Messages in this thread | | | Date | Mon, 29 Feb 2016 11:35:06 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v4 1/5] getcpu_cache system call: cache CPU number of running thread |
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On Sun, Feb 28, 2016 at 02:32:28PM +0000, Mathieu Desnoyers wrote: > The part of ABI I'm trying to express here is for discoverability > of available features by user-space. For instance, a kernel > could be configured with "CONFIG_RSEQ=n", and userspace should > not rely on the rseq fields of the thread-local ABI in that case.
Per the just proposed interface; discoverability would end with:
thread_local_abi_register(NULL, TLA_ENABLE_RSEQ, 0);
failing. This would indicate your kernel does not support (or your glibc failed to register, depending on error code I suppose).
Then your program can either fall back to full atomics or just bail.
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