From: Damien Le Moal <damien.lemoal@opensource.wdc.com>
To: John Garry <john.garry@huawei.com>,
axboe@kernel.dk, jejb@linux.ibm.com, martin.petersen@oracle.com,
jinpu.wang@cloud.ionos.com, hare@suse.de, bvanassche@acm.org,
hch@lst.de, ming.lei@redhat.com, niklas.cassel@wdc.com
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org,
linuxarm@huawei.com
Subject: Re: [PATCH RFC v3 03/22] scsi: core: Implement reserved command handling
Date: Thu, 27 Oct 2022 10:18:20 +0900 [thread overview]
Message-ID: <cd5df8e0-03d1-8f22-0367-eb7c76bc70e7@opensource.wdc.com> (raw)
In-Reply-To: <1666693096-180008-4-git-send-email-john.garry@huawei.com>
On 10/25/22 19:17, John Garry wrote:
> From: Hannes Reinecke <hare@suse.de>
>
> Quite some drivers are using management commands internally, which
> typically use the same hardware tag pool (ie they are being allocated
> from the same hardware resources) as the 'normal' I/O commands.
> These commands are set aside before allocating the block-mq tag bitmap,
> so they'll never show up as busy in the tag map.
> The block-layer, OTOH, already has 'reserved_tags' to handle precisely
> this situation.
> So this patch adds a new field 'nr_reserved_cmds' to the SCSI host
> template to instruct the block layer to set aside a tag space for these
> management commands by using reserved tags.
>
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> #jpg: Set tag_set->queue_depth = shost->can_queue, and not
> = shost->can_queue + shost->nr_reserved_cmds;
> Signed-off-by: John Garry <john.garry@huawei.com>
> ---
> drivers/scsi/hosts.c | 3 +++
> drivers/scsi/scsi_lib.c | 2 ++
> include/scsi/scsi_host.h | 15 ++++++++++++++-
> 3 files changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
> index 12346e2297fd..db89afc37bc9 100644
> --- a/drivers/scsi/hosts.c
> +++ b/drivers/scsi/hosts.c
> @@ -489,6 +489,9 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
> if (sht->virt_boundary_mask)
> shost->virt_boundary_mask = sht->virt_boundary_mask;
>
> + if (sht->nr_reserved_cmds)
> + shost->nr_reserved_cmds = sht->nr_reserved_cmds;
> +
Nit: the if is not really necessary I think. But it does not hurt.
> device_initialize(&shost->shost_gendev);
> dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
> shost->shost_gendev.bus = &scsi_bus_type;
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 39d4fd124375..a8c4e7c037ae 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -1978,6 +1978,8 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost)
> tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1;
> tag_set->nr_maps = shost->nr_maps ? : 1;
> tag_set->queue_depth = shost->can_queue;
> + tag_set->reserved_tags = shost->nr_reserved_cmds;
> +
Why the blank line ?
> tag_set->cmd_size = cmd_size;
> tag_set->numa_node = dev_to_node(shost->dma_dev);
> tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
> diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
> index 750ccf126377..91678c77398e 100644
> --- a/include/scsi/scsi_host.h
> +++ b/include/scsi/scsi_host.h
> @@ -360,10 +360,17 @@ struct scsi_host_template {
> /*
> * This determines if we will use a non-interrupt driven
> * or an interrupt driven scheme. It is set to the maximum number
> - * of simultaneous commands a single hw queue in HBA will accept.
> + * of simultaneous commands a single hw queue in HBA will accept
> + * including reserved commands.
> */
> int can_queue;
>
> + /*
> + * This determines how many commands the HBA will set aside
> + * for reserved commands.
> + */
> + int nr_reserved_cmds;
> +
> /*
> * In many instances, especially where disconnect / reconnect are
> * supported, our host also has an ID on the SCSI bus. If this is
> @@ -611,6 +618,12 @@ struct Scsi_Host {
> */
> unsigned nr_hw_queues;
> unsigned nr_maps;
> +
> + /*
> + * Number of reserved commands to allocate, if any.
