On 01/27/2014 11:01 PM, Ren Qiaowei wrote: > > Yes. Though all non-MPX threads are slowed down, the whole process > benefit from MPX. > > Anyway, HPA suggest these syscalls, which use MMU notifier, should be > not needed, we can do what they do in userspace runtime. What do you > think about it? I guess that I should remove the third patch which adds > new prctl() syscalls in next version of this patchset. >
The syscalls is one thing, managing the bounds map in kernel space is another. We could manage the bounds map entirely in user space in a signal handler, but that has both ABI issues (#BR currently turns into SIGSEGV which is commonly hooked by applications; we could switch to a different signal but there aren't many unclaimed ones) and performance issues. I would think it would be extremely unusual for an application to have some MPX and some non-MPX threads, since they would share the same address space and the non-MPX threads would mess up the bounds. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/