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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 55178C433EF for ; Fri, 19 Nov 2021 19:58:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 426F2610A1 for ; Fri, 19 Nov 2021 19:58:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235083AbhKSUB4 (ORCPT ); Fri, 19 Nov 2021 15:01:56 -0500 Received: from mail-pj1-f42.google.com ([209.85.216.42]:37445 "EHLO mail-pj1-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236210AbhKSUBt (ORCPT ); Fri, 19 Nov 2021 15:01:49 -0500 Received: by mail-pj1-f42.google.com with SMTP id cq22-20020a17090af99600b001a9550a17a5so11778021pjb.2 for ; Fri, 19 Nov 2021 11:58:47 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=1/KqamDFUllDDt4JBg8BsSRY3ZHEeUO2jb7QeQ204zI=; b=daNN48NEmvvPqFm+i5hQ5IeLVGC1+MTkdZL4wPIhCQ3CKxDw3AJJzeX9t2V9nTyqgp PSCagEl3yWpqzJmd7zQt4oEc6elyGRLfgo48nFi3HDYzL25cp7rXf2PVcdqFdQU1L5fu OS+ItREtJwv6o5sx3Y8zxw/1Z+zyydpq3gFZFiyJMqjUSkUasbLKch8qgFZ9BnMotbCX yZX2zDaGb723rvOuiIDBpeLr4tewF1aV1YSTrWCes1fFU4MbLz68ZfI72oaZ/grTKXYy 1Ob7l0Tct0wEQvITRN7QxeXNXe/8lAIu0djPfyNBoolTF984k17SUsUuGsWga+ym2W6a voDw== X-Gm-Message-State: AOAM533UQP476lC+sJFsK98uDhkCy4UB6uQilpnWch0xhjzoMPPc4Hpo ijo4SUdIiaQ2Ws5CIpy7fZA= X-Google-Smtp-Source: ABdhPJyNDfqpGWCgo/JDagGmZM5Ma3MO8HhKZC41VkPjIuzl5NV6hUK5zw1b/Sg1kLsQWLXjKiRCeQ== X-Received: by 2002:a17:902:8f97:b0:143:88c2:e2d5 with SMTP id z23-20020a1709028f9700b0014388c2e2d5mr80752499plo.70.1637351927147; Fri, 19 Nov 2021 11:58:47 -0800 (PST) Received: from asus.hsd1.ca.comcast.net ([2601:647:4000:d7:feaa:14ff:fe9d:6dbd]) by smtp.gmail.com with ESMTPSA id g11sm379010pgn.41.2021.11.19.11.58.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 19 Nov 2021 11:58:46 -0800 (PST) From: Bart Van Assche To: "Martin K . Petersen" Cc: Jaegeuk Kim , Adrian Hunter , linux-scsi@vger.kernel.org, Bart Van Assche , "James E.J. Bottomley" , Bean Huo , Can Guo , Avri Altman , Stanley Chu , Asutosh Das , Keoseong Park Subject: [PATCH v2 18/20] scsi: ufs: Optimize the command queueing code Date: Fri, 19 Nov 2021 11:57:41 -0800 Message-Id: <20211119195743.2817-19-bvanassche@acm.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211119195743.2817-1-bvanassche@acm.org> References: <20211119195743.2817-1-bvanassche@acm.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Remove the clock scaling lock from ufshcd_queuecommand() since it is a performance bottleneck. Freeze request queues instead of polling the doorbell registers to wait until pending commands have completed. Signed-off-by: Bart Van Assche --- drivers/scsi/ufs/ufshcd.c | 124 +++++++++++++------------------------- drivers/scsi/ufs/ufshcd.h | 1 + 2 files changed, 44 insertions(+), 81 deletions(-) diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index a6d3f71c6b00..9cf4a22f1950 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -1070,65 +1070,6 @@ static bool ufshcd_is_devfreq_scaling_required(struct ufs_hba *hba, return false; } -static int ufshcd_wait_for_doorbell_clr(struct ufs_hba *hba, - u64 wait_timeout_us) -{ - unsigned long flags; - int ret = 0; - u32 tm_doorbell; - u32 tr_doorbell; - bool timeout = false, do_last_check = false; - ktime_t start; - - ufshcd_hold(hba, false); - spin_lock_irqsave(hba->host->host_lock, flags); - /* - * Wait for all the outstanding tasks/transfer requests. - * Verify by checking the doorbell registers are clear. - */ - start = ktime_get(); - do { - if (hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL) { - ret = -EBUSY; - goto out; - } - - tm_doorbell = ufshcd_readl(hba, REG_UTP_TASK_REQ_DOOR_BELL); - tr_doorbell = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL); - if (!tm_doorbell && !tr_doorbell) { - timeout = false; - break; - } else if (do_last_check) { - break; - } - - spin_unlock_irqrestore(hba->host->host_lock, flags); - schedule(); - if (ktime_to_us(ktime_sub(ktime_get(), start)) > - wait_timeout_us) { - timeout = true; - /* - * We might have scheduled out for long time so make - * sure to check if doorbells