When ist littlefs garbage collection / flash erase block called?

RE: When ist littlefs garbage collection / flash erase block called?

Einar Thorsrud — Thu, 03 Mar 2022 15:54:29 GMT

Hi Erwin,

I do not know the reason for this, unfortunately. You could ask the Zephyr community on Discord and see if someone there knows about why this is.

RE: When ist littlefs garbage collection / flash erase block called?

ErwinCes — Wed, 02 Mar 2022 14:32:41 GMT

Hi Einar,

I expected to get an email when someout updates this ticket. But this didn't happen because of your update so I see your response only today.

Before raising this ticket I read the design document from GitHub which helped much and where I get this understanding of gargabe Collection. But your mentioned post is interesting. May be I tweak littlefs a Little bit.

In the meantime I've played around with the Zephyr variant of littleFS on the nrf5340 development board. According my Observation there is no garbage Collection. Every time a new page is required, i.e. littleFS wants to write data on it, the page is erase. I guess, even when the page is already empty. I hope the time to erase just one page is short enough that it doesn't harm our product too much.

Another think I've observed is that the Format function is not exported to fs Level (littleFS is only a speciallized implementation of the General file System. Do you know whether there is a Special reason for this? I realized it by calling lfs_format directly. But after that I have to call unmount and mount again to get the file System working.

Hopefully I turned now Reply notifications on. So I might receive an email when you or someone else responds.

Regards
Erwin

RE: When ist littlefs garbage collection / flash erase block called?

Einar Thorsrud — Tue, 01 Mar 2022 13:56:31 GMT

Hi Erwin,

I must admit that I don't have a intimate knowledge of littlefs, and it is not written by us. However, you can read a bit about this in the littlefs documentation. I suggest you search for "garbage" under DESIGN. I also see a post here about how you can do garbage collection when there is time to do it, which should prevent garbage collection from happening at other times.