sz_sub == 0 || sz_sub >= sz_region)
continue;
@@ -2380,7 +2388,7 @@ static void kdamond_split_regions(struct damon_ctx *ctx)
nr_subregions = 3;
damon_for_each_target(t, ctx)
- damon_split_regions_of(t, nr_subregions);
+ damon_split_regions_of(t, nr_subregions, ctx->min_region);
last_nr_regions = nr_regions;
}
@@ -2769,7 +2777,7 @@ int damon_set_region_biggest_system_ram_default(struct damon_target *t,
addr_range.start = *start;
addr_range.end = *end;
- return damon_set_regions(t, &addr_range, 1);
+ return damon_set_regions(t, &addr_range, 1, DAMON_MIN_REGION);
}
/*
diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 98bf15d403b2..840b3a73147a 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -1329,7 +1329,8 @@ static int damon_sysfs_set_attrs(struct damon_ctx *ctx,
}
static int damon_sysfs_set_regions(struct damon_target *t,
- struct damon_sysfs_regions *sysfs_regions)
+ struct damon_sysfs_regions *sysfs_regions,
+ unsigned long min_region)
{
struct damon_addr_range *ranges = kmalloc_array(sysfs_regions->nr,
sizeof(*ranges), GFP_KERNEL | __GFP_NOWARN);
@@ -1351,7 +1352,7 @@ static int damon_sysfs_set_regions(struct damon_target *t,
if (ranges[i - 1].end > ranges[i].start)
goto out;
}
- err = damon_set_regions(t, ranges, sysfs_regions->nr);
+ err = damon_set_regions(t, ranges, sysfs_regions->nr, min_region);
out:
kfree(ranges);
return err;
@@ -1372,7 +1373,7 @@ static int damon_sysfs_add_target(struct damon_sysfs_target *sys_target,
/* caller will destroy targets */
return -EINVAL;
}
- return damon_sysfs_set_regions(t, sys_target->regions);
+ return damon_sysfs_set_regions(t, sys_target->regions, ctx->min_region);
}
static int damon_sysfs_add_targets(struct damon_ctx *ctx,
@@ -1430,6 +1431,7 @@ static int damon_sysfs_apply_inputs(struct damon_ctx *ctx,
if (err)
return err;
ctx->addr_unit = sys_ctx->addr_unit;
+ ctx->min_region = max(DAMON_MIN_REGION / ctx->addr_unit, 1);
err = damon_sysfs_set_attrs(ctx, sys_ctx->attrs);
if (err)
return err;
diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index 5f5dc9db2e90..a7fa078da405 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -230,14 +230,14 @@ static void damon_test_split_regions_of(struct kunit *test)
t = damon_new_target();
r = damon_new_region(0, 22);
damon_add_region(r, t);
- damon_split_regions_of(t, 2);
+ damon_split_regions_of(t, 2, DAMON_MIN_REGION);
KUNIT_EXPECT_LE(test, damon_nr_regions(t), 2u);
damon_free_target(t);
t = damon_new_target();
r = damon_new_region(0, 220);
damon_add_region(r, t);
- damon_split_regions_of(t, 4);
+ damon_split_regions_of(t, 4, DAMON_MIN_REGION);
KUNIT_EXPECT_LE(test, damon_nr_regions(t), 4u);
damon_free_target(t);
damon_destroy_ctx(c);
@@ -303,7 +303,7 @@ static void damon_test_set_regions(struct kunit *test)
damon_add_region(r1, t);
damon_add_region(r2, t);
- damon_set_regions(t, &range, 1);
+ damon_set_regions(t, &range, 1, DAMON_MIN_REGION);
KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 3);
damon_for_each_region(r, t) {
