From patchwork Fri Nov 23 01:15:30 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiubo Li X-Patchwork-Id: 10694999 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 11C2115A7 for ; Fri, 23 Nov 2018 01:16:07 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EA7A82C3C3 for ; Fri, 23 Nov 2018 01:16:06 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C75592C48A; Fri, 23 Nov 2018 01:16:06 +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 DECBE2C3C3 for ; Fri, 23 Nov 2018 01:16:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2439244AbeKWL6G (ORCPT ); Fri, 23 Nov 2018 06:58:06 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54224 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392819AbeKWL6G (ORCPT ); Fri, 23 Nov 2018 06:58:06 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E151D4E90B; Fri, 23 Nov 2018 01:16:02 +0000 (UTC) Received: from rhel3.localdomain (ovpn-12-88.pek2.redhat.com [10.72.12.88]) by smtp.corp.redhat.com (Postfix) with ESMTP id 11B1C60BE5; Fri, 23 Nov 2018 01:15:59 +0000 (UTC) From: xiubli@redhat.com To: martin.petersen@oracle.com, nab@linux-iscsi.org, mchristi@redhat.com, target-devel@vger.kernel.org, linux-scsi@vger.kernel.org Cc: pkalever@redhat.com, Xiubo Li Subject: [PATCH v4] scsi: tcmu: avoid cmd/qfull timers updated whenever a new cmd comes Date: Fri, 23 Nov 2018 09:15:30 +0800 Message-Id: <20181123011530.2477-1-xiubli@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Fri, 23 Nov 2018 01:16:02 +0000 (UTC) Sender: target-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: target-devel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Xiubo Li Currently there has one cmd timeout timer and one qfull timer for each udev, and whenever there has any new coming cmd it will update the cmd timer or qfull timer. And for some corner case the timers are always working only for the ringbuffer's and full queue's newest cmd. That's to say the timer won't be fired even there has one cmd stuck for a very long time and the deadline is reached. This fix will keep the cmd/qfull timers to be pended for the oldest cmd in ringbuffer and full queue, and will update them with the next cmd's deadline only when the old cmd's deadline is reached or removed from the ringbuffer and full queue. Signed-off-by: Xiubo Li Acked-by: Mike Christie --- Changed in V4: - Addressed all the new comments. Changed in V3: - Add inflight queue support, thanks Mike. Changed in V2: - Add qfull timer - Addressed all the comments from Mike, thanks. drivers/target/target_core_user.c | 88 +++++++++++++++++++++++++++------------ 1 file changed, 61 insertions(+), 27 deletions(-) diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index 9cd404a..ac76201 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -148,7 +148,7 @@ struct tcmu_dev { size_t ring_size; struct mutex cmdr_lock; - struct list_head cmdr_queue; + struct list_head qfull_queue; uint32_t dbi_max; uint32_t dbi_thresh; @@ -159,6 +159,7 @@ struct tcmu_dev { struct timer_list cmd_timer; unsigned int cmd_time_out; + struct list_head inflight_queue; struct timer_list qfull_timer; int qfull_time_out; @@ -179,7 +180,7 @@ struct tcmu_dev { struct tcmu_cmd { struct se_cmd *se_cmd; struct tcmu_dev *tcmu_dev; - struct list_head cmdr_queue_entry; + struct list_head queue_entry; uint16_t cmd_id; @@ -192,6 +193,7 @@ struct tcmu_cmd { unsigned long deadline; #define TCMU_CMD_BIT_EXPIRED 0 +#define TCMU_CMD_BIT_INFLIGHT 1 unsigned long flags; }; /* @@ -586,7 +588,7 @@ static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd) if (!tcmu_cmd) return NULL; - INIT_LIST_HEAD(&tcmu_cmd->cmdr_queue_entry); + INIT_LIST_HEAD(&tcmu_cmd->queue_entry); tcmu_cmd->se_cmd = se_cmd; tcmu_cmd->tcmu_dev = udev; @@ -915,11 +917,13 @@ static