From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <io-uring-owner@kernel.org>
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on
	aws-us-west-2-korg-lkml-1.web.codeaurora.org
Received: from vger.kernel.org (vger.kernel.org [23.128.96.18])
	by smtp.lore.kernel.org (Postfix) with ESMTP id B1045C433F5
	for <io-uring@archiver.kernel.org>; Fri, 18 Feb 2022 05:05:20 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S229717AbiBRFFf (ORCPT <rfc822;io-uring@archiver.kernel.org>);
        Fri, 18 Feb 2022 00:05:35 -0500
Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:35982 "EHLO
        lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S229477AbiBRFFc (ORCPT
        <rfc822;io-uring@vger.kernel.org>); Fri, 18 Feb 2022 00:05:32 -0500
Received: from cloud48395.mywhc.ca (cloud48395.mywhc.ca [173.209.37.211])
        by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C541D98
        for <io-uring@vger.kernel.org>; Thu, 17 Feb 2022 21:05:14 -0800 (PST)
Received: from [45.44.224.220] (port=44640 helo=[192.168.1.179])
        by cloud48395.mywhc.ca with esmtpsa  (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
        (Exim 4.94.2)
        (envelope-from <olivier@trillion01.com>)
        id 1nKvSD-00022E-BD; Fri, 18 Feb 2022 00:05:13 -0500
Message-ID: <51b4d363a9bd926243a2f7928335cdd2ac3f1218.camel@trillion01.com>
Subject: Re: napi_busy_poll
From:   Olivier Langlois <olivier@trillion01.com>
To:     Hao Xu <haoxu@linux.alibaba.com>, Jens Axboe <axboe@kernel.dk>,
        io-uring@vger.kernel.org
Date:   Fri, 18 Feb 2022 00:05:12 -0500
In-Reply-To: <f7f658cd-d76f-26c4-6549-0b3d2008d249@linux.alibaba.com>
References: <21bfe359aa45123b36ee823076a036146d1d9518.camel@trillion01.com>
         <fc9664c4-11db-54e1-d3b6-c35ea345166a@kernel.dk>
         <f408374a-c0aa-1ca0-936a-0bbed68a01f6@linux.alibaba.com>
         <d3412259cb13e9e76d45387e171228655ebe91b0.camel@trillion01.com>
         <0446f39d-f926-0ae4-7ea4-00aff9236322@linux.alibaba.com>
         <995e65ce3d353cacea4d426c9876b2a5e88faa99.camel@trillion01.com>
         <a5e58292ff6207161af287ccd116ebf3c5b8a0fb.camel@trillion01.com>
         <f7f658cd-d76f-26c4-6549-0b3d2008d249@linux.alibaba.com>
Organization: Trillion01 Inc
Content-Type: text/plain; charset="ISO-8859-1"
User-Agent: Evolution 3.42.3 
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
X-AntiAbuse: This header was added to track abuse, please include it with any abuse report
X-AntiAbuse: Primary Hostname - cloud48395.mywhc.ca
X-AntiAbuse: Original Domain - vger.kernel.org
X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12]
X-AntiAbuse: Sender Address Domain - trillion01.com
X-Get-Message-Sender-Via: cloud48395.mywhc.ca: authenticated_id: olivier@trillion01.com
X-Authenticated-Sender: cloud48395.mywhc.ca: olivier@trillion01.com
X-Source: 
X-Source-Args: 
X-Source-Dir: 
Precedence: bulk
List-ID: <io-uring.vger.kernel.org>
X-Mailing-List: io-uring@vger.kernel.org

On Wed, 2022-02-16 at 20:14 +0800, Hao Xu wrote:
> 
> @@ -5583,6 +5650,7 @@ static void io_poll_task_func(struct io_kiocb 
> *req, bool *locked)
>          struct io_ring_ctx *ctx = req->ctx;
>          int ret;
> 
> +       io_add_napi(req->file, req->ctx);
>          ret = io_poll_check_events(req);
>          if (ret > 0)
>                  return;
> @@ -5608,6 +5676,7 @@ static void io_apoll_task_func(struct io_kiocb 
> *req, bool *locked)
>          struct io_ring_ctx *ctx = req->ctx;
>          int ret;
> 
> +       io_add_napi(req->file, req->ctx);
>          ret = io_poll_check_events(req);
>          if (ret > 0)
>                  return;
> 
I have a doubt about these call sites for adding the napi_id into the
list. AFAIK, these are the functions called when the desired events are
ready therefore, it is too late for polling the device.

OTOH, my choice of doing it from io_file_get_normal() was perhaps a
poor choice too because it is premature.

Possibly the best location might be __io_arm_poll_handler()...