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=-17.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 44FB2C433DB for ; Wed, 24 Feb 2021 10:26:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F286864ED4 for ; Wed, 24 Feb 2021 10:26:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232475AbhBXK0I (ORCPT ); Wed, 24 Feb 2021 05:26:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59636 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232560AbhBXK0B (ORCPT ); Wed, 24 Feb 2021 05:26:01 -0500 Received: from mail-pg1-x535.google.com (mail-pg1-x535.google.com [IPv6:2607:f8b0:4864:20::535]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CD8EFC061574 for ; Wed, 24 Feb 2021 02:25:20 -0800 (PST) Received: by mail-pg1-x535.google.com with SMTP id o38so1147629pgm.9 for ; Wed, 24 Feb 2021 02:25:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=6zEjknucr9elP+ydtyngud8wtITgLH3Mt7MahX/VoD4=; b=C4mWvnUDAckqeOK9M/vqYnzAK3BXpw35g0You47lsCmvbU02kbv0uYL5hUp3L4W08S LbZwMW9TofNYCljuqdJxmzS2gs1wuCJGhMBAKytbEdTSNRj+GfaBD2Li/kc/8OanRU+B iBfIhN4J54kq8PbVRWUgtnNvMAKDBN7Vtdu4MejJo1J2TDJTTdfkAWj5YL2fPdPpV35g UtADqRIBZUt8z4fXkrtFC8dX+eX/uj+YDrsv8PfE4j5IOOvd2Hb69bIgcPB1hl/jtRtE snnx7M+7DeBCzVUc4yZUOAN+XWXH08DOMCtaSgcQCJ5pXrVQGL7s6FjVvakErgH7/KhQ xrFQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=6zEjknucr9elP+ydtyngud8wtITgLH3Mt7MahX/VoD4=; b=Bshl6ql4RpLns2wotnbRR/nzj7LpiRTxvjRE8tH/Yv3EvJ9NVaGz8oCCP2CWdEAQLU 2raS3stYIysh+NnjFUEMxQAVQQQEpkLHN/1U+q4lPU/GRwOTshq/DIDxjMNf92KE3ByG oO3rytAJvKgJHgsYRdt7RcnGLK40Fcz4wzok91I0wV5EwwyfgpUSL9Y8MbjAV34bsDKz F1dEPmSfpqcklm/HxGdehViiO6VqtH/C6AizXxDYdrm5SCqtESSkWCNSxK4lO9I1vTXv FyF8nzNSpmjgt9rVo2JTJiU9+Cc1GJV30vSWgUCgUDgsLGKSOWatlp0fp8kLjxNdOHV2 vnig== X-Gm-Message-State: AOAM533USVnNHi+EN7oS6YRlVT2/6IjZ//VcH1PuYe+EEd1F/28c2ui2 q2+zO/X5D7a2myeQfD5b/s2947RbG2Vu X-Google-Smtp-Source: ABdhPJxuT8sC2csKNnK+T1lYLoJDrlE1cW26Nw9gepYWBGzI0vLBtpBLp9XS/1WI1UzI4ELZdq24ng== X-Received: by 2002:a63:4761:: with SMTP id w33mr28504189pgk.118.1614162320324; Wed, 24 Feb 2021 02:25:20 -0800 (PST) Received: from work ([103.66.79.25]) by smtp.gmail.com with ESMTPSA id c29sm1952617pgb.58.2021.02.24.02.25.17 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Wed, 24 Feb 2021 02:25:19 -0800 (PST) Date: Wed, 24 Feb 2021 15:55:16 +0530 From: Manivannan Sadhasivam To: Loic Poulain Cc: hemantk@codeaurora.org, linux-arm-msm@vger.kernel.org, bbhatt@codeaurora.org Subject: Re: [PATCH] mhi: pci_generic: Remove WQ_MEM_RECLAIM flag from state workqueue Message-ID: <20210224102516.GW27945@work> References: <1614161930-8513-1-git-send-email-loic.poulain@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1614161930-8513-1-git-send-email-loic.poulain@linaro.org> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Wed, Feb 24, 2021 at 11:18:50AM +0100, Loic Poulain wrote: > A recent change created a dedicated workqueue for the state-change work > with WQ_HIGHPRI (no strong reason for that) and WQ_MEM_RECLAIM flags, > but the state-change work (mhi_pm_st_worker) does not guarantee forward > progress under memory pressure, and will even wait on various memory > allocations when e.g. creating devices, loading firmware, etc... The > work is then not part of a memory reclaim path... > > Moreover, this causes a warning in check_flush_dependency() since we end > up in code that flushes a non-reclaim workqueue: > > [ 40.969601] workqueue: WQ_MEM_RECLAIM mhi_hiprio_wq:mhi_pm_st_worker [mhi] is flushing !WQ_MEM_RECLAIM events_highpri:flush_backlog > [ 40.969612] WARNING: CPU: 4 PID: 158 at kernel/workqueue.c:2607 check_flush_dependency+0x11c/0x140 > [ 40.969733] Call Trace: > [ 40.969740] __flush_work+0x97/0x1d0 > [ 40.969745] ? wake_up_process+0x15/0x20 > [ 40.969749] ? insert_work+0x70/0x80 > [ 40.969750] ? __queue_work+0x14a/0x3e0 > [ 40.969753] flush_work+0x10/0x20 > [ 40.969756] rollback_registered_many+0x1c9/0x510 > [ 40.969759] unregister_netdevice_queue+0x94/0x120 > [ 40.969761] unregister_netdev+0x1d/0x30 > [ 40.969765] mhi_net_remove+0x1a/0x40 [mhi_net] > [ 40.969770] mhi_driver_remove+0x124/0x250 [mhi] > [ 40.969776] device_release_driver_internal+0xf0/0x1d0 > [ 40.969778] device_release_driver+0x12/0x20 > [ 40.969782] bus_remove_device+0xe1/0x150 > [ 40.969786] device_del+0x17b/0x3e0 > [ 40.969791] mhi_destroy_device+0x9a/0x100 [mhi] > [ 40.969796] ? mhi_unmap_single_use_bb+0x50/0x50 [mhi] > [ 40.969799] device_for_each_child+0x5e/0xa0 > [ 40.969804] mhi_pm_st_worker+0x921/0xf50 [mhi] > > Fixes: 8f7039787687 ("bus: mhi: core: Move to using high priority workqueue") > Signed-off-by: Loic Poulain Fix looks good to me but I want Bhaumik to share his review since he authored the offending patch. Thanks, Mani > --- > drivers/bus/mhi/core/init.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c > index 32eb90f..03ddd6e 100644 > --- a/drivers/bus/mhi/core/init.c > +++ b/drivers/bus/mhi/core/init.c > @@ -890,8 +890,7 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl, > INIT_WORK(&mhi_cntrl->st_worker, mhi_pm_st_worker); > init_waitqueue_head(&mhi_cntrl->state_event); > > - mhi_cntrl->hiprio_wq = alloc_ordered_workqueue > - ("mhi_hiprio_wq", WQ_MEM_RECLAIM | WQ_HIGHPRI); > + mhi_cntrl->hiprio_wq = alloc_ordered_workqueue("mhi_hiprio_wq", WQ_HIGHPRI); > if (!mhi_cntrl->hiprio_wq) { > dev_err(mhi_cntrl->cntrl_dev, "Failed to allocate workqueue\n"); > ret = -ENOMEM; > -- > 2.7.4 >