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[195.135.220.15]) by mx.google.com with ESMTPS id h28si17229743edh.128.2019.05.20.23.50.02 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 20 May 2019 23:50:02 -0700 (PDT) Received-SPF: softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) client-ip=195.135.220.15; Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) smtp.mailfrom=mhocko@kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 5C37FAF70; Tue, 21 May 2019 06:50:01 +0000 (UTC) Date: Tue, 21 May 2019 08:50:00 +0200 From: Michal Hocko To: Oleksandr Natalenko Cc: Minchan Kim , Andrew Morton , LKML , linux-mm , Johannes Weiner , Tim Murray , Joel Fernandes , Suren Baghdasaryan , Daniel Colascione , Shakeel Butt , Sonny Rao , Brian Geffon Subject: Re: [RFC 4/7] mm: factor out madvise's core functionality Message-ID: <20190521065000.GH32329@dhcp22.suse.cz> References: <20190520035254.57579-1-minchan@kernel.org> <20190520035254.57579-5-minchan@kernel.org> <20190520142633.x5d27gk454qruc4o@butterfly.localdomain> <20190521012649.GE10039@google.com> <20190521063628.x2npirvs75jxjilx@butterfly.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190521063628.x2npirvs75jxjilx@butterfly.localdomain> User-Agent: Mutt/1.10.1 (2018-07-13) 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 Tue 21-05-19 08:36:28, Oleksandr Natalenko wrote: [...] > Regarding restricting the hints, I'm definitely interested in having > remote MADV_MERGEABLE/MADV_UNMERGEABLE. But, OTOH, doing it via remote > madvise() introduces another issue with traversing remote VMAs reliably. > IIUC, one can do this via userspace by parsing [s]maps file only, which > is not very consistent, and once some range is parsed, and then it is > immediately gone, a wrong hint will be sent. > > Isn't this a problem we should worry about? See http://lkml.kernel.org/r/20190520091829.GY6836@dhcp22.suse.cz -- Michal Hocko SUSE Labs