are cleared by this time - * or not. - */ - do_last_check = true; - } - spin_lock_irqsave(hba->host->host_lock, flags); - } while (tm_doorbell || tr_doorbell); - - if (timeout) { - dev_err(hba->dev, - "%s: timedout waiting for doorbell to clear (tm=0x%x, tr=0x%x)\n", - __func__, tm_doorbell, tr_doorbell); - ret = -EBUSY; - } -out: - spin_unlock_irqrestore(hba->host->host_lock, flags); - ufshcd_release(hba); - return ret; -} - /** * ufshcd_scale_gear - scale up/down UFS gear * @hba: per adapter instance @@ -1176,37 +1117,63 @@ static int ufshcd_scale_gear(struct ufs_hba *hba, bool scale_up) static int ufshcd_clock_scaling_prepare(struct ufs_hba *hba) { - #define DOORBELL_CLR_TOUT_US (1000 * 1000) /* 1 sec */ - int ret = 0; + struct scsi_device *sdev; + /* - * make sure that there are no outstanding requests when - * clock scaling is in progress + * Make sure that no commands are in progress while the clock frequency + * is being modified. + * + * Since ufshcd_exec_dev_cmd() and ufshcd_issue_devman_upiu_cmd() lock + * the clk_scaling_lock before calling blk_get_request(), lock + * clk_scaling_lock before freezing the request queues to prevent lock + * inversion. */ - ufshcd_scsi_block_requests(hba); down_write(&hba->clk_scaling_lock); - - if (!hba->clk_scaling.is_allowed || - ufshcd_wait_for_doorbell_clr(hba, DOORBELL_CLR_TOUT_US)) { - ret = -EBUSY; - up_write(&hba->clk_scaling_lock); - ufshcd_scsi_unblock_requests(hba); - goto out; - } - + if (!hba->clk_scaling.is_allowed) + goto busy; + blk_freeze_queue_start(hba->tmf_queue); + blk_freeze_queue_start(hba->cmd_queue); + shost_for_each_device(sdev, hba->host) + blk_freeze_queue_start(sdev->request_queue); + /* + * Calling synchronize_rcu_expedited() reduces the time required to + * freeze request queues from milliseconds to microseconds. + */ + synchronize_rcu_expedited(); + shost_for_each_device(sdev, hba->host) + if (blk_mq_freeze_queue_wait_timeout(sdev->request_queue, HZ) + <= 0) + goto unfreeze; + if (blk_mq_freeze_queue_wait_timeout(hba->cmd_queue, HZ) <= 0 || + blk_mq_freeze_queue_wait_timeout(hba->tmf_queue, HZ / 10) <= 0) + goto unfreeze; /* let's not get into low power until clock scaling is completed */ ufshcd_hold(hba, false); + return 0; -out: - return ret; +unfreeze: + shost_for_each_device(sdev, hba->host) + blk_mq_unfreeze_queue(sdev->request_queue); + blk_mq_unfreeze_queue(hba->cmd_queue); + blk_mq_unfreeze_queue(hba->tmf_queue); + +busy: + up_write(&hba->clk_scaling_lock); + return -EBUSY; } static void ufshcd_clock_scaling_unprepare(struct ufs_hba *hba, bool writelock) { + struct scsi_device *sdev; + + shost_for_each_device(sdev, hba->host) + blk_mq_unfreeze_queue(sdev->request_queue); + blk_mq_unfreeze_queue(hba->cmd_queue); + blk_mq_unfreeze_queue(hba->tmf_queue); if (writelock) up_write(&hba->clk_scaling_lock); else up_read(&hba->clk_scaling_lock); - ufshcd_scsi_unblock_requests(hba); ufshcd_release(hba); } @@ -2699,9 +2666,6 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd) WARN_ONCE(tag < 0, "Invalid tag %d\n", tag); - if (!down_read_trylock(&hba->clk_scaling_lock)) - return SCSI_MLQUEUE_HOST_BUSY; - /* * Allows the UFS error handler to wait for prior ufshcd_queuecommand() * calls. @@ -2790,8 +2754,6 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd) out: rcu_read_unlock(); - up_read(&hba->clk_scaling_lock); - if (ufs_trigger_eh()) { unsigned long flags; diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h index e9bc07c69a80..7ec463c97d64 100644 --- a/drivers/scsi/ufs/ufshcd.h +++ b/drivers/scsi/ufs/ufshcd.h @@ -778,6 +778,7 @@ struct ufs_hba_monitor { * @clk_list_head: UFS host controller clocks list node head * @pwr_info: holds current power mode * @max_pwr_info: keeps the device max valid pwm + * @clk_scaling_lock: used to serialize device commands and clock scaling * @desc_size: descriptor sizes reported by device * @urgent_bkops_lvl: keeps track of urgent bkops level for device * @is_urgent_bkops_lvl_checked: keeps track if the urgent bkops level for