From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx115.postini.com [74.125.245.115]) by kanga.kvack.org (Postfix) with SMTP id 699B46B0113 for ; Tue, 26 Jun 2012 09:38:48 -0400 (EDT) Received: by qcsp15 with SMTP id p15so3330664qcs.30 for ; Tue, 26 Jun 2012 06:38:47 -0700 (PDT) Date: Tue, 26 Jun 2012 15:38:41 +0200 From: Frederic Weisbecker Subject: Re: [PATCH 11/11] protect architectures where THREAD_SIZE >= PAGE_SIZE against fork bombs Message-ID: <20120626133838.GA11519@somewhere.redhat.com> References: <1340633728-12785-1-git-send-email-glommer@parallels.com> <1340633728-12785-12-git-send-email-glommer@parallels.com> <4FE89807.50708@redhat.com> <20120625183818.GH3869@google.com> <4FE9AF88.5070803@parallels.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4FE9AF88.5070803@parallels.com> Sender: owner-linux-mm@kvack.org List-ID: To: Glauber Costa Cc: Tejun Heo , Frederic Weisbecker , cgroups@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , linux-kernel@vger.kernel.org, David Rientjes , Pekka Enberg , Michal Hocko , Johannes Weiner , Christoph Lameter , devel@openvz.org, kamezawa.hiroyu@jp.fujitsu.com, Pekka Enberg , Suleiman Souhlal On Tue, Jun 26, 2012 at 04:48:08PM +0400, Glauber Costa wrote: > On 06/25/2012 10:38 PM, Tejun Heo wrote: > >On Mon, Jun 25, 2012 at 06:55:35PM +0200, Frederic Weisbecker wrote: > >>On 06/25/2012 04:15 PM, Glauber Costa wrote: > >> > >>>Because those architectures will draw their stacks directly from > >>>the page allocator, rather than the slab cache, we can directly > >>>pass __GFP_KMEMCG flag, and issue the corresponding free_pages. > >>> > >>>This code path is taken when the architecture doesn't define > >>>CONFIG_ARCH_THREAD_INFO_ALLOCATOR (only ia64 seems to), and has > >>>THREAD_SIZE >= PAGE_SIZE. Luckily, most - if not all - of the > >>>remaining architectures fall in this category. > >>> > >>>This will guarantee that every stack page is accounted to the memcg > >>>the process currently lives on, and will have the allocations to fail > >>>if they go over limit. > >>> > >>>For the time being, I am defining a new variant of THREADINFO_GFP, not > >>>to mess with the other path. Once the slab is also tracked by memcg, > >>>we can get rid of that flag. > >>> > >>>Tested to successfully protect against :(){ :|:& };: > >>> > >>>Signed-off-by: Glauber Costa > >>>CC: Christoph Lameter > >>>CC: Pekka Enberg > >>>CC: Michal Hocko > >>>CC: Kamezawa Hiroyuki > >>>CC: Johannes Weiner > >>>CC: Suleiman Souhlal > >> > >> > >>Acked-by: Frederic Weisbecker > > > >Frederic, does this (with proper slab accounting added later) achieve > >what you wanted with the task counter? > > > > A note: Frederic may confirm, but I think he doesn't even need > the slab accounting to follow to achieve that goal. Limiting is enough. But that requires internal accounting. -- 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