Re: [RFC PATCH v3 6/7] mm/damon/paddr: introduce DAMOS_MIGRATE_HOT action for promotion
On Fri, 5 Apr 2024 15:08:55 +0900 Honggyu Kim wrote:
> From: Hyeongtak Ji
>
> This patch introduces DAMOS_MIGRATE_HOT action, which is similar to
> DAMOS_MIGRATE_COLD, but it is targeted to migrate hot pages.
My understanding of our last discussion was that 'HOT/COLD' here is only for
prioritization score function. If I'm not wrong, this is not for targeting,
but just prioritize migrating hot pages first under the quota.
>
> 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/
> $ cat contexts//schemes//action
> migrate_hot
> $ echo 0 > contexts//schemes//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 0601 1101
>
> Signed-off-by: Hyeongtak Ji
> Signed-off-by: Honggyu Kim
> ---
> include/linux/damon.h| 2 ++
> mm/damon/paddr.c | 12 ++--
> mm/damon/sysfs-schemes.c | 4 +++-
> 3 files changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/damon.h b/include/linux/damon.h
> index df8671e69a70..934c95a7c042 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 for the given hot region.
As commented on the previous patch, this could be bit re-phrased.
Also, let's use tabs consistently.
> * @DAMOS_MIGRATE_COLD: Migrate for the given cold region.
> * @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 fe217a26f788..fd9d35b5cc83 100644
> --- a/mm/damon/paddr.c
> +++ b/mm/damon/paddr.c
> @@ -229,6 +229,7 @@ static bool damos_pa_filter_out(struct damos *scheme,
> struct folio *folio)
>
> enum migration_mode {
> MIG_PAGEOUT,
> + MIG_MIGRATE_HOT,
> MIG_MIGRATE_COLD,
> };
It looks like we don't need MIG_MIGRATE_HOT and MIG_MIGRATE_COLD in real, but
just one, say, MIG_MIGRATE, since the code can know if it should use what
prioritization score function with DAMOS action?
Also, as I commented on the previous one, I'd prefer having DAMOS_ prefix.
>
> @@ -375,8 +376,10 @@ static unsigned long damon_pa_migrate(struct
> damon_region *r, struct damos *s,
> if (damos_pa_filter_out(s, folio))
> goto put_folio;
>
> - folio_clear_referenced(folio);
> - folio_test_clear_young(folio);
> + if (mm != MIG_MIGRATE_HOT) {
> + folio_clear_referenced(folio);
> + folio_test_clear_young(folio);
> + }
We agreed to this check via 'young' page type DAMOS filter, and let this
doesn't care about it, right? If I'm not wrong, I think this should be
removed?
> if (!folio_isolate_lru(folio))
> goto put_folio;
> /*
> @@ -394,6 +397,7 @@ static unsigned long damon_pa_migrate(struct damon_region
> *r, struct damos *s,
> case MIG_PAGEOUT:
> applied = reclaim_pages(_list);
> break;
> + case MIG_MIGRATE_HOT:
> case MIG_MIGRATE_COLD:
> applied = damon_pa_migrate_pages(_list, mm,
>s->target_nid);
> @@ -454,6 +458,8 @@ 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:
> + return damon_pa_migrate(r, scheme, MIG_MIGRATE_HOT);
> case DAMOS_MIGRATE_COLD:
> return damon_pa_migrate(r, scheme, MIG_MIGRATE_COLD);
> case DAMOS_STAT:
> @@ -476,6 +482,8 @@ 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
[RFC PATCH v3 6/7] mm/damon/paddr: introduce DAMOS_MIGRATE_HOT action for promotion
From: Hyeongtak Ji
This patch introduces DAMOS_MIGRATE_HOT action, which is similar to
DAMOS_MIGRATE_COLD, but it is targeted to migrate 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/
$ cat contexts//schemes//action
migrate_hot
$ echo 0 > contexts//schemes//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 0601 1101
Signed-off-by: Hyeongtak Ji
Signed-off-by: Honggyu Kim
---
include/linux/damon.h| 2 ++
mm/damon/paddr.c | 12 ++--
mm/damon/sysfs-schemes.c | 4 +++-
3 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/include/linux/damon.h b/include/linux/damon.h
index df8671e69a70..934c95a7c042 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 for the given hot region.
* @DAMOS_MIGRATE_COLD: Migrate for the given cold region.
* @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 fe217a26f788..fd9d35b5cc83 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -229,6 +229,7 @@ static bool damos_pa_filter_out(struct damos *scheme,
struct folio *folio)
enum migration_mode {
MIG_PAGEOUT,
+ MIG_MIGRATE_HOT,
MIG_MIGRATE_COLD,
};
@@ -375,8 +376,10 @@ static unsigned long damon_pa_migrate(struct damon_region
*r, struct damos *s,
if (damos_pa_filter_out(s, folio))
goto put_folio;
- folio_clear_referenced(folio);
- folio_test_clear_young(folio);
+ if (mm != MIG_MIGRATE_HOT) {
+ folio_clear_referenced(folio);
+ folio_test_clear_young(folio);
+ }
if (!folio_isolate_lru(folio))
goto put_folio;
/*
@@ -394,6 +397,7 @@ static unsigned long damon_pa_migrate(struct damon_region
*r, struct damos *s,
case MIG_PAGEOUT:
applied = reclaim_pages(_list);
break;
+ case MIG_MIGRATE_HOT:
case MIG_MIGRATE_COLD:
applied = damon_pa_migrate_pages(_list, mm,
s->target_nid);
@@ -454,6 +458,8 @@ 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:
+ return damon_pa_migrate(r, scheme, MIG_MIGRATE_HOT);
case DAMOS_MIGRATE_COLD:
return damon_pa_migrate(r, scheme, MIG_MIGRATE_COLD);
case DAMOS_STAT:
@@ -476,6 +482,8 @@ 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 18b7d054c748..1d2f62aa79ca 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -1406,6 +1406,7 @@ static const char * const damon_sysfs_damos_action_strs[]
= {
"nohugepage",
"lru_prio",
"lru_deprio",
+ "migrate_hot",
"migrate_cold",
"stat",
};
@@ -1660,7 +1661,8 @@ static ssize_t target_nid_store(struct kobject *kobj,
struct damon_sysfs_scheme, kobj);
int err = 0;
-if (scheme->action != DAMOS_MIGRATE_COLD)
+if (scheme->action != DAMOS_MIGRATE_HOT &&
+scheme->action != DAMOS_MIGRATE_COLD)
return -EINVAL;
/* TODO: error handling for target_nid range. */
--
2.34.1
