[PATCH] Align the scratch allocation to 64 bytes

[Chao-ying Fu]

On Thu, Jan 9, 2025 at 8:15 PM Xiang W <wxjstz at 126.com> wrote:
>
> 在 2025-01-09四的 16:34 -0800，Chao-ying Fu写道：
> > We increase the scratch allocation alignment to 64 bytes
> > as the cache line size, to avoid two atomic variables from
> > the same cache line that may cause livelock on some platforms.
> > ---
> >  lib/sbi/sbi_scratch.c | 11 +++++++++--
> >  1 file changed, 9 insertions(+), 2 deletions(-)
> >
> > diff --git a/lib/sbi/sbi_scratch.c b/lib/sbi/sbi_scratch.c
> > index ccbbc68..6b161bc 100644
> > --- a/lib/sbi/sbi_scratch.c
> > +++ b/lib/sbi/sbi_scratch.c
> > @@ -14,6 +14,9 @@
> >  #include <sbi/sbi_scratch.h>
> >  #include <sbi/sbi_string.h>
> >
> > +/* Minimum size and alignment of scratch allocations */
> > +#define SCRATCH_ALLOC_ALIGN 64
> This appears to be a platform-specific need and should not affect all platforms.
> Can be like this:
>
> #ifndef SCRATCH_ALLOC_ALIGN
> #define SCRATCH_ALLOC_ALIGN __SIZEOF_POINTER__
> #endif
>
> Regards,
> Xiang W

Yes, I will revise the patch to use the original alignment, if
SCRATCH_ALLOC_ALIGN is not defined.
Thanks a lot!

Regards,
Chao-ying