On 11/18/22 02:47, Adrian Hunter wrote:
On 26/10/22 10:30, Christian Löhle wrote:
Mmcblk relies on block layer requeueing to fulfill some requests under
certain conditions. Improve the handling to get nicely ordered requests.
Using the terms a bit loosely to get a point across:
Current behavior for 512 blksz and max_blk_count = 1 the scenario would
be as follows:
- request for page 0 lba 0 to 7
- request for page 1 lba 8 to 15
- request for page 2 lba 16 to 23
- request for page 3 lba 24 to 31
mmcblk modifies data->blocks = 1 for each and requeues,
this leads to:
Access lba 0
Access lba 8
Access lba 16
Access lba 24
Access lba 1 (1. Requeue for page 0)
Access lba 9 (1. Requeue for page 1)
Access lba 17 (1. Requeue for page 2)
Access lba 25 (1. Requeue for page 3)
Access lba 2 (2. Requeue for page 0)
...
Of course we would rather have lbas consecutive.
Does anyone know why the block layer does not support
(max_hw_sectors << 9) < PAGE_SIZE ?
Hi Adrian,
Does this mean that the following patch series would not only be
useful for UFS but also for MMC? "[PATCH 00/10] Support DMA segments
smaller than the page size"
(https://lore.kernel.org/linux-block/20221019222324.362705-1-bvanassche@xxxxxxx/).
Thanks,
Bart.
