Messages in this thread | | | From | Guo Ren <> | Date | Tue, 1 Aug 2023 19:17:08 -0400 | Subject | Re: [PATCH] LoongArch: Fixup cmpxchg sematic for memory barrier |
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On Tue, Aug 1, 2023 at 12:37 PM WANG Rui <wangrui@loongson.cn> wrote: > > On Tue, Aug 1, 2023 at 6:50 PM Guo Ren <guoren@kernel.org> wrote: > > > > On Tue, Aug 1, 2023 at 5:32 PM WANG Rui <wangrui@loongson.cn> wrote: > > > No. LL and LL won't reorder because LL implies a memory barrier(though > > > not acquire semantics). > > That means we could remove __WEAK_LLSC_MB totally, right? > > More precisely, __WEAK_LLSC_MB is intended to prevent reordering > between LL and normal LD used to fetch the expected value for cmpxchg. Oh, that's unnecessary when cmpxchg fails.
Maybe you treat cmpxchg as a CoRR antidote in coincidence. Please solve the CoRR problem by READ_ONCE.
See alpha architecture.
> > Regards, > -- > WANG Rui >
-- Best Regards Guo Ren
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