On Wed, Aug 21, 2024 at 03:03:01PM GMT, Andreas Dilger wrote:
> On Aug 21, 2024, at 9:47 AM, Christian Brauner <brauner@xxxxxxxxxx> wrote:
> >
> > Now that we use the wait var event mechanism make i_state a u32 and free
> > up 4 bytes. This means we currently have two 4 byte holes in struct
> > inode which we can pack.
> >
> > Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
> > ---
> > include/linux/fs.h | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/linux/fs.h b/include/linux/fs.h
> > index 8525f8bfd7b9..a673173b6896 100644
> > --- a/include/linux/fs.h
> > +++ b/include/linux/fs.h
> > @@ -681,7 +681,7 @@ struct inode {
> > #endif
> >
> > /* Misc */
> > - unsigned long i_state;
> > + u32 i_state;
>
> Is it worthwhile to add a comment that there is a hole here, instead
> of leaving it for future re-discovery?
>
> /* 32-bit hole */
>
> > struct rw_semaphore i_rwsem;
> >
> > unsigned long dirtied_when; /* jiffies of first dirtying */
>
> Normally this would be excess noise, but since struct inode is
> micro-optimized (like struct page) it probably makes sense to
> document this case.
Good idea. Added now!
