From nobody Thu Dec 18 22:16:20 2025 Received: from mail-pg1-f202.google.com (mail-pg1-f202.google.com [209.85.215.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5020DDDAB for ; Thu, 5 Sep 2024 00:31:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725496318; cv=none; b=CJt8PCi6yUyVF0PrBPOLxnLkn+As0G9XywXYYJapb4P6fFb4XF/s9PyYxPkSvBpww6eMx+t6ck786qneTCvc/GOMLEkIt536qD20y4799q1/lZs7LUW5e+Xrffad+jLC9qlcS7/v4+m+QDCkfyeOLNHThfXJLy0u/J/Un0RgWfU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725496318; c=relaxed/simple; bh=rNTFMsSf4ipv9IfY2q02hT078vD9+pCTekO9b6Df+h4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=DKjx58kP9gd+X7A6LKnFmWQMA3nASHTAYfDO5YsJYGRyxbE/2kBJKrS/nny8JukaK3q5N5Ewy+oUS9T5/KUmC2J8reJTOrw5ctMH9x3Ms7kW4xL31ObZHnw9eBeUQh9lVuw9hELmG3/hfE+XxnxemjbgK7QktpZ3WLsjnICsqLI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--kinseyho.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=aLHhJAhB; arc=none smtp.client-ip=209.85.215.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--kinseyho.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="aLHhJAhB" Received: by mail-pg1-f202.google.com with SMTP id 41be03b00d2f7-7cf546bbcffso289074a12.1 for ; Wed, 04 Sep 2024 17:31:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1725496317; x=1726101117; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:from:to:cc:subject:date:message-id :reply-to; bh=UFlJk+bdMFXrL5bkGb5l4QnCCI5p7k/K3Pj8oKz1txU=; b=aLHhJAhBI8aHQsrfn5T2wGgEdvoqYMAihfPSqMf7j71JfQQf95Qjhr9OUaPxkBNqm7 bIbw2SWiHwkDTXHEiKVFfHT2XQXJVvNQE+fGpPR2eFoAG903g9rsECuXJ6xAda67ZdZO zwabj2j1YQGv7G7BNlScoTqGE9eWH7+3HKohzIGxvFa4iFjd2OO10G6AaaOh7xFwLkFk cvByu+MdmIhbg8+FLZ1oQl5qkcMw6gEq+Oq2VFFQSJIej0MBQ2g/gCdKqw/6JUauL2WH pPLcUeNJw5Vwxg4K6wEoK1KYQ0oycGwzWOUpuENJ+HeESptf9/nlwgCKLHwPvEPaH89w qnAw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1725496317; x=1726101117; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=UFlJk+bdMFXrL5bkGb5l4QnCCI5p7k/K3Pj8oKz1txU=; b=lPH9mDfdS1rSnArV451AZdR1lWy3f8GpN4Qt8+RPNHwACUFJGgjZ+knENRGADIjBpA aV+GGO0XUn0ydeY2i/JM4qCGYlJEC8qPRU3JwpQ+X36aKMFjJnSCdl3LAV+nB0zRMWbt Be76hjFeI3DrP+KB0a2aaQojzK6Put3hUGxCIFw09rPVFau57uqHzV8d7N4pbdDa8Xqi PBKiwkCOtp8IGhs7Mr1/fDK7RZByUZlOka8IpKR+chO8OjdfINIGpU0BQZNmj4xeZgjG 2mkRKazRJkTfig2O/XmVPvPE74yQ4VE/+5TKGBV4+fRdo0Ck8aMjC7A5hrUwqu+87bs8 PWTA== X-Forwarded-Encrypted: i=1; AJvYcCUGaKaHsg8lC2osFK1wBm+AqdtOi99Ht3QEqqE4yy491SX1Pdj/c0MTCFi6o3SiP9zNVx7zRziAhHkhdvY=@vger.kernel.org X-Gm-Message-State: AOJu0Yx/IPgWZbAwbDo/n1Lg5piZ3Gg4CyrTnO/lpqAge6SKeLJFbMwx ugX04YeKqxLESXPuOYUIRcvygdiNRckt5rlqeSYEx1LIzxVdJmPsiX08NPz2qI+nQ1Z0wEZ1+XH wR+XpVXkrMA== X-Google-Smtp-Source: AGHT+IFCmyZz1oeuwdzh9ujb+lyKCdb7Lv33IMyUDlAfA9IgJETASTtABlliPQg/ISAiLVSGlddqDM0VzXnGuQ== X-Received: from kinseyct.