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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 01332C433F5 for ; Sat, 21 May 2022 14:15:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236216AbiEUOPI (ORCPT ); Sat, 21 May 2022 10:15:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51868 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233155AbiEUOPI (ORCPT ); Sat, 21 May 2022 10:15:08 -0400 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 20F415DE58; Sat, 21 May 2022 07:15:06 -0700 (PDT) Received: from kwepemi500022.china.huawei.com (unknown [172.30.72.55]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4L55DJ0tJMz1JBZ5; Sat, 21 May 2022 22:13:36 +0800 (CST) Received: from kwepemm600004.china.huawei.com (7.193.23.242) by kwepemi500022.china.huawei.com (7.221.188.64) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sat, 21 May 2022 22:15:01 +0800 Received: from huawei.com (10.175.124.27) by kwepemm600004.china.huawei.com (7.193.23.242) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sat, 21 May 2022 22:15:00 +0800 From: Guo Xuenan To: , , CC: , , , , Subject: [PATCH] io_uring: add a schedule condition in io_submit_sqes Date: Sat, 21 May 2022 22:33:27 +0800 Message-ID: <20220521143327.3959685-1-guoxuenan@huawei.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemm600004.china.huawei.com (7.193.23.242) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org when set up sq ring size with IORING_MAX_ENTRIES, io_submit_sqes may looping ~32768 times which may trigger soft lockups. add need_resched condition to avoid this bad situation. set sq ring size 32768 and using io_sq_thread to perform stress test as follows: watchdog: BUG: soft lockup - CPU#2 stuck for 26s! [iou-sqp-600:601] Kernel panic - not syncing: softlockup: hung tasks CPU: 2 PID: 601 Comm: iou-sqp-600 Tainted: G L 5.18.0-rc7+ #3 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x218/0x228 show_stack+0x20/0x68 dump_stack_lvl+0x68/0x84 dump_stack+0x1c/0x38 panic+0x1ec/0x3ec watchdog_timer_fn+0x28c/0x300 __hrtimer_run_queues+0x1d8/0x498 hrtimer_interrupt+0x238/0x558 arch_timer_handler_virt+0x48/0x60 handle_percpu_devid_irq+0xdc/0x270 generic_handle_domain_irq+0x50/0x70 gic_handle_irq+0x8c/0x4bc call_on_irq_stack+0x2c/0x38 do_interrupt_handler+0xc4/0xc8 el1_interrupt+0x48/0xb0 el1h_64_irq_handler+0x18/0x28 el1h_64_irq+0x74/0x78 console_unlock+0x5d0/0x908 vprintk_emit+0x21c/0x470 vprintk_default+0x40/0x50 vprintk+0xd0/0x128 _printk+0xb4/0xe8 io_issue_sqe+0x1784/0x2908 io_submit_sqes+0x538/0x2880 io_sq_thread+0x328/0x7b0 ret_from_fork+0x10/0x20 SMP: stopping secondary CPUs Kernel Offset: 0x40f1e8600000 from 0xffff800008000000 PHYS_OFFSET: 0xfffffa8c80000000 CPU features: 0x110,0000cf09,00001006 Memory Limit: none ---[ end Kernel panic - not syncing: softlockup: hung tasks ]--- Signed-off-by: Guo Xuenan --- fs/io_uring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 92ac50f139cd..d897c6798f00 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -7864,7 +7864,7 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr) if (!(ctx->flags & IORING_SETUP_SUBMIT_ALL)) break; } - } while (submitted < nr); + } while (submitted < nr && !need_resched()); if (unlikely(submitted != nr)) { int ref_used = (submitted == -EAGAIN) ? 0 : submitted; -- 2.25.1