Re: [RFC PATCH] tools/sched_ext: Use u64 for kind field to fix ARM64 atomic ops

[Xuewen Yan]

On Tue, Feb 10, 2026 at 3:11 AM Tejun Heo <tj@xxxxxxxxxx> wrote:
>
> On Mon, Feb 09, 2026 at 04:55:36PM +0800, Xuewen Yan wrote:
> > From: Guohua Yan <guohua.yan@xxxxxxxxxx>
> >
> > There are following compile errors in arm64:
> >
> > bpftools/CORE/scx_simple.bpf.c:144:2: error: unsupported atomic operation, please use 64 bit version
> >   144 |         UEI_RECORD(uei, ei);
> >       |         ^
> >
> > Convert kind from int to u64 to resolve ARM64 atomic operation
> > limitations. ARM64 primarily supports 64-bit atomic operations.
>
> Alexei says this is llvm bpf backend error and the answer is to upgrade to a
> modern llvm that defaults to -mcpu=v3.

Thank you for the insight. We'll upgrade our LLVM toolchain and test
with -mcpu=v3.
Appreciate your guidance on this backend issue.

Thanks！