linux-kernel - [RFC PATCH 04/11] mm/damon/paddr: activate DAMOS_LRU

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Message-Id: <20250628165144.55528-5-sj@kernel.org>
Date: Sat, 28 Jun 2025 09:51:37 -0700
From: SeongJae Park <sj@...nel.org>
To: 
Cc: SeongJae Park <sj@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	damon@...ts.linux.dev,
	kernel-team@...a.com,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org
Subject: [RFC PATCH 04/11] mm/damon/paddr: activate DAMOS_LRU_PRIO targets instead of marking accessed

DAMOS_LRU_DEPRIOD directly deactivate the pages, while DAMOS_LRU_PRIO
calls folio_mark_accessed(), which does incremental activation.  The
incremental activation was assumed to be useful for making sure the
pages of the hot memory region are really hot.  After the introduction
of DAMOS_LRU_PRIO, the young page filter has added.  Users can use the
young page filter to make sure the page is eligible to be activated.
Meanwhile, the asymmetric behavior of DAMOS_LRU_[DE]PRIO can confuse
users.

Directly activate given pages for DAMOS_LRU_PRIO, to eliminate the
unnecessary incremental activation steps, and be symmetric with
DAMOS_LRU_DEPRIO for easier usages.

Signed-off-by: SeongJae Park <sj@...nel.org>
---
 mm/damon/paddr.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index d4261da48b0a..34d4b3017043 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -474,8 +474,8 @@ static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s,
 	return applied * PAGE_SIZE;
 }
 
-static inline unsigned long damon_pa_mark_accessed_or_deactivate(
-		struct damon_region *r, struct damos *s, bool mark_accessed,
+static inline unsigned long damon_pa_de_activate(
+		struct damon_region *r, struct damos *s, bool activate,
 		unsigned long *sz_filter_passed)
 {
 	unsigned long addr, applied = 0;
@@ -494,8 +494,8 @@ static inline unsigned long damon_pa_mark_accessed_or_deactivate(
 		else
 			*sz_filter_passed += folio_size(folio);
 
-		if (mark_accessed)
-			folio_mark_accessed(folio);
+		if (activate)
+			folio_activate(folio);
 		else
 			folio_deactivate(folio);
 		applied += folio_nr_pages(folio);
@@ -507,18 +507,16 @@ static inline unsigned long damon_pa_mark_accessed_or_deactivate(
 	return applied * PAGE_SIZE;
 }
 
-static unsigned long damon_pa_mark_accessed(struct damon_region *r,
+static unsigned long damon_pa_activate_pages(struct damon_region *r,
 	struct damos *s, unsigned long *sz_filter_passed)
 {
-	return damon_pa_mark_accessed_or_deactivate(r, s, true,
-			sz_filter_passed);
+	return damon_pa_de_activate(r, s, true, sz_filter_passed);
 }
 
 static unsigned long damon_pa_deactivate_pages(struct damon_region *r,
 	struct damos *s, unsigned long *sz_filter_passed)
 {
-	return damon_pa_mark_accessed_or_deactivate(r, s, false,
-			sz_filter_passed);
+	return damon_pa_de_activate(r, s, false, sz_filter_passed);
 }
 
 static unsigned int __damon_pa_migrate_folio_list(
@@ -803,7 +801,7 @@ static unsigned long damon_pa_apply_scheme(struct damon_ctx *ctx,
 	case DAMOS_PAGEOUT:
 		return damon_pa_pageout(r, scheme, sz_filter_passed);
 	case DAMOS_LRU_PRIO:
-		return damon_pa_mark_accessed(r, scheme, sz_filter_passed);
+		return damon_pa_activate_pages(r, scheme, sz_filter_passed);
 	case DAMOS_LRU_DEPRIO:
 		return damon_pa_deactivate_pages(r, scheme, sz_filter_passed);
 	case DAMOS_MIGRATE_HOT:
-- 
2.39.5