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=-5.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 7AA06C48BE8 for ; Mon, 24 Jun 2019 10:07:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4DCE0208E3 for ; Mon, 24 Jun 2019 10:07:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561370832; bh=An5phQpq7aWiAOCZ323cp9UcJjDhRvvPkOFdLDUsgBE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=cGJtcuqxEKjfeD6VfwXkXVWch7rX/EiOVlSQkByTZjQLNfMEusMsugN00X5N5LXfn KPQn+F4K1qn9VkpEJ4HY+Ld0Hed8wj1LeHvpJSO0w0Qt5ETQUmD0687pvbwKJoLAjo u1diENIQqJojgx6fS0OtjfvKKYudnNovoxw9f2ts= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730274AbfFXKHL (ORCPT ); Mon, 24 Jun 2019 06:07:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:39634 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728987AbfFXKHL (ORCPT ); Mon, 24 Jun 2019 06:07:11 -0400 Received: from localhost (f4.8f.5177.ip4.static.sl-reverse.com [119.81.143.244]) (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 CC7842089F; Mon, 24 Jun 2019 10:07:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561370830; bh=An5phQpq7aWiAOCZ323cp9UcJjDhRvvPkOFdLDUsgBE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=G0VrSZgOEZNkvGKvco9RWHjAZPZoze+M08katqXZuCJhvrDbiH9DioZlYp0ydT5hm G/qg8QEBveOlucfueTwLxRPH+g9kvFRXu1Z0Zo78xWJlFk0xLJhpKMLxbUVvWdOXdM yY88oVtIP0csVYgeLKfRW+gTfRv3m/cyc/gf4R7U= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dennis Dalessandro , Mike Marciniszyn , Doug Ledford Subject: [PATCH 5.1 017/121] IB/hfi1: Avoid hardlockup with flushlist_lock Date: Mon, 24 Jun 2019 17:55:49 +0800 Message-Id: <20190624092321.503399665@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190624092320.652599624@linuxfoundation.org> References: <20190624092320.652599624@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Mike Marciniszyn 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. 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: Greg Kroah-Hartman --- drivers/infiniband/hw/hfi1/sdma.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) --- a/drivers/infiniband/hw/hfi1/sdma.c +++ b/drivers/infiniband/hw/hfi1/sdma.c @@ -410,10 +410,7 @@ static void sdma_flush(struct sdma_engin 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) @@ -2413,7 +2410,7 @@ unlock_noconn: list_add_tail(&tx->list, &sde->flushlist); spin_unlock(&sde->flushlist_lock); iowait_inc_wait_count(wait, tx->num_desc); - schedule_work(&sde->flush_worker); + queue_work_on(sde->cpu, system_highpri_wq, &sde->flush_worker); ret = -ECOMM; goto unlock; nodesc: @@ -2511,7 +2508,7 @@ unlock_noconn: iowait_inc_wait_count(wait, tx->num_desc); } 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: