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From: jmoyer@redhat.com (Jeff Moyer)
Subject: [PATCH 03/47] block: defer timeouts to a workqueue
Date: Mon, 23 Nov 2015 15:31:32 -0500
Message-ID: <x49r3jgmp97.fsf@segfault.boston.devel.redhat.com> (raw)
In-Reply-To: <1448037342-18384-4-git-send-email-hch@lst.de> (Christoph Hellwig's message of "Fri, 20 Nov 2015 17:34:58 +0100")

Christoph Hellwig <hch at lst.de> writes:

> Timer context is not very useful for drivers to perform any meaningful abort
> action from.  So instead of calling the driver from this useless context
> defer it to a workqueue as soon as possible.
>
> Note that while a delayed_work item would seem the right thing here I didn't
> dare to use it due to the magic in blk_add_timer that pokes deep into timer
> internals.  But maybe this encourages Tejun to add a sensible API for that to
> the workqueue API and we'll all be fine in the end :)

I don't see where the blk-mq timeout work is ever scheduled.  You
removed the call to setup_timer for the mq case, so what causes the mq
timeout work to run?  I must be missing something.

-Jeff

>
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> ---
>  block/blk-core.c       | 8 ++++++++
>  block/blk-mq.c         | 8 +++++---
>  block/blk-timeout.c    | 5 +++--
>  block/blk.h            | 2 +-
>  include/linux/blkdev.h | 1 +
>  5 files changed, 18 insertions(+), 6 deletions(-)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 5131993b..1de0974 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -664,6 +664,13 @@ static void blk_queue_usage_counter_release(struct percpu_ref *ref)
>  	wake_up_all(&q->mq_freeze_wq);
>  }
>  
> +static void blk_rq_timed_out_timer(unsigned long data)
> +{
> +	struct request_queue *q = (struct request_queue *)data;
> +
> +	kblockd_schedule_work(&q->timeout_work);
> +}
> +
>  struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
>  {
>  	struct request_queue *q;
> @@ -825,6 +832,7 @@ blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
>  	if (blk_init_rl(&q->root_rl, q, GFP_KERNEL))
>  		goto fail;
>  
> +	INIT_WORK(&q->timeout_work, blk_timeout_work);
>  	q->request_fn		= rfn;
>  	q->prep_rq_fn		= NULL;
>  	q->unprep_rq_fn		= NULL;
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 3ae09de..8354601 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -85,6 +85,7 @@ void blk_mq_freeze_queue_start(struct request_queue *q)
>  	freeze_depth = atomic_inc_return(&q->mq_freeze_depth);
>  	if (freeze_depth == 1) {
>  		percpu_ref_kill(&q->q_usage_counter);
> +		cancel_work_sync(&q->timeout_work);
>  		blk_mq_run_hw_queues(q, false);
>  	}
>  }
> @@ -617,9 +618,10 @@ static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx,
>  	}
>  }
>  
> -static void blk_mq_rq_timer(unsigned long priv)
> +static void blk_mq_timeout_work(struct work_struct *work)
>  {
> -	struct request_queue *q = (struct request_queue *)priv;
> +	struct request_queue *q =
> +		container_of(work, struct request_queue, timeout_work);
>  	struct blk_mq_timeout_data data = {
>  		.next		= 0,
>  		.next_set	= 0,
> @@ -2015,7 +2017,7 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
>  		hctxs[i]->queue_num = i;
>  	}
>  
> -	setup_timer(&q->timeout, blk_mq_rq_timer, (unsigned long) q);
> +	INIT_WORK(&q->timeout_work, blk_mq_timeout_work);
>  	blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);
>  
>  	q->nr_queues = nr_cpu_ids;
> diff --git a/block/blk-timeout.c b/block/blk-timeout.c
> index aa40aa9..aedd128 100644
> --- a/block/blk-timeout.c
> +++ b/block/blk-timeout.c
> @@ -127,9 +127,10 @@ static void blk_rq_check_expired(struct request *rq, unsigned long *next_timeout
>  	}
>  }
>  
> -void blk_rq_timed_out_timer(unsigned long data)
> +void blk_timeout_work(struct work_struct *work)
>  {
> -	struct request_queue *q = (struct request_queue *) data;
> +	struct request_queue *q =
> +		container_of(work, struct request_queue, timeout_work);
>  	unsigned long flags, next = 0;
>  	struct request *rq, *tmp;
>  	int next_set = 0;
> diff --git a/block/blk.h b/block/blk.h
> index da722eb..37b9165 100644
> --- a/block/blk.h
> +++ b/block/blk.h
> @@ -95,7 +95,7 @@ static inline void blk_flush_integrity(void)
>  }
>  #endif
>  
> -void blk_rq_timed_out_timer(unsigned long data);
> +void blk_timeout_work(struct work_struct *work);
>  unsigned long blk_rq_timeout(unsigned long timeout);
>  void blk_add_timer(struct request *req);
>  void blk_delete_timer(struct request *);
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index 3fe27f8..9a8424a 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -407,6 +407,7 @@ struct request_queue {
>  
>  	unsigned int		rq_timeout;
>  	struct timer_list	timeout;
> +	struct work_struct	timeout_work;
>  	struct list_head	timeout_list;
>  
>  	struct list_head	icq_list;