int tcmu_setup_cmd_timer(struct tcmu_cmd *tcmu_cmd, unsigned int tmo, return 0; tcmu_cmd->deadline = round_jiffies_up(jiffies + msecs_to_jiffies(tmo)); - mod_timer(timer, tcmu_cmd->deadline); + if (!timer_pending(timer)) + mod_timer(timer, tcmu_cmd->deadline); + return 0; } -static int add_to_cmdr_queue(struct tcmu_cmd *tcmu_cmd) +static int add_to_qfull_queue(struct tcmu_cmd *tcmu_cmd) { struct tcmu_dev *udev = tcmu_cmd->tcmu_dev; unsigned int tmo; @@ -942,7 +946,7 @@ static int add_to_cmdr_queue(struct tcmu_cmd *tcmu_cmd) if (ret) return ret; - list_add_tail(&tcmu_cmd->cmdr_queue_entry, &udev->cmdr_queue); + list_add_tail(&tcmu_cmd->queue_entry, &udev->qfull_queue); pr_debug("adding cmd %u on dev %s to ring space wait queue\n", tcmu_cmd->cmd_id, udev->name); return 0; @@ -999,7 +1003,7 @@ static sense_reason_t queue_cmd_ring(struct tcmu_cmd *tcmu_cmd, int *scsi_err) base_command_size = tcmu_cmd_get_base_cmd_size(tcmu_cmd->dbi_cnt); command_size = tcmu_cmd_get_cmd_size(tcmu_cmd, base_command_size); - if (!list_empty(&udev->cmdr_queue)) + if (!list_empty(&udev->qfull_queue)) goto queue; mb = udev->mb_addr; @@ -1096,13 +1100,16 @@ static sense_reason_t queue_cmd_ring(struct tcmu_cmd *tcmu_cmd, int *scsi_err) UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size); tcmu_flush_dcache_range(mb, sizeof(*mb)); + list_add_tail(&tcmu_cmd->queue_entry, &udev->inflight_queue); + set_bit(TCMU_CMD_BIT_INFLIGHT, &tcmu_cmd->flags); + /* TODO: only if FLUSH and FUA? */ uio_event_notify(&udev->uio_info); return 0; queue: - if (add_to_cmdr_queue(tcmu_cmd)) { + if (add_to_qfull_queue(tcmu_cmd)) { *scsi_err = TCM_OUT_OF_RESOURCES; return -1; } @@ -1145,6 +1152,8 @@ static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry * if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) goto out; + list_del_init(&cmd->queue_entry); + tcmu_cmd_reset_dbi_cur(cmd); if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) { @@ -1194,9 +1203,29 @@ static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry * tcmu_free_cmd(cmd); } +static void tcmu_set_next_deadline(struct list_head *queue, + struct timer_list *timer) +{ + struct tcmu_cmd *tcmu_cmd, *tmp_cmd; + unsigned long deadline = 0; + + list_for_each_entry_safe(tcmu_cmd, tmp_cmd, queue, queue_entry) { + if (!time_after(jiffies, tcmu_cmd->deadline)) { + deadline = tcmu_cmd->deadline; + break; + } + } + + if (deadline) + mod_timer(timer, deadline); + else + del_timer(timer); +} + static unsigned int tcmu_handle_completions(struct tcmu_dev *udev) { struct tcmu_mailbox *mb; + struct tcmu_cmd *cmd; int handled = 0; if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) { @@ -1210,7 +1239,6 @@ static unsigned int tcmu_handle_completions(struct tcmu_dev *udev) while (udev->cmdr_last_cleaned != READ_ONCE(mb->cmd_tail)) { struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned; - struct tcmu_cmd *cmd; tcmu_flush_dcache_range(entry, sizeof(*entry)); @@ -1243,7 +1271,7 @@ static unsigned int tcmu_handle_completions(struct tcmu_dev *udev) /* no more pending commands */ del_timer(&udev->cmd_timer); - if (list_empty(&udev->cmdr_queue)) { + if (list_empty(&udev->qfull_queue)) { /* * no more pending or waiting commands so try to * reclaim blocks if needed. @@ -1252,6 +1280,8 @@ static unsigned int tcmu_handle_completions(struct tcmu_dev *udev) tcmu_global_max_blocks) schedule_delayed_work(&tcmu_unmap_work, 0); } + } else if (udev->cmd_time_out) { + tcmu_set_next_deadline(&udev->inflight_queue, &udev->cmd_timer); } return handled; @@ -1271,7 +1301,7 @@ static int tcmu_check_expired_cmd(int id, void *p, void *data) if (!time_after(jiffies, cmd->deadline)) return 0; - is_running = list_empty(&cmd->cmdr_queue_entry); + is_running = test_bit(TCMU_CMD_BIT_INFLIGHT, &cmd->flags); se_cmd = cmd->se_cmd; if (is_running) { @@ -1288,12 +1318,11 @@ static int tcmu_check_expired_cmd(int id, void *p, void *data) */ scsi_status = SAM_STAT_CHECK_CONDITION; } else { - list_del_init(&cmd->cmdr_queue_entry); - idr_remove(&udev->commands, id); tcmu_free_cmd(cmd); scsi_status = SAM_STAT_TASK_SET_FULL; } + list_del_init(&cmd->queue_entry); pr_debug("Timing out cmd %u on dev %s that is %s.