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 4604ECCD1BF for ; Tue, 28 Oct 2025 14:04:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A2E3B8015D; Tue, 28 Oct 2025 10:04:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9DDDB8013F; Tue, 28 Oct 2025 10:04:08 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8CCD58015D; Tue, 28 Oct 2025 10:04:08 -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 781638013F for ; Tue, 28 Oct 2025 10:04:08 -0400 (EDT) Received: from smtpin16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 25ECF13B0DC for ; Tue, 28 Oct 2025 14:04:08 +0000 (UTC) X-FDA: 84047692176.16.A38A8FF Received: from out-170.mta0.migadu.com (out-170.mta0.migadu.com [91.218.175.170]) by imf09.hostedemail.com (Postfix) with ESMTP id 41EC8140004 for ; Tue, 28 Oct 2025 14:04:05 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=pWzdGFK9; spf=pass (imf09.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.170 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=1761660246; 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=d2EOOSlZh8oRwtRfQtnzgpJLzbPe1acyr5pcLzwWU68=; b=OpxMcTVgwJQE7bCOsOWHj17HemIZQu55Mktfw35F/7opGDt8BkAwF9qbG633fek2m7RyXz 8RFEMCy4JN1+p1TXd06zFcWSK2R30cdbL+/NPOr66IngqKQZ3dP+gQYOAbPX0tJFCtqgyz TSswmat2XWSYH+/D8xrp0H76DBlTc0Y= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=pWzdGFK9; spf=pass (imf09.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.170 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=1761660246; a=rsa-sha256; cv=none; b=KIHgc8CW0N25rUa2Q1AqHT40cv9VuFd8cEN33SWRG3ikTJUmUYU3jPEqWAv9aJwzAfSuFB nVuHEFhTXwj+z8DsTSDg4voKD/KQbT0/WwkvX4vQ7qEoxiWa7H7ZksLWmFLV9EhkGRSuzM C1QZtNNYVWaRllUbgrqOJZRJombo7jY= 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=1761660244; 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=d2EOOSlZh8oRwtRfQtnzgpJLzbPe1acyr5pcLzwWU68=; b=pWzdGFK9jp5/gKWOoMPYfN/1zgwDvyk5R6UyUH2ocXAJcYLiJkqMhI+d2hIraioYk881Hw 7rzlQkLG3uO06lrW3XshXYI5VB2JcP+sh5murHeNw1f62HR7cktjcNoiJHB7FiwL0hTSM1 7bK+5TfatVR2jrRm9JSuNcGrGdlqOCQ= 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 17/26] mm: workingset: prevent lruvec release in workingset_refault() Date: Tue, 28 Oct 2025 21:58:30 +0800 Message-ID: <7d58f7f924961bc9ce386b3101448a49d7aa1daa.1761658310.git.zhengqi.arch@bytedance.com> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Stat-Signature: er8zet795axtiz1ogdep96mngxmi6upz X-Rspamd-Queue-Id: 41EC8140004 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1761660245-249827 X-HE-Meta: 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 DbrgxgEa 2xmMzlBEh5MyF9DPoit8OEI6xZ0WBbEDfEMEf5oTSp87LEDuzjlXaDsI6pXKmP7yZy475jZHFea/3zaFvLz/YANh9rwOIfCr+Y6g63lx0MdChzreU4wnAPKvG1zPs8b9Vr6uyvQwCeT4ZvN/NiNkWZp1eJ56347PFyzt/75gL86D9RXsYulIQF7iSUY2icEelYuXi7DOW1ENh5ftp3nvbR2eH2sYErtWt7tV570fOfHkVXa9mXLuPS5K3vVgYdIxp2NAKJazdQCsKToU= 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 workingset_refault(). This serves as a preparatory measure for the reparenting of the LRU pages. Signed-off-by: Muchun Song Signed-off-by: Qi Zheng --- mm/workingset.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/workingset.c b/mm/workingset.c index c4d21c15bad51..a69cc7bf9246d 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -560,11 +560,12 @@ void workingset_refault(struct folio *folio, void *shadow) * locked to guarantee folio_memcg() stability throughout. */ nr = folio_nr_pages(folio); + rcu_read_lock(); lruvec = folio_lruvec(folio); mod_lruvec_state(lruvec, WORKINGSET_REFAULT_BASE + file, nr); if (!workingset_test_recent(shadow, file, &workingset, true)) - return; + goto out; folio_set_active(folio); workingset_age_nonresident(lruvec, nr); @@ -580,6 +581,8 @@ void workingset_refault(struct folio *folio, void *shadow) lru_note_cost_refault(folio); mod_lruvec_state(lruvec, WORKINGSET_RESTORE_BASE + file, nr); } +out: + rcu_read_unlock(); } /** -- 2.20.1