Storage EXT4 journal in enhanced area of eMMC

Registered by Saugata Das

Storage EXT4 journal in the enhanced area of eMMC

Blueprint information

Arnd Bergmann
Saugata Das
Needs approval
Balaji T K
Series goal:
Accepted for kernel-merge-window
Milestone target:
milestone icon backlog
Started by
Saugata Das

Related branches



Headline: Storage EXT4 journal in the enhanced area
Roadmap id: KWG2011-EMMC-4.5-SUPPORT
Refer storage mini-summit conclusions,

[jakub-pavelek 2013-01-02] Blocked, no developer. Can go deferred if not resolved
[jakub-pavelek 2013-02-06] Un-blocking, Balaji is back
[jakub-pavelek 2013-04-10] Blocked, no development in two months. Removing target kernel release - we do not have one.
[jakub-pavelek 2013-06-10] Un-blocking, Balaji is back.

First tests with a small fs entirely on enhanced area showed worse performance for Micron and better performance with Sandisk hardware compared to non-enhanced area. We assume this is only true for non-aged file systems and that for any hardware, the long-term effect of enhanced area should be positive.

Write on enhanced area stills show no improvement over user area with Micron eMMC
To retry with another Micron eMMC device and confirm.

balajitk: mkfs command to keep inode and bitmaps metadata in one super block
mke4fs -G 64 flex_bg

mkfs.ext4 -O flex_bg -G 64
to move block bitmap, inode bitmap and inode table on subsequent blocks


Work Items

Work items for 12.11:
[saugata.das] Enable enhanced area on eMMC : DONE

Work items for 13.06:
[balajik] Experiment with mkfs using journal on enhanced area : INPROGRESS
[balajitk] Experiment with mkfs to put inode metadata in single block group: DONE
[balajik] Experiment with mkfs to put all metadata in front (single block group) : DONE
[balajitk] Patch mkfs to move journal data from middle to start of the partition (Jun 28): DONE

Work items for 13.07:
[balajitk] Club journal and metadata together in enhanced area : DONE
[balajitk] Performance benchmark with journal and metadata on enhanced area : INPROGRESS
[balajitk] Kernel build time as performance benchmark : INPROGRESS

Work items for backlog:
[balajik] Study mkfs tool : TODO
[balajik] Implement automatic marking of enhanced area in mkfs for the above : TODO

Dependency tree

* Blueprints in grey have been implemented.

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