  reply index

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-20 16:34 NVMe mega patchbomb for Linux 4.5-rc Christoph Hellwig
2015-11-20 16:34 ` [PATCH 01/47] nvme: add missing unmaps in nvme_queue_rq Christoph Hellwig
2015-11-20 16:34 ` [PATCH 02/47] block: fix blk_abort_request for blk-mq drivers Christoph Hellwig
2015-11-20 21:43   ` Jeff Moyer
2015-11-20 21:47     ` Jens Axboe
2015-11-20 21:54       ` Jeff Moyer
2015-11-20 22:20   ` Jeff Moyer
2015-11-21  7:34     ` Christoph Hellwig
2015-11-20 16:34 ` [PATCH 03/47] block: defer timeouts to a workqueue Christoph Hellwig
2015-11-23 20:31   ` Jeff Moyer [this message]
2015-11-23 20:48     ` Christoph Hellwig
2015-11-23 20:59       ` Jeff Moyer
2015-11-20 16:34 ` [PATCH 04/47] block: provide a new BLK_EH_QUIESCED timeout return value Christoph Hellwig
2015-11-24 15:16   ` Jeff Moyer
2015-11-24 15:40     ` Christoph Hellwig
2015-11-24 15:51       ` Jeff Moyer
2015-11-24 15:56         ` Christoph Hellwig
2015-11-24 16:34           ` Jeff Moyer
2015-11-24 16:47             ` Keith Busch
2015-11-24 17:56             ` Christoph Hellwig
2015-11-24 18:12               ` Jeff Moyer
2015-11-24 19:40                 ` Christoph Hellwig
2015-11-20 16:35 ` [PATCH 05/47] block: remoe REQ_ATOM_COMPLETE wrappers Christoph Hellwig
2015-11-23 21:23   ` Jeff Moyer
2015-11-24 21:22   ` Jens Axboe
2015-11-20 16:35 ` [PATCH 06/47] blk-mq: add a flags parameter to blk_mq_alloc_request Christoph Hellwig
2015-11-24 15:19   ` Jeff Moyer
2015-11-24 15:32     ` Christoph Hellwig
2015-11-24 21:21   ` Jens Axboe
2015-11-24 22:22     ` Christoph Hellwig
2015-11-24 22:25       ` Jens Axboe
2015-11-20 16:35 ` [PATCH 07/47] nvme: move struct nvme_iod to pci.c Christoph Hellwig
2015-11-20 16:35 ` [PATCH 08/47] nvme: split command submission helpers out of pci.c Christoph Hellwig
2015-11-20 16:35 ` [PATCH 09/47] nvme: add a vendor field to struct nvme_dev Christoph Hellwig
2015-11-20 16:35 ` [PATCH 10/47] nvme: use offset instead of a struct for registers Christoph Hellwig
2015-11-20 16:35 ` [PATCH 11/47] nvme: split a new struct nvme_ctrl out of struct nvme_dev Christoph Hellwig
2015-11-20 16:35 ` [PATCH 12/47] nvme: simplify nvme_setup_prps calling convention Christoph Hellwig
2015-11-20 16:35 ` [PATCH 13/47] nvme: refactor nvme_queue_rq Christoph Hellwig
2015-11-20 16:35 ` [PATCH 14/47] nvme: move nvme_error_status to common code Christoph Hellwig
