From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f197.google.com (mail-wr0-f197.google.com [209.85.128.197]) by kanga.kvack.org (Postfix) with ESMTP id 843826B03AA for ; Tue, 11 Apr 2017 14:15:26 -0400 (EDT) Received: by mail-wr0-f197.google.com with SMTP id m26so508282wrm.5 for ; Tue, 11 Apr 2017 11:15:26 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id 39si6505237wry.53.2017.04.11.11.15.25 for (version=TLS1 cipher=AES128-SHA bits=128/128); Tue, 11 Apr 2017 11:15:25 -0700 (PDT) Date: Tue, 11 Apr 2017 20:15:20 +0200 From: Michal Hocko Subject: Re: [PATCH v7 0/7] Introduce ZONE_CMA Message-ID: <20170411181519.GC21171@dhcp22.suse.cz> References: <1491880640-9944-1-git-send-email-iamjoonsoo.kim@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1491880640-9944-1-git-send-email-iamjoonsoo.kim@lge.com> Sender: owner-linux-mm@kvack.org List-ID: To: js1304@gmail.com Cc: Andrew Morton , Rik van Riel , Johannes Weiner , mgorman@techsingularity.net, Laura Abbott , Minchan Kim , Marek Szyprowski , Michal Nazarewicz , "Aneesh Kumar K . V" , Vlastimil Babka , Russell King , Will Deacon , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@lge.com, Joonsoo Kim Hi, I didn't get to read though patches yet but the cover letter didn't really help me to understand the basic concepts to have a good starting point before diving into implementation details. It contains a lot of history remarks which is not bad but IMHO too excessive here. I would appreciate the following information (some of that is already provided in the cover but could benefit from some rewording/text reorganization). - what is ZONE_CMA and how it is configured (from admin POV) - how does ZONE_CMA compare to other zones - who is allowed to allocate from this zone and what are the guarantees/requirements for successful allocation - how does the zone compare to a preallocate allocation pool - how is ZONE_CMA balanced/reclaimed due to internal memory pressure (from CMA users) - is this zone reclaimable for the global memory reclaim - why this was/is controversial -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org