From: Joel Fernandes <joelagnelf@nvidia.com>
To: Danilo Krummrich <dakr@kernel.org>
Cc: linux-kernel@vger.kernel.org, Miguel Ojeda <ojeda@kernel.org>,
Boqun Feng <boqun@kernel.org>, Gary Guo <gary@garyguo.net>,
Bjorn Roy Baron <bjorn3_gh@protonmail.com>,
Benno Lossin <lossin@kernel.org>,
Andreas Hindborg <a.hindborg@kernel.org>,
Alice Ryhl <aliceryhl@google.com>,
Trevor Gross <tmgross@umich.edu>,
Dave Airlie <airlied@redhat.com>,
Daniel Almeida <daniel.almeida@collabora.com>,
Koen Koning <koen.koning@linux.intel.com>,
dri-devel@lists.freedesktop.org, rust-for-linux@vger.kernel.org,
Nikola Djukic <ndjukic@nvidia.com>,
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Alexandre Courbot <acourbot@nvidia.com>,
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Balbir Singh <balbirs@nvidia.com>,
Philipp Stanner <phasta@kernel.org>,
Elle Rhumsaa <elle@weathered-steel.dev>,
alexeyi@nvidia.com, Eliot Courtney <ecourtney@nvidia.com>,
joel@joelfernandes.org, linux-doc@vger.kernel.org,
amd-gfx@lists.freedesktop.org, intel-gfx@lists.freedesktop.org,
intel-xe@lists.freedesktop.org, linux-fbdev@vger.kernel.org
Subject: Re: [PATCH v11 07/20] gpu: nova-core: mm: Add TLB flush support
Date: Thu, 16 Apr 2026 18:18:24 -0400 [thread overview]
Message-ID: <1e3c423e-1cf5-48b1-b012-c4af0eb6b95f@nvidia.com> (raw)
In-Reply-To: <DHUWPQX14ZGZ.26BV7GQCJDZQI@kernel.org>
On 4/16/2026 5:45 PM, Danilo Krummrich wrote:
> On Thu Apr 16, 2026 at 11:23 PM CEST, Joel Fernandes wrote:
>> Btw, I changed this to doing it in 2 phases to avoid holding the RCU readlock
>> across read_poll_timeout, which can sleep. Will squash it in for v12.
>
> Why do we need the try_access() dance in the first place? I assume this ends up
> being called from the BarAccess destructor?
BarAccess is different. The try_access() calls here are in tlb.rs and
pramin.rs for Bar0. BarAccess uses &'a Bar1 directly — its Drop impl just
calls self.vmm.unmap_pages(self.mm, mapped), without needing try_access().
>
> If so, I think this is solvable. Gary and me are currently working on
> higher-ranked types and a chained Devres type.
Hmm, the issue here is we cannot hold revocable guard while sleeping, but
we have read the bar as a condition in the body of the poll. So I split the
try_access()'es. First phase for writing and second for reading (bar 0).
>
> With that, such use-cases should be cleanly solvable without the need for
> try_access().
>
> Besides that, I can't find where BarAccess is ever constructed.
BarUser::map() constructs it.
https://lore.kernel.org/all/20260415210548.3776595-18-joelagnelf@nvidia.com/
>
> It already has a lifetime 'a for &'a Bar1, so I don't see why you can't do the
> same for Bar0.>
> But again, I don't see this being constructed and I'm not sure the whole
> construct works in the first place.
BarAccess uses &'a Bar1 because it's a short-lived scoped object. In long
lived objects I am trying to avoid this. I guess I would be Ok with
switching &'a Bar1 to Devres as well. But let me know your suggestions!
If it is easier to look at a git tree to get a complete picture, here is
the git tag of v11:
https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git/tag/?h=nova-mm-v11-20260415
Thanks.
next prev parent reply other threads:[~2026-04-16 22:18 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-15 21:05 [PATCH v11 01/20] gpu: nova-core: gsp: Return GspStaticInfo from boot() Joel Fernandes
2026-04-15 21:05 ` [PATCH v11 02/20] gpu: nova-core: gsp: Extract usable FB region from GSP Joel Fernandes
2026-04-16 23:04 ` John Hubbard
2026-04-16 23:26 ` John Hubbard
2026-04-15 21:05 ` [PATCH v11 03/20] gpu: nova-core: gsp: Expose total physical VRAM end from FB region info Joel Fernandes
2026-04-15 21:05 ` [PATCH v11 04/20] gpu: nova-core: mm: Add support to use PRAMIN windows to write to VRAM Joel Fernandes
2026-04-15 21:05 ` [PATCH v11 05/20] docs: gpu: nova-core: Document the PRAMIN aperture mechanism Joel Fernandes
2026-04-15 21:05 ` [PATCH v11 06/20] gpu: nova-core: mm: Add common memory management types Joel Fernandes
2026-04-15 21:05 ` [PATCH v11 07/20] gpu: nova-core: mm: Add TLB flush support Joel Fernandes
2026-04-16 21:23 ` Joel Fernandes
2026-04-16 21:45 ` Danilo Krummrich
2026-04-16 22:18 ` Joel Fernandes [this message]
2026-04-16 22:53 ` Danilo Krummrich
2026-04-15 21:05 ` [PATCH v11 08/20] gpu: nova-core: mm: Add GpuMm centralized memory manager Joel Fernandes
2026-04-15 21:05 ` [PATCH v11 09/20] gpu: nova-core: mm: Add common types for all page table formats Joel Fernandes
2026-04-15 21:05 ` [PATCH v11 10/20] gpu: nova-core: mm: Add MMU v2 page table types Joel Fernandes
2026-04-15 21:05 ` [PATCH v11 11/20] gpu: nova-core: mm: Add MMU v3 " Joel Fernandes
2026-04-15 21:05 ` [PATCH v11 12/20] gpu: nova-core: mm: Add unified page table entry wrapper enums Joel Fernandes
2026-04-15 21:05 ` [PATCH v11 13/20] gpu: nova-core: mm: Add page table walker for MMU v2/v3 Joel Fernandes
2026-04-15 21:05 ` [PATCH v11 14/20] gpu: nova-core: mm: Add Virtual Memory Manager Joel Fernandes
2026-04-15 21:05 ` [PATCH v11 15/20] gpu: nova-core: mm: Add virtual address range tracking to VMM Joel Fernandes
2026-04-15 21:05 ` [PATCH v11 16/20] gpu: nova-core: mm: Add multi-page mapping API " Joel Fernandes
2026-04-15 21:05 ` [PATCH v11 17/20] gpu: nova-core: Add BAR1 aperture type and size constant Joel Fernandes
2026-04-15 21:05 ` [PATCH v11 18/20] gpu: nova-core: mm: Add BAR1 user interface Joel Fernandes
2026-04-15 21:05 ` [PATCH v11 19/20] gpu: nova-core: mm: Add BAR1 memory management self-tests Joel Fernandes
2026-04-15 21:05 ` [PATCH v11 20/20] gpu: nova-core: mm: Add PRAMIN aperture self-tests Joel Fernandes
2026-04-15 21:05 ` [PATCH v11 00/21] gpu: nova-core: Add memory management support Joel Fernandes
2026-04-16 22:57 ` [PATCH v11 01/20] gpu: nova-core: gsp: Return GspStaticInfo from boot() John Hubbard
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