Re: [PATCH] proc: introduce proc_statfs()

From: Alexey Dobriyan
Date: Tue Jan 10 2023 - 12:59:41 EST


On Tue, Jan 10, 2023 at 11:20:03PM +0800, Chao Yu wrote:
> Introduce proc_statfs() to replace simple_statfs(), so that
> f_bsize queried from statfs() can be consistent w/ the value we
> set in s_blocksize.
>
> stat -f /proc/
>
> Before:
> ID: 0 Namelen: 255 Type: proc
> Block size: 4096 Fundamental block size: 4096
> Blocks: Total: 0 Free: 0 Available: 0
> Inodes: Total: 0 Free: 0
>
> After:
> ID: 0 Namelen: 255 Type: proc
> Block size: 1024 Fundamental block size: 1024
> Blocks: Total: 0 Free: 0 Available: 0
> Inodes: Total: 0 Free: 0

4096 is better value is in fact.

seq_files allocate 1 page and fill it, therefore reading less than
PAGE_SIZE from /proc is mostly waste of syscalls.

I doubt anything uses f_bsize.

BTW this patch is not self contained.