lkml.org 
[lkml]   [2022]   [Oct]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Subject[PATCH 0/3] mmc: Improve block layer requeueing behavior
Date
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.
Hyperstone GmbH | Reichenaustr. 39a | 78467 Konstanz
Managing Director: Dr. Jan Peter Berns.
Commercial register of local courts: Freiburg HRB381782

\
 
 \ /
  Last update: 2022-10-26 09:31    [W:0.065 / U:0.752 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site