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[209.85.220.65]) by mx.google.com with SMTPS id g15sor9465433qtc.63.2019.06.15.09.20.08 for (Google Transport Security); Sat, 15 Jun 2019 09:20:08 -0700 (PDT) Received-SPF: pass (google.com: domain of htejun@gmail.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=r+pPrVqA; spf=pass (google.com: domain of htejun@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=htejun@gmail.com; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=eX2SsF5NLCHpL5vWayCPj5W8iQ02n38k3DDKs0RQPsc=; b=r+pPrVqAooiurT+r/1q1YOmCwatUD8JpCV7NTTno22ito/5zCfh0NLhl4iMS76Apur od3597crTGgH49Iea/iv0Hn+0dlF/nDVBakGN4yUlzBbBCV7oNn3R/Bmj4uooW+AvzSq CoDrMHiPzNMxHFiIA2AVcMJEvoDu3Sre8J0jWQfHXmstDyO/JzqBUfsw3itDzLJSBcrs ygygJfj+TtVYs+wlFzjkcpQDIS/nIKFEb6axYc6x/QK0djwkF2fCJNAc/y61BV3vka5B 8mAN5LXYOY+ViRwZe6TnrbIBxANgmaxXVVIjq7dZoY1LghPPCg6/kI93rpDyZAqEeGiF eErw== X-Google-Smtp-Source: APXvYqzYKArsrn7PLBHxWCNzaRPRtCR+Ia5hnnBaEJfJot7DPD4U31BQXQuIuLwjHEBGGLC6yj+Wdw== X-Received: by 2002:ac8:1e15:: with SMTP id n21mr59570805qtl.20.1560615607770; Sat, 15 Jun 2019 09:20:07 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::673a]) by smtp.gmail.com with ESMTPSA id 5sm3807720qkr.68.2019.06.15.09.20.06 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 15 Jun 2019 09:20:06 -0700 (PDT) Date: Sat, 15 Jun 2019 09:20:04 -0700 From: Tejun Heo To: Xi Ruoyao Cc: Johannes Weiner , Michal Hocko , Vladimir Davydov , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, dschatzberg@fb.com Subject: Re: [PATCH RFC] mm: memcontrol: add cgroup v2 interface to read memory watermark Message-ID: <20190615162004.GG657710@devbig004.ftw2.facebook.com> References: <0f1be041f8de95603753ffe989bd25069efa13bb.camel@mengyan1223.wang> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0f1be041f8de95603753ffe989bd25069efa13bb.camel@mengyan1223.wang> User-Agent: Mutt/1.5.21 (2010-09-15) 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 Sat, Jun 15, 2019 at 04:20:04PM +0800, Xi Ruoyao wrote: > Introduce a control file memory.watermark showing the watermark > consumption of the cgroup and its descendants, in bytes. > > Signed-off-by: Xi Ruoyao Memory usage w/o pressure metric isn't all that useful and reporting just the historical maximum of memory.current can be outright misleading. The use case of determining maximum amount of required memory is legit but it needs to maintain sustained positive pressure while taking measurements. There are efforts on this front, so let's not merge this one for now. Nacked-by: Tejun Heo Thanks. -- tejun