Storage EXT4 journal in enhanced area of eMMC

Registered by Saugata Das on 2012-02-10

Storage EXT4 journal in the enhanced area of eMMC

Blueprint information

Status:
Started
Approver:
Arnd Bergmann
Priority:
High
Drafter:
Saugata Das
Direction:
Needs approval
Assignee:
Balaji T K
Definition:
Approved
Series goal:
Accepted for kernel-merge-window
Implementation:
Started
Milestone target:
milestone icon backlog
Started by
Saugata Das on 2012-05-11

Related branches

Sprints

Whiteboard

Meta:
Headline: Storage EXT4 journal in the enhanced area
Roadmap id: KWG2011-EMMC-4.5-SUPPORT
Acceptance:
Refer storage mini-summit conclusions, http://summit.linaro.org/lcq1-12/meeting/20093/linaro-kernel-q112-storage-mini-summit/

[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.

[Balaji]
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

balajitk
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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