From: David Hildenbrand <david@redhat.com>
To: Alistair Popple <apopple@nvidia.com>,
linux-mm@kvack.org, cgroups@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, jgg@nvidia.com,
jhubbard@nvidia.com, tjmercier@google.com, hannes@cmpxchg.org,
surenb@google.com, mkoutny@suse.com, daniel@ffwll.ch,
linuxppc-dev@lists.ozlabs.org, linux-fpga@vger.kernel.org,
linux-rdma@vger.kernel.org,
virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
netdev@vger.kernel.org, io-uring@vger.kernel.org,
bpf@vger.kernel.org, rds-devel@oss.oracle.com,
linux-kselftest@vger.kernel.org
Subject: Re: [RFC PATCH 01/19] mm: Introduce vm_account
Date: Tue, 31 Jan 2023 15:00:08 +0100 [thread overview]
Message-ID: <658eda9c-d716-fcb7-ba0c-b36f646195f1@redhat.com> (raw)
In-Reply-To: <748338ffe4c42d86669923159fe0426808ecb04d.1674538665.git-series.apopple@nvidia.com>
On 24.01.23 06:42, Alistair Popple wrote:
> Kernel drivers that pin pages should account these pages against
> either user->locked_vm or mm->pinned_vm and fail the pinning if
> RLIMIT_MEMLOCK is exceeded and CAP_IPC_LOCK isn't held.
>
> Currently drivers open-code this accounting and use various methods to
> update the atomic variables and check against the limits leading to
> various bugs and inconsistencies. To fix this introduce a standard
> interface for charging pinned and locked memory. As this involves
> taking references on kernel objects such as mm_struct or user_struct
> we introduce a new vm_account struct to hold these references. Several
> helper functions are then introduced to grab references and check
> limits.
>
> As the way these limits are charged and enforced is visible to
> userspace we need to be careful not to break existing applications by
> charging to different counters. As a result the vm_account functions
> support accounting to different counters as required.
>
> A future change will extend this to also account against a cgroup for
> pinned pages.
The term "vm_account" is misleading, no? VM_ACCOUNT is for accounting
towards the commit limit ....
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2023-01-31 14:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.f52b9eb2792bccb8a9ecd6bc95055705cfe2ae03.1674538665.git-series.apopple@nvidia.com>
2023-01-24 5:42 ` [RFC PATCH 01/19] mm: Introduce vm_account Alistair Popple
2023-01-24 6:29 ` Christoph Hellwig
2023-01-24 14:32 ` Jason Gunthorpe
2023-01-30 11:36 ` Alistair Popple
2023-01-31 14:00 ` David Hildenbrand [this message]
2023-01-24 5:42 ` [RFC PATCH 13/19] fpga: dfl: afu: convert to use vm_account Alistair Popple
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