linux-kernel - [PATCH 1/7] mm/damon/paddr: implement damon_folio

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Date: Fri, 26 Apr 2024 12:52:40 -0700
From: SeongJae Park <sj@...nel.org>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: SeongJae Park <sj@...nel.org>,
	damon@...ts.linux.dev,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	Honggyu Kim <honggyu.kim@...com>
Subject: [PATCH 1/7] 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.  A
following commit will reuse the internal logic for checking access to a
given folio.  To avoid duplication of the code, split the internal
logic.  Also, change the rmap walker function's name from
__damon_pa_young() to damon_folio_young_one(), following the change of
the caller's name and the naming rule that more commonly used by other
rmap walkers.

Signed-off-by: SeongJae Park <sj@...nel.org>
Tested-by: Honggyu Kim <honggyu.kim@...com>
---
 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 5e6dc312072cd..25c3ba2a9eaf4 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