| Message ID | 20200325105511.20882-2-jgross@suse.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | xen/rcu: let rcu work better with core scheduling | expand |
On 25.03.2020 11:55, Juergen Gross wrote: > When using atomic variables for synchronization barriers are needed > to ensure proper data serialization. Introduce smp_mb__before_atomic() > and smp_mb__after_atomic() as in the Linux kernel for that purpose. > > Use the same definitions as in the Linux kernel. > > Suggested-by: Jan Beulich <jbeulich@suse.com> > Signed-off-by: Juergen Gross <jgross@suse.com> Acked-by: Jan Beulich <jbeulich@suse.com>
Hi Juergen, On 25/03/2020 10:55, Juergen Gross wrote: > When using atomic variables for synchronization barriers are needed > to ensure proper data serialization. Introduce smp_mb__before_atomic() > and smp_mb__after_atomic() as in the Linux kernel for that purpose. > > Use the same definitions as in the Linux kernel. > > Suggested-by: Jan Beulich <jbeulich@suse.com> > Signed-off-by: Juergen Gross <jgross@suse.com> Acked-by: Julien Grall <jgrall@amazon.com> Cheers, > --- > V7: > - new patch > --- > xen/include/asm-arm/system.h | 3 +++ > xen/include/asm-x86/system.h | 3 +++ > 2 files changed, 6 insertions(+) > > diff --git a/xen/include/asm-arm/system.h b/xen/include/asm-arm/system.h > index e5d062667d..65d5c8e423 100644 > --- a/xen/include/asm-arm/system.h > +++ b/xen/include/asm-arm/system.h > @@ -30,6 +30,9 @@ > > #define smp_wmb() dmb(ishst) > > +#define smp_mb__before_atomic() smp_mb() > +#define smp_mb__after_atomic() smp_mb() > + > /* > * This is used to ensure the compiler did actually allocate the register we > * asked it for some inline assembly sequences. Apparently we can't trust > diff --git a/xen/include/asm-x86/system.h b/xen/include/asm-x86/system.h > index 069f422f0d..7e5891f3df 100644 > --- a/xen/include/asm-x86/system.h > +++ b/xen/include/asm-x86/system.h > @@ -233,6 +233,9 @@ static always_inline unsigned long __xadd( > #define set_mb(var, value) do { xchg(&var, value); } while (0) > #define set_wmb(var, value) do { var = value; smp_wmb(); } while (0) > > +#define smp_mb__before_atomic() do { } while (0) > +#define smp_mb__after_atomic() do { } while (0) > + > /** > * array_index_mask_nospec() - generate a mask that is ~0UL when the > * bounds check succeeds and 0 otherwise >
diff --git a/xen/include/asm-arm/system.h b/xen/include/asm-arm/system.h index e5d062667d..65d5c8e423 100644 --- a/xen/include/asm-arm/system.h +++ b/xen/include/asm-arm/system.h @@ -30,6 +30,9 @@ #define smp_wmb() dmb(ishst) +#define smp_mb__before_atomic() smp_mb() +#define smp_mb__after_atomic() smp_mb() + /* * This is used to ensure the compiler did actually allocate the register we * asked it for some inline assembly sequences. Apparently we can't trust diff --git a/xen/include/asm-x86/system.h b/xen/include/asm-x86/system.h index 069f422f0d..7e5891f3df 100644 --- a/xen/include/asm-x86/system.h +++ b/xen/include/asm-x86/system.h @@ -233,6 +233,9 @@ static always_inline unsigned long __xadd( #define set_mb(var, value) do { xchg(&var, value); } while (0) #define set_wmb(var, value) do { var = value; smp_wmb(); } while (0) +#define smp_mb__before_atomic() do { } while (0) +#define smp_mb__after_atomic() do { } while (0) + /** * array_index_mask_nospec() - generate a mask that is ~0UL when the * bounds check succeeds and 0 otherwise
When using atomic variables for synchronization barriers are needed to ensure proper data serialization. Introduce smp_mb__before_atomic() and smp_mb__after_atomic() as in the Linux kernel for that purpose. Use the same definitions as in the Linux kernel. Suggested-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com> --- V7: - new patch --- xen/include/asm-arm/system.h | 3 +++ xen/include/asm-x86/system.h | 3 +++ 2 files changed, 6 insertions(+)