From: Yosry Ahmed <yosryahmed@google.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: "T.J. Mercier" <tjmercier@google.com>,
Alistair Popple <apopple@nvidia.com>, Tejun Heo <tj@kernel.org>,
Michal Hocko <mhocko@suse.com>,
linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org, jhubbard@nvidia.com,
hannes@cmpxchg.org, surenb@google.com, mkoutny@suse.com,
daniel@ffwll.ch, "Daniel P . Berrange" <berrange@redhat.com>,
Alex Williamson <alex.williamson@redhat.com>,
Zefan Li <lizefan.x@bytedance.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 14/19] mm: Introduce a cgroup for pinned memory
Date: Thu, 23 Feb 2023 10:03:50 -0800 [thread overview]
Message-ID: <CAJD7tkadBRP22qP63-SjKSch1im9sHLoMzc6c2h10+ggbuxqMg@mail.gmail.com> (raw)
In-Reply-To: <Y/eiLBo88pgr2IUm@nvidia.com>
On Thu, Feb 23, 2023 at 9:28 AM Jason Gunthorpe <jgg@nvidia.com> wrote:
>
> On Thu, Feb 23, 2023 at 09:18:23AM -0800, T.J. Mercier wrote:
>
> > > Solving that problem means figuring out when every cgroup stops using
> > > the memory - pinning or not. That seems to be very costly.
> > >
> > This is the current behavior of accounting for memfds, and I suspect
> > any kind of shared memory.
> >
> > If cgroup A creates a memfd, maps and faults in pages, shares the
> > memfd with cgroup B and then A unmaps and closes the memfd, then
> > cgroup A is still charged for the pages it faulted in.
>
> As we discussed, as long as the memory is swappable then eventually
> memory pressure on cgroup A will evict the memfd pages and then cgroup
> B will swap it in and be charged for it.
I am not familiar with memfd, but based on
mem_cgroup_swapin_charge_folio() it seems like if cgroup B swapped in
the pages they will remain charged to cgroup A, unless cgroup A is
removed/offlined. Am I missing something?
>
> > FWIW this is also the behavior I was trying to use to attribute
> > dma-buffers to their original allocators. Whoever touches it first
> > gets charged as long as the memory is alive somewhere.
> >
> > Can't we do the same thing for pins?
>
> If pins are tracked independently from memcg then definately not,
> a process in cgroup A should never be able to make a charge on cgroup
> B as a matter of security.
>
> If pins are part of the memcg then we can't always turn the pin
> request in to a NOP - the current cgroup always has to be charged for
> the memory. Otherwise what is the point from a security perspective?
>
> Jason
next prev parent reply other threads:[~2023-02-23 18:04 UTC|newest]
Thread overview: 128+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-06 7:47 [PATCH 00/19] mm: Introduce a cgroup to limit the amount of locked and pinned memory Alistair Popple
2023-02-06 7:47 ` Alistair Popple
2023-02-06 7:47 ` [PATCH 01/19] mm: Introduce vm_account Alistair Popple
2023-02-06 7:47 ` Alistair Popple
2023-02-06 7:47 ` Alistair Popple
2023-02-06 7:47 ` [PATCH 02/19] drivers/vhost: Convert to use vm_account Alistair Popple
2023-02-06 7:47 ` Alistair Popple
2023-02-06 7:47 ` [PATCH 03/19] drivers/vdpa: Convert vdpa to use the new vm_structure Alistair Popple
2023-02-06 7:47 ` Alistair Popple
2023-02-06 7:47 ` [PATCH 04/19] infiniband/umem: Convert to use vm_account Alistair Popple
2023-02-06 7:47 ` Alistair Popple
2023-02-06 7:47 ` [PATCH 05/19] RMDA/siw: " Alistair Popple
2023-02-06 7:47 ` Alistair Popple
2023-02-12 17:32 ` Bernard Metzler
2023-02-06 7:47 ` [PATCH 06/19] RDMA/usnic: convert " Alistair Popple
2023-02-06 7:47 ` Alistair Popple
2023-02-06 7:47 ` [PATCH 07/19] vfio/type1: Charge pinned pages to pinned_vm instead of locked_vm Alistair Popple
2023-02-06 7:47 ` Alistair Popple
2023-02-06 7:47 ` [PATCH 08/19] vfio/spapr_tce: Convert accounting to pinned_vm Alistair Popple
2023-02-06 7:47 ` Alistair Popple
2023-02-06 7:47 ` [PATCH 09/19] io_uring: convert to use vm_account Alistair Popple
2023-02-06 15:29 ` Jens Axboe
2023-02-06 15:29 ` Jens Axboe
2023-02-07 1:03 ` Alistair Popple
2023-02-07 1:03 ` Alistair Popple
2023-02-07 14:28 ` Jens Axboe
2023-02-07 14:55 ` Jason Gunthorpe
2023-02-07 14:55 ` Jason Gunthorpe
