Messages in this thread | | | Date | Fri, 18 Nov 2022 09:27:13 -0800 | Subject | Re: [PATCH 0/3] mmc: Improve block layer requeueing behavior | From | Bart Van Assche <> |
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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@acm.org/).
Thanks,
Bart.
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