linux-kernel - [RFC PATCH v2 1/4] mm/damon/paddr: implement damon_folio

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Date: Mon, 11 Mar 2024 13:45:42 -0700
From: SeongJae Park <sj@...nel.org>
To: 
Cc: honggyu.kim@...com,
	hyeongtak.ji@...com,
	kernel_team@...ynix.com,
	SeongJae Park <sj@...nel.org>,
	damon@...ts.linux.dev,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: [RFC PATCH v2 1/4] mm/damon/paddr: implement damon_folio_young()

damon_pa_young() receives physical address, get the folio covering the
address, and show if the folio is accessed since the last check.  Split
the internal logic for checking access to the given folio, for future
reuse of the logic from code that already got the folio of the address
of the question.  Also, change the rmap walker function's name from
__damon_pa_young() to damon_folio_young_one(), for consistent naming.

Signed-off-by: SeongJae Park <sj@...nel.org>
---
 mm/damon/paddr.c | 32 +++++++++++++++++++-------------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index 5e6dc312072c..25c3ba2a9eaf 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -79,8 +79,8 @@ static void damon_pa_prepare_access_checks(struct damon_ctx *ctx)
 	}
 }
 
-static bool __damon_pa_young(struct folio *folio, struct vm_area_struct *vma,
-		unsigned long addr, void *arg)
+static bool damon_folio_young_one(struct folio *folio,
+		struct vm_area_struct *vma, unsigned long addr, void *arg)
 {
 	bool *accessed = arg;
 	DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, addr, 0);
@@ -111,38 +111,44 @@ 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,
-		.rmap_one = __damon_pa_young,
+		.rmap_one = damon_folio_young_one,
 		.anon_lock = folio_lock_anon_vma_read,
 	};
 	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