Re: [PATCH 87/87] fs: move i_blocks up a few places in struct inode

Jeff Layton
2023-09-28T12:02:14Z

On Thu, 2023-09-28 at 14:35 +0300, Amir Goldstein wrote:
> On Thu, Sep 28, 2023 at 2:06 PM Jeff Layton <jlayton@kernel.org> wrote:
> >
> > The recent change to use discrete integers instead of struct timespec64
> > in struct inode shaved 8 bytes off of it, but it also moves the i_lock
> > into the previous cacheline, away from the fields that it protects.
> >
> > Move i_blocks up above the i_lock, which moves the new 4 byte hole to
> > just after the timestamps, without changing the size of the structure.
> >
>
> Instead of creating an implicit hole, can you please move i_generation
> to fill the 4 bytes hole.
>
> It makes sense in the same cache line with i_ino and I could
> use the vacant 4 bytes hole above i_fsnotify_mask to expand the
> mask to 64bit (the 32bit event mask space is running out).
>
> Thanks,
> Amir.
>

Sounds like a plan. Resulting struct inode size is the same (616 bytes
with my kdevops kconfig). BTW: all of these changes are in my "amtime"
branch if anyone wants to pull them down.
--
Jeff Layton <jlayton@kernel.org>