From: Frank Arnold <[email protected]>
Commit 93789b32dbf355e70f18b17a82e8661677a7f7fb introduced
cpuinfo_x86 *c for brevity. It is used to check for the
mwait feature flag. The same can be done with a subsequent
check for clflsh and save us a second per-cpu pointer
dereference.
Signed-off-by: Frank Arnold <[email protected]>
Acked-by: Borislav Petkov <[email protected]>
---
arch/x86/kernel/smpboot.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index c2871d3..93a0066 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1334,7 +1334,7 @@ static inline void mwait_play_dead(void)
if (!(cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)))
return;
- if (!cpu_has(__this_cpu_ptr(&cpu_info), X86_FEATURE_CLFLSH))
+ if (!cpu_has(c, X86_FEATURE_CLFLSH))
return;
if (__this_cpu_read(cpu_info.cpuid_level) < CPUID_MWAIT_LEAF)
return;
--
1.7.3.4
On 04/13/2011 09:11 AM, Frank Arnold wrote:
> From: Frank Arnold <[email protected]>
>
> Commit 93789b32dbf355e70f18b17a82e8661677a7f7fb introduced
> cpuinfo_x86 *c for brevity. It is used to check for the
> mwait feature flag. The same can be done with a subsequent
> check for clflsh and save us a second per-cpu pointer
> dereference.
>
> Signed-off-by: Frank Arnold <[email protected]>
> Acked-by: Borislav Petkov <[email protected]>
> ---
> arch/x86/kernel/smpboot.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
This should be using this_cpu_has()... if that's not in the tree yet we
should add it.
Creating an absolute pointer for a percpu references is a big lose.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
On Wed, Apr 13, 2011 at 09:52:40AM -0700, H. Peter Anvin wrote:
> On 04/13/2011 09:11 AM, Frank Arnold wrote:
> > From: Frank Arnold <[email protected]>
> >
> > Commit 93789b32dbf355e70f18b17a82e8661677a7f7fb introduced
> > cpuinfo_x86 *c for brevity. It is used to check for the
> > mwait feature flag. The same can be done with a subsequent
> > check for clflsh and save us a second per-cpu pointer
> > dereference.
> >
> > Signed-off-by: Frank Arnold <[email protected]>
> > Acked-by: Borislav Petkov <[email protected]>
> > ---
> > arch/x86/kernel/smpboot.c | 2 +-
> > 1 files changed, 1 insertions(+), 1 deletions(-)
> >
>
> This should be using this_cpu_has()... if that's not in the tree yet we
> should add it.
Looks like it is still in tip/x86/mm.
We could either redo the patch properly when this_cpu_has() is merged or
add the change against that branch.
--
Regards/Gruss,
Boris.
Advanced Micro Devices GmbH
Einsteinring 24, 85609 Dornach
General Managers: Alberto Bozzo, Andrew Bowd
Registration: Dornach, Gemeinde Aschheim, Landkreis Muenchen
Registergericht Muenchen, HRB Nr. 43632
On 04/13/2011 10:36 AM, Borislav Petkov wrote:
>>
>> This should be using this_cpu_has()... if that's not in the tree yet we
>> should add it.
>
> Looks like it is still in tip/x86/mm.
>
> We could either redo the patch properly when this_cpu_has() is merged or
> add the change against that branch.
>
It really should probably have been in tip:x86/cpu not x86/mm, but since
this is so simple we can just add it to the branch.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
* Borislav Petkov <[email protected]> wrote:
> On Wed, Apr 13, 2011 at 09:52:40AM -0700, H. Peter Anvin wrote:
> > On 04/13/2011 09:11 AM, Frank Arnold wrote:
> > > From: Frank Arnold <[email protected]>
> > >
> > > Commit 93789b32dbf355e70f18b17a82e8661677a7f7fb introduced
> > > cpuinfo_x86 *c for brevity. It is used to check for the
> > > mwait feature flag. The same can be done with a subsequent
> > > check for clflsh and save us a second per-cpu pointer
> > > dereference.
> > >
> > > Signed-off-by: Frank Arnold <[email protected]>
> > > Acked-by: Borislav Petkov <[email protected]>
> > > ---
> > > arch/x86/kernel/smpboot.c | 2 +-
> > > 1 files changed, 1 insertions(+), 1 deletions(-)
> > >
> >
> > This should be using this_cpu_has()... if that's not in the tree yet we
> > should add it.
>
> Looks like it is still in tip/x86/mm.
Yeah - that patch was sent at around the beginning of the merge window, so it
was too late for .39.
> We could either redo the patch properly when this_cpu_has() is merged or add
> the change against that branch.
Yeah - please do one against tip:master and we'll put it into the right topic
branch.
Thanks,
Ingo
On Wed, 2011-04-13 at 13:49 -0400, Ingo Molnar wrote:
> * Borislav Petkov <[email protected]> wrote:
>
> > On Wed, Apr 13, 2011 at 09:52:40AM -0700, H. Peter Anvin wrote:
> > > On 04/13/2011 09:11 AM, Frank Arnold wrote:
> > > > From: Frank Arnold <[email protected]>
> > > >
> > > > Commit 93789b32dbf355e70f18b17a82e8661677a7f7fb introduced
> > > > cpuinfo_x86 *c for brevity. It is used to check for the
> > > > mwait feature flag. The same can be done with a subsequent
> > > > check for clflsh and save us a second per-cpu pointer
> > > > dereference.
> > > >
> > > > Signed-off-by: Frank Arnold <[email protected]>
> > > > Acked-by: Borislav Petkov <[email protected]>
> > > > ---
> > > > arch/x86/kernel/smpboot.c | 2 +-
> > > > 1 files changed, 1 insertions(+), 1 deletions(-)
> > > >
> > >
> > > This should be using this_cpu_has()... if that's not in the tree yet we
> > > should add it.
> >
> > Looks like it is still in tip/x86/mm.
>
> Yeah - that patch was sent at around the beginning of the merge window, so it
> was too late for .39.
>
> > We could either redo the patch properly when this_cpu_has() is merged or add
> > the change against that branch.
>
> Yeah - please do one against tip:master and we'll put it into the right topic
> branch.
It's already fixed in tip:master with the proper use of this_cpu_has().
commit 349c004e3d31fda23ad225b61861be38047fff16
Sorry for the noise.
--
Frank.
Advanced Micro Devices GmbH
Sitz: Dornach, Gemeinde Aschheim,
Landkreis München Registergericht München,
HRB Nr. 43632 - WEEE Registrierungsnummer 129 19551
Geschäftsführer: Alberto Bozzo, Andrew Bowd