From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754440Ab3GBSjA (ORCPT ); Tue, 2 Jul 2013 14:39:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33557 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754013Ab3GBSi7 (ORCPT ); Tue, 2 Jul 2013 14:38:59 -0400 Date: Tue, 2 Jul 2013 14:38:22 -0400 From: Luiz Capitulino To: Anton Vorontsov Cc: Andrew Morton , Minchan Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org, mhocko@suse.cz, kmpark@infradead.org, hyunhee.kim@samsung.com Subject: Re: [PATCH v2] vmpressure: implement strict mode Message-ID: <20130702143822.4af2ebe3@redhat.com> In-Reply-To: <20130702172409.GA13695@teo> References: <20130628043411.GA9100@teo> <20130628050712.GA10097@teo> <20130628100027.31504abe@redhat.com> <20130628165722.GA12271@teo> <20130628170917.GA12610@teo> <20130628144507.37d28ed9@redhat.com> <20130628185547.GA14520@teo> <20130628154402.4035f2fa@redhat.com> <20130629005637.GA16068@teo> <20130702105911.2830181d@redhat.com> <20130702172409.GA13695@teo> Organization: Red Hat Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2 Jul 2013 10:24:09 -0700 Anton Vorontsov wrote: > > Honestly, what Andrew suggested is the best design for me: apps > > are notified on all events but the event name is sent to the application. > > I am fine with this approach (or any other, I'm really indifferent to the > API itself -- read/netlink/notification per file/whatever for the > payload), That's a very good thing because we've managed to agree on something :) I'm also indifferent to the API, as long as we have 100% of the policy in user-space. To me this means we do absolutely no filtering in the kernel, which in turn means user-space gets all the events. Of course, we need the event name as a payload. Do we agree this solves all use-cases we have discussed so far? > except that you still have the similar problem: > > read() old read() new > -------------------------- > "low" "low" > "low" "foo" -- the app does not know what does this mean > "med" "bar" -- ditto It can just ignore it, have a special handling, log it, fail or whatever. That's the good of having the policy in user-space.