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 5A0EDE92702 for ; Thu, 5 Oct 2023 13:56:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230082AbjJENz6 (ORCPT ); Thu, 5 Oct 2023 09:55:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243972AbjJENud (ORCPT ); Thu, 5 Oct 2023 09:50:33 -0400 X-Greylist: delayed 533 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Thu, 05 Oct 2023 02:34:49 PDT Received: from out-190.mta1.migadu.com (out-190.mta1.migadu.com [IPv6:2001:41d0:203:375::be]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0C8C2A5FE for ; Thu, 5 Oct 2023 02:34:48 -0700 (PDT) Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1696497937; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8/XbE8gP0R5n5VOgy0224cCsYOet41U373eOZr5Idw8=; b=PRoEAk6RYEcN6+72/6ZuSklLwRz/qUwiSpgtJxplv8LhZFN//iHB1hi6qRoGlxpNdfsT3+ X/2YlXgOJrk9oX3a6nqMpLBJLkO/NQ0kf00CSKxr1FfIZ6xBEK/vm575ZKlRfGRiFp1jhp U6wyvUBCjXNDSY+mDNhp7v+2OIXWUUc= Date: Thu, 5 Oct 2023 17:25:29 +0800 MIME-Version: 1.0 Subject: Re: [PATCH 1/1] Revert "RDMA/rxe: Add workqueue support for rxe tasks" To: Jason Gunthorpe , Bart Van Assche Cc: Bob Pearson , Leon Romanovsky , zyjzyj2000@gmail.com, linux-rdma@vger.kernel.org, matsuda-daisuke@fujitsu.com, shinichiro.kawasaki@wdc.com, linux-scsi@vger.kernel.org, Zhu Yanjun References: <20230922163231.2237811-1-yanjun.zhu@intel.com> <169572143704.2702191.3921040309512111011.b4-ty@kernel.org> <20230926140656.GM1642130@unreal> <2d5e02d7-cf84-4170-b1a3-a65316ac84ee@acm.org> <2fcef3c8-808e-8e6a-b23d-9f1b3f98c1f9@linux.dev> <552f2342-e800-43bc-b859-d73297ce940f@acm.org> <20231004183824.GQ13795@ziepe.ca> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Zhu Yanjun In-Reply-To: <20231004183824.GQ13795@ziepe.ca> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org 在 2023/10/5 2:38, Jason Gunthorpe 写道: > On Wed, Oct 04, 2023 at 10:43:20AM -0700, Bart Van Assche wrote: > >> Thank you for having reported this. I'm OK with integrating the >> above change in my patch. However, code changes must be >> motivated. Do you perhaps have an explanation of why WQ_HIGHPRI >> makes the issue disappear that you observed? > > I think it is clear there are locking bugs in all this, so it is not > surprising that changing the scheduling behavior can make locking bugs > hide > > Jason With the flag WQ_HIGHPRI, an ordered workqueue with high priority is allocated. With this workqueue, to now, the test has run for several days. And the problem did not appear. So to my test environment, this problem seems fixed with the above commit. I doubt, without the flag WQ_HIGHPRI, the workqueue is allocated with normal priority. The work item in this workqueue is more likely preempted than high priority work queue. Best Regards, Zhu Yanjun