From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Mackall Subject: Re: [PATCH] - support inheritance of mlocks across fork/exec V2 Date: Mon, 08 Dec 2008 15:33:05 -0600 Message-ID: <1228771985.3726.32.camel@calx> References: <1227561707.6937.61.camel@lts-notebook> <20081125152651.b4c3c18f.akpm@linux-foundation.org> <1228331069.6693.73.camel@lts-notebook> <20081206220729.042a926e.akpm@linux-foundation.org> <1228770337.31442.44.camel@lts-notebook> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1228770337.31442.44.camel@lts-notebook> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Lee Schermerhorn Cc: Andrew Morton , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, linux-kernel , riel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, hugh-DTz5qymZ9yRBDgjK7y7TUQ@public.gmane.org, kosaki.motohiro-+CUm20s59erQFUHtdCDX3A@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-api@vger.kernel.org On Mon, 2008-12-08 at 16:05 -0500, Lee Schermerhorn wrote: > > > In support of a "lock prefix command"--e.g., mlock > ... > > > Analogous to taskset(1) for cpu affinity or numactl(8) for numa memory > > > policy. > > > > > > Together with patches to keep mlocked pages off the LRU, this will > > > allow users/admins to lock down applications without modifying them, > > > if their RLIMIT_MEMLOCK is sufficiently large, keeping their pages > > > off the LRU and out of consideration for reclaim. > > > > > > Potentially useful, as well, in real-time environments to force > > > prefaulting and residency for applications that don't mlock themselves. This is a bit scary to me. Privilege and mode inheritance across processes is the root of many nasty surprises, security and otherwise. Here's a crazy alternative: add a flag to containers instead? I think this is a better match to what you're trying to do and will keep people from being surprised when an mlockall call in one thread causes a fork/exec in another thread to crash their box, but only sometimes. -- Mathematics is the supreme nostalgia of our time. -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html