[PATCH 1/5] x86: change_page_attr_clear fix

[PATCH 1/5] x86: change_page_attr_clear fix

[Huang, Ying]

This patch replaces __change_page_attr_set_clr() with
change_page_attr_set_clr() in change_page_attr_clear() to flush the
TLB/cache properly.

Signed-off-by: Huang Ying <ying.huang@intel.com>

---
 arch/x86/mm/pageattr.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -426,8 +426,7 @@ static inline int change_page_attr_set(u
 static inline int change_page_attr_clear(unsigned long addr, int numpages,
 					 pgprot_t mask)
 {
-	return __change_page_attr_set_clr(addr, numpages, __pgprot(0), mask);
-
+	return change_page_attr_set_clr(addr, numpages, __pgprot(0), mask);
 }
 
 int set_memory_uc(unsigned long addr, int numpages)

Re: [PATCH 1/5] x86: change_page_attr_clear fix

[Andi Kleen]

On Thursday 31 January 2008 08:35:59 Huang, Ying wrote:
> This patch replaces __change_page_attr_set_clr() with
> change_page_attr_set_clr() in change_page_attr_clear() to flush the
> TLB/cache properly.

Good catch :-) It actually only needs to flush TLBs not caches in this 
case.

-Andi

Re: [PATCH 1/5] x86: change_page_attr_clear fix

[Ingo Molnar]

* Huang, Ying <ying.huang@intel.com> wrote:

> This patch replaces __change_page_attr_set_clr() with 
> change_page_attr_set_clr() in change_page_attr_clear() to flush the 
> TLB/cache properly.

thanks, applied. Thomas just found this bug today too :-)

	Ingo

Re: [PATCH 1/5] x86: change_page_attr_clear fix

[Thomas Gleixner]

On Thu, 31 Jan 2008, Andi Kleen wrote:

> On Thursday 31 January 2008 08:35:59 Huang, Ying wrote:
> > This patch replaces __change_page_attr_set_clr() with
> > change_page_attr_set_clr() in change_page_attr_clear() to flush the
> > TLB/cache properly.
> 
> Good catch :-) It actually only needs to flush TLBs not caches in this 
> case.

That's one of the items on our optimizations todo list already. There
are more low hanging fruits, but we need to make sure that the non
optimized version is bullet proof first.

Thanks,

	tglx

Re: [PATCH 1/5] x86: change_page_attr_clear fix

[Andi Kleen]

On Thursday 31 January 2008 13:38:45 Thomas Gleixner wrote:
> On Thu, 31 Jan 2008, Andi Kleen wrote:
> 
> > On Thursday 31 January 2008 08:35:59 Huang, Ying wrote:
> > > This patch replaces __change_page_attr_set_clr() with
> > > change_page_attr_set_clr() in change_page_attr_clear() to flush the
> > > TLB/cache properly.
> > 
> > Good catch :-) It actually only needs to flush TLBs not caches in this 
> > case.
> 
> That's one of the items on our optimizations todo list already. There
> are more low hanging fruits, but we need to make sure that the non
> optimized version is bullet proof first.

I actually ported it already forward from my old patchkit (together
with some other improvements). Will post later.

-Andi