Re: [guv v2 20/31] powerpc: Replace __get_cpu_var uses
On Tue, 27 Aug 2013, Geert Uytterhoeven wrote: > On Mon, Aug 26, 2013 at 10:44 PM, Christoph Lameter wrote: > > __get_cpu_var() is used for multiple purposes in the kernel source. One of > > them is > > address calculation via the form &__get_cpu_var(x). This calculates the > > address for > > the instance of the percpu variable of the current processor based on an > > offset. > > > > Others usage cases are for storing and retrieving data from the current > > processors percpu area. > > use cases > > > __get_cpu_var() always only does a address determination. However, store > > and retrieve operations > > an address > > > This patch converts __get_cpu_var into either and explicit address > > calculation using this_cpu_ptr() > > an explicit > > > 4. Retrieve the content of a percpu struct > > > > DEFINE_PER_CPU(struct mystruct, y); > > struct mystruct x = __get_cpu_var(y); > > > >Converts to > > > > memcpy(this_cpu_ptr(), x, sizeof(x)); > > Let's hope the actual code copies in the other direction ;-) Ok fixed that as well. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [guv v2 20/31] powerpc: Replace __get_cpu_var uses
On Mon, Aug 26, 2013 at 10:44 PM, Christoph Lameter wrote:
> __get_cpu_var() is used for multiple purposes in the kernel source. One of
> them is
> address calculation via the form &__get_cpu_var(x). This calculates the
> address for
> the instance of the percpu variable of the current processor based on an
> offset.
>
> Others usage cases are for storing and retrieving data from the current
> processors percpu area.
use cases
> __get_cpu_var() always only does a address determination. However, store and
> retrieve operations
an address
> This patch converts __get_cpu_var into either and explicit address
> calculation using this_cpu_ptr()
an explicit
> 4. Retrieve the content of a percpu struct
>
> DEFINE_PER_CPU(struct mystruct, y);
> struct mystruct x = __get_cpu_var(y);
>
>Converts to
>
> memcpy(this_cpu_ptr(), x, sizeof(x));
Let's hope the actual code copies in the other direction ;-)
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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Please read the FAQ at http://www.tux.org/lkml/
Re: [guv v2 20/31] powerpc: Replace __get_cpu_var uses
On Mon, Aug 26, 2013 at 10:44 PM, Christoph Lameter c...@linux.com wrote:
__get_cpu_var() is used for multiple purposes in the kernel source. One of
them is
address calculation via the form __get_cpu_var(x). This calculates the
address for
the instance of the percpu variable of the current processor based on an
offset.
Others usage cases are for storing and retrieving data from the current
processors percpu area.
use cases
__get_cpu_var() always only does a address determination. However, store and
retrieve operations
an address
This patch converts __get_cpu_var into either and explicit address
calculation using this_cpu_ptr()
an explicit
4. Retrieve the content of a percpu struct
DEFINE_PER_CPU(struct mystruct, y);
struct mystruct x = __get_cpu_var(y);
Converts to
memcpy(this_cpu_ptr(y), x, sizeof(x));
Let's hope the actual code copies in the other direction ;-)
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say programmer or something like that.
-- Linus Torvalds
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [guv v2 20/31] powerpc: Replace __get_cpu_var uses
On Tue, 27 Aug 2013, Geert Uytterhoeven wrote: On Mon, Aug 26, 2013 at 10:44 PM, Christoph Lameter c...@linux.com wrote: __get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form __get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Others usage cases are for storing and retrieving data from the current processors percpu area. use cases __get_cpu_var() always only does a address determination. However, store and retrieve operations an address This patch converts __get_cpu_var into either and explicit address calculation using this_cpu_ptr() an explicit 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(this_cpu_ptr(y), x, sizeof(x)); Let's hope the actual code copies in the other direction ;-) Ok fixed that as well. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[guv v2 20/31] powerpc: Replace __get_cpu_var uses
__get_cpu_var() is used for multiple purposes in the kernel source. One of them
is
address calculation via the form &__get_cpu_var(x). This calculates the address
for
the instance of the percpu variable of the current processor based on an offset.
