Hi Andy, On Tue, Sep 16, 2014 at 10:00 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote: > I think that the patch should instead tweak the vvar mapping to tell > the vdso not to use rdtsc. It should be based on this: I've been working on this approach which extends the vvar from 2 to 3 pages. The third page would initially be mapped to a zero page but then through a prctl a task could replace it with a real page that could then be inherited through fork and exec. That would make it possible to have per-task vvar contents. We could use some of those values as flags to indicate whether vdso routines may use RDTSC or not. In the future, we're planning to also use that to store clock offsets so that we can ensure CLOCK_MONOTONIC works after CRIU migration without having to turn off the VDSO or have to always fallback to full syscalls on every case. Do you think that would be a reasonable way to accomplish that? Thanks, Filipe -- 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
