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charset=utf-8; format=flowed Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.14.7 (2020-08-29) Content-Transfer-Encoding: quoted-printable 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: Chunxin Zang writes: >On Tue, Sep 22, 2020 at 5:51 PM Chris Down wrote: >> >> Chunxin Zang writes: >> >My usecase is that there are two types of services in one server. The= y >> >have difference >> >priorities. Type_A has the highest priority, we need to ensure it's >> >schedule latency=E3=80=81I/O >> >latency=E3=80=81memory enough. Type_B has the lowest priority, we exp= ect it >> >will not affect >> >Type_A when executed. >> >So Type_A could use memory without any limit. Type_B could use memory >> >only when the >> >memory is absolutely sufficient. But we cannot estimate how much >> >memory Type_B should >> >use. Because everything is dynamic. So we can't set Type_B's memory.h= igh. >> > >> >So we want to release the memory of Type_B when global memory is >> >insufficient in order >> >to ensure the quality of service of Type_A . In the past, we used the >> >'force_empty' interface >> >of cgroup v1. >> >> This sounds like a perfect use case for memory.low on Type_A, and it's= pretty >> much exactly what we invented it for. What's the problem with that? > >But we cannot estimate how much memory Type_A uses at least. memory.low allows ballparking, you don't have to know exactly how much it= uses. =20 Any amount of protection biases reclaim away from that cgroup. >For example: >total memory: 100G >At the beginning, Type_A was in an idle state, and it only used 10G of m= emory. >The load is very low. We want to run Type_B to avoid wasting machine res= ources. >When Type_B runs for a while, it used 80G of memory. >At this time Type_A is busy, it needs more memory. Ok, so set memory.low for Type_A close to your maximum expected value.