Re: [GIT PULL] One more vdso fix for 3.19

[Ingo Molnar]

* Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:

> Hi Ingo et al,
> 
> Please consider pulling for x86/urgent.
> 
> Thanks,
> Andy
> 
> 
> The following changes since commit 394f56fe480140877304d342dec46d50dc823d46:
> 
>   x86_64, vdso: Fix the vdso address randomization algorithm
> (2014-12-20 16:56:57 -0800)
> 
> are available in the git repository at:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git
> tags/pr-20141223-x86-vdso
> 
> for you to fetch changes up to 1ddf0b1b11aa8a90cef6706e935fc31c75c406ba:
> 
>   x86, vdso: Use asm volatile in __getcpu (2014-12-23 13:05:30 -0800)
> 
> ----------------------------------------------------------------
> This is hopefully the last vdso fix for 3.19.  It should be very
> safe (it just adds a volatile).
> 
> I don't think it fixes an actual bug (the __getcpu calls in the
> pvclock code may not have been needed in the first place), but
> discussion on that point is ongoing.
> 
> It also fixes a big performance issue in 3.18 and earlier in which
> the lsl instructions in vclock_gettime got hoisted so far up the
> function that they happened even when the function they were in was
> never called.  n 3.19, the performance issue seems to be gone due to
> the whims of my compiler and some interaction with a branch that's
> now gone.
> 
> I'll hopefully have a much bigger overhaul of the pvclock code
> for 3.20, but it needs careful review.
> 
> ----------------------------------------------------------------
> Andy Lutomirski (1):
>       x86, vdso: Use asm volatile in __getcpu
> 
>  arch/x86/include/asm/vgtod.h | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)

Pulled into tip:x86/urgent, thanks Andy!

I've attached the full commit below - I'm not sure it was sent to 
lkml.

Thanks,

	Ingo

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