From nobody Wed Dec 17 10:57:12 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4DCF2EE49AA for ; Tue, 22 Aug 2023 01:54:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232159AbjHVByc (ORCPT ); Mon, 21 Aug 2023 21:54:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54812 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232108AbjHVBy3 (ORCPT ); Mon, 21 Aug 2023 21:54:29 -0400 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A3D06113; Mon, 21 Aug 2023 18:54:26 -0700 (PDT) Received: from dggpemm500009.china.huawei.com (unknown [172.30.72.55]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4RVC6K1X1rz1L9Kv; Tue, 22 Aug 2023 09:52:57 +0800 (CST) Received: from huawei.com (10.175.113.32) by dggpemm500009.china.huawei.com (7.185.36.225) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Tue, 22 Aug 2023 09:54:24 +0800 From: Liu Shixin To: Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Andrew Morton , CC: , , , Liu Shixin Subject: [PATCH v2] mm: vmscan: reclaim anon pages if there are swapcache pages Date: Tue, 22 Aug 2023 10:49:01 +0800 Message-ID: <20230822024901.2412520-1-liushixin2@huawei.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.175.113.32] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm500009.china.huawei.com (7.185.36.225) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" When spaces of swap devices are exhausted, only file pages can be reclaimed. But there are still some swapcache pages in anon lru list. This can lead to a premature out-of-memory. This problem can be fixed by checking number of swapcache pages in can_reclaim_anon_pages(). For memcg v2, there are swapcache stat that can be used directly. For memcg v1, use total_swapcache_pages() instead, which may not accurate but can solve the problem. Signed-off-by: Liu Shixin --- include/linux/swap.h | 6 ++++++ mm/memcontrol.c | 8 ++++++++ mm/vmscan.c | 12 ++++++++---- 3 files changed, 22 insertions(+), 4 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index 456546443f1f..0318e918bfa4 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -669,6 +669,7 @@ static inline void mem_cgroup_uncharge_swap(swp_entry_t= entry, unsigned int nr_p } =20 extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg); +extern long mem_cgroup_get_nr_swapcache_pages(struct mem_cgroup *memcg); extern bool mem_cgroup_swap_full(struct folio *folio); #else static inline void mem_cgroup_swapout(struct folio *folio, swp_entry_t ent= ry) @@ -691,6 +692,11 @@ static inline long mem_cgroup_get_nr_swap_pages(struct= mem_cgroup *memcg) return get_nr_swap_pages(); } =20 +static inline long mem_cgroup_get_nr_swapcache_pages(struct mem_cgroup *me= mcg) +{ + return total_swapcache_pages(); +} + static inline bool mem_cgroup_swap_full(struct folio *folio) { return vm_swap_full(); diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e8ca4bdcb03c..3e578f41023e 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -7567,6 +7567,14 @@ long mem_cgroup_get_nr_swap_pages(struct mem_cgroup = *memcg) return nr_swap_pages; } =20 +long mem_cgroup_get_nr_swapcache_pages(struct mem_cgroup *memcg) +{ + if (mem_cgroup_disabled() || do_memsw_account()) + return total_swapcache_pages(); + + return memcg_page_state(memcg, NR_SWAPCACHE); +} + bool mem_cgroup_swap_full(struct folio *folio) { struct mem_cgroup *memcg; diff --git a/mm/vmscan.c b/mm/vmscan.c index 7c33c5b653ef..bcb6279cbae7 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -609,13 +609,17 @@ static inline bool can_reclaim_anon_pages(struct mem_= cgroup *memcg, if (memcg =3D=3D NULL) { /* * For non-memcg reclaim, is there - * space in any swap device? + * space in any swap device or swapcache pages? */ - if (get_nr_swap_pages() > 0) + if (get_nr_swap_pages() + total_swapcache_pages() > 0) return true; } else { - /* Is the memcg below its swap limit? */ - if (mem_cgroup_get_nr_swap_pages(memcg) > 0) + /* + * Is the memcg below its swap limit or is there swapcache + * pages can be freed? + */ + if (mem_cgroup_get_nr_swap_pages(memcg) + + mem_cgroup_get_nr_swapcache_pages(memcg) > 0) return true; } =20 --=20 2.25.1