Re: [PATCHv4 5/5] io_uring: cache nodes and mapped buffers

[Pavel Begunkov <asml.silence@gmail.com>]

On 2/18/25 22:42, Keith Busch wrote:
> From: Keith Busch <kbusch@kernel.org>
> 
> Frequent alloc/free cycles on these is pretty costly. Use an io cache to
> more efficiently reuse these buffers.
> 
> Signed-off-by: Keith Busch <kbusch@kernel.org>
> ---
>   include/linux/io_uring_types.h |  18 ++---
>   io_uring/filetable.c           |   2 +-
>   io_uring/rsrc.c                | 120 +++++++++++++++++++++++++--------
>   io_uring/rsrc.h                |   2 +-
>   4 files changed, 104 insertions(+), 38 deletions(-)
> 
> diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
> index 810d1dccd27b1..bbfb651506522 100644
> --- a/include/linux/io_uring_types.h
> +++ b/include/linux/io_uring_types.h
> @@ -69,8 +69,18 @@ struct io_file_table {
>   	unsigned int alloc_hint;
...
> -struct io_rsrc_node *io_rsrc_node_alloc(int type)
> +struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx, int type)
>   {
>   	struct io_rsrc_node *node;
>   
> -	node = kzalloc(sizeof(*node), GFP_KERNEL);
> +	if (type == IORING_RSRC_FILE)
> +		node = kmalloc(sizeof(*node), GFP_KERNEL);
> +	else
> +		node = io_cache_alloc(&ctx->buf_table.node_cache, GFP_KERNEL);

That's why node allocators shouldn't be a part of the buffer table.

-- 
Pavel Begunkov