Re: [PATCH] fs: load the ->i_sb pointer once in inode_sb_list_{add,del}

[Jan Kara]

On Wed 19-03-25 17:16:06, Mateusz Guzik wrote:
> On Wed, Mar 19, 2025 at 5:11 PM Jan Kara <jack@xxxxxxx> wrote:
> >
> > On Wed 19-03-25 01:46:35, Mateusz Guzik wrote:
> > > While this may sound like a pedantic clean up, it does in fact impact
> > > code generation -- the patched add routine is slightly smaller.
> > >
> > > Signed-off-by: Mateusz Guzik <mjguzik@xxxxxxxxx>
> >
> > I'm surprised it matters for the compiler but as Christian wrote, why not.
> > Feel free to add:
> >
> 
> In stock code the fence in spin_lock forces the compiler to load
> ->i_sb again -- as far as it knows it could have changed.
> 
> On the other this patch forces the compiler to remember the value for
> the same reason, which turns out to produce less code.

I see. Thanks for explanation!

								Honza
-- 
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR