| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <CAJD7tkavoSu9WOnw4Nbxz41nq+Rm6Sq5EeOjh3CTyA=AT5=ujg@mail.gmail.com>
Date: Tue, 24 Jan 2023 10:26:49 -0800
From: Yosry Ahmed <yosryahmed@...gle.com>
To: Alistair Popple <apopple@...dia.com>
Cc: linux-mm@...ck.org, cgroups@...r.kernel.org,
linux-kernel@...r.kernel.org, jgg@...dia.com, jhubbard@...dia.com,
tjmercier@...gle.com, hannes@...xchg.org, surenb@...gle.com,
mkoutny@...e.com, daniel@...ll.ch
Subject: Re: [RFC PATCH 00/19] mm: Introduce a cgroup to limit the amount of
locked and pinned memory
On Mon, Jan 23, 2023 at 9:43 PM Alistair Popple <apopple@...dia.com> wrote:
>
> Having large amounts of unmovable or unreclaimable memory in a system
> can lead to system instability due to increasing the likelihood of
> encountering out-of-memory conditions. Therefore it is desirable to
> limit the amount of memory users can lock or pin.
>
> From userspace such limits can be enforced by setting
> RLIMIT_MEMLOCK. However there is no standard method that drivers and
> other in-kernel users can use to check and enforce this limit.
>
> This has lead to a large number of inconsistencies in how limits are
> enforced. For example some drivers will use mm->locked_mm while others
> will use mm->pinned_mm or user->locked_mm. It is therefore possible to
> have up to three times RLIMIT_MEMLOCKED pinned.
>
> Having pinned memory limited per-task also makes it easy for users to
> exceed the limit. For example drivers that pin memory with
> pin_user_pages() it tends to remain pinned after fork. To deal with
> this and other issues this series introduces a cgroup for tracking and
> limiting the number of pages pinned or locked by tasks in the group.
>
> However the existing behaviour with regards to the rlimit needs to be
> maintained. Therefore the lesser of the two limits is
> enforced. Furthermore having CAP_IPC_LOCK usually bypasses the rlimit,
> but this bypass is not allowed for the cgroup.
>
> The first part of this series converts existing drivers which
> open-code the use of locked_mm/pinned_mm over to a common interface
> which manages the refcounts of the associated task/mm/user
> structs. This ensures accounting of pages is consistent and makes it
> easier to add charging of the cgroup.
>
> The second part of the series adds the cgroup and converts core mm
> code such as mlock over to charging the cgroup before finally
> introducing some selftests.
I didn't go through the entire series, so apologies if this was
mentioned somewhere, but do you mind elaborating on why this is added
as a separate cgroup controller rather than an extension of the memory
cgroup controller?
>
>
> As I don't have access to systems with all the various devices I
> haven't been able to test all driver changes. Any help there would be
> appreciated.
>
> Alistair Popple (19):
> mm: Introduce vm_account
> drivers/vhost: Convert to use vm_account
> drivers/vdpa: Convert vdpa to use the new vm_structure
> infiniband/umem: Convert to use vm_account
> RMDA/siw: Convert to use vm_account
> RDMA/usnic: convert to use vm_account
> vfio/type1: Charge pinned pages to pinned_vm instead of locked_vm
> vfio/spapr_tce: Convert accounting to pinned_vm
> io_uring: convert to use vm_account
> net: skb: Switch to using vm_account
> xdp: convert to use vm_account
> kvm/book3s_64_vio: Convert account_locked_vm() to vm_account_pinned()
> fpga: dfl: afu: convert to use vm_account
> mm: Introduce a cgroup for pinned memory
> mm/util: Extend vm_account to charge pages against the pin cgroup
> mm/util: Refactor account_locked_vm
> mm: Convert mmap and mlock to use account_locked_vm
> mm/mmap: Charge locked memory to pins cgroup
> selftests/vm: Add pins-cgroup selftest for mlock/mmap
>
> MAINTAINERS | 8 +-
> arch/powerpc/kvm/book3s_64_vio.c | 10 +-
> arch/powerpc/mm/book3s64/iommu_api.c | 29 +--
> drivers/fpga/dfl-afu-dma-region.c | 11 +-
> drivers/fpga/dfl-afu.h | 1 +-
> drivers/infiniband/core/umem.c | 16 +-
> drivers/infiniband/core/umem_odp.c | 6 +-
> drivers/infiniband/hw/usnic/usnic_uiom.c | 13 +-
> drivers/infiniband/hw/usnic/usnic_uiom.h | 1 +-
> drivers/infiniband/sw/siw/siw.h | 2 +-
> drivers/infiniband/sw/siw/siw_mem.c | 20 +--
> drivers/infiniband/sw/siw/siw_verbs.c | 15 +-
> drivers/vdpa/vdpa_user/vduse_dev.c | 20 +--
> drivers/vfio/vfio_iommu_spapr_tce.c | 15 +-
> drivers/vfio/vfio_iommu_type1.c | 59 +----
> drivers/vhost/vdpa.c | 9 +-
> drivers/vhost/vhost.c | 2 +-
> drivers/vhost/vhost.h | 1 +-
> include/linux/cgroup.h | 20 ++-
> include/linux/cgroup_subsys.h | 4 +-
> include/linux/io_uring_types.h | 3 +-
> include/linux/kvm_host.h | 1 +-
> include/linux/mm.h | 5 +-
> include/linux/mm_types.h | 88 ++++++++-
> include/linux/skbuff.h | 6 +-
> include/net/sock.h | 2 +-
> include/net/xdp_sock.h | 2 +-
> include/rdma/ib_umem.h | 1 +-
> io_uring/io_uring.c | 20 +--
> io_uring/notif.c | 4 +-
> io_uring/notif.h | 10 +-
> io_uring/rsrc.c | 38 +---
> io_uring/rsrc.h | 9 +-
> mm/Kconfig | 11 +-
> mm/Makefile | 1 +-
> mm/internal.h | 2 +-
> mm/mlock.c | 76 +------
> mm/mmap.c | 76 +++----
> mm/mremap.c | 54 +++--
> mm/pins_cgroup.c | 273 ++++++++++++++++++++++++-
> mm/secretmem.c | 6 +-
> mm/util.c | 196 +++++++++++++++--
> net/core/skbuff.c | 47 +---
> net/rds/message.c | 9 +-
> net/xdp/xdp_umem.c | 38 +--
> tools/testing/selftests/vm/Makefile | 1 +-
> tools/testing/selftests/vm/pins-cgroup.c | 271 ++++++++++++++++++++++++-
> virt/kvm/kvm_main.c | 3 +-
> 48 files changed, 1114 insertions(+), 401 deletions(-)
> create mode 100644 mm/pins_cgroup.c
> create mode 100644 tools/testing/selftests/vm/pins-cgroup.c
>
> base-commit: 2241ab53cbb5cdb08a6b2d4688feb13971058f65
> --
> git-series 0.9.1
>
Powered by blists - more mailing lists