linux-kernel - Re: [RFC v2 4/5] io_uring/bpf: add handle events callback

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Message-ID: <CAADnVQKOmYmFZwMZJmtAc5v9v1gBJqO-FyGeBZDZe1tT5qPKWA@mail.gmail.com>
Date: Wed, 11 Jun 2025 19:28:50 -0700
From: Alexei Starovoitov <alexei.starovoitov@...il.com>
To: Pavel Begunkov <asml.silence@...il.com>
Cc: io-uring@...r.kernel.org, Martin KaFai Lau <martin.lau@...ux.dev>, 
	bpf <bpf@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [RFC v2 4/5] io_uring/bpf: add handle events callback

On Fri, Jun 6, 2025 at 6:58 AM Pavel Begunkov <asml.silence@...il.com> wrote:
>
> +static inline int io_run_bpf(struct io_ring_ctx *ctx, struct iou_loop_state *state)
> +{
> +       scoped_guard(mutex, &ctx->uring_lock) {
> +               if (!ctx->bpf_ops)
> +                       return IOU_EVENTS_STOP;
> +               return ctx->bpf_ops->handle_events(ctx, state);
> +       }
> +}

you're grabbing the mutex before calling bpf prog and doing
it in a loop million times a second?
Looks like massive overhead for program invocation.
I'm surprised it's fast.