linux-kernel - [RFC PATCH 2/3] mm/damon/paddr: implement damon_folio

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Date: Wed,  6 Mar 2024 19:00:12 -0800
From: SeongJae Park <sj@...nel.org>
To: 
Cc: SeongJae Park <sj@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	honggyu.kim@...com,
	hyeongtak.ji@...com,
	kernel_team@...ynix.com,
	damon@...ts.linux.dev,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: [RFC PATCH 2/3] mm/damon/paddr: implement damon_folio_young()

damon_pa_young() receives physical address, get the folio covering the
address, and return if the folio is accessed since the last check.
Split the internal logic for checking access to given folio, for future
reuse of the logic from code that already got the folio of the address
of the question.

Signed-off-by: SeongJae Park <sj@...nel.org>
---
 mm/damon/paddr.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index 5e6dc312072c..deee0fdf2e5b 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -111,9 +111,8 @@ static bool __damon_pa_young(struct folio *folio, struct vm_area_struct *vma,
 	return *accessed == false;
 }
 
-static bool damon_pa_young(unsigned long paddr, unsigned long *folio_sz)
+static bool damon_folio_young(struct folio *folio)
 {
-	struct folio *folio = damon_get_folio(PHYS_PFN(paddr));
 	bool accessed = false;
 	struct rmap_walk_control rwc = {
 		.arg = &accessed,
@@ -122,27 +121,34 @@ static bool damon_pa_young(unsigned long paddr, unsigned long *folio_sz)
 	};
 	bool need_lock;
 
-	if (!folio)
-		return false;
-
 	if (!folio_mapped(folio) || !folio_raw_mapping(folio)) {
 		if (folio_test_idle(folio))
-			accessed = false;
+			return false;
 		else
-			accessed = true;
-		goto out;
+			return true;
 	}
 
 	need_lock = !folio_test_anon(folio) || folio_test_ksm(folio);
 	if (need_lock && !folio_trylock(folio))
-		goto out;
+		return false;
 
 	rmap_walk(folio, &rwc);
 
 	if (need_lock)
 		folio_unlock(folio);
 
-out:
+	return accessed;
+}
+
+static bool damon_pa_young(unsigned long paddr, unsigned long *folio_sz)
+{
+	struct folio *folio = damon_get_folio(PHYS_PFN(paddr));
+	bool accessed;
+
+	if (!folio)
+		return false;
+
+	accessed = damon_folio_young(folio);
 	*folio_sz = folio_size(folio);
 	folio_put(folio);
 	return accessed;
-- 
2.39.2