[PATCH v6 6/7] mm/damon/paddr: introduce DAMOS_MIGRATE_HOT action for promotion

From: Honggyu Kim
Date: Thu Jun 13 2024 - 23:01:25 EST


From: Hyeongtak Ji <hyeongtak.ji@xxxxxx>

This patch introduces DAMOS_MIGRATE_HOT action, which is similar to
DAMOS_MIGRATE_COLD, but proritizes hot pages.

It migrates pages inside the given region to the 'target_nid' NUMA node
in the sysfs.

Here is one of the example usage of this 'migrate_hot' action.

$ cd /sys/kernel/mm/damon/admin/kdamonds/<N>
$ cat contexts/<N>/schemes/<N>/action
migrate_hot
$ echo 0 > contexts/<N>/schemes/<N>/target_nid
$ echo commit > state
$ numactl -p 2 ./hot_cold 500M 600M &
$ numastat -c -p hot_cold

Per-node process memory usage (in MBs)
PID Node 0 Node 1 Node 2 Total
-------------- ------ ------ ------ -----
701 (hot_cold) 501 0 601 1101

Signed-off-by: Hyeongtak Ji <hyeongtak.ji@xxxxxx>
Signed-off-by: Honggyu Kim <honggyu.kim@xxxxxx>
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
---
include/linux/damon.h | 2 ++
mm/damon/paddr.c | 3 +++
mm/damon/sysfs-schemes.c | 1 +
3 files changed, 6 insertions(+)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 56714b6eb0d7..3d62d98d6359 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -105,6 +105,7 @@ struct damon_target {
* @DAMOS_NOHUGEPAGE: Call ``madvise()`` for the region with MADV_NOHUGEPAGE.
* @DAMOS_LRU_PRIO: Prioritize the region on its LRU lists.
* @DAMOS_LRU_DEPRIO: Deprioritize the region on its LRU lists.
+ * @DAMOS_MIGRATE_HOT: Migrate the regions prioritizing warmer regions.
* @DAMOS_MIGRATE_COLD: Migrate the regions prioritizing colder regions.
* @DAMOS_STAT: Do nothing but count the stat.
* @NR_DAMOS_ACTIONS: Total number of DAMOS actions
@@ -123,6 +124,7 @@ enum damos_action {
DAMOS_NOHUGEPAGE,
DAMOS_LRU_PRIO,
DAMOS_LRU_DEPRIO,
+ DAMOS_MIGRATE_HOT,
DAMOS_MIGRATE_COLD,
DAMOS_STAT, /* Do nothing but only record the stat */
NR_DAMOS_ACTIONS,
diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index 882ae54af829..af6aac388a43 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -486,6 +486,7 @@ static unsigned long damon_pa_apply_scheme(struct damon_ctx *ctx,
return damon_pa_mark_accessed(r, scheme);
case DAMOS_LRU_DEPRIO:
return damon_pa_deactivate_pages(r, scheme);
+ case DAMOS_MIGRATE_HOT:
case DAMOS_MIGRATE_COLD:
return damon_pa_migrate(r, scheme);
case DAMOS_STAT:
@@ -508,6 +509,8 @@ static int damon_pa_scheme_score(struct damon_ctx *context,
return damon_hot_score(context, r, scheme);
case DAMOS_LRU_DEPRIO:
return damon_cold_score(context, r, scheme);
+ case DAMOS_MIGRATE_HOT:
+ return damon_hot_score(context, r, scheme);
case DAMOS_MIGRATE_COLD:
return damon_cold_score(context, r, scheme);
default:
diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index 880015d5b5ea..66fccfa776d7 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -1458,6 +1458,7 @@ static const char * const damon_sysfs_damos_action_strs[] = {
"nohugepage",
"lru_prio",
"lru_deprio",
+ "migrate_hot",
"migrate_cold",
"stat",
};
--
2.34.1