Re: [f2fs-dev] [PATCH v2] f2fs: add sysfs nodes to get accumulated compression info

[Chao Yu]

On 2021/3/9 21:00, Daeho Jeong wrote:
> 2021년 3월 9일 (화) 오후 6:22, Chao Yu <yuchao0@xxxxxxxxxx>님이 작성:
> > On 2021/3/5 10:24, Daeho Jeong wrote:
> > > From: Daeho Jeong <daehojeong@xxxxxxxxxx>
> > >
> > > Added acc_compr_inodes to show accumulated compressed inode count and
> > > acc_compr_blocks to show accumulated secured block count with
> >
> > I noticed that these stat numbers are recorded in extra reserved area in
> > hot node curseg journal, the journal will be persisted only for umount
> > or fastboot checkpoint, so the numbers are not so accurate... does this
> > satisfy your requirement?
>
> Yes, we are satisfied with just getting rough number of them. But, it

Alright,

> would be better if you suggest more accurate way. :)

I think this is the cheapest way to store rough number, otherwise it needs to change
f2fs_checkpoint structure layout or add a new inner inode to persist these stat
numbers if we want more accurate one.

> > > compression in sysfs. These can be re-initialized to "0" by writing "0"
> > > value in one of both.
> >
> > Why do we allow reset the stat numbers?
>
> Actually, I want to have a way to clear any stale number of them, but
> I agree we don't need this.
>
> > Why not covering all code with macro CONFIG_F2FS_FS_COMPRESSION, since these
> > numbers are only be updated when we enable compression.
>
> I wanted to keep the info even in the kernel with doesn't support
> per-file compression if those had been written once. What do you
> think?

Sure, if so it's fine to me. :)

Thanks,

> > Thanks,
> .