From mboxrd@z Thu Jan 1 00:00:00 1970 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BB9CCCCD1BF for ; Tue, 28 Oct 2025 14:04:24 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 23F238015F; Tue, 28 Oct 2025 10:04:24 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1EF378013F; Tue, 28 Oct 2025 10:04:24 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0B7C58015F; Tue, 28 Oct 2025 10:04:24 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id EBEB08013F for ; Tue, 28 Oct 2025 10:04:23 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id B8DA112A883 for ; Tue, 28 Oct 2025 14:04:23 +0000 (UTC) X-FDA: 84047692806.07.20C2F53 Received: from out-172.mta0.migadu.com (out-172.mta0.migadu.com [91.218.175.172]) by imf25.hostedemail.com (Postfix) with ESMTP id F13F2A000C for ; Tue, 28 Oct 2025 14:04:21 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=NVJozt+A; spf=pass (imf25.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.172 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1761660262; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=aojrlW5QM0w8YO0ADBtzTkECPDUg/Z5IsfaLfTy6jEI=; b=SjjmhIydTtNPkjVJkArgxX0+qFUs1v+vHTQuu8XLpgFCjH75LHSj9DfBfO7h/iv1tD2kAq g7XGyNRtJTa26wy+6PCxmA9gHlnXnrZwu4z2hu793p8voYnRMZDoO5+bwaoJovz3/dHo3X vjuxrwFqc/eB+mB0H8heZFboqz/M02Q= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=NVJozt+A; spf=pass (imf25.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.172 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1761660262; a=rsa-sha256; cv=none; b=HWY0R8YERdF+HnLFG5Ojfuu41vG7fBZE+LswD+snAmHSaPsezmlPvmNJYJX1yYioomZWRV Ao84HEjaxj8gkNqwQWrg4Ms5uVON2GIMBzjdwDqK9rrKPoO0IKDrcGy9AjiRlGfk2yiC+9 wuXAt2b/ZJORUIrCeziiF3P6ZOv8yFg= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1761660260; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=aojrlW5QM0w8YO0ADBtzTkECPDUg/Z5IsfaLfTy6jEI=; b=NVJozt+AdVtBShZigadtoWRY1WbWR7ZpmjhNfD5oqkNoSunHh7O3bg0e+LXQkCnelRdVjj X2BHIa3BeXi0buSPXZBq2lboVKZxjmF0FxqfxBUTEsaKvpiCYNFVxur3NjE4kwmfm6s7zF MSovgm+6YsP2wyb9q6luD8mzY6ZfbjY= From: Qi Zheng To: hannes@cmpxchg.org, hughd@google.com, mhocko@suse.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, david@redhat.com, lorenzo.stoakes@oracle.com, ziy@nvidia.com, harry.yoo@oracle.com, imran.f.khan@oracle.com, kamalesh.babulal@oracle.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Qi Zheng Subject: [PATCH v1 19/26] mm: swap: prevent lruvec release in swap module Date: Tue, 28 Oct 2025 21:58:32 +0800 Message-ID: In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: F13F2A000C X-Rspamd-Server: rspam11 X-Rspam-User: X-Stat-Signature: 45ticze3n7ectpwt91ay6hre3ph34i33 X-HE-Tag: 1761660261-459854 X-HE-Meta: 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 P2SmXxq2 f4X3STzdpz9QxuMlr7cePgV0kdwxzlgkBaTduroUybh42FRWMQczG5sBbuZyDZZhH5/3M/dbbT5UC7ZgqTXhg9q1GbPACKocwKzI4hoTmonTORFaHUf+GmQ6i/TFJX3r1no2yBAtG/XHpncuKit7fn9d8RRBdCCUuI+QINuOLUqMzMZIi6PzWGvGfiyjvE8fM/CELT0rFMrut+j/Ru7qICxsgAg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Muchun Song In the near future, a folio will no longer pin its corresponding memory cgroup. So an lruvec returned by folio_lruvec() could be released without the rcu read lock or a reference to its memory cgroup. In the current patch, the rcu read lock is employed to safeguard against the release of the lruvec in lru_note_cost_refault() and lru_activate(). This serves as a preparatory measure for the reparenting of the LRU pages. Signed-off-by: Muchun Song Signed-off-by: Qi Zheng --- mm/swap.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/mm/swap.c b/mm/swap.c index ec0c654e128dc..0606795f3ccf3 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -412,18 +412,20 @@ static void lru_gen_inc_refs(struct folio *folio) static bool lru_gen_clear_refs(struct folio *folio) { - struct lru_gen_folio *lrugen; int gen = folio_lru_gen(folio); int type = folio_is_file_lru(folio); + unsigned long seq; if (gen < 0) return true; set_mask_bits(&folio->flags.f, LRU_REFS_FLAGS | BIT(PG_workingset), 0); - lrugen = &folio_lruvec(folio)->lrugen; + rcu_read_lock(); + seq = READ_ONCE(folio_lruvec(folio)->lrugen.min_seq[type]); + rcu_read_unlock(); /* whether can do without shuffling under the LRU lock */ - return gen == lru_gen_from_seq(READ_ONCE(lrugen->min_seq[type])); + return gen == lru_gen_from_seq(seq); } #else /* !CONFIG_LRU_GEN */ -- 2.20.1