From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f43.google.com (mail-wm1-f43.google.com [209.85.128.43]) (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 628B71E7C12 for ; Wed, 30 Oct 2024 14:45:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.43 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730299529; cv=none; b=T3jhNWI4Dblv0SqPXZlVPts8MJR9yMrZM4XBhTznMCk2glP9YixsMDDOaRXcxKJbv7qCRDkNdxoDbzdkrS8ZbvDeD8QfeVft/b/vFLvcq34hriNnQ8Q1ZoX9wBrMP8Vj3nZGq7a2ZqCJvJKRUf9hFbyQHS60XDBxgJY37WQASm4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730299529; c=relaxed/simple; bh=KDd7q3izCIy2uvDUHvhTjP4ypFwyOPbe7o9FvoUAM1g=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=pcpDc/2In6/iPd5HapvxrBsBNDANzcmQDejpSqNz0bUH062V2D+s/IxXWTTDSB4Q93bZZZ8mVSHhl8mgM1GshSHMKY4MjlXtKtl2NADS6csT/8YVRwyz724UB7GeosRofWBTXTpNZL7c1p/F1dVzIIfjRLkec1IK11by5cfGE3Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=chrisdown.name; spf=pass smtp.mailfrom=chrisdown.name; dkim=pass (1024-bit key) header.d=chrisdown.name header.i=@chrisdown.name header.b=Lrr13xIA; arc=none smtp.client-ip=209.85.128.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=chrisdown.name Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chrisdown.name Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chrisdown.name header.i=@chrisdown.name header.b="Lrr13xIA" Received: by mail-wm1-f43.google.com with SMTP id 5b1f17b1804b1-4316e9f4a40so65497585e9.2 for ; Wed, 30 Oct 2024 07:45:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chrisdown.name; s=google; t=1730299526; x=1730904326; darn=vger.kernel.org; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=RoDDm8JP2udkrNnIMKPZ0hp9VS+cBdfycpwS1j/FcSQ=; b=Lrr13xIABXUsQxCdwbtR9/zCPuHmCNB1klafpPDyXYSTkRMvkMKoA5dTcKFJaFtBe4 8MMcvgBBe5mYmeK5rcMmhu9YKe0DJaQzcSgkqlDcchl04KHwVhY7c8moVLiwruHPJaUt 7/AxYbdgKOaheMN7v76w0MI4EWKjqxMRskN2I= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1730299526; x=1730904326; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=RoDDm8JP2udkrNnIMKPZ0hp9VS+cBdfycpwS1j/FcSQ=; b=d/3Oxa0vlRfppuv4Ko4UptoLNqbNiJf3Ia2VE/zK+lGNS2owRZ/fVVnFhwW6xaTysU Elxg0G3FqmGZggVqx3SOP01cdfLPqLcxHnmB/aolW0gvn871RXj7MxOBwiE6AYqqBaUf WB5oq8Mk0o+pgpK2Ah7eu9NbG/XDnhXhJudBaGGRGTUAAVQeO/TwwmhAsQYvDZn6VnIR risKnsbYMwbMpUf5puKeGPTXuadHjBKmo5mLaSP9dZf8j/O7bhGULvvNUNQtQw6eAu2t NEjKe+9aBWCPfqHBV5MlQM1K0TybP1FpZOCrgCx32y8M+KOthkzVWGooec0608IQqFc4 ukcw== X-Forwarded-Encrypted: i=1; AJvYcCXsBHltG3+G5rypx7NXnYscFi7QiocysqkFYflGa0yXWTM39ArVEdJr1p5OopIGstyEslc3pe1E@vger.kernel.org X-Gm-Message-State: AOJu0YxZjICfOyL2T7l13pWyc6DXNmsef0+HlJEBJCVIXoLYyyWlnWk9 eJBfFg11rk2dAOSwwyg/jIlg+0eorjzcLl1/7kyBVCjRhO2r3L9WlxVcft142AI= X-Google-Smtp-Source: AGHT+IEPjKO/h/MskOFjZ6ZLRebfzAiOStur116BnuhCa7N+oewBVmpTVB5mh8kB+XAVvtST6mt7RA== X-Received: by 2002:a05:600c:3c8c:b0:431:4fa0:2e0b with SMTP id 5b1f17b1804b1-4319ad146b1mr126147855e9.28.1730299525369; Wed, 30 Oct 2024 07:45:25 -0700 (PDT) Received: from localhost ([93.115.193.42]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-431bd947b2bsm23699315e9.25.2024.10.30.07.45.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 30 Oct 2024 07:45:24 -0700 (PDT) Date: Wed, 30 Oct 2024 14:45:24 +0000 From: Chris Down To: gutierrez.asier@huawei-partners.com Cc: akpm@linux-foundation.org, david@redhat.com, ryan.roberts@arm.com, baohua@kernel.org, willy@infradead.org, peterx@redhat.com, hannes@cmpxchg.org, hocko@kernel.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stepanov.anatoly@huawei.com, alexander.kozhevnikov@huawei-partners.com, guohanjun@huawei.com, weiyongjun1@huawei.com, wangkefeng.wang@huawei.com, judy.chenhui@huawei.com, yusongping@huawei.com, artem.kuzin@huawei.com, kang.sun@huawei.com Subject: Re: [RFC PATCH 0/3] Cgroup-based THP control Message-ID: References: <20241030083311.965933-1-gutierrez.asier@huawei-partners.com> Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20241030083311.965933-1-gutierrez.asier@huawei-partners.com> User-Agent: Mutt/2.2.13 (00d56288) (2024-03-09) gutierrez.asier@huawei-partners.com writes: >New memcg files are exposed: memory.thp_enabled and memory.thp_defrag, which >have completely the same format as global THP enabled/defrag. cgroup controls exist because there are things we want to do for an entire class of processes (group OOM, resource control, etc). Enabling or disabling some specific setting is generally not one of them, hence why we got rid of things like per-cgroup vm.swappiness. We know that these controls do not compose well and have caused a lot of pain in the past. So my immediate reaction is a nack on the general concept, unless there's some absolutely compelling case here. I talked a little at Kernel Recipes last year about moving away from sysctl and other global interfaces and making things more granular. Don't get me wrong, I think that is a good thing (although, of course, a very large undertaking) -- but it is a mistake to overload the amount of controls we expose as part of the cgroup interface. I am up for thinking overall about how we can improve the state of global tunables to make them more granular overall, but this can't set a precedent as the way to do it.