@@ -450,25 +450,25 @@ static void damos_test_filter_out(struct kunit *test)
damon_add_region(r, t);
/* region in the range */
- KUNIT_EXPECT_TRUE(test, damos_filter_match(NULL, t, r, f));
+ KUNIT_EXPECT_TRUE(test, damos_filter_match(NULL, t, r, f, DAMON_MIN_REGION));
KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 1);
/* region before the range */
r->ar.start = DAMON_MIN_REGION * 1;
r->ar.end = DAMON_MIN_REGION * 2;
- KUNIT_EXPECT_FALSE(test, damos_filter_match(NULL, t, r, f));
+ KUNIT_EXPECT_FALSE(test, damos_filter_match(NULL, t, r, f, DAMON_MIN_REGION));
KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 1);
/* region after the range */
r->ar.start = DAMON_MIN_REGION * 6;
r->ar.end = DAMON_MIN_REGION * 8;
- KUNIT_EXPECT_FALSE(test, damos_filter_match(NULL, t, r, f));
+ KUNIT_EXPECT_FALSE(test, damos_filter_match(NULL, t, r, f, DAMON_MIN_REGION));
KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 1);
/* region started before the range */
r->ar.start = DAMON_MIN_REGION * 1;
r->ar.end = DAMON_MIN_REGION * 4;
- KUNIT_EXPECT_FALSE(test, damos_filter_match(NULL, t, r, f));
+ KUNIT_EXPECT_FALSE(test, damos_filter_match(NULL, t, r, f, DAMON_MIN_REGION));
/* filter should have split the region */
KUNIT_EXPECT_EQ(test, r->ar.start, DAMON_MIN_REGION * 1);
KUNIT_EXPECT_EQ(test, r->ar.end, DAMON_MIN_REGION * 2);
@@ -481,7 +481,7 @@ static void damos_test_filter_out(struct kunit *test)
/* region started in the range */
r->ar.start = DAMON_MIN_REGION * 2;
r->ar.end = DAMON_MIN_REGION * 8;
- KUNIT_EXPECT_TRUE(test, damos_filter_match(NULL, t, r, f));
+ KUNIT_EXPECT_TRUE(test, damos_filter_match(NULL, t, r, f, DAMON_MIN_REGION));
/* filter should have split the region */
KUNIT_EXPECT_EQ(test, r->ar.start, DAMON_MIN_REGION * 2);
KUNIT_EXPECT_EQ(test, r->ar.end, DAMON_MIN_REGION * 6);
diff --git a/mm/damon/tests/vaddr-kunit.h b/mm/damon/tests/vaddr-kunit.h
index d2b37ccf2cc0..fce38dd53cf8 100644
--- a/mm/damon/tests/vaddr-kunit.h
+++ b/mm/damon/tests/vaddr-kunit.h
@@ -141,7 +141,7 @@ static void damon_do_test_apply_three_regions(struct kunit *test,
damon_add_region(r, t);
}
- damon_set_regions(t, three_regions, 3);
+ damon_set_regions(t, three_regions, 3, DAMON_MIN_REGION);
for (i = 0; i < nr_expected / 2; i++) {
r = __nth_region_of(t, i);
diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index 66ef9869eafe..8c048f9b129e 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -299,7 +299,7 @@ static void damon_va_update(struct damon_ctx *ctx)
damon_for_each_target(t, ctx) {
if (damon_va_three_regions(t, three_regions))
continue;
- damon_set_regions(t, three_regions, 3);
+ damon_set_regions(t, three_regions, 3, DAMON_MIN_REGION);
}
}
--
2.43.0On Wed, 20 Aug 2025 16:06:21 +0800 Quanmin Yan <yanquanmin1@huawei.com> wrote:
> Adopting addr_unit would make DAMON_MINREGION 'addr_unit * 4096'
> bytes and cause data alignment issues[1].
>
> Add damon_ctx->min_region to change DAMON_MIN_REGION from a global
> macro value to per-context variable.