Others usage cases are for storing and retrieving data from the current
processors percpu area.
__get_cpu_var() can be used as an lvalue when writing data or on the right side
of an assignment.
__get_cpu_var() is defined as :
#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))
__get_cpu_var() always only does a address determination. However, store and
retrieve operations
could use a segment prefix (or global register on other platforms) to avoid the
address calculation.
this_cpu_write() and this_cpu_read() can directly take an offset into a percpu
area and use
optimized assembly code to read and write per cpu variables.
This patch converts __get_cpu_var into either and explicit address calculation
using this_cpu_ptr()
or into a use of this_cpu operations that use the offset. Thereby address
calcualtions are avoided
and less registers are used when code is generated.
At the end of the patchset all uses of __get_cpu_var have been removed so the
macro is removed too.
The patchset includes passes over all arches as well. Once these operations are
used throughout then
specialized macros can be defined in non -x86 arches as well in order to
optimize per cpu access by
f.e. using a global register that may be set to the per cpu base.
Transformations done to __get_cpu_var()
1. Determine the address of the percpu instance of the current processor.
DEFINE_PER_CPU(int, y);
int *x = &__get_cpu_var(y);
Converts to
int *x = this_cpu_ptr();
2. Same as #1 but this time an array structure is involved.
DEFINE_PER_CPU(int, y[20]);
int *x = __get_cpu_var(y);
Converts to
int *x = this_cpu_ptr(y);
3. Retrieve the content of the current processors instance of a per cpu
variable.
DEFINE_PER_CPU(int, u);
int x = __get_cpu_var(y)
Converts to
int x = __this_cpu_read(y);
4. Retrieve the content of a percpu struct
DEFINE_PER_CPU(struct mystruct, y);
struct mystruct x = __get_cpu_var(y);
Converts to
memcpy(this_cpu_ptr(), x, sizeof(x));
5. Assignment to a per cpu variable
DEFINE_PER_CPU(int, y)
__get_cpu_var(y) = x;
Converts to
this_cpu_write(y, x);
6. Increment/Decrement etc of a per cpu variable
DEFINE_PER_CPU(int, y);
__get_cpu_var(y)++
Converts to
this_cpu_inc(y)
Signed-off-by: Christoph Lameter
Index: linux/arch/powerpc/include/asm/cputime.h
===
--- linux.orig/arch/powerpc/include/asm/cputime.h 2013-08-22
14:56:47.939059652 -0500
+++ linux/arch/powerpc/include/asm/cputime.h2013-08-22 14:56:47.935059693
-0500
@@ -56,10 +56,10 @@ static inline unsigned long cputime_to_j
static inline cputime_t cputime_to_scaled(const cputime_t ct)
{
if (cpu_has_feature(CPU_FTR_SPURR) &&
- __get_cpu_var(cputime_last_delta))
+ __this_cpu_read(cputime_last_delta))
return (__force u64) ct *
- __get_cpu_var(cputime_scaled_last_delta) /
- __get_cpu_var(cputime_last_delta);
+ __this_cpu_read(cputime_scaled_last_delta) /
+ __this_cpu_read(cputime_last_delta);
return ct;
}
Index: linux/arch/powerpc/include/asm/hardirq.h
===
--- linux.orig/arch/powerpc/include/asm/hardirq.h 2013-08-22
14:56:47.939059652 -0500
+++ linux/arch/powerpc/include/asm/hardirq.h2013-08-22 14:56:47.935059693
-0500
@@ -19,7 +19,7 @@ DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpust
#define __ARCH_IRQ_STAT
-#define local_softirq_pending()
__get_cpu_var(irq_stat).__softirq_pending
+#define local_softirq_pending()
__this_cpu_read(irq_stat.__softirq_pending)
static inline void ack_bad_irq(unsigned int irq)
{
Index: linux/arch/powerpc/include/asm/tlbflush.h