2023-02-07 17:05 ` Jens Axboe
2023-02-07 17:05 ` Jens Axboe
2023-02-13 11:30 ` Alistair Popple
2023-02-13 11:30 ` Alistair Popple
2023-02-06 7:47 ` [PATCH 10/19] net: skb: Switch to using vm_account Alistair Popple
2023-02-06 7:47 ` [PATCH 11/19] xdp: convert to use vm_account Alistair Popple
2023-02-06 7:47 ` [PATCH 12/19] kvm/book3s_64_vio: Convert account_locked_vm() to vm_account_pinned() Alistair Popple
2023-02-06 7:47 ` Alistair Popple
2023-02-06 7:47 ` [PATCH 13/19] fpga: dfl: afu: convert to use vm_account Alistair Popple
2023-02-06 7:47 ` Alistair Popple
2023-02-06 7:47 ` [PATCH 14/19] mm: Introduce a cgroup for pinned memory Alistair Popple
2023-02-06 7:47 ` Alistair Popple
2023-02-06 21:01 ` Yosry Ahmed
2023-02-06 21:01 ` Yosry Ahmed
2023-02-06 21:14 ` Tejun Heo
2023-02-06 21:14 ` Tejun Heo
2023-02-06 22:32 ` Yosry Ahmed
2023-02-06 22:32 ` Yosry Ahmed
2023-02-06 22:36 ` Tejun Heo
2023-02-06 22:39 ` Yosry Ahmed
2023-02-06 22:39 ` Yosry Ahmed
2023-02-06 23:25 ` Tejun Heo
2023-02-06 23:25 ` Tejun Heo
2023-02-06 23:34 ` Yosry Ahmed
2023-02-06 23:34 ` Yosry Ahmed
2023-02-06 23:40 ` Jason Gunthorpe
2023-02-06 23:40 ` Jason Gunthorpe
2023-02-07 0:32 ` Tejun Heo
2023-02-07 0:32 ` Tejun Heo
2023-02-07 12:19 ` Jason Gunthorpe
2023-02-07 12:19 ` Jason Gunthorpe
2023-02-15 19:00 ` Michal Hocko
2023-02-15 19:00 ` Michal Hocko
2023-02-15 19:07 ` Jason Gunthorpe
2023-02-15 19:07 ` Jason Gunthorpe
2023-02-16 8:04 ` Michal Hocko
2023-02-16 8:04 ` Michal Hocko
2023-02-16 12:45 ` Jason Gunthorpe
2023-02-16 12:45 ` Jason Gunthorpe
2023-02-21 16:51 ` Tejun Heo
2023-02-21 16:51 ` Tejun Heo
2023-02-21 17:25 ` Jason Gunthorpe
2023-02-21 17:29 ` Tejun Heo
2023-02-21 17:29 ` Tejun Heo
2023-02-21 17:51 ` Jason Gunthorpe
2023-02-21 17:51 ` Jason Gunthorpe
2023-02-21 18:07 ` Tejun Heo
2023-02-21 18:07 ` Tejun Heo
2023-02-21 19:26 ` Jason Gunthorpe
2023-02-21 19:26 ` Jason Gunthorpe
2023-02-21 19:45 ` Tejun Heo
2023-02-21 19:45 ` Tejun Heo
2023-02-21 19:49 ` Tejun Heo
2023-02-21 19:49 ` Tejun Heo
2023-02-21 19:57 ` Jason Gunthorpe
2023-02-22 11:38 ` Alistair Popple
2023-02-22 11:38 ` Alistair Popple
2023-02-22 12:57 ` Jason Gunthorpe
2023-02-22 12:57 ` Jason Gunthorpe
2023-02-22 22:59 ` Alistair Popple
2023-02-22 22:59 ` Alistair Popple
2023-02-23 0:05 ` Christoph Hellwig
2023-02-23 0:35 ` Alistair Popple
2023-02-23 0:35 ` Alistair Popple
2023-02-23 1:53 ` Jason Gunthorpe
2023-02-23 1:53 ` Jason Gunthorpe
2023-02-23 9:12 ` Daniel P. Berrangé
2023-02-23 17:31 ` Jason Gunthorpe
2023-02-23 17:31 ` Jason Gunthorpe
2023-02-23 17:18 ` T.J. Mercier
2023-02-23 17:28 ` Jason Gunthorpe
2023-02-23 17:28 ` Jason Gunthorpe
2023-02-23 18:03 ` Yosry Ahmed [this message]
2023-02-23 18:10 ` Jason Gunthorpe
2023-02-23 18:10 ` Jason Gunthorpe
2023-02-23 18:14 ` Yosry Ahmed
2023-02-23 18:14 ` Yosry Ahmed
2023-02-23 18:15 ` Tejun Heo
2023-02-23 18:17 ` Jason Gunthorpe
2023-02-23 18:17 ` Jason Gunthorpe
2023-02-23 18:22 ` Tejun Heo
2023-02-23 18:22 ` Tejun Heo
2023-02-07 1:00 ` Waiman Long
2023-02-07 1:00 ` Waiman Long
2023-02-07 1:03 ` Tejun Heo
2023-02-07 1:50 ` Alistair Popple
2023-02-07 1:50 ` Alistair Popple
2023-02-06 7:47 ` [PATCH 15/19] mm/util: Extend vm_account to charge pages against the pin cgroup Alistair Popple
2023-02-06 7:47 ` Alistair Popple
2023-02-06 7:47 ` [PATCH 16/19] mm/util: Refactor account_locked_vm Alistair Popple
2023-02-06 7:47 ` Alistair Popple
2023-02-06 7:47 ` [PATCH 17/19] mm: Convert mmap and mlock to use account_locked_vm Alistair Popple
2023-02-06 7:47 ` Alistair Popple
2023-02-06 7:47 ` [PATCH 18/19] mm/mmap: Charge locked memory to pins cgroup Alistair Popple
2023-02-06 7:47 ` Alistair Popple
2023-02-06 21:12 ` Yosry Ahmed
2023-02-06 7:47 ` [PATCH 19/19] selftests/vm: Add pins-cgroup selftest for mlock/mmap Alistair Popple
2023-02-06 7:47 ` Alistair Popple
2023-02-16 11:01 ` [PATCH 00/19] mm: Introduce a cgroup to limit the amount of locked and pinned memory David Hildenbrand
2023-02-16 11:01 ` David Hildenbrand
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