From: Vivek Goyal <vgoyal@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: Jeff Moyer <jmoyer@redhat.com>,
axboe@kernel.dk, ctalbott@google.com, rni@google.com,
linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
containers@lists.linux-foundation.org, fengguang.wu@intel.com,
hughd@google.com, akpm@linux-foundation.org
Subject: Re: [PATCH 11/11] blkcg: implement per-blkg request allocation
Date: Fri, 27 Apr 2012 12:19:59 -0400 [thread overview]
Message-ID: <20120427161959.GL10579@redhat.com> (raw)
In-Reply-To: <20120427155612.GK10579@redhat.com>
On Fri, Apr 27, 2012 at 11:56:12AM -0400, Vivek Goyal wrote:
> On Fri, Apr 27, 2012 at 08:51:40AM -0700, Tejun Heo wrote:
> > On Fri, Apr 27, 2012 at 11:48:41AM -0400, Vivek Goyal wrote:
> > > Not an unpriviliged malicious application. In typical cgroup scenario, we
> > > can allow unpriviliged users to create child cgroups so that it can
> > > further subdivide its resources to its children group. (ex. put firefox
> > > in one cgroup, open office in another group etc.).
> > >
> > > So it is not same as jack up nr_requests.
> >
> > I find allowing unpriv users creating cgroups dumb. cgroup consumes
> > kernel memory. Sans using kmemcg, what prevents them from creating
> > gazillion cgroups and consuming all memories? The idea of allowing
> > cgroups to !priv users is just broken from the get go.
>
> Well creating a task consumes memory too but we allow unpriv users to
> create tasks. :-)
Well, kernel can kill tasks and reclaim that memory so this is not an
appropriate example.
A more suitable example probably is AIO where kernel pins down some
memory and we limit that amount by upper limit on number of aio requests.
Thanks
Vivek
next prev parent reply other threads:[~2012-04-27 16:20 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-26 21:59 [PATCHSET] block: implement per-blkg request allocation Tejun Heo
2012-04-26 21:59 ` [PATCH 01/11] blkcg: fix blkg_alloc() failure path Tejun Heo
2012-04-27 14:26 ` Vivek Goyal
2012-04-27 14:27 ` Tejun Heo
2012-04-26 21:59 ` [PATCH 02/11] blkcg: __blkg_lookup_create() doesn't have to fail on radix tree preload failure Tejun Heo
2012-04-27 14:42 ` Vivek Goyal
2012-04-27 14:47 ` Tejun Heo
2012-04-27 21:18 ` [PATCH UPDATED 02/11] blkcg: __blkg_lookup_create() doesn't need radix preload Tejun Heo
2012-04-26 21:59 ` [PATCH 03/11] blkcg: make root blkcg allocation use %GFP_KERNEL Tejun Heo
2012-04-27 21:19 ` [PATCH UPDATED " Tejun Heo
2012-04-26 21:59 ` [PATCH 04/11] mempool: add @gfp_mask to mempool_create_node() Tejun Heo
2012-04-26 21:59 ` [PATCH 05/11] block: drop custom queue draining used by scsi_transport_{iscsi|fc} Tejun Heo
2012-05-02 4:55 ` Mike Christie
2012-04-26 21:59 ` [PATCH 06/11] block: refactor get_request[_wait]() Tejun Heo
2012-04-26 21:59 ` [PATCH 07/11] block: allocate io_context upfront Tejun Heo
2012-04-26 21:59 ` [PATCH 08/11] blkcg: inline bio_blkcg() and friends Tejun Heo
2012-04-26 21:59 ` [PATCH 09/11] block: add q->nr_rqs[] and move q->rq.elvpriv to q->nr_rqs_elvpriv Tejun Heo
2012-04-26 21:59 ` [PATCH 10/11] block: prepare for multiple request_lists Tejun Heo
2012-04-26 21:59 ` [PATCH 11/11] blkcg: implement per-blkg request allocation Tejun Heo
2012-04-27 14:54 ` Jeff Moyer
2012-04-27 15:02 ` Tejun Heo
2012-04-27 15:40 ` Vivek Goyal
2012-04-27 15:45 ` Tejun Heo
2012-04-27 15:48 ` Vivek Goyal
2012-04-27 15:51 ` Tejun Heo
2012-04-27 15:56 ` Vivek Goyal
2012-04-27 16:19 ` Vivek Goyal [this message]
2012-04-27 16:20 ` Tejun Heo
2012-04-27 17:21 ` Vivek Goyal
2012-04-27 17:25 ` Tejun Heo
2012-04-27 19:46 ` Vivek Goyal
2012-04-27 20:15 ` Tejun Heo
2012-04-27 20:21 ` Vivek Goyal
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