On Tue, Mar 01, 2016 at 10:32:02PM +0100, Peter Zijlstra wrote: > > /* > > * Thread-local ABI rseq_seqnum field. > > * Updated by the kernel, and read by user-space with > > * single-copy atomicity semantics. Aligned on 32-bit. > > * Values: > > * >= 0: current seqnum for this thread (feature is active). > > * -1 (initial value): means the rseq feature is inactive. > > * -2: rseq feature is not available. > > */ > > int32_t rseq_seqnum; > > So I really hate that, that makes we have to check for these special > values whenever we increment the seq count and cannot have it wrap > naturally.
Also, since it will wrap, uint32_t is more natural, since the whole signed overflow thing is somewhat undefined in C.