>
> [1] https://lore.kernel.org/all/527714dd-0e33-43ab-bbbd-d89670ba79e7@huawei.com
>
> Signed-off-by: Quanmin Yan <yanquanmin1@huawei.com>
> ---
> include/linux/damon.h | 4 ++-
> mm/damon/core.c | 68 ++++++++++++++++++++----------------
> mm/damon/sysfs.c | 8 +++--
> mm/damon/tests/core-kunit.h | 16 ++++-----
> mm/damon/tests/vaddr-kunit.h | 2 +-
> mm/damon/vaddr.c | 2 +-
> 6 files changed, 56 insertions(+), 44 deletions(-)
>
> diff --git a/include/linux/damon.h b/include/linux/damon.h
> index 6fa52f7495d9..bebd791f37f1 100644
> --- a/include/linux/damon.h
> +++ b/include/linux/damon.h
> @@ -747,6 +747,7 @@ struct damon_attrs {
> *
> * @ops: Set of monitoring operations for given use cases.
> * @addr_unit: Scale factor for core to ops address conversion.
> + * @min_region: Minimum Region Size.
The name feels not very clear to me. What about min_sz_region? Also, the
description can be like more general sentence, e.g., 'Minimum region size.'
Apparently the name came from DAMON_MIN_REGION, which I named. Let's blame SJ
of 2021 :) Let's not change DAMON_MIN_REGION's name, though. Maybe such a
change is not really necessary for now.
I was thinking I gave a same comment to RFC v1, but I didn't. Seems I forgot
sending a draft. Sorry for late comment.
> * @adaptive_targets: Head of monitoring targets (&damon_target) list.
> * @schemes: Head of schemes (&damos) list.
> */
> @@ -789,6 +790,7 @@ struct damon_ctx {
>
> struct damon_operations ops;
> unsigned long addr_unit;
> + unsigned long min_region;
>
> struct list_head adaptive_targets;
> struct list_head schemes;
> @@ -877,7 +879,7 @@ static inline void damon_insert_region(struct damon_region *r,
> void damon_add_region(struct damon_region *r, struct damon_target *t);
> void damon_destroy_region(struct damon_region *r, struct damon_target *t);
> int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges,
> - unsigned int nr_ranges);
> + unsigned int nr_ranges, unsigned long min_region);
> void damon_update_region_access_rate(struct damon_region *r, bool accessed,
> struct damon_attrs *attrs);
>
> diff --git a/mm/damon/core.c b/mm/damon/core.c
> index 8f8aa84953ac..980e271e42e9 100644
> --- a/mm/damon/core.c
> +++ b/mm/damon/core.c
> @@ -208,7 +208,7 @@ static int damon_fill_regions_holes(struct damon_region *first,
> * 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)
> + unsigned int nr_ranges, unsigned long min_region)
> {
> struct damon_region *r, *next;
> unsigned int i;
> @@ -245,16 +245,16 @@ int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges,
> /* no region intersects with this range */
> newr = damon_new_region(
> ALIGN_DOWN(range->start,
> - DAMON_MIN_REGION),
> - ALIGN(range->end, DAMON_MIN_REGION));
> + min_region),
> + ALIGN(range->end, 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);
> + min_region);
> + last->ar.end = ALIGN(range->end, min_region);
>
> /* fill possible holes in the range */
> err = damon_fill_regions_holes(first, last, t);
> @@ -545,6 +545,7 @@ struct damon_ctx *damon_new_ctx(void)
> ctx->attrs.max_nr_regions = 1000;
>
> ctx->addr_unit = 1;
> + ctx->min_region = DAMON_MIN_REGION;
>
> INIT_LIST_HEAD(&ctx->adaptive_targets);
> INIT_LIST_HEAD(&ctx->schemes);
> @@ -1127,8 +1128,8 @@ static struct damon_target *damon_nth_target(int n, struct damon_ctx *ctx)
> *
> * If @src has no region, @dst keeps current regions.
