The subject says limits for copy-offload...
On Mon, Feb 14, 2022 at 01:29:52PM +0530, Nitesh Shetty wrote:
> Add device limits as sysfs entries,
> - copy_offload (RW)
> - copy_max_bytes (RW)
> - copy_max_hw_bytes (RO)
> - copy_max_range_bytes (RW)
> - copy_max_range_hw_bytes (RO)
> - copy_max_nr_ranges (RW)
> - copy_max_nr_ranges_hw (RO)
Some of these seem like generic... and also I see a few more max_hw ones
not listed above...
> --- a/block/blk-settings.c
> +++ b/block/blk-settings.c
> +/**
> + * blk_queue_max_copy_sectors - set max sectors for a single copy payload
> + * @q: the request queue for the device
> + * @max_copy_sectors: maximum number of sectors to copy
> + **/
> +void blk_queue_max_copy_sectors(struct request_queue *q,
> + unsigned int max_copy_sectors)
> +{
> + q->limits.max_hw_copy_sectors = max_copy_sectors;
> + q->limits.max_copy_sectors = max_copy_sectors;
> +}
> +EXPORT_SYMBOL(blk_queue_max_copy_sectors);
Please use EXPORT_SYMBOL_GPL() for all new things.
Why is this setting both? The documentation does't seem to say.
What's the point?
> +
> +/**
> + * blk_queue_max_copy_range_sectors - set max sectors for a single range, in a copy payload
> + * @q: the request queue for the device
> + * @max_copy_range_sectors: maximum number of sectors to copy in a single range
> + **/
> +void blk_queue_max_copy_range_sectors(struct request_queue *q,
> + unsigned int max_copy_range_sectors)
> +{
> + q->limits.max_hw_copy_range_sectors = max_copy_range_sectors;
> + q->limits.max_copy_range_sectors = max_copy_range_sectors;
> +}
> +EXPORT_SYMBOL(blk_queue_max_copy_range_sectors);
Same here.
> +/**
> + * blk_queue_max_copy_nr_ranges - set max number of ranges, in a copy payload
> + * @q: the request queue for the device
> + * @max_copy_nr_ranges: maximum number of ranges
> + **/
> +void blk_queue_max_copy_nr_ranges(struct request_queue *q,
> + unsigned int max_copy_nr_ranges)
> +{
> + q->limits.max_hw_copy_nr_ranges = max_copy_nr_ranges;
> + q->limits.max_copy_nr_ranges = max_copy_nr_ranges;
> +}
> +EXPORT_SYMBOL(blk_queue_max_copy_nr_ranges);
Same.
> +
> /**
> * blk_queue_max_write_same_sectors - set max sectors for a single write same
> * @q: the request queue for the device
> @@ -541,6 +592,14 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
> t->max_segment_size = min_not_zero(t->max_segment_size,
> b->max_segment_size);
>
> + t->max_copy_sectors = min(t->max_copy_sectors, b->max_copy_sectors);
> + t->max_hw_copy_sectors = min(t->max_hw_copy_sectors, b->max_hw_copy_sectors);
> + t->max_copy_range_sectors = min(t->max_copy_range_sectors, b->max_copy_range_sectors);
> + t->max_hw_copy_range_sectors = min(t->max_hw_copy_range_sectors,
> + b->max_hw_copy_range_sectors);
> + t->max_copy_nr_ranges = min(t->max_copy_nr_ranges, b->max_copy_nr_ranges);
> + t->max_hw_copy_nr_ranges = min(t->max_hw_copy_nr_ranges, b->max_hw_copy_nr_ranges);
> +
> t->misaligned |= b->misaligned;
>
> alignment = queue_limit_alignment_offset(b, start);
> diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
> index 9f32882ceb2f..9ddd07f142d9 100644
> --- a/block/blk-sysfs.c
> +++ b/block/blk-sysfs.c
> @@ -212,6 +212,129 @@ static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *pag
> return queue_var_show(0, page);
> }
>
> +static ssize_t queue_copy_offload_show(struct request_queue *q, char *page)
> +{
> + return queue_var_show(blk_queue_copy(q), page);
> +}
> +
> +static ssize_t queue_copy_offload_store(struct request_queue *q,
> + const char *page, size_t count)
> +{
> + unsigned long copy_offload;
> + ssize_t ret = queue_var_store(©_offload, page, count);
> +
> + if (ret < 0)
> + return ret;
> +
> + if (copy_offload && !q->limits.max_hw_copy_sectors)
> + return -EINVAL;
If the kernel schedules, copy_offload may still be true and
max_hw_copy_sectors may be set to 0. Is that an issue?
> +
> + if (copy_offload)
> + blk_queue_flag_set(QUEUE_FLAG_COPY, q);
> + else
> + blk_queue_flag_clear(QUEUE_FLAG_COPY, q);
The flag may be set but the queue flag could be set. Is that an issue?
> @@ -597,6 +720,14 @@ QUEUE_RO_ENTRY(queue_nr_zones, "nr_zones");
> QUEUE_RO_ENTRY(queue_max_open_zones, "max_open_zones");
> QUEUE_RO_ENTRY(queue_max_active_zones, "max_active_zones");
>
> +QUEUE_RW_ENTRY(queue_copy_offload, "copy_offload");
> +QUEUE_RO_ENTRY(queue_copy_max_hw, "copy_max_hw_bytes");
> +QUEUE_RW_ENTRY(queue_copy_max, "copy_max_bytes");
> +QUEUE_RO_ENTRY(queue_copy_range_max_hw, "copy_max_range_hw_bytes");
> +QUEUE_RW_ENTRY(queue_copy_range_max, "copy_max_range_bytes");
> +QUEUE_RO_ENTRY(queue_copy_nr_ranges_max_hw, "copy_max_nr_ranges_hw");
> +QUEUE_RW_ENTRY(queue_copy_nr_ranges_max, "copy_max_nr_ranges");
Seems like you need to update Documentation/ABI/stable/sysfs-block.
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index efed3820cbf7..792e6d556589 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -254,6 +254,13 @@ struct queue_limits {
> unsigned int discard_alignment;
> unsigned int zone_write_granularity;
>
> + unsigned long max_hw_copy_sectors;
> + unsigned long max_copy_sectors;
> + unsigned int max_hw_copy_range_sectors;
> + unsigned int max_copy_range_sectors;
> + unsigned short max_hw_copy_nr_ranges;
> + unsigned short max_copy_nr_ranges;
Before limits start growing more.. I wonder if we should just
stuff hw offload stuff to its own struct within queue_limits.
Christoph?
Luis
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