\n", id, udev->name, is_running ? "inflight" : "queued"); @@ -1372,7 +1401,8 @@ static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name) INIT_LIST_HEAD(&udev->node); INIT_LIST_HEAD(&udev->timedout_entry); - INIT_LIST_HEAD(&udev->cmdr_queue); + INIT_LIST_HEAD(&udev->qfull_queue); + INIT_LIST_HEAD(&udev->inflight_queue); idr_init(&udev->commands); timer_setup(&udev->qfull_timer, tcmu_qfull_timedout, 0); @@ -1383,7 +1413,7 @@ static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name) return &udev->se_dev; } -static bool run_cmdr_queue(struct tcmu_dev *udev, bool fail) +static bool run_qfull_queue(struct tcmu_dev *udev, bool fail) { struct tcmu_cmd *tcmu_cmd, *tmp_cmd; LIST_HEAD(cmds); @@ -1391,15 +1421,15 @@ static bool run_cmdr_queue(struct tcmu_dev *udev, bool fail) sense_reason_t scsi_ret; int ret; - if (list_empty(&udev->cmdr_queue)) + if (list_empty(&udev->qfull_queue)) return true; pr_debug("running %s's cmdr queue forcefail %d\n", udev->name, fail); - list_splice_init(&udev->cmdr_queue, &cmds); + list_splice_init(&udev->qfull_queue, &cmds); - list_for_each_entry_safe(tcmu_cmd, tmp_cmd, &cmds, cmdr_queue_entry) { - list_del_init(&tcmu_cmd->cmdr_queue_entry); + list_for_each_entry_safe(tcmu_cmd, tmp_cmd, &cmds, queue_entry) { + list_del_init(&tcmu_cmd->queue_entry); pr_debug("removing cmd %u on dev %s from queue\n", tcmu_cmd->cmd_id, udev->name); @@ -1437,14 +1467,13 @@ static bool run_cmdr_queue(struct tcmu_dev *udev, bool fail) * cmd was requeued, so just put all cmds back in * the queue */ - list_splice_tail(&cmds, &udev->cmdr_queue); + list_splice_tail(&cmds, &udev->qfull_queue); drained = false; - goto done; + break; } } - if (list_empty(&udev->cmdr_queue)) - del_timer(&udev->qfull_timer); -done: + + tcmu_set_next_deadline(&udev->qfull_queue, &udev->qfull_timer); return drained; } @@ -1454,7 +1483,7 @@ static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on) mutex_lock(&udev->cmdr_lock); tcmu_handle_completions(udev); - run_cmdr_queue(udev, false); + run_qfull_queue(udev, false); mutex_unlock(&udev->cmdr_lock); return 0; @@ -1982,7 +2011,7 @@ static void tcmu_block_dev(struct tcmu_dev *udev) /* complete IO that has executed successfully */ tcmu_handle_completions(udev); /* fail IO waiting to be queued */ - run_cmdr_queue(udev, true); + run_qfull_queue(udev, true); unlock: mutex_unlock(&udev->cmdr_lock); @@ -1997,7 +2026,7 @@ static void tcmu_reset_ring(struct tcmu_dev *udev, u8 err_level) mutex_lock(&udev->cmdr_lock); idr_for_each_entry(&udev->commands, cmd, i) { - if (!list_empty(&cmd->cmdr_queue_entry)) + if (!test_bit(TCMU_CMD_BIT_INFLIGHT, &cmd->flags)) continue; pr_debug("removing cmd %u on dev %s from ring (is expired %d)\n", @@ -2006,6 +2035,7 @@ static void tcmu_reset_ring(struct tcmu_dev *udev, u8 err_level) idr_remove(&udev->commands, i); if (!test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) { + list_del_init(&cmd->queue_entry); if (err_level == 1) { /* * Userspace was not able to start the @@ -2666,6 +2696,10 @@ static void check_timedout_devices(void) mutex_lock(&udev->cmdr_lock); idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL); + + tcmu_set_next_deadline(&udev->inflight_queue, &udev->cmd_timer); + tcmu_set_next_deadline(&udev->qfull_queue, &udev->qfull_timer); + mutex_unlock(&udev->cmdr_lock); spin_lock_bh(&timed_out_udevs_lock);