From patchwork Fri Jun 14 16:32:26 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dennis Dalessandro X-Patchwork-Id: 10995925 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4315176 for ; Fri, 14 Jun 2019 16:32:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3199C284D4 for ; Fri, 14 Jun 2019 16:32:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 259D52868C; Fri, 14 Jun 2019 16:32:30 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C1906284D4 for ; Fri, 14 Jun 2019 16:32:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726115AbfFNQc3 (ORCPT ); Fri, 14 Jun 2019 12:32:29 -0400 Received: from mga11.intel.com ([192.55.52.93]:4453 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725859AbfFNQc2 (ORCPT ); Fri, 14 Jun 2019 12:32:28 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 14 Jun 2019 09:32:28 -0700 X-ExtLoop1: 1 Received: from sedona.ch.intel.com ([10.2.136.157]) by orsmga005.jf.intel.com with ESMTP; 14 Jun 2019 09:32:27 -0700 Received: from awfm-01.aw.intel.com (awfm-01.aw.intel.com [10.228.212.213]) by sedona.ch.intel.com (8.14.3/8.14.3/Standard MailSET/Hub) with ESMTP id x5EGWRp1060957; Fri, 14 Jun 2019 09:32:27 -0700 Received: from awfm-01.aw.intel.com (localhost [127.0.0.1]) by awfm-01.aw.intel.com (8.14.7/8.14.7) with ESMTP id x5EGWQeK045017; Fri, 14 Jun 2019 12:32:26 -0400 Subject: [PATCH for-rc 1/7] IB/hfi1: Avoid hardlockup with flushlist_lock From: Dennis Dalessandro To: jgg@ziepe.ca, dledford@redhat.com Cc: linux-rdma@vger.kernel.org, Mike Marciniszyn , stable@vger.kernel.org Date: Fri, 14 Jun 2019 12:32:26 -0400 Message-ID: <20190614163225.44927.41903.stgit@awfm-01.aw.intel.com> In-Reply-To: <20190614163146.44927.95985.stgit@awfm-01.aw.intel.com> References: <20190614163146.44927.95985.stgit@awfm-01.aw.intel.com> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Mike Marciniszyn 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 --- 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 b011072..70828de 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) @@ -2413,7 +2410,7 @@ int sdma_send_txreq(struct sdma_engine *sde, 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 @@ int sdma_send_txlist(struct sdma_engine *sde, struct iowait_work *wait, 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: