Received-SPF: pass (google.com: domain of linux-kernel+bounces-30038-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
From: Barry Song <21cnbao@gmail.com>
To: ryan.roberts@arm.com,
	akpm@linux-foundation.org,
	david@redhat.com,
	linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org,
	mhocko@suse.com,
	shy828301@gmail.com,
	wangkefeng.wang@huawei.com,
	willy@infradead.org,
	xiang@kernel.org,
	ying.huang@intel.com,
	yuzhao@google.com,
	surenb@google.com,
	steven.price@arm.com,
	Chuanhua Han <hanchuanhua@oppo.com>,
	Barry Song <v-songbaohua@oppo.com>
Subject: [PATCH RFC 3/6] mm: swap: make should_try_to_free_swap() support large-folio
Date: Fri, 19 Jan 2024 00:10:33 +1300
Message-Id: <20240118111036.72641-4-21cnbao@gmail.com>
In-Reply-To: <20240118111036.72641-1-21cnbao@gmail.com>
References: <20231025144546.577640-1-ryan.roberts@arm.com>
 <20240118111036.72641-1-21cnbao@gmail.com>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

From: Chuanhua Han <hanchuanhua@oppo.com>

should_try_to_free_swap() works with an assumption that swap-in is always done
at normal page granularity, aka, folio_nr_pages = 1. To support large folio
swap-in, this patch removes the assumption.

Signed-off-by: Chuanhua Han <hanchuanhua@oppo.com>
Co-developed-by: Barry Song <v-songbaohua@oppo.com>
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
---
 mm/memory.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memory.c b/mm/memory.c
index 7e1f4849463a..f61a48929ba7 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3714,7 +3714,7 @@ static inline bool should_try_to_free_swap(struct folio *folio,
 	 * reference only in case it's likely that we'll be the exlusive user.
 	 */
 	return (fault_flags & FAULT_FLAG_WRITE) && !folio_test_ksm(folio) &&
-		folio_ref_count(folio) == 2;
+		folio_ref_count(folio) == (1 + folio_nr_pages(folio));
 }
 
 static vm_fault_t pte_marker_clear(struct vm_fault *vmf)
-- 
2.34.1