> */
> -static int damon_commit_target_regions(
> - struct damon_target *dst, struct damon_target *src)
> +static int damon_commit_target_regions(struct damon_target *dst,
> + struct damon_target *src, unsigned long src_min_region)
> {
> struct damon_region *src_region;
> struct damon_addr_range *ranges;
> @@ -1145,18 +1146,19 @@ static int damon_commit_target_regions(
> i = 0;
> damon_for_each_region(src_region, src)
> ranges[i++] = src_region->ar;
> - err = damon_set_regions(dst, ranges, i);
> + err = damon_set_regions(dst, ranges, i, src_min_region);
> kfree(ranges);
> return err;
> }
>
> static int damon_commit_target(
> struct damon_target *dst, bool dst_has_pid,
> - struct damon_target *src, bool src_has_pid)
> + struct damon_target *src, bool src_has_pid,
> + unsigned long src_min_region)
> {
> int err;
>
> - err = damon_commit_target_regions(dst, src);
> + err = damon_commit_target_regions(dst, src, src_min_region);
> if (err)
> return err;
> if (dst_has_pid)
> @@ -1178,7 +1180,8 @@ static int damon_commit_targets(
> if (src_target) {
> err = damon_commit_target(
> dst_target, damon_target_has_pid(dst),
> - src_target, damon_target_has_pid(src));
> + src_target, damon_target_has_pid(src),
> + src->min_region);
> if (err)
> return err;
> } else {
> @@ -1201,7 +1204,8 @@ static int damon_commit_targets(
> if (!new_target)
> return -ENOMEM;
> err = damon_commit_target(new_target, false,
> - src_target, damon_target_has_pid(src));
> + src_target, damon_target_has_pid(src),
> + src->min_region);
> if (err) {
> damon_destroy_target(new_target, NULL);
> return err;
> @@ -1248,6 +1252,7 @@ int damon_commit_ctx(struct damon_ctx *dst, struct damon_ctx *src)
> }
> dst->ops = src->ops;
> dst->addr_unit = src->addr_unit;
> + dst->min_region = max(DAMON_MIN_REGION / dst->addr_unit, 1);
Can't we set this as src->min_region?
>
> return 0;
> }
> @@ -1280,8 +1285,8 @@ static unsigned long damon_region_sz_limit(struct damon_ctx *ctx)
>
> if (ctx->attrs.min_nr_regions)
> sz /= ctx->attrs.min_nr_regions;
> - if (sz < DAMON_MIN_REGION)
> - sz = DAMON_MIN_REGION;
> + if (sz < ctx->min_region)
> + sz = ctx->min_region;
>
> return sz;
> }
> @@ -1641,8 +1646,9 @@ static bool damos_valid_target(struct damon_ctx *c, struct damon_target *t,
> *
> * Return: true if the region should be entirely skipped, false otherwise.
> */
> -static bool damos_skip_charged_region(struct damon_target *t,
> - struct damon_region **rp, struct damos *s)
> +static bool damos_skip_charged_region(
The above line is not really required to be changed. Let's keep it.
