From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 50956C43331 for ; Fri, 8 Nov 2019 01:24:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2796E21D7E for ; Fri, 8 Nov 2019 01:24:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727024AbfKHBY0 convert rfc822-to-8bit (ORCPT ); Thu, 7 Nov 2019 20:24:26 -0500 Received: from smtpbg702.qq.com ([203.205.195.102]:39759 "EHLO smtpproxy21.qq.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726094AbfKHBYZ (ORCPT ); Thu, 7 Nov 2019 20:24:25 -0500 X-Greylist: delayed 2460 seconds by postgrey-1.27 at vger.kernel.org; Thu, 07 Nov 2019 20:24:24 EST X-QQ-mid: bizesmtp26t1573176259tcfhr4wb Received: from [192.168.142.168] (unknown [218.76.23.26]) by esmtp10.qq.com (ESMTP) with id ; Fri, 08 Nov 2019 09:24:18 +0800 (CST) X-QQ-SSF: 00400000002000S0ZU90000A0000000 X-QQ-FEAT: JYOFLJLLthhaOXZmuR17vavtLIQLgxWxnJb8ElaNk2NJobA6kmmmGcZg6pNFM asyESvBWd4moSaGVt5SUtGgXq3+q7kHDXALBQKvVBRn5It6MW/2rovfT/tjHa7t/pRyedK0 ilE5fOzUKBAk6Yy32OizPhADPVC5eKmTTK0w4HQK6UC6Ge2YgnQApnh2aYJbok9WdPR/kyN GfpfBd5Sec3vKATdYTcjlZa5gHhvv376jPVsJPcc9elLIpCoSW7hhRT5mt03tm9MqXmzdw9 gta/DsXXfXGdkMh7SYSzzfdM7szVusdQF54ee5Zhv9TF3Y6lDM7y68dgPb+YtXVA0NnicBU JmvFxO0c9WmVIO/7moaart81bdQTw== X-QQ-GoodBg: 2 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 13.0 \(3601.0.10\)) Subject: Re: [PATCH v2] io_uring: add support for linked SQE timeouts From: Jackie Liu In-Reply-To: Date: Fri, 8 Nov 2019 09:24:20 +0800 Cc: io-uring@vger.kernel.org Content-Transfer-Encoding: 8BIT Message-Id: References: To: Jens Axboe X-Mailer: Apple Mail (2.3601.0.10) X-QQ-SENDSIZE: 520 Feedback-ID: bizesmtp:kylinos.cn:qybgforeign:qybgforeign5 X-QQ-Bgrelay: 1 Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org > 2019年11月7日 10:05，Jens Axboe 写道： > > While we have support for generic timeouts, we don't have a way to tie > a timeout to a specific SQE. The generic timeouts simply trigger wakeups > on the CQ ring. > > This adds support for IORING_OP_LINK_TIMEOUT. This command is only valid > as a link to a previous command. The timeout specific can be either > relative or absolute, following the same rules as IORING_OP_TIMEOUT. If > the timeout triggers before the dependent command completes, it will > attempt to cancel that command. Likewise, if the dependent command > completes before the timeout triggers, it will cancel the timeout. > > Signed-off-by: Jens Axboe > > --- > > Changes since v1: > - Move required locking outside of io_req_link_next(), it's much > cleaner this way and avoids sparse complaining. > - Avoid 32-bit complaint on casting to pointer of different size > - Fix IORING_TIMEOUT_ABS, used sqe->flags instead of timeout_flags > - Rebase on top of current tree > > diff --git a/fs/io_uring.c b/fs/io_uring.c > index c39d1c50a3be..e29ecc1b0218 100644 > --- a/fs/io_uring.c > +++ b/fs/io_uring.c > @@ -329,6 +329,7 @@ struct io_kiocb { > #define REQ_F_IO_DRAIN 16 /* drain existing IO first */ > #define REQ_F_IO_DRAINED 32 /* drain done */ > #define REQ_F_LINK 64 /* linked sqes */ > +#define REQ_F_LINK_TIMEOUT 128 /* has linked timeout */ > #define REQ_F_FAIL_LINK 256 /* fail rest of links */ > #define REQ_F_SHADOW_DRAIN 512 /* link-drain shadow req */ > #define REQ_F_TIMEOUT 1024 /* timeout request */ > @@ -371,6 +372,7 @@ static void io_wq_submit_work(struct io_wq_work **workptr); > static void io_cqring_fill_event(struct io_ring_ctx *ctx, u64 ki_user_data, > long res); > static void __io_free_req(struct io_kiocb *req); > +static void io_put_req(struct io_kiocb *req, struct io_kiocb **nxtptr); > > static struct kmem_cache *req_cachep; > > @@ -712,9 +714,28 @@ static void __io_free_req(struct io_kiocb *req) > kmem_cache_free(req_cachep, req); > } > > +static bool io_link_cancel_timeout(struct io_ring_ctx *ctx, > + struct io_kiocb *req) > +{ > + int ret; > + > + ret = hrtimer_try_to_cancel(&req->timeout.timer); > + if (ret != -1) { > + io_cqring_fill_event(ctx, req->user_data, -ECANCELED); > + io_commit_cqring(ctx); > + req->flags &= ~REQ_F_LINK; > + __io_free_req(req); > + return true; > + } > + > + return false; > +} > + > static void io_req_link_next(struct io_kiocb *req, struct io_kiocb **nxtptr) > { > + struct io_ring_ctx *ctx = req->ctx; > struct io_kiocb *nxt; > + bool wake_ev = false; > > /* > * The list should never be empty when we are called here. But could > @@ -722,7 +743,7 @@ static void io_req_link_next(struct io_kiocb *req, struct io_kiocb **nxtptr) > * safe side. > */ > nxt = list_first_entry_or_null(&req->link_list, struct io_kiocb, list); > - if (nxt) { > + while (nxt) { > list_del(&nxt->list); > if (!list_empty(&req->link_list)) { > INIT_LIST_HEAD(&nxt->link_list); > @@ -734,11 +755,23 @@ static void io_req_link_next(struct io_kiocb *req, struct io_kiocb **nxtptr) > * If we're in async work, we can continue processing the chain > * in this context instead of having to queue up new async work. > */ > - if (nxtptr && current_work()) > + if (req->flags & REQ_F_LINK_TIMEOUT) { > + wake_ev = io_link_cancel_timeout(ctx, nxt); > + > + /* we dropped this link, get next */ > + nxt = list_first_entry_or_null(&req->link_list, > + struct io_kiocb, list); > + } else if (nxtptr && current_work()) { > *nxtptr = nxt; > - else > + nxt = NULL; Use 'break' is more better? no need to set variables and compare. > + } else { > io_queue_async_work(req->ctx, nxt); > + nxt = NULL; > + } > } -- BR, Jackie Liu