linux-kernel - Re: [PATCH v4 03/36] mm/slub: Mark slab_free_freelist_hook() __always

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Message-ID: <CAJuCfpHBgZeJN_O1ZQg_oLbAXc-Y+jmUpB02jznkEySpd4rzvw@mail.gmail.com>
Date: Fri, 23 Feb 2024 18:02:24 -0800
From: Suren Baghdasaryan <surenb@...gle.com>
To: Pasha Tatashin <pasha.tatashin@...een.com>
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Subject: Re: [PATCH v4 03/36] mm/slub: Mark slab_free_freelist_hook() __always_inline

On Wed, Feb 21, 2024 at 1:16 PM Pasha Tatashin
<pasha.tatashin@...een.com> wrote:
>
> On Wed, Feb 21, 2024 at 2:41 PM Suren Baghdasaryan <surenb@...glecom> wrote:
> >
> > From: Kent Overstreet <kent.overstreet@...ux.dev>
> >
> > It seems we need to be more forceful with the compiler on this one.
> > This is done for performance reasons only.
> >
> > Signed-off-by: Kent Overstreet <kent.overstreet@...ux.dev>
> > Signed-off-by: Suren Baghdasaryan <surenb@...gle.com>
> > Reviewed-by: Kees Cook <keescook@...omium.org>
> > ---
> >  mm/slub.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/mm/slub.c b/mm/slub.c
> > index 2ef88bbf56a3..d31b03a8d9d5 100644
> > --- a/mm/slub.c
> > +++ b/mm/slub.c
> > @@ -2121,7 +2121,7 @@ bool slab_free_hook(struct kmem_cache *s, void *x, bool init)
> >         return !kasan_slab_free(s, x, init);
> >  }
> >
> > -static inline bool slab_free_freelist_hook(struct kmem_cache *s,
> > +static __always_inline bool slab_free_freelist_hook(struct kmem_cache *s,
>
> __fastpath_inline seems to me more appropriate here. It prioritizes
> memory vs performance.

Hmm. AFAIKT this function is used only in one place and we do not add
any additional users, so I don't think changing to __fastpath_inline
here would gain us anything.

>
> >                                            void **head, void **tail,
> >                                            int *cnt)
> >  {
> > --
> > 2.44.0.rc0.258.g7320e95886-goog
> >