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 2EAB6CCF9E0 for ; Tue, 28 Oct 2025 14:02:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8C97A8014D; Tue, 28 Oct 2025 10:02:12 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8532D8013F; Tue, 28 Oct 2025 10:02:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 71B968014D; Tue, 28 Oct 2025 10:02:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 597628013F for ; Tue, 28 Oct 2025 10:02:12 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id F0EA087D05 for ; Tue, 28 Oct 2025 14:02:11 +0000 (UTC) X-FDA: 84047687262.13.4E363CE Received: from out-179.mta0.migadu.com (out-179.mta0.migadu.com [91.218.175.179]) by imf28.hostedemail.com (Postfix) with ESMTP id 226E0C0005 for ; Tue, 28 Oct 2025 14:02:09 +0000 (UTC) Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=m5pB3ZWQ; spf=pass (imf28.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.179 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=1761660130; 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=moQWsyM34kheODhB4m6le5EmBuxmXNZC4RNHBl5yhm4=; b=bYmpBT9AO4VRAbar7mYvs6PgU4QoK6lNtmIU+bgC88K+IRIYohwR7VtCvOCFKYUf2/MN0e A3vYWnz+1g6kU7wXTP5z91661lEcp+JcciwC364GgkN/LOGfRIg+6bck82LvZtD7qQy2sr Eqv3A/yIPcA5kpPGDowhDedui9AR7pg= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=m5pB3ZWQ; spf=pass (imf28.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.179 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=1761660130; a=rsa-sha256; cv=none; b=kzAN6VBH92gygdbkJwhJHhCz+WEZemRCChvSkFGXl9wFadRvlsaIVmnwqQT8l3K1Y3m9Po DAve2IZjeAQ8LAiiuxnTkgJ8T3iqwq9oHDR4JTNw1tcCD9rQh7kerMSGO7C2i+X84mTRYw F9heZ6gwZKV1Ie6ssMKuuwruxCKX5ZU= 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=1761660126; 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=moQWsyM34kheODhB4m6le5EmBuxmXNZC4RNHBl5yhm4=; b=m5pB3ZWQxP+sPvfEGsIWUd01+4Ud8CDRin+yJXxv+vXSeS/tvgW6+9V1cnAIEUEP3kL5MZ RaHdbjXmDsivF+rDsb1cYJID3SmV1vSRE9OWuD5IA/+/ky8Jp1kroJNOvTdF4t7i7+aH52 RZkxvRVNH2wWtx9OLxFAJtiTkeNOIqU= 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 01/26] mm: memcontrol: remove dead code of checking parent memory cgroup Date: Tue, 28 Oct 2025 21:58:14 +0800 Message-ID: In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 226E0C0005 X-Stat-Signature: wmnj3jefn6u8a18aetssgidnxfeyacc7 X-Rspam-User: X-HE-Tag: 1761660129-36823 X-HE-Meta: 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 jbgM66VB 2WNhxACd63Z/mYAqpwFi1hQ7qrrvCiBORmegaQcTcuR39Ou66UaU2rNZqrAAjmPXVhGaOs02wy1/yQLZnHbc1KI4jx4+G+eSC9bpf2QBCZSD2CvFp7t1OAxGO3cZPk64Bnylx6Hy9knEdDAfKSFtCNgo1uHJ36mfKFFGazZuniSJJxZP9qWEr7DgIXfTo36F/2dkmxwQomLZ9FoEh4fSIMB2CEY8plMYKLuRfVDqiT2T9ytjyTj++LyV7cA== 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 Since the no-hierarchy mode has been deprecated after the commit: commit bef8620cd8e0 ("mm: memcg: deprecate the non-hierarchical mode"). As a result, parent_mem_cgroup() will not return NULL except when passing the root memcg, and the root memcg cannot be offline. Hence, it's safe to remove the check on the returned value of parent_mem_cgroup(). Remove the corresponding dead code. Signed-off-by: Muchun Song Acked-by: Roman Gushchin Acked-by: Johannes Weiner Signed-off-by: Qi Zheng --- mm/memcontrol.c | 5 ----- mm/shrinker.c | 6 +----- 2 files changed, 1 insertion(+), 10 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 93f7c76f0ce96..d5257465c9d75 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3339,9 +3339,6 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg) return; parent = parent_mem_cgroup(memcg); - if (!parent) - parent = root_mem_cgroup; - memcg_reparent_list_lrus(memcg, parent); /* @@ -3632,8 +3629,6 @@ struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg) break; } memcg = parent_mem_cgroup(memcg); - if (!memcg) - memcg = root_mem_cgroup; } return memcg; } diff --git a/mm/shrinker.c b/mm/shrinker.c index 4a93fd433689a..e8e092a2f7f41 100644 --- a/mm/shrinker.c +++ b/mm/shrinker.c @@ -286,14 +286,10 @@ void reparent_shrinker_deferred(struct mem_cgroup *memcg) { int nid, index, offset; long nr; - struct mem_cgroup *parent; + struct mem_cgroup *parent = parent_mem_cgroup(memcg); struct shrinker_info *child_info, *parent_info; struct shrinker_info_unit *child_unit, *parent_unit; - parent = parent_mem_cgroup(memcg); - if (!parent) - parent = root_mem_cgroup; - /* Prevent from concurrent shrinker_info expand */ mutex_lock(&shrinker_mutex); for_each_node(nid) { -- 2.20.1