On 3/16/21 12:44 AM, Changheun Lee wrote:
> Add limit_bio_size block sysfs node to limit bio size.
> Queue flag QUEUE_FLAG_LIMIT_BIO_SIZE will be set if limit_bio_size is set.
> And bio max size will be limited by queue max sectors via
> QUEUE_FLAG_LIMIT_BIO_SIZE set.
>
> Signed-off-by: Changheun Lee <nanich....@samsung.com>
> ---
> Documentation/ABI/testing/sysfs-block | 10 ++++++++++
> Documentation/block/queue-sysfs.rst | 7 +++++++
> block/blk-sysfs.c | 3 +++
> 3 files changed, 20 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-block
> b/Documentation/ABI/testing/sysfs-block
> index e34cdeeeb9d4..86a7b15410cf 100644
> --- a/Documentation/ABI/testing/sysfs-block
> +++ b/Documentation/ABI/testing/sysfs-block
> @@ -316,3 +316,13 @@ Description:
> does not complete in this time then the block driver timeout
> handler is invoked. That timeout handler can decide to retry
> the request, to fail it or to start a device recovery strategy.
> +
> +What: /sys/block/<disk>/queue/limit_bio_size
> +Date: Feb, 2021
> +Contact: Changheun Lee <nanich....@samsung.com>
> +Description:
> + (RW) Toggle for set/clear QUEUE_FLAG_LIMIT_BIO_SIZE queue flag.
> + Queue flag QUEUE_FLAG_LIMIT_BIO_SIZE will be set if
> limit_bio_size
> + is set. And bio max size will be limited by queue max sectors.
> + QUEUE_FLAG_LIMIT_BIO_SIZE will be cleared if limit_bio_size is
> + cleard. And limit of bio max size will be cleard.
> diff --git a/Documentation/block/queue-sysfs.rst
> b/Documentation/block/queue-sysfs.rst
> index 2638d3446b79..cd371a821855 100644
> --- a/Documentation/block/queue-sysfs.rst
> +++ b/Documentation/block/queue-sysfs.rst
> @@ -273,4 +273,11 @@ devices are described in the ZBC (Zoned Block Commands)
> and ZAC
> do not support zone commands, they will be treated as regular block devices
> and zoned will report "none".
>
> +limit_bio_size (RW)
> +-------------------
> +This indicates QUEUE_FLAG_LIMIT_BIO_SIZE queue flag value. And
> +QUEUE_FLAG_LIMIT_BIO_SIZE can be changed via set(1)/clear(0) this node.
> +bio max size will be limited by queue max sectors via set this node. And
> +limit of bio max size will be cleard via clear this node.
> +
> Jens Axboe <jens.ax...@oracle.com>, February 2009
> diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
> index b513f1683af0..840d97f427e6 100644
> --- a/block/blk-sysfs.c
> +++ b/block/blk-sysfs.c
> @@ -288,6 +288,7 @@ QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
> QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
> QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
> QUEUE_SYSFS_BIT_FNS(stable_writes, STABLE_WRITES, 0);
> +QUEUE_SYSFS_BIT_FNS(limit_bio_size, LIMIT_BIO_SIZE, 0);
> #undef QUEUE_SYSFS_BIT_FNS
>
> static ssize_t queue_zoned_show(struct request_queue *q, char *page)
> @@ -615,6 +616,7 @@ QUEUE_RW_ENTRY(queue_nonrot, "rotational");
> QUEUE_RW_ENTRY(queue_iostats, "iostats");
> QUEUE_RW_ENTRY(queue_random, "add_random");
> QUEUE_RW_ENTRY(queue_stable_writes, "stable_writes");
> +QUEUE_RW_ENTRY(queue_limit_bio_size, "limit_bio_size");
>
> static struct attribute *queue_attrs[] = {
> &queue_requests_entry.attr,
> @@ -648,6 +650,7 @@ static struct attribute *queue_attrs[] = {
> &queue_rq_affinity_entry.attr,
> &queue_iostats_entry.attr,
> &queue_stable_writes_entry.attr,
> + &queue_limit_bio_size_entry.attr,
> &queue_random_entry.attr,
> &queue_poll_entry.attr,
> &queue_wc_entry.attr,
Has it been considered to introduce a function to set the BIO size limit
instead of introducing a new sysfs attribute? See also
blk_queue_max_hw_sectors().
Thanks,
Bart.
