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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 D48FDC606C6 for ; Mon, 8 Jul 2019 15:20:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AE7DB217D6 for ; Mon, 8 Jul 2019 15:20:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562599215; bh=F5ChGmoebv9E+y8/z1Bl6v1Dw13JI3HmgOrnE90SSAw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ISaE/HDKhNJWMv3kTqj7eHR2/j8O9j4gHQJULZnGCjELanUg4gZ3QwZRCJ0s+VRSN Tsnhlwy9BBBcrQQexv5mLRnIoVbryBugGKaLLxEgCClrZM3AvSnVjLENgBrdzsG8pl hXUMipoqsC5xofH18/6zq4gkuyRuff0k54F0CKHA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387552AbfGHPT7 (ORCPT ); Mon, 8 Jul 2019 11:19:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:44566 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729739AbfGHPT4 (ORCPT ); Mon, 8 Jul 2019 11:19:56 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C3AC821734; Mon, 8 Jul 2019 15:19:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562599195; bh=F5ChGmoebv9E+y8/z1Bl6v1Dw13JI3HmgOrnE90SSAw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EhpjXUzC6KsfKqurf2yaY1HAToVfExpDu6g5G6cHCH9ZzZNtNP7/2gukU96vdt1qN gbqFW4/DCzcTerjQRHIAgXqB0lJAjfDQzsQQMTH8r2zuIBZGBKfqLW7X83r8Fy9mGf SMJi0rs02t+cwBO2VMvovygFE1NxqpQL/740ZG9o= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dennis Dalessandro , Mike Marciniszyn , Doug Ledford , Sasha Levin Subject: [PATCH 4.9 036/102] IB/hfi1: Avoid hardlockup with flushlist_lock Date: Mon, 8 Jul 2019 17:12:29 +0200 Message-Id: <20190708150528.272739806@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190708150525.973820964@linuxfoundation.org> References: <20190708150525.973820964@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org commit cf131a81967583ae737df6383a0893b9fee75b4e upstream. Heavy contention of the sde flushlist_lock can cause hard lockups at extreme scale when the flushing logic is under stress. Mitigate by replacing the item at a time copy to the local list with an O(1) list_splice_init() and using the high priority work queue to do the flushes. Ported to linux-4.9.y. Fixes: 7724105686e7 ("IB/hfi1: add driver files") Cc: Reviewed-by: Dennis Dalessandro Signed-off-by: Mike Marciniszyn Signed-off-by: Dennis Dalessandro Signed-off-by: Doug Ledford Signed-off-by: Sasha Levin --- drivers/infiniband/hw/hfi1/sdma.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/drivers/infiniband/hw/hfi1/sdma.c b/drivers/infiniband/hw/hfi1/sdma.c index 9cbe52d21077..76e63c88a87a 100644 --- a/drivers/infiniband/hw/hfi1/sdma.c +++ b/drivers/infiniband/hw/hfi1/sdma.c @@ -410,10 +410,7 @@ static void sdma_flush(struct sdma_engine *sde) sdma_flush_descq(sde); spin_lock_irqsave(&sde->flushlist_lock, flags); /* copy flush list */ - list_for_each_entry_safe(txp, txp_next, &sde->flushlist, list) { - list_del_init(&txp->list); - list_add_tail(&txp->list, &flushlist); - } + list_splice_init(&sde->flushlist, &flushlist); spin_unlock_irqrestore(&sde->flushlist_lock, flags); /* flush from flush list */ list_for_each_entry_safe(txp, txp_next, &flushlist, list) @@ -2406,7 +2403,7 @@ int sdma_send_txreq(struct sdma_engine *sde, wait->tx_count++; wait->count += tx->num_desc; } - schedule_work(&sde->flush_worker); + queue_work_on(sde->cpu, system_highpri_wq, &sde->flush_worker); ret = -ECOMM; goto unlock; nodesc: @@ -2504,7 +2501,7 @@ int sdma_send_txlist(struct sdma_engine *sde, struct iowait *wait, } } spin_unlock(&sde->flushlist_lock); - schedule_work(&sde->flush_worker); + queue_work_on(sde->cpu, system_highpri_wq, &sde->flush_worker); ret = -ECOMM; goto update_tail; nodesc: -- 2.20.1