[PATCH] D116088: [compiler-rt] Implement ARM atomic operations for architectures without SMP support
Pavel Kosov via Phabricator via cfe-commits
cfe-commits at lists.llvm.org
Thu Jan 20 06:17:57 PST 2022
kpdev42 added a comment.
In D116088#3254400 <https://reviews.llvm.org/D116088#3254400>, @joerg wrote:
> Correct me if I'm wrong, but I don't think this stubs are async signal safe nor will they work for preemptive multitasking systems?
Those stubs are basically cas loops (https://en.wikipedia.org/wiki/Compare-and-swap) which are not much different from their SMP counterparts, except memory sync ops are not used. This should work normally in case of preemption (preempting thread will spend its quota in busy-wait). Signal can be a problem if it preempt a thread executing atomic op, but I wonder if SMP code handles this
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