> + struct damon_target *t, struct damon_region **rp,
> + struct damos *s, unsigned long min_region)
> {
> struct damon_region *r = *rp;
> struct damos_quota *quota = &s->quota;
> @@ -1664,11 +1670,11 @@ static bool damos_skip_charged_region(struct damon_target *t,
> if (quota->charge_addr_from && r->ar.start <
> quota->charge_addr_from) {
> sz_to_skip = ALIGN_DOWN(quota->charge_addr_from -
> - r->ar.start, DAMON_MIN_REGION);
> + r->ar.start, min_region);
> if (!sz_to_skip) {
> - if (damon_sz_region(r) <= DAMON_MIN_REGION)
> + if (damon_sz_region(r) <= min_region)
> return true;
> - sz_to_skip = DAMON_MIN_REGION;
> + sz_to_skip = min_region;
> }
> damon_split_region_at(t, r, sz_to_skip);
> r = damon_next_region(r);
> @@ -1693,7 +1699,8 @@ static void damos_update_stat(struct damos *s,
> }
>
> static bool damos_filter_match(struct damon_ctx *ctx, struct damon_target *t,
> - struct damon_region *r, struct damos_filter *filter)
> + struct damon_region *r, struct damos_filter *filter,
> + unsigned long min_region)
> {
> bool matched = false;
> struct damon_target *ti;
> @@ -1710,8 +1717,8 @@ static bool damos_filter_match(struct damon_ctx *ctx, struct damon_target *t,
> matched = target_idx == filter->target_idx;
> break;
> case DAMOS_FILTER_TYPE_ADDR:
> - start = ALIGN_DOWN(filter->addr_range.start, DAMON_MIN_REGION);
> - end = ALIGN_DOWN(filter->addr_range.end, DAMON_MIN_REGION);
> + start = ALIGN_DOWN(filter->addr_range.start, min_region);
> + end = ALIGN_DOWN(filter->addr_range.end, min_region);
>
> /* inside the range */
> if (start <= r->ar.start && r->ar.end <= end) {
> @@ -1747,7 +1754,7 @@ static bool damos_filter_out(struct damon_ctx *ctx, struct damon_target *t,
>
> s->core_filters_allowed = false;
> damos_for_each_filter(filter, s) {
> - if (damos_filter_match(ctx, t, r, filter)) {
> + if (damos_filter_match(ctx, t, r, filter, ctx->min_region)) {
> if (filter->allow)
> s->core_filters_allowed = true;
> return !filter->allow;
> @@ -1882,7 +1889,7 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
> if (c->ops.apply_scheme) {
> if (quota->esz && quota->charged_sz + sz > quota->esz) {
> sz = ALIGN_DOWN(quota->esz - quota->charged_sz,
> - DAMON_MIN_REGION);
> + c->min_region);
> if (!sz)
> goto update_stat;
> damon_split_region_at(t, r, sz);
> @@ -1930,7 +1937,7 @@ static void damon_do_apply_schemes(struct damon_ctx *c,
> if (quota->esz && quota->charged_sz >= quota->esz)
> continue;
>
> - if (damos_skip_charged_region(t, &r, s))
> + if (damos_skip_charged_region(t, &r, s, c->min_region))
> continue;
>
> if (!damos_valid_target(c, t, r, s))
> @@ -2324,7 +2331,8 @@ static void damon_split_region_at(struct damon_target *t,
> }
>
> /* Split every region in the given target into 'nr_subs' regions */
> -static void damon_split_regions_of(struct damon_target *t, int nr_subs)
> +static void damon_split_regions_of(struct damon_target *t,
> + int nr_subs, unsigned long min_region)
Let's keep having nr_subs on the upper line.
> {
> struct damon_region *r, *next;
> unsigned long sz_region, sz_sub = 0;
> @@ -2334,13 +2342,13 @@ static void damon_split_regions_of(struct damon_target *t, int nr_subs)
> sz_region = damon_sz_region(r);
>
> for (i = 0; i < nr_subs - 1 &&
> - sz_region > 2 * DAMON_MIN_REGION; i++) {
> + sz_region > 2 * min_region; i++) {
> /*
> * Randomly select size of left sub-region to be at
> * least 10 percent and at most 90% of original region
> */
> sz_sub = ALIGN_DOWN(damon_rand(1, 10) *
> - sz_region / 10, DAMON_MIN_REGION);
> + sz_region / 10, min_region);
> /* Do not allow blank region */
