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 6C87BEFD202 for ; Wed, 25 Feb 2026 07:54:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CF8C06B00AC; Wed, 25 Feb 2026 02:54:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id CC2BB6B00AD; Wed, 25 Feb 2026 02:54:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BDC366B00AE; Wed, 25 Feb 2026 02:54:09 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id AC60D6B00AC for ; Wed, 25 Feb 2026 02:54:09 -0500 (EST) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 758F41A03ED for ; Wed, 25 Feb 2026 07:54:09 +0000 (UTC) X-FDA: 84482215818.12.3A918EC Received: from out-182.mta0.migadu.com (out-182.mta0.migadu.com [91.218.175.182]) by imf03.hostedemail.com (Postfix) with ESMTP id ACDE42000D for ; Wed, 25 Feb 2026 07:54:07 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=BMUSbSUB; spf=pass (imf03.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.182 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=1772006047; a=rsa-sha256; cv=none; b=4O5OzJVs2f1amMtxJIsLEJvrmCMUPO+MOv7St5RknReExv41VbFkDBSTIa+yV3G/TML3cP ajppke7hzE8xIKNyW2GgSJnT5ayRS0BZ3nSd9SS8CLHRyATjYSs4RzCavU7iX2vvMvR8Y3 f/JtDl3CSyDy2gDYIPQOI2+EYykRO2c= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=BMUSbSUB; spf=pass (imf03.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.182 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=1772006047; 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=ZbG23+zJ5fPDETZsA4JYiiScdZSpnAwzCU/omjW9+7Y=; b=bFgG9nTwSDmUFKKBBSdEPCghvlkyNlQ28xTKFs86Bre8YY3LMwAFFbBEBH4EgO2sdxQGKm yEUOw7oe0YhGQDERvGJ9paLLhykdtoC86SLE46zOf4Ziy9AvYFnlygqMOXYRMJEz5kab1H 5Tc5XeOtjKW5BJCfbnb9TDGULE9Gkxg= 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=1772006045; 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=ZbG23+zJ5fPDETZsA4JYiiScdZSpnAwzCU/omjW9+7Y=; b=BMUSbSUB9b0CUfjuJnGDI/tuLRw6TRcPbpRrczT3aPDD23ATtsAMtWmpYfqNGVaUEeW2UU cwQM30u+/x52CKIC/AfFvG8864Aefndlz0CohgHCbBn2zaNN0YUa5uarz2XuosEkn/GP8o UUDHi4ztvEyVObtAm5KBYOel08RHm+8= 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, yosry.ahmed@linux.dev, 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, bhe@redhat.com, usamaarif642@gmail.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Qi Zheng Subject: [PATCH v5 16/32] mm: workingset: prevent memory cgroup release in lru_gen_eviction() Date: Wed, 25 Feb 2026 15:52:59 +0800 Message-ID: In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: ACDE42000D X-Stat-Signature: hwmxnisp818c51s34t1roaihffs4jh73 X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1772006047-277513 X-HE-Meta: U2FsdGVkX18cjDazu1ivxScE2ODl7QWTYpVpgjx0N0LJIFcuqK5DpQiGQvwAm1ca3UU8aCIPmvpDpLWVbT1lliJ3FNd0DNZD9YslfbeffOYZrEv5UBDVznzj/m588ihizVfINDHRQcLIyYQkb2CodMB0jbXCNRl2zwNSNRlvzwSNMXvBPXa9L5KB4IUm5c/Y1YBlEO597PqOO6bK1Yi3gQ1Rd5iBDA1bPLi5PnP/ltzXoLpA8EiSRBmV/WkJNo16fCqC4dsTHLc3KfB6fwsRwQMKXWLkjjzkUAIYmQ4dr4yDw9tsvMWkQezUWBM91JTxYkyV92LmjMbvQbdYAhERSQV8Zowox082yRqxME32k5XiMjJViOv84UuPpi7J9SGOu2g/Z/gFRrhJxoO5o9volnoCPFYi/tpyhsfrDX0sTva9qDyzEgKXS4Ppg6H1yT0AjuebbYeUE3WAtjTa6iiqMWPrxoYbmoW9DQnN4Iby1ZM3/T6XNdna4ZOjPuf0orgdnGULUvwgjxmWNUiCN798n11Sgf8ee0J0c+1mF39vQDKigMQQroTJDMZde1u28KQIyGCI0GdwVGIl99RfTtm9jockFQb+U96LYuNSmnCNihLAW17pb00xk5xNlkyXzLYOgEEEn4ZDSO5zmDFzYpLjRZZzJyqD1xSwwYxCaENV3P+LO3ddHEIrfmWiMYzcXIxz0A69U4cQcANDjQYW6TSkwJNR9+fNyKy8azNAycQe5CGRMn8Dyl5oJZQYSsXX2nXMQXs+74jZtSbl4RfaYXuef88LuCIe/yf3ofMfdAoZz/NeCEw7ZVPTD+SRETirOZhrre//HI+1bZjLcoklqyEyowsCs9CTLMiG1orqbK70pDZsC32s5UuvFMNJFez2mNHVJAJW6TefTbVufi4Yz5IkHAWHruUf9cnC2/rSOGV3FBwC6Zc0RykIVC3vzmDAZD3FyXQf4LE00G+AMvtS5eL m0Rl9ann LKutmKAAnY/oYWeI53d4mTJHKz+lIx3+qqU42xAYXB2VUrq/b8HcDnvNW20qBFG7xolJAOx0rixGdwQzTyXrZMwfcdEE1znwqhpurg60kO21vl65ofJK6Owi8UaIiOz3GW/oLLptoPcoy5QqDhB9/YdCpQYv//yZqxuiL/RBZILlASYv8d85nwnHTmQ4NouAZFYu36SuQczTydllw63IRYlGvL+kIIa1WEfUdTM7AswcRj3YPD9H2ur6Yv5lI5TaSIlZWlseIYoSOpNJNLBfwogJqUsh4Bj2TtBW8yd/EJaO6e5WUhSVtTzhA1l280fyxw1P5 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 lru_gen_eviction(). 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 Acked-by: Johannes Weiner Acked-by: Shakeel Butt --- mm/workingset.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/mm/workingset.c b/mm/workingset.c index 5e8b6e62a6175..6971aa163e466 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -244,12 +244,15 @@ static void *lru_gen_eviction(struct folio *folio) int refs = folio_lru_refs(folio); bool workingset = folio_test_workingset(folio); int tier = lru_tier_from_refs(refs, workingset); - struct mem_cgroup *memcg = folio_memcg(folio); + struct mem_cgroup *memcg; struct pglist_data *pgdat = folio_pgdat(folio); + unsigned short memcg_id; BUILD_BUG_ON(LRU_GEN_WIDTH + LRU_REFS_WIDTH > BITS_PER_LONG - max(EVICTION_SHIFT, EVICTION_SHIFT_ANON)); + rcu_read_lock(); + memcg = folio_memcg(folio); lruvec = mem_cgroup_lruvec(memcg, pgdat); lrugen = &lruvec->lrugen; min_seq = READ_ONCE(lrugen->min_seq[type]); @@ -257,8 +260,10 @@ static void *lru_gen_eviction(struct folio *folio) hist = lru_hist_from_seq(min_seq); atomic_long_add(delta, &lrugen->evicted[hist][type][tier]); + memcg_id = mem_cgroup_private_id(memcg); + rcu_read_unlock(); - return pack_shadow(mem_cgroup_private_id(memcg), pgdat, token, workingset, type); + return pack_shadow(memcg_id, pgdat, token, workingset, type); } /* -- 2.20.1