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:46b]) (user=kinseyho job=sendgmr) by 2002:a05:6a02:2385:b0:6c4:5b35:c986 with SMTP id 41be03b00d2f7-7d50176fca8mr4225a12.8.1725496316657; Wed, 04 Sep 2024 17:31:56 -0700 (PDT) Date: Thu, 5 Sep 2024 00:30:54 +0000 In-Reply-To: <20240905003058.1859929-1-kinseyho@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240905003058.1859929-1-kinseyho@google.com> X-Mailer: git-send-email 2.46.0.469.g59c65b2a67-goog Message-ID: <20240905003058.1859929-6-kinseyho@google.com> Subject: [PATCH mm-unstable v4 5/5] mm: clean up mem_cgroup_iter() From: Kinsey Ho To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Yosry Ahmed , Roman Gushchin , Johannes Weiner , Michal Hocko , Shakeel Butt , Muchun Song , Tejun Heo , Zefan Li , mkoutny@suse.com, "T . J . Mercier" , Hugh Dickins , Kinsey Ho Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" A clean up to make variable names more clear and to improve code readability. No functional change. Signed-off-by: Kinsey Ho Reviewed-by: T.J. Mercier Cc: Johannes Weiner Cc: Michal Hocko Cc: Michal Koutn=C3=BD Cc: Muchun Song Cc: Roman Gushchin Cc: Shakeel Butt Cc: Tejun Heo Cc: Yosry Ahmed Cc: Zefan Li Cc: Hugh Dickins --- mm/memcontrol.c | 32 ++++++++++++-------------------- 1 file changed, 12 insertions(+), 20 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index ce5d066393c9..31db8467f19d 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -989,8 +989,8 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *r= oot, { struct mem_cgroup_reclaim_iter *iter; struct cgroup_subsys_state *css; - struct mem_cgroup *memcg; - struct mem_cgroup *pos =3D NULL; + struct mem_cgroup *pos; + struct mem_cgroup *next; =20 if (mem_cgroup_disabled()) return NULL; @@ -1000,14 +1000,13 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgrou= p *root, =20 rcu_read_lock(); restart: - memcg =3D NULL; + next =3D NULL; =20 if (reclaim) { int gen; - struct mem_cgroup_per_node *mz; + int nid =3D reclaim->pgdat->node_id; =20 - mz =3D root->nodeinfo[reclaim->pgdat->node_id]; - iter =3D &mz->iter; + iter =3D &root->nodeinfo[nid]->iter; gen =3D atomic_read(&iter->generation); =20 /* @@ -1020,29 +1019,22 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgrou= p *root, goto out_unlock; =20 pos =3D READ_ONCE(iter->position); - } else if (prev) { + } else pos =3D prev; - } =20 css =3D pos ? &pos->css : NULL; =20 - for (;;) { - css =3D css_next_descendant_pre(css, &root->css); - if (!css) { - break; - } - + while ((css =3D css_next_descendant_pre(css, &root->css))) { /* * Verify the css and acquire a reference. The root * is provided by the caller, so we know it's alive * and kicking, and don't take an extra reference. */ - if (css =3D=3D &root->css || css_tryget(css)) { + if (css =3D=3D &root->css || css_tryget(css)) break; - } } =20 - memcg =3D mem_cgroup_from_css(css); + next =3D mem_cgroup_from_css(css); =20 if (reclaim) { /* @@ -1050,13 +1042,13 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgrou= p *root, * thread, so check that the value hasn't changed since we read * it to avoid reclaiming from the same cgroup twice. */ - if (cmpxchg(&iter->position, pos, memcg) !=3D pos) { + if (cmpxchg(&iter->position, pos, next) !=3D pos) { if (css && css !=3D &root->css) css_put(css); goto restart; } =20 - if (!memcg) { + if (!next) { atomic_inc(&iter->generation); =20 /* @@ -1075,7 +1067,7 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup = *root, if (prev && prev !=3D root) css_put(&prev->css); =20 - return memcg; + return next; } =20 /** --=20 2.46.0.469.g59c65b2a67-goog