Re: [RFC PATCH 03/24] erofs: add Errno in Rust

From: Gao Xiang
Date: Thu Sep 26 2024 - 07:09:54 EST




On 2024/9/26 19:01, Ariel Miculas wrote:

..


I believe they basically equal to your `Unified size`s, so
the result is

Your unified size
EROFS (LZ4HC,12,64k) 54.2
PuzzleFS compressed 53?
EROFS (DEFLATE,9,32k) 46.4

That is why I used your 53 unified size to show EROFS is much
smaller than PuzzleFS.

The reason why EROFS and SquashFS doesn't have the `Total Size`s
is just because we cannot store every individual chunk into some
seperate file.

Well storing individual chunks into separate files is the entire point
of PuzzleFS.


Currently, I have seen no reason to open arbitary kernel files
(maybe hundreds due to large folio feature at once) in the page
fault context. If I modified `mkfs.erofs` tool, I could give
some similar numbers, but I don't want to waste time now due
to `open arbitary kernel files in the page fault context`.

As I said, if PuzzleFS finally upstream some work to open kernel
files in page fault context, I will definitely work out the same
feature for EROFS soon, but currently I don't do that just
because it's very controversal and no in-tree kernel filesystem
does that.

The PuzzleFS kernel filesystem driver is still in an early POC stage, so
there's still a lot more work to be done.

I suggest that you could just ask FS/MM folks about this ("open
kernel files when reading in the page fault") first.

If they say "no", I suggest please don't waste on this anymore.

Thanks,
Gao Xiang


Regards,
Ariel


Thanks,
Gao Xiang