> if (sz_sub == 0 || sz_sub >= sz_region)
> continue;
> @@ -2380,7 +2388,7 @@ static void kdamond_split_regions(struct damon_ctx *ctx)
> nr_subregions = 3;
>
> damon_for_each_target(t, ctx)
> - damon_split_regions_of(t, nr_subregions);
> + damon_split_regions_of(t, nr_subregions, ctx->min_region);
>
> last_nr_regions = nr_regions;
> }
> @@ -2769,7 +2777,7 @@ int damon_set_region_biggest_system_ram_default(struct damon_target *t,
>
> addr_range.start = *start;
> addr_range.end = *end;
> - return damon_set_regions(t, &addr_range, 1);
> + return damon_set_regions(t, &addr_range, 1, DAMON_MIN_REGION);
> }
>
> /*
> diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
> index 98bf15d403b2..840b3a73147a 100644
> --- a/mm/damon/sysfs.c
> +++ b/mm/damon/sysfs.c
> @@ -1329,7 +1329,8 @@ static int damon_sysfs_set_attrs(struct damon_ctx *ctx,
> }
>
> static int damon_sysfs_set_regions(struct damon_target *t,
> - struct damon_sysfs_regions *sysfs_regions)
> + struct damon_sysfs_regions *sysfs_regions,
> + unsigned long min_region)
> {
> struct damon_addr_range *ranges = kmalloc_array(sysfs_regions->nr,
> sizeof(*ranges), GFP_KERNEL | __GFP_NOWARN);
> @@ -1351,7 +1352,7 @@ static int damon_sysfs_set_regions(struct damon_target *t,
> if (ranges[i - 1].end > ranges[i].start)
> goto out;
> }
> - err = damon_set_regions(t, ranges, sysfs_regions->nr);
> + err = damon_set_regions(t, ranges, sysfs_regions->nr, min_region);
> out:
> kfree(ranges);
> return err;
> @@ -1372,7 +1373,7 @@ static int damon_sysfs_add_target(struct damon_sysfs_target *sys_target,
> /* caller will destroy targets */
> return -EINVAL;
> }
> - return damon_sysfs_set_regions(t, sys_target->regions);
> + return damon_sysfs_set_regions(t, sys_target->regions, ctx->min_region);
> }
>
> static int damon_sysfs_add_targets(struct damon_ctx *ctx,
> @@ -1430,6 +1431,7 @@ static int damon_sysfs_apply_inputs(struct damon_ctx *ctx,
> if (err)
> return err;
> ctx->addr_unit = sys_ctx->addr_unit;
> + ctx->min_region = max(DAMON_MIN_REGION / ctx->addr_unit, 1);
> err = damon_sysfs_set_attrs(ctx, sys_ctx->attrs);
> if (err)
> return err;
> diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
> index 5f5dc9db2e90..a7fa078da405 100644
> --- a/mm/damon/tests/core-kunit.h
> +++ b/mm/damon/tests/core-kunit.h
> @@ -230,14 +230,14 @@ static void damon_test_split_regions_of(struct kunit *test)
> t = damon_new_target();
> r = damon_new_region(0, 22);
> damon_add_region(r, t);
> - damon_split_regions_of(t, 2);
> + damon_split_regions_of(t, 2, DAMON_MIN_REGION);
> KUNIT_EXPECT_LE(test, damon_nr_regions(t), 2u);
> damon_free_target(t);
>
> t = damon_new_target();
> r = damon_new_region(0, 220);
> damon_add_region(r, t);
> - damon_split_regions_of(t, 4);
> + damon_split_regions_of(t, 4, DAMON_MIN_REGION);
> KUNIT_EXPECT_LE(test, damon_nr_regions(t), 4u);
> damon_free_target(t);
> damon_destroy_ctx(c);
> @@ -303,7 +303,7 @@ static void damon_test_set_regions(struct kunit *test)
>
> damon_add_region(r1, t);
> damon_add_region(r2, t);
> - damon_set_regions(t, &range, 1);
> + damon_set_regions(t, &range, 1, DAMON_MIN_REGION);
>
> KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 3);
> damon_for_each_region(r, t) {
> @@ -450,25 +450,25 @@ static void damos_test_filter_out(struct kunit *test)
> damon_add_region(r, t);
>
> /* region in the range */
> - KUNIT_EXPECT_TRUE(test, damos_filter_match(NULL, t, r, f));
> + KUNIT_EXPECT_TRUE(test, damos_filter_match(NULL, t, r, f, DAMON_MIN_REGION));
Let's break lines longer than 80 columns. Same for below four changes.
