From: Philip J Kelleher <[email protected]> The RHEL 6.x version of the driver is using the legacy worqueue create function, 'create_singlethread_workqueue'. This would cause heavy usage of one CPU if data was being thrashed pretty hard. So, in order to fix it, workqueues are now being created with 'create_workqueue' and synchronization with mutexes.
Signed-off-by: Philip J Kelleher <[email protected]> ------------------------------------------------------------------------------- diff -uprN -X linux-block-vanilla/Documentation/dontdiff linux-block-vanilla/drivers/block/rsxx/dma.c linux-block/drivers/block/rsxx/dma.c --- linux-block-vanilla/drivers/block/rsxx/dma.c 2013-05-01 18:58:43.428185108 -0500 +++ linux-block/drivers/block/rsxx/dma.c 2013-05-01 19:03:48.504367557 -0500 @@ -383,15 +383,13 @@ static void dma_engine_stalled(unsigned } } -static void rsxx_issue_dmas(struct work_struct *work) +static void rsxx_issue_dmas(struct rsxx_dma_ctrl *ctrl) { - struct rsxx_dma_ctrl *ctrl; struct rsxx_dma *dma; int tag; int cmds_pending = 0; struct hw_cmd *hw_cmd_buf; - ctrl = container_of(work, struct rsxx_dma_ctrl, issue_dma_work); hw_cmd_buf = ctrl->cmd.buf; if (unlikely(ctrl->card->halt) || @@ -471,9 +469,8 @@ static void rsxx_issue_dmas(struct work_ } } -static void rsxx_dma_done(struct work_struct *work) +static void rsxx_dma_done(struct rsxx_dma_ctrl *ctrl) { - struct rsxx_dma_ctrl *ctrl; struct rsxx_dma *dma; unsigned long flags; u16 count; @@ -481,7 +478,6 @@ static void rsxx_dma_done(struct work_st u8 tag; struct hw_status *hw_st_buf; - ctrl = container_of(work, struct rsxx_dma_ctrl, dma_done_work); hw_st_buf = ctrl->status.buf; if (unlikely(ctrl->card->halt) || @@ -557,6 +553,28 @@ static void rsxx_dma_done(struct work_st spin_unlock_bh(&ctrl->queue_lock); } +static void rsxx_schedule_issue(struct work_struct *work) +{ + struct rsxx_dma_ctrl *ctrl; + + ctrl = container_of(work, struct rsxx_dma_ctrl, issue_dma_work); + + mutex_lock(&ctrl->work_lock); + rsxx_issue_dmas(ctrl); + mutex_unlock(&ctrl->work_lock); +} + +static void rsxx_schedule_done(struct work_struct *work) +{ + struct rsxx_dma_ctrl *ctrl; + + ctrl = container_of(work, struct rsxx_dma_ctrl, dma_done_work); + + mutex_lock(&ctrl->work_lock); + rsxx_dma_done(ctrl); + mutex_unlock(&ctrl->work_lock); +} + static int rsxx_queue_discard(struct rsxx_cardinfo *card, struct list_head *q, unsigned int laddr, @@ -801,6 +819,7 @@ static int rsxx_dma_ctrl_init(struct pci spin_lock_init(&ctrl->trackers->lock); spin_lock_init(&ctrl->queue_lock); + mutex_init(&ctrl->work_lock); INIT_LIST_HEAD(&ctrl->queue); setup_timer(&ctrl->activity_timer, dma_engine_stalled, @@ -814,8 +833,8 @@ static int rsxx_dma_ctrl_init(struct pci if (!ctrl->done_wq) return -ENOMEM; - INIT_WORK(&ctrl->issue_dma_work, rsxx_issue_dmas); - INIT_WORK(&ctrl->dma_done_work, rsxx_dma_done); + INIT_WORK(&ctrl->issue_dma_work, rsxx_schedule_issue); + INIT_WORK(&ctrl->dma_done_work, rsxx_schedule_done); st = rsxx_hw_buffers_init(dev, ctrl); if (st) diff -uprN -X linux-block-vanilla/Documentation/dontdiff linux-block-vanilla/drivers/block/rsxx/rsxx_priv.h linux-block/drivers/block/rsxx/rsxx_priv.h --- linux-block-vanilla/drivers/block/rsxx/rsxx_priv.h 2013-05-01 18:58:43.434186795 -0500 +++ linux-block/drivers/block/rsxx/rsxx_priv.h 2013-05-01 19:04:14.938188138 -0500 @@ -115,6 +115,7 @@ struct rsxx_dma_ctrl { struct timer_list activity_timer; struct dma_tracker_list *trackers; struct rsxx_dma_stats stats; + struct mutex work_lock; }; struct rsxx_cardinfo { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
