From patchwork Thu Oct 22 00:35:03 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Christie X-Patchwork-Id: 11850019 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id ED82B1580 for ; Thu, 22 Oct 2020 00:35:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C878322249 for ; Thu, 22 Oct 2020 00:35:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="Oa6QMx+P" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2894383AbgJVAf3 (ORCPT ); Wed, 21 Oct 2020 20:35:29 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:51090 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2894372AbgJVAf0 (ORCPT ); Wed, 21 Oct 2020 20:35:26 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 09M0UJEO175045; Thu, 22 Oct 2020 00:35:22 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : subject : date : message-id : in-reply-to : references; s=corp-2020-01-29; bh=tD4l6hgSw3EK127NilJ16s5B/kUYm96URryFtF3SN7k=; b=Oa6QMx+PjD3Gw61zlfK4/RCOa20cRfjFMUGNbPHc8PS0pFEE523KO/7rLW45tZR1Gm26 4gtDKk60dA4O2d1UqaG5O4+1myiWnU9kAZpkZIWcWj+MNef8TTWPOthRjc7KdCgtovHR 6f5GquiaJ4kkyp8KLe0DZjuQjHmfRp2FXr1/3twx64+E0v3toHp1Ma+C5PWlhqLOf2RX /dCM//0DGIETeEXniGAgoAbu43abdDUa93m13gcYyQp2pKpeJVBw1C17sBq6govshEBr WSv7cJ2PX4iHTk3HaTjriabfNoVAn8EQUbbeQ4KCy+3VfP4FO6Wu0D24AiOVltB/hmB+ cg== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2120.oracle.com with ESMTP id 34ak16kp3r-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 22 Oct 2020 00:35:22 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 09M0U8iL177306; Thu, 22 Oct 2020 00:35:21 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by aserp3030.oracle.com with ESMTP id 348a6q15uj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 22 Oct 2020 00:35:21 +0000 Received: from abhmp0014.oracle.com (abhmp0014.oracle.com [141.146.116.20]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 09M0ZLBE030031; Thu, 22 Oct 2020 00:35:21 GMT Received: from ol2.localdomain (/73.88.28.6) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 21 Oct 2020 17:35:20 -0700 From: Mike Christie To: martin.petersen@oracle.com, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, mst@redhat.com, jasowang@redhat.com, pbonzini@redhat.com, stefanha@redhat.com, virtualization@lists.linux-foundation.org Subject: [PATCH 17/17] vhost scsi: drop submission workqueue Date: Wed, 21 Oct 2020 19:35:03 -0500 Message-Id: <1603326903-27052-18-git-send-email-michael.christie@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1603326903-27052-1-git-send-email-michael.christie@oracle.com> References: <1603326903-27052-1-git-send-email-michael.christie@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9781 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 mlxlogscore=999 bulkscore=0 spamscore=0 adultscore=0 suspectscore=0 mlxscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2010220001 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9781 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 phishscore=0 priorityscore=1501 clxscore=1015 malwarescore=0 mlxscore=0 adultscore=0 lowpriorityscore=0 impostorscore=0 spamscore=0 mlxlogscore=999 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2010220001 Precedence: bulk List-ID: X-Mailing-List: target-devel@vger.kernel.org We can't control a VM's vhost scsi IO right now because the vhost worker is added to the VM's blk cgroup, but the vhost worker thread actually just passes the cmd to a vhost-scsi driver workqueue which ends up submitting the cmd to the block layer. This patch has us submit from the vhost worker thread and removes the work queue. Signed-off-by: Mike Christie --- drivers/vhost/scsi.c | 30 +++--------------------------- 1 file changed, 3 insertions(+), 27 deletions(-) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index 4e91a90..3178bf54 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -101,8 +101,6 @@ struct vhost_scsi_cmd { struct vhost_scsi_nexus *tvc_nexus; /* The TCM I/O descriptor that is accessed via container_of() */ struct se_cmd tvc_se_cmd; - /* work item used for cmwq dispatch to vhost_scsi_submission_work() */ - struct work_struct work; /* Copy of the incoming SCSI command descriptor block (CDB) */ unsigned char tvc_cdb[VHOST_SCSI_MAX_CDB_SIZE]; /* Sense buffer that will be mapped into outgoing status */ @@ -240,8 +238,6 @@ struct vhost_scsi_ctx { struct iov_iter out_iter; }; -static struct workqueue_struct *vhost_scsi_workqueue; - /* Global spinlock to protect vhost_scsi TPG list for vhost IOCTL access */ static DEFINE_MUTEX(vhost_scsi_mutex); static LIST_HEAD(vhost_scsi_list); @@ -776,10 +772,8 @@ static int vhost_scsi_to_tcm_attr(int attr) return TCM_SIMPLE_TAG; } -static void vhost_scsi_submission_work(struct work_struct *work) +static void vhost_scsi_target_submit(struct vhost_scsi_cmd *cmd) { - struct vhost_scsi_cmd *cmd = - container_of(work, struct vhost_scsi_cmd, work); struct vhost_scsi_nexus *tv_nexus; struct se_cmd *se_cmd = &cmd->tvc_se_cmd; struct scatterlist *sg_ptr, *sg_prot_ptr = NULL; @@ -1126,14 +1120,7 @@ static u16 vhost_buf_to_lun(u8 *lun_buf) * vhost_scsi_queue_data_in() and vhost_scsi_queue_status() */ cmd->tvc_vq_desc = vc.head; - /* - * Dispatch cmd descriptor for cmwq execution in process - * context provided by vhost_scsi_workqueue. This also ensures - * cmd is executed on the same kworker CPU as this vhost - * thread to gain positive L2 cache locality effects. - */ - INIT_WORK(&cmd->work, vhost_scsi_submission_work); - queue_work(vhost_scsi_workqueue, &cmd->work); + vhost_scsi_target_submit(cmd); ret = 0; err: /* @@ -2511,17 +2498,9 @@ static int __init vhost_scsi_init(void) " on "UTS_RELEASE"\n", VHOST_SCSI_VERSION, utsname()->sysname, utsname()->machine); - /* - * Use our own dedicated workqueue for submitting I/O into - * target core to avoid contention within system_wq. - */ - vhost_scsi_workqueue = alloc_workqueue("vhost_scsi", 0, 0); - if (!vhost_scsi_workqueue) - goto out; - ret = vhost_scsi_register(); if (ret < 0) - goto out_destroy_workqueue; + goto out; ret = target_register_template(&vhost_scsi_ops); if (ret < 0) @@ -2531,8 +2510,6 @@ static int __init vhost_scsi_init(void) out_vhost_scsi_deregister: vhost_scsi_deregister(); -out_destroy_workqueue: - destroy_workqueue(vhost_scsi_workqueue); out: return ret; }; @@ -2541,7 +2518,6 @@ static void vhost_scsi_exit(void) { target_unregister_template(&vhost_scsi_ops); vhost_scsi_deregister(); - destroy_workqueue(vhost_scsi_workqueue); }; MODULE_DESCRIPTION("VHOST_SCSI series fabric driver");