Re: [PATCH 6/7] io_uring: account the ring context and SQPOLL thread data to memcg

[Tao Cui <cui.tao@linux.dev>]

Hi,

在 2026/11/7 21:27, sashiko-bot@kernel.org 写道:
> Thank you for your contribution! Sashiko AI review found 1 potential
> issue to consider:
> - [Low] io_uring: commit message omits rsrc and tctx changes and
>   uncharged allocs
Thanks for catching this.

You're right that the changelog should better match the actual changes.
Besides io_ring_ctx and io_sq_data, this patch also switches the
allocations in io_coalesce_buffer(), io_init_wq_offload(), and
io_uring_alloc_task_context() to GFP_KERNEL_ACCOUNT.  I'll mention
those explicitly in v2.

You're also right that "the last per-ring allocations" overstates the
current state.  Patch 7 still leaves some infrastructure allocations,
such as the percpu pieces and the io-wq cpumask, unchanged.  I'll drop
that wording and instead describe what this patch accounts and what
remains.

As for commits 075d5837bafc and 0b34e7b20a48, this series is based on
linux-next (next-20261104), which already includes the
io_uring-7.4-20261029 tag containing those commits.  If the review is
performed against a tree without that tag, those objects will indeed
still appear uncharged.

Thanks,
Tao
> --
> 
> commit 3d47975c4208930279f98824279734ca99b5e9bd
> Author: Tao Cui <cuitao@kylinos.cn>
> 
>> io_uring: account the ring context and SQPOLL thread data to memcg
>>
>> The io_ring_ctx and the SQPOLL io_sqd are the last per-ring allocations
>> made with plain GFP_KERNEL.  The larger surfaces around them are
>> already charged: io_mapped_ubuf and io_rsrc_node since commit
>> 075d5837bafc ("io_uring/rsrc: charge buffer arrays and nodes to memcg"),
>> the tctx node and its XArrays since commit 0b34e7b20a48 ("io_uring:
>> charge tctx nodes and personalities").
>>
>> Charge the context and the SQPOLL thread data the same way.
>>
>> Signed-off-by: Tao Cui <cuitao@kylinos.cn>
> 
> [Severity: Low]
> Does the commit message match the actual changes and current tree state?
> 
> Alongside io_ring_ctx and io_sq_data, the patch also switches new_array in
> io_coalesce_buffer(), ctx->hash_map in io_init_wq_offload(), and
> io_uring_task in io_uring_alloc_task_context() to GFP_KERNEL_ACCOUNT without
> mentioning them in the subject or changelog.
> 
> The changelog also says these are the last per-ring GFP_KERNEL allocations.
> While commit "io_uring: account the remaining per-object allocations to
> memcg" later in the series converts io_alloc_cache_init() and io_wq_create(),
> percpu_ref_init(&ctx->refs, ...) in io_ring_ctx_alloc(),
> percpu_counter_init(&tctx->inflight, ...) in io_uring_alloc_task_context(),
> and alloc_cpumask_var(&wq->cpu_mask, ...) in io_wq_create() still use plain
> GFP_KERNEL.
> 
> Finally, the cited commits 075d5837bafc ("io_uring/rsrc: charge buffer
> arrays and nodes to memcg") and 0b34e7b20a48 ("io_uring: charge tctx nodes
> and personalities") are not present in the base tree, so io_alloc_imu(),
> io_rsrc_node_alloc(), io_tctx_install_node(), tctx->xa, and
> ctx->personalities remain uncharged.
>