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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=s9NS8aTMNXwzeLlthekcCZHp7SQir7/xZefiPP7egKI=; b=LYM2m8U0RNlvjM7QcJEZY22bmkXBrwQcFMdkXaDqW/mApVSae3mSH14IpiSKUEA88E 1hXkyijf1NfL9TGgS1kuPmcG6dU3sQfg/Sq0GoAvSYjIE6EagzL7NBx7MpVgBgcxrgdY 5HEBe51O6/SGco56isEt3Kr870yA+Q1FLVcXPM5fvthXNjSPNcolKdQs4Cwh/VcOQ0Ng JF45Azhq9SM9hyZRE54O231BWvAbYLl8Cm++7m0YCWQ7y2nbYzM/YAlKpdNba68u5mzk g0bnBy5pjh56pzUl1uDH72YEGLsA+cbUHlkop1WEqweO0NHPYqTSjen+gyZOgbiWga36 HY2w== X-Gm-Message-State: AO0yUKVynjd5g9LvqU7CpBK/ejXf1BV3GOQYsGxE/tNnqc+KAEUMVVR7 I3qngduzWqoHTZ55EA95ccwY642Cvncc7mmTonxGnQ== X-Google-Smtp-Source: AK7set8AggMm56FhRMju0xnLlIqmwLNBbTYCISFZ/w6URWQ+GAck8xfnfOOCoJEKrQU2oWewAHldfm04bzdjrW+WeRA= X-Received: by 2002:a25:ae01:0:b0:7fb:feb3:3828 with SMTP id a1-20020a25ae01000000b007fbfeb33828mr1066702ybj.450.1675362259617; Thu, 02 Feb 2023 10:24:19 -0800 (PST) MIME-Version: 1.0 References: <1675312377-4782-1-git-send-email-zhaoyang.huang@unisoc.com> In-Reply-To: From: Shakeel Butt Date: Thu, 2 Feb 2023 10:24:08 -0800 Message-ID: Subject: Re: [PATCH] mm: introduce entrance for root_mem_cgroup's current To: Michal Hocko Cc: "zhaoyang.huang" , Andrew Morton , Johannes Weiner , Peter Zijlstra , Roman Gushchin , linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Zhaoyang Huang , ke.wang@unisoc.com Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam03 X-Stat-Signature: cr4xzw851g9jcnkqeeg5a9rofgtf6e96 X-Rspamd-Queue-Id: 98FF14001A X-HE-Tag: 1675362260-433555 X-HE-Meta: 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 LG8aUQAX ABVq+We6pzoCAPpj1tPDoK0vHa9aghQHUlSyXkKe0YCOZJwjqwurlbR1BttVTq/ItSUdHaMSvSYMqA/txQWwVlKgfZH9IWqEdYNsi8l+sXOnQOZAfpOampUFj5RmCWcjUW/otWlQOgO1RbE+c1k3KcL2VZTtS1C52wQ7Wxs5T/0dsLZZHC1mKCGa7h37M9MDF98bkd1HfMACt9ygJIsWCqHa9VYzTz6PfATM53GBkaIYKNWXK14L0i74zMtMU5Xy0NL+1iFxXEcX9A+moaRCD654HXCHiRjmlAvVGrl/zZhZfmpmxH+ZloY6PFtqfbUZGlRi86jx8rSWL9en105OVtO8oofvYHAh6orvxHYbP6wQ/4FfTgHGWc68MbdnMzydrEKi1SVo/7V/gu8TEcacjwhS2JA== 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: On Thu, Feb 2, 2023 at 12:27 AM Michal Hocko wrote: > > On Thu 02-02-23 12:32:57, zhaoyang.huang wrote: > > From: Zhaoyang Huang > > > > Introducing memory.root_current for the memory charges on root_mem_cgroup. > > Charges are not currently accounted for the root memcg universally. See > try_charge which is used for all user space and skmem charges. I am not > 100% sure about objcg based accounting because there is no explicit > check for the root memcg but this might be hidden somewhere as well. Yes in __get_obj_cgroup_from_memcg(). However the reason to use try_charge_memcg() to bypass root check was to avoid the race with reparenting. More details in c5c8b16b596e ("mm: memcontrol: fix root_mem_cgroup charging"). > > That means that the patch as is doesn't really provide and usable value. > The root exemption has been removed in the past but that has been > reverted due to a regression. See ce00a967377b ("mm: memcontrol: revert > use of root_mem_cgroup res_counter") for more. > One advantage I can see is if someone is looking for usage for all top containers (alive or zombie) but I wanted to know if that was the real motivation behind the patch.