[1] https://docs.kernel.org/process/coding-style.html#breaking-long-lines-and-strings
> KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 1);
>
> /* region before the range */
> r->ar.start = DAMON_MIN_REGION * 1;
> r->ar.end = DAMON_MIN_REGION * 2;
> - KUNIT_EXPECT_FALSE(test, damos_filter_match(NULL, t, r, f));
> + KUNIT_EXPECT_FALSE(test, damos_filter_match(NULL, t, r, f, DAMON_MIN_REGION));
> KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 1);
>
> /* region after the range */
> r->ar.start = DAMON_MIN_REGION * 6;
> r->ar.end = DAMON_MIN_REGION * 8;
> - KUNIT_EXPECT_FALSE(test, damos_filter_match(NULL, t, r, f));
> + KUNIT_EXPECT_FALSE(test, damos_filter_match(NULL, t, r, f, DAMON_MIN_REGION));
> KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 1);
>
> /* region started before the range */
> r->ar.start = DAMON_MIN_REGION * 1;
> r->ar.end = DAMON_MIN_REGION * 4;
> - KUNIT_EXPECT_FALSE(test, damos_filter_match(NULL, t, r, f));
> + KUNIT_EXPECT_FALSE(test, damos_filter_match(NULL, t, r, f, DAMON_MIN_REGION));
> /* filter should have split the region */
> KUNIT_EXPECT_EQ(test, r->ar.start, DAMON_MIN_REGION * 1);
> KUNIT_EXPECT_EQ(test, r->ar.end, DAMON_MIN_REGION * 2);
> @@ -481,7 +481,7 @@ static void damos_test_filter_out(struct kunit *test)
> /* region started in the range */
> r->ar.start = DAMON_MIN_REGION * 2;
> r->ar.end = DAMON_MIN_REGION * 8;
> - KUNIT_EXPECT_TRUE(test, damos_filter_match(NULL, t, r, f));
> + KUNIT_EXPECT_TRUE(test, damos_filter_match(NULL, t, r, f, DAMON_MIN_REGION));
> /* filter should have split the region */
> KUNIT_EXPECT_EQ(test, r->ar.start, DAMON_MIN_REGION * 2);
> KUNIT_EXPECT_EQ(test, r->ar.end, DAMON_MIN_REGION * 6);
> diff --git a/mm/damon/tests/vaddr-kunit.h b/mm/damon/tests/vaddr-kunit.h
> index d2b37ccf2cc0..fce38dd53cf8 100644
> --- a/mm/damon/tests/vaddr-kunit.h
> +++ b/mm/damon/tests/vaddr-kunit.h
> @@ -141,7 +141,7 @@ static void damon_do_test_apply_three_regions(struct kunit *test,
> damon_add_region(r, t);
> }
>
> - damon_set_regions(t, three_regions, 3);
> + damon_set_regions(t, three_regions, 3, DAMON_MIN_REGION);
>
> for (i = 0; i < nr_expected / 2; i++) {
> r = __nth_region_of(t, i);
> diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
> index 66ef9869eafe..8c048f9b129e 100644
> --- a/mm/damon/vaddr.c
> +++ b/mm/damon/vaddr.c
> @@ -299,7 +299,7 @@ static void damon_va_update(struct damon_ctx *ctx)
> damon_for_each_target(t, ctx) {
> if (damon_va_three_regions(t, three_regions))
> continue;
> - damon_set_regions(t, three_regions, 3);
> + damon_set_regions(t, three_regions, 3, DAMON_MIN_REGION);
> }
> }
>
> --
> 2.43.0
Other than the abovely added comments, looks good to me, overall.
Thanks,
SJ
© 2016 - 2026 Red Hat, Inc.