2015-11-20 16:35 ` [PATCH 15/47] nvme: move nvme_setup_flush and nvme_setup_rw " Christoph Hellwig
2015-11-20 16:35 ` [PATCH 16/47] nvme: split __nvme_submit_sync_cmd Christoph Hellwig
2015-11-20 16:35 ` [PATCH 17/47] nvme: use the block layer for userspace passthrough metadata Christoph Hellwig
2015-11-20 16:35 ` [PATCH 18/47] nvme: move block_device_operations and ns/ctrl freeing to common code Christoph Hellwig
2015-11-20 16:35 ` [PATCH 19/47] nvme: add explicit quirk handling Christoph Hellwig
2015-11-20 16:35 ` [PATCH 20/47] nvme: add a common helper to read Identify Controller data Christoph Hellwig
2015-11-20 16:35 ` [PATCH 21/47] nvme: move the call to nvme_init_identify earlier Christoph Hellwig
2015-11-20 16:35 ` [PATCH 22/47] nvme: move namespace scanning to common code Christoph Hellwig
2015-11-20 16:35 ` [PATCH 23/47] nvme: move chardev and sysfs interface " Christoph Hellwig
2015-11-20 16:35 ` [PATCH 24/47] nvme: only add a controller to dev_list after it's been fully initialized Christoph Hellwig
2015-11-20 16:35 ` [PATCH 25/47] nvme: don't take the I/O queue q_lock in nvme_timeout Christoph Hellwig
2017-03-10 12:51   ` David Woodhouse
2017-03-10 14:24     ` Christoph Hellwig
2015-11-20 16:35 ` [PATCH 26/47] nvme: merge nvme_abort_req and nvme_timeout Christoph Hellwig
2015-11-20 16:35 ` [PATCH 27/47] nvme: do not restart the request timeout if we're resetting the controller Christoph Hellwig
2015-11-20 16:35 ` [PATCH 28/47] nvme: simplify resets Christoph Hellwig
2015-11-20 16:35 ` [PATCH 29/47] nvme: merge probe_work and reset_work Christoph Hellwig
2015-11-20 16:35 ` [PATCH 30/47] nvme: remove dead controllers from a work item Christoph Hellwig
2015-11-20 16:35 ` [PATCH 31/47] nvme: switch abort_limit to an atomic_t Christoph Hellwig
2015-11-20 16:35 ` [PATCH 32/47] NVMe: Implement namespace list scanning Christoph Hellwig
2015-11-20 16:35 ` [PATCH 33/47] NVMe: Use unbounded work queue for all work Christoph Hellwig
2015-11-20 16:35 ` [PATCH 34/47] NVMe: Remove device management handles on remove Christoph Hellwig
2015-11-20 16:50 ` NVMe mega patchbomb for Linux 4.5-rc Christoph Hellwig
2015-11-21  7:19 NVMe mega patchbomb for Linux 4.5-rc (resend) Christoph Hellwig
2015-11-21  7:19 ` [PATCH 03/47] block: defer timeouts to a workqueue Christoph Hellwig

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