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 1A14DD64085 for ; Wed, 17 Dec 2025 07:31:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7DFEE6B00A3; Wed, 17 Dec 2025 02:31:21 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 780A56B00A5; Wed, 17 Dec 2025 02:31:21 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 699516B00A6; Wed, 17 Dec 2025 02:31:21 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 539226B00A3 for ; Wed, 17 Dec 2025 02:31:21 -0500 (EST) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 083575B85B for ; Wed, 17 Dec 2025 07:31:21 +0000 (UTC) X-FDA: 84228142362.23.BFDB9D7 Received: from out-185.mta0.migadu.com (out-185.mta0.migadu.com [91.218.175.185]) by imf27.hostedemail.com (Postfix) with ESMTP id 583A64000C for ; Wed, 17 Dec 2025 07:31:19 +0000 (UTC) Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=K96tzvyH; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf27.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.185 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1765956679; a=rsa-sha256; cv=none; b=fulHFTwTD1tW0qaiNedMBn8FZqUzLSEoO7W6c6H8+MRAHCfHL43OY5fHKtDHzzd5XEr1Zr BxRxsZxwEMUyXs9cGWAvcpyFKUCOqXlx0x1cQ7mAZFfzBumyfwWte/uc+DFhrpcY4MO4Qd zsaFU+ooxZ6B6mMAhKKyDH/hHT0NoJY= ARC-Authentication-Results: i=1; imf27.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=K96tzvyH; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf27.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.185 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1765956679; 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=7JUakH8RoGEUpXQwlompW3asRykfRFAg5UucbZpTDd8=; b=Sqk4KgwSvjhQv7zXnbESN2tI71Mji9H0FqY2S/XUjLnlkKMtOl5W/yHsB1lNPAbD8+DFa3 HnCbemL6ZSgfiYGF4aHMvkRCqB7xEdFT4SO9AOyvjri0L2TWYOZS4GHe33nkRi8egR+ILi axepb2IWWyKW/RA6YvslbdKLK5LOzGQ= 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=1765956669; 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=7JUakH8RoGEUpXQwlompW3asRykfRFAg5UucbZpTDd8=; b=K96tzvyHVSfFjEQWFZYsknQeYErc4m9UCrZguyLOTm1EyoGLAezAyOquWDuHyYDHzdGvES vvyK28/fhaNwYlaxHWbq2BeRB5FUUSU+2+nQGRLWo979MFTMFgx97t5vmdwCw7NpWXk+sS w7mWHISxfr/ZIzsS97XE2xuRSP96qV8= 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@kernel.org, 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, chenridong@huaweicloud.com, mkoutny@suse.com, akpm@linux-foundation.org, hamzamahfooz@linux.microsoft.com, apais@linux.microsoft.com, lance.yang@linux.dev Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Qi Zheng Subject: [PATCH v2 12/28] mm: page_io: prevent memory cgroup release in page_io module Date: Wed, 17 Dec 2025 15:27:36 +0800 Message-ID: <30588f984137d557e4663ae8dcf398b8c408169b.1765956025.git.zhengqi.arch@bytedance.com> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 583A64000C X-Rspamd-Server: rspam03 X-Stat-Signature: yuwfum78mq8sa3ottxzwm6m311yazt5j X-Rspam-User: X-HE-Tag: 1765956679-500203 X-HE-Meta: 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 6R3k3PR7 ChAjvxRiQ803/Xyg59l02sHKfc1lRhEw9Ap80Yfz4zUWg3jGiyD1O3i73htncj6uRgknvsruR2EdruHcgOR1zR25HYOTWxamVz2xfgahwmWarW5pKuT+GtJhRkDoS/7idsmKYjyAZlZEXZd3a34N+XUXoVJq/zZ1Alh4I396A8ebdeJ0kxi3VD60Sshjl2Bxyk8scAqNpAePefG4oBQqYQuDVYdIlO3fMHeYpZvZzq7P+oV9V3RQ3tLPPGFm41foUPizh 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. To ensure safety, it will only be appropriate to hold the rcu read lock or acquire a reference to the memory cgroup returned by folio_memcg(), thereby preventing it from being released. In the current patch, the rcu read lock is employed to safeguard against the release of the memory cgroup in swap_writeout() and bio_associate_blkg_from_page(). This serves as a preparatory measure for the reparenting of the LRU pages. Signed-off-by: Muchun Song Signed-off-by: Qi Zheng Reviewed-by: Harry Yoo --- mm/page_io.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/mm/page_io.c b/mm/page_io.c index 3c342db77ce38..ec7720762042c 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -276,10 +276,14 @@ int swap_writeout(struct folio *folio, struct swap_iocb **swap_plug) count_mthp_stat(folio_order(folio), MTHP_STAT_ZSWPOUT); goto out_unlock; } + + rcu_read_lock(); if (!mem_cgroup_zswap_writeback_enabled(folio_memcg(folio))) { + rcu_read_unlock(); folio_mark_dirty(folio); return AOP_WRITEPAGE_ACTIVATE; } + rcu_read_unlock(); __swap_writepage(folio, swap_plug); return 0; @@ -307,11 +311,11 @@ static void bio_associate_blkg_from_page(struct bio *bio, struct folio *folio) struct cgroup_subsys_state *css; struct mem_cgroup *memcg; - memcg = folio_memcg(folio); - if (!memcg) + if (!folio_memcg_charged(folio)) return; rcu_read_lock(); + memcg = folio_memcg(folio); css = cgroup_e_css(memcg->css.cgroup, &io_cgrp_subsys); bio_associate_blkg_from_css(bio, css); rcu_read_unlock(); -- 2.20.1