> + */
> + unsigned int nr_reserved_cmds;
> +
> unsigned active_mode:2;
>
> /*
--
Damien Le Moal
Western Digital Research
next prev parent reply other threads:[~2022-10-27 1:18 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-25 10:17 [PATCH RFC v3 00/22] blk-mq/libata/scsi: SCSI driver tagging improvements Part I John Garry
2022-10-25 10:11 ` John Garry
2022-10-25 10:17 ` [PATCH RFC v3 01/22] blk-mq: Don't get budget for reserved requests John Garry
2022-10-27 1:16 ` Damien Le Moal
2022-10-27 9:09 ` John Garry
2022-10-25 10:17 ` [PATCH RFC v3 02/22] scsi: core: Add scsi_get_dev() John Garry
2022-10-25 10:17 ` [PATCH RFC v3 03/22] scsi: core: Implement reserved command handling John Garry
2022-10-27 1:18 ` Damien Le Moal [this message]
2022-10-27 7:51 ` Hannes Reinecke
2022-10-27 8:16 ` John Garry
2022-10-27 9:11 ` John Garry
2022-10-25 10:17 ` [PATCH RFC v3 04/22] scsi: core: Add support to send reserved commands John Garry
2022-10-27 1:21 ` Damien Le Moal
2022-10-27 9:13 ` John Garry
2022-10-27 9:18 ` Damien Le Moal
2022-10-25 10:17 ` [PATCH RFC v3 05/22] scsi: core: Add support for reserved command timeout handling John Garry
2022-10-25 10:18 ` [PATCH RFC v3 06/22] scsi: libsas: Improve sas_ex_discover_expander() error handling John Garry
2022-10-25 10:18 ` [PATCH RFC v3 07/22] scsi: libsas: Notify LLDD expander found before calling sas_rphy_add() John Garry
2022-10-25 10:18 ` [PATCH RFC v3 08/22] scsi: scsi_transport_sas: Alloc sdev for expander John Garry
2022-10-25 10:18 ` [PATCH RFC v3 09/22] scsi: libsas: Add sas_alloc_slow_task_rq() John Garry
2022-10-25 10:18 ` [PATCH RFC v3 10/22] scsi: libsas: Add sas_queuecommand_internal() John Garry
2022-10-25 10:18 ` [PATCH RFC v3 11/22] scsi: libsas: Add sas_internal_timeout() John Garry
2022-10-25 10:18 ` [PATCH RFC v3 12/22] scsi: core: Use SCSI_SCAN_RESCAN in __scsi_add_device() John Garry
2022-10-25 10:18 ` [PATCH RFC v3 13/22] scsi: scsi_transport_sas: Allocate end device target id in the rphy alloc John Garry
2022-10-25 10:18 ` [PATCH RFC v3 14/22] ata: libata-scsi: Add ata_scsi_setup_sdev() John Garry
2022-10-25 10:18 ` [PATCH RFC v3 15/22] scsi: libsas: Add sas_ata_setup_device() John Garry
2022-10-25 10:18 ` [PATCH RFC v3 16/22] ata: libata-scsi: Allocate sdev early in port probe John Garry
2022-10-27 1:34 ` Damien Le Moal
2022-10-27 8:11 ` Hannes Reinecke
2022-10-27 9:16 ` Damien Le Moal
2022-10-27 9:51 ` Hannes Reinecke
2022-11-07 10:09 ` John Garry
2022-11-07 10:20 ` Hannes Reinecke
2022-10-25 10:18 ` [PATCH RFC v3 17/22] scsi: libsas drivers: Reserve tags John Garry
2022-10-25 10:18 ` [PATCH RFC v3 18/22] scsi: libsas: Queue SMP commands as requests John Garry
2022-10-27 1:36 ` Damien Le Moal
2022-10-27 10:45 ` John Garry
2022-10-25 10:18 ` [PATCH RFC v3 19/22] scsi: libsas: Queue TMF " John Garry
2022-10-25 10:18 ` [PATCH RFC v3 20/22] scsi: core: Add scsi_alloc_request_hwq() John Garry
2022-10-25 10:18 ` [PATCH RFC v3 21/22] scsi: libsas: Queue internal abort commands as requests John Garry
2022-10-29 1:15 ` chenxiang (M)
2022-11-02 10:04 ` John Garry
2022-11-03 3:09 ` chenxiang (M)
2022-10-25 10:18 ` [PATCH RFC v3 22/22] scsi: libsas: Delete sas_task_slow.timer John Garry
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