Re: [PATCH v3 1/8] memcg: Add MEMCG_DMABUF accounting infrastructure

[sashiko-bot@kernel.org]

> From: "T.J. Mercier" <tjmercier@google.com>
> 
> Introduce a MEMCG_DMABUF stat counter and helpers for
> reserve/commit/cancel and uncharging dma-buf memory against a
> memory cgroup:
> 
> The charge is tracked on struct dma_buf via a new memcg pointer. The
> page count is derived internally from PAGE_ALIGN(dmabuf->size), and
> the memcg reference is stored into (or cleared from) dmabuf->memcg by
> the helpers themselves, removing the need for callers to manage those
> details. The release path in dma_buf_release() is reduced to a single
> mem_cgroup_uncharge_dmabuf() call.
> 
> This decouples accounting from the backing page allocator, avoiding the
> need for every exporter to pass __GFP_ACCOUNT and enabling cross-cgroup
> charge transfer, which is impractical with page-level accounting.
> 
> The next patch wires up the charging policy in the dma-heap ioctl.
> 
> Signed-off-by: T.J. Mercier <tjmercier@google.com>
> Signed-off-by: Albert Esteve <aesteve@redhat.com>

Sashiko has reviewed this patch and found no issues.

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