From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrea Arcangeli Subject: Re: [PATCH 4/4] add ksm kernel shared memory driver. Date: Tue, 31 Mar 2009 17:02:18 +0200 Message-ID: <20090331150218.GS9137@random.random> References: <1238457560-7613-1-git-send-email-ieidus@redhat.com> <1238457560-7613-2-git-send-email-ieidus@redhat.com> <1238457560-7613-3-git-send-email-ieidus@redhat.com> <1238457560-7613-4-git-send-email-ieidus@redhat.com> <1238457560-7613-5-git-send-email-ieidus@redhat.com> <49D17C04.9070307@codemonkey.ws> <49D20B63.8020709@redhat.com> <49D21B33.4070406@codemonkey.ws> <20090331142533.GR9137@random.random> <49D22A9D.4050403@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Izik Eidus , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, avi@redhat.com, chrisw@redhat.com, riel@redhat.com, jeremy@goop.org, mtosatti@redhat.com, hugh@veritas.com, corbet@lwn.net, yaniv@redhat.com, dmonakhov@openvz.org To: Anthony Liguori Return-path: Received: from mx2.redhat.com ([66.187.237.31]:36185 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761375AbZCaPC4 (ORCPT ); Tue, 31 Mar 2009 11:02:56 -0400 Content-Disposition: inline In-Reply-To: <49D22A9D.4050403@codemonkey.ws> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, Mar 31, 2009 at 09:37:17AM -0500, Anthony Liguori wrote: > In the very least, if you insist on not using sysfs, you should have a > separate character device that's used for control (like /dev/ksmctl). I'm fine to use sysfs that's not the point, if you've to add a ksmctl device, then sysfs is surely better. Besides ksm would normally be enabled at boot, tasks jailed by selinux will better not start/stop this thing. If people wants /sys/kernel/mm/ksm instead of the start_stop ioctl we surely can add it (provided there's a way to intercept write to the sysfs file). Problem is registering memory could also be done with 'echo 0 -1 >/proc/self/ksm' and be inherited by childs, it's not just start/stop. I mean this is more a matter of taste I'm afraid... Personally I'm more concerned about the registering of the ram API than the start/stop thing which I cannot care less about, so my logic is that as long as this pseudodevice exists, we should use it for everything. If we go away from it, then we should remove it as a whole.