Re: [PATCH v5 9/9] x86-64: Add CONFIG_UNSAFE_VSYSCALLS tofeature-removal-schedule

[Ingo Molnar]

* Andrew Lutomirski <luto@xxxxxxx> wrote:

> > don't even bother making it a config option for now. If we can 
> > replace the vsyscall page with a page fault or int3 or whatever, 
> > and it's only used for the 'time()' system call, just do it.
> 
> Really?
> 
> I won't personally complain about the 200+ ns hit, but I'm sure 
> someone will cc: me on a regression report if there's no option.

Well, for 0.2 usecs to show up one would have to do like a million of 
them per second.

Why an application would want to query the *same value* from the 
kernel a million times per second is beyond me. vgettimeofday()? 
Sure. But vtime()?

Thanks,

	Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/