On Fri, 15 Dec 2017, Mathieu Desnoyers wrote: > Another aspect that worries me is applications using the gs segment selector > for other purposes. Suddenly reserving the gs segment selector for use by a > library like glibc may lead to incompatibilities with applications already > using it. fs/gs seems to be reserved for thread local storage. So it would be shared in user space like the corresponding cpu segment register in kernel space where multiple subsystems share %gs. The same can be done in user space. Ulrich Drepper has a writeup on this https://www.akkadia.org/drepper/tls.pdf Savings in execution time could come about because there would not be the need to determine the address of the processor specific memory area in each restartable sequence and there would be memory free of contention for such a sequence in order f.e. to realize fast counters. -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
