From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9998D331A5B; Tue, 18 Aug 2026 05:38:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787031504; cv=none; b=qkkv0vExO1zszz1HKbojIXxLaBSlX9WQCHOJk9Unmspreq2DA0YKl+e6jC3YIMDjW3ECFSuJpQws13xDzKm01T8pu9gNyYaEc2iIjwCaXEAC/oKxRmz+IKDQeSr7yGGyz5XyFdS/4GxnRKm7/VHBAn0X/FJkyo99OvKZDwOaa4s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787031504; c=relaxed/simple; bh=/Dap8HX+JALspR15co61JO/ZEe5sgXMBY1Lvt6lrf0U=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=qWIs7ELeGzwfPx1rBqZPn/Ag5hZcZYc9OWxOHMOJoGvDStiHvPhvqjvLdFlSHLS+QxZGt3NVMLiQn4LsEsZh7Ezg9yw7czA7c00C93JkmugtTXgFuLGjqoc9V0fnBAY83J6ETxx+TF73T8BhZybmrhcCc3MBYdZVlJqIGoApuVA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KpA3xO6c; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="KpA3xO6c" Received: by smtp.kernel.org (Postfix) with ESMTPS id 41221C2BCFD; Tue, 18 Aug 2026 05:38:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1787031504; bh=/Dap8HX+JALspR15co61JO/ZEe5sgXMBY1Lvt6lrf0U=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=KpA3xO6c41IaXbmqmCFFQNGgoiKoADBI9iIN5v1UtOj5mM5iCtENnL3NuKy0jae6Y saGmVezGKNIRYu8komaX1eDr3C+spdAJdi1wB6tPXleDN8/7T++ZqESkDbPfmhxYuI Cvk4cqMjQuRFLZjUHLHHWHfUWGXHRka/450fgn2lPYrZCMSNGaXWmxd/gieSKlnhFG 9N+cxxdoUt9gHa38bAozYxLZRWsDp0JirwdS5lk1u73wU9CUy9IP3HKh1y1g/W3NCK M7Bc01TLYjpmzv/bWS4ZONcjF/ZmpCnl9/bf/VsWH6VDXHgoPn9FL5tnT/6nm9ZeaN ZQPFwMA/qgt9A== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2A8CCC5DF82; Tue, 18 Aug 2026 05:38:24 +0000 (UTC) From: Kairui Song via B4 Relay Date: Tue, 18 Aug 2026 13:38:05 +0800 Subject: [PATCH 3/7] mm/migrate: copy the referenced state via folio_migrate_refs() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260818-mglru-flags-cleanup-v1-3-8dbbdac0d28c@tencent.com> References: <20260818-mglru-flags-cleanup-v1-0-8dbbdac0d28c@tencent.com> In-Reply-To: <20260818-mglru-flags-cleanup-v1-0-8dbbdac0d28c@tencent.com> To: linux-mm@kvack.org Cc: Andrew Morton , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Shakeel Butt , Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , Chris Li , Baolin Wang , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Yu Zhao , Zi Yan , Qi Zheng , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Kairui Song , Kairui Song X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1787031500; l=2602; i=kasong@tencent.com; s=kasong-sign-tencent; h=from:subject:message-id; bh=MnXqCrD+kNnVgk+e93wC9DHznJeWbyePZC5TTqXqepo=; b=11ce+XvCl2hD19O2/CuCgrvBrmVTUm6nz/9U0YfjPuhZy1wZ8IJb0amYtFNhwztQfIB/4LtWh dx0NKZPYnYMBdFtD1f5AZ3c3/MzE+JFMBVWgnVPkcoVz/2/dB4v2kvE X-Developer-Key: i=kasong@tencent.com; a=ed25519; pk=kCdoBuwrYph+KrkJnrr7Sm1pwwhGDdZKcKrqiK8Y1mI= X-Endpoint-Received: by B4 Relay for kasong@tencent.com/kasong-sign-tencent with auth_id=562 X-Original-From: Kairui Song Reply-To: kasong@tencent.com From: Kairui Song folio_migrate_flags() copies PG_referenced separately, while folio_migrate_refs() copies the rest of the reference state. Make folio_migrate_refs() copy the complete state, i.e., PG_referenced plus the MGLRU refs counter, in both LRU implementations, and drop the open-coded copy so the reference state is transferred in one place. Signed-off-by: Kairui Song --- include/linux/mm_inline.h | 16 +++++++++++++--- mm/migrate.c | 4 ++-- 2 files changed, 15 insertions(+), 5 deletions(-) diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h index 93bf3fa221f8..df62daaa2ee7 100644 --- a/include/linux/mm_inline.h +++ b/include/linux/mm_inline.h @@ -366,11 +366,19 @@ static inline bool lru_gen_del_folio(struct lruvec *lruvec, struct folio *folio, return true; } +/** + * folio_migrate_refs - copy the reference state to a new folio + * @new: the destination folio + * @old: the source folio + * + * Transfer the reference state to @new during migration: the MGLRU + * refs count, including PG_referenced, or just PG_referenced for the + * active/inactive LRU. + */ static inline void folio_migrate_refs(struct folio *new, const struct folio *old) { - unsigned long refs = READ_ONCE(old->flags.f) & LRU_REFS_MASK; - - set_mask_bits(&new->flags.f, LRU_REFS_MASK, refs); + BUILD_BUG_ON(LRU_REFS_MASK & BIT(PG_referenced)); + folio_set_lru_refs(new, folio_lru_refs(old)); } #else /* !CONFIG_LRU_GEN */ @@ -401,6 +409,8 @@ static inline bool lru_gen_del_folio(struct lruvec *lruvec, struct folio *folio, static inline void folio_migrate_refs(struct folio *new, const struct folio *old) { + if (folio_test_referenced(old)) + folio_set_referenced(new); } #endif /* CONFIG_LRU_GEN */ diff --git a/mm/migrate.c b/mm/migrate.c index 15b45832bcfa..82307332711f 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -776,8 +776,6 @@ void folio_migrate_flags(struct folio *newfolio, struct folio *folio) { int cpupid; - if (folio_test_referenced(folio)) - folio_set_referenced(newfolio); if (folio_test_uptodate(folio)) folio_mark_uptodate(newfolio); if (folio_test_clear_active(folio)) { @@ -807,7 +805,9 @@ void folio_migrate_flags(struct folio *newfolio, struct folio *folio) if (folio_test_idle(folio)) folio_set_idle(newfolio); + /* Copy the reference state, including PG_referenced */ folio_migrate_refs(newfolio, folio); + /* * Copy NUMA information to the new page, to prevent over-eager * future migrations of this same page. -- 2.55.0