Re: Why disable vdso by default with CONFIG_PARAVIRT?

Jeremy Fitzhardinge wrote:

Zachary Amsden wrote:
  

quoted

Jeremy Fitzhardinge wrote:
    

quoted

Hi Andi,

What problem do they cause together?  There's certainly no problem with
Xen+vdso (in fact, its actually very useful so that it picks up the
right libc with Xen-friendly TLS).
  
      

Methinks the compat VDSO support got broken in the config?  Paravirt +
COMPAT_VDSO are incompatible. 
    

Yes, that's true, but I'm looking at arch/i386/kernel/sysenter.c:

#ifdef CONFIG_PARAVIRT
unsigned int __read_mostly vdso_enabled = 0;
#else
unsigned int __read_mostly vdso_enabled = 1;
#endif

I can't think of any reason why that should be necessary.
  

It's not for us or Xen.  Perhaps it came from lhype?