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[109.81.81.105]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a9b1e75ff3bsm576041266b.1.2024.10.30.08.04.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 30 Oct 2024 08:04:55 -0700 (PDT) Date: Wed, 30 Oct 2024 16:04:54 +0100 From: Michal Hocko To: Chris Down Cc: gutierrez.asier@huawei-partners.com, 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Stat-Signature: uns6su5doe6qmjfmekn368qibgdfriw6 X-Rspamd-Queue-Id: 149C720021 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1730300670-176672 X-HE-Meta: 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 2j19TkSf /SDlQgz+avq90XLA1nML+BDLLXAHF+BxShVwUVTCLgTmrAbWbGf3QPdggi2cYcPEWxBIcpoR4Omh5HZFLO02c7akqBvTH9BXo2LSygLzGCS3FWKbEjWk/VprKc+/lQSv86vofav9kcURTqZEJW6wOXUHZjUWIghTPRwjwv/UfJCZyNrkvJX6WJ2q2xFnXzQt47lYfItUNRlUD8YgIXKl8ijXf0hrNlMEV4zUgc5WdXYw5YDIQuqoSGz8eKwbX4b4HbQ7LMGTGBNzYIjOD4+7x3d00tMThKWDiQy+O7DCl9OJsFVfEJSG7sxzg/z13k/GI/yK9aD0/CopqP7eg0E30n0cdRwn4kVcf2NIghD8yPJjARXkkEIlypED2SQ== 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: On Wed 30-10-24 14:45:24, Chris Down wrote: > 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. Completely agreed! -- Michal Hocko SUSE Labs