From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexey Dobriyan Subject: Re: Banning checkpoint (was: Re: What can OpenVZ do?) Date: Tue, 24 Feb 2009 23:09:34 +0300 Message-ID: <20090224200934.GA16862@x200.localdomain> References: <20090218003217.GB25856@elte.hu> <1234917639.4816.12.camel@nimitz> <20090218051123.GA9367@x200.localdomain> <20090218181644.GD19995@elte.hu> <1234992447.26788.12.camel@nimitz> <20090218231545.GA17524@elte.hu> <20090219190637.GA4846@x200.localdomain> <1235070714.26788.56.camel@nimitz> <20090224044752.GB3202@x200.localdomain> <1235452285.26788.226.camel@nimitz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1235452285.26788.226.camel@nimitz> Sender: owner-linux-mm@kvack.org To: Dave Hansen Cc: Ingo Molnar , Nathan Lynch , linux-api@vger.kernel.org, containers@lists.linux-foundation.org, mpm@selenic.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, viro@zeniv.linux.org.uk, hpa@zytor.com, Andrew Morton , torvalds@linux-foundation.org, tglx@linutronix.de, xemul@openvz.org List-Id: linux-api@vger.kernel.org On Mon, Feb 23, 2009 at 09:11:25PM -0800, Dave Hansen wrote: > On Tue, 2009-02-24 at 07:47 +0300, Alexey Dobriyan wrote: > > > I think what I posted is a decent compromise. It gets you those > > > warnings at runtime and is a one-way trip for any given process. But, > > > it does detect in certain cases (fork() and unshare(FILES)) when it is > > > safe to make the trip back to the "I'm checkpointable" state again. > > > > "Checkpointable" is not even per-process property. > > > > Imagine, set of SAs (struct xfrm_state) and SPDs (struct xfrm_policy). > > They are a) per-netns, b) persistent. > > > > You can hook into socketcalls to mark process as uncheckpointable, > > but since SAs and SPDs are persistent, original process already exited. > > You're going to walk every process with same netns as SA adder and mark > > it as uncheckpointable. Definitely doable, but ugly, isn't it? > > > > Same for iptable rules. > > > > "Checkpointable" is container property, OK? > > Ideally, I completely agree. > > But, we don't currently have a concept of a true container in the > kernel. Do you have any suggestions for any current objects that we > could use in its place for a while? After all foo_ns changes struct nsproxy is such thing. More specific, a process with fully cloned nsproxy acting as init, all its children. In terms of data structures, every task_struct in such tree, every nsproxy of them, every foo_ns, and so on to lower levels. -- 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