===
--- linux.orig/arch/powerpc/include/asm/tlbflush.h 2013-08-22
14:56:47.939059652 -0500
+++ linux/arch/powerpc/include/asm/tlbflush.h 2013-08-22 14:56:47.935059693
-0500
@@ -107,14 +107,14 @@ extern void __flush_tlb_pending(struct p
static inline void arch_enter_lazy_mmu_mode(void)
{
- struct ppc64_tlb_batch *batch = &__get_cpu_var(ppc64_tlb_batch);
+ struct ppc64_tlb_batch *batch = this_cpu_ptr(_tlb_batch);
batch->active = 1;
}
static inline void arch_leave_lazy_mmu_mode(void)
{
- struct ppc64_tlb_batch *batch = &__get_cpu_var(ppc64_tlb_batch);
+ struct ppc64_tlb_batch *batch = this_cpu_ptr(_tlb_batch);
if (batch->index)
[guv v2 20/31] powerpc: Replace __get_cpu_var uses
__get_cpu_var() is used for multiple purposes in the kernel source. One of them
is
address calculation via the form __get_cpu_var(x). This calculates the address
for
the instance of the percpu variable of the current processor based on an offset.
Others usage cases are for storing and retrieving data from the current
processors percpu area.
__get_cpu_var() can be used as an lvalue when writing data or on the right side
of an assignment.
__get_cpu_var() is defined as :
#define __get_cpu_var(var) (*this_cpu_ptr((var)))
__get_cpu_var() always only does a address determination. However, store and
retrieve operations
could use a segment prefix (or global register on other platforms) to avoid the
address calculation.
this_cpu_write() and this_cpu_read() can directly take an offset into a percpu
area and use
optimized assembly code to read and write per cpu variables.
This patch converts __get_cpu_var into either and explicit address calculation
using this_cpu_ptr()
or into a use of this_cpu operations that use the offset. Thereby address
calcualtions are avoided
and less registers are used when code is generated.
At the end of the patchset all uses of __get_cpu_var have been removed so the
macro is removed too.
The patchset includes passes over all arches as well. Once these operations are
used throughout then
specialized macros can be defined in non -x86 arches as well in order to
optimize per cpu access by
f.e. using a global register that may be set to the per cpu base.
Transformations done to __get_cpu_var()
1. Determine the address of the percpu instance of the current processor.
DEFINE_PER_CPU(int, y);
int *x = __get_cpu_var(y);
Converts to
int *x = this_cpu_ptr(y);
2. Same as #1 but this time an array structure is involved.
DEFINE_PER_CPU(int, y[20]);
int *x = __get_cpu_var(y);
Converts to
int *x = this_cpu_ptr(y);
3. Retrieve the content of the current processors instance of a per cpu
variable.
DEFINE_PER_CPU(int, u);
int x = __get_cpu_var(y)
Converts to
int x = __this_cpu_read(y);
4. Retrieve the content of a percpu struct
DEFINE_PER_CPU(struct mystruct, y);
struct mystruct x = __get_cpu_var(y);
Converts to
memcpy(this_cpu_ptr(y), x, sizeof(x));
5. Assignment to a per cpu variable
DEFINE_PER_CPU(int, y)
__get_cpu_var(y) = x;
Converts to
this_cpu_write(y, x);
6. Increment/Decrement etc of a per cpu variable
DEFINE_PER_CPU(int, y);
__get_cpu_var(y)++
Converts to
this_cpu_inc(y)
Signed-off-by: Christoph Lameter c...@linux.com
Index: linux/arch/powerpc/include/asm/cputime.h
===
--- linux.orig/arch/powerpc/include/asm/cputime.h 2013-08-22
14:56:47.939059652 -0500
+++ linux/arch/powerpc/include/asm/cputime.h2013-08-22 14:56:47.935059693
-0500
@@ -56,10 +56,10 @@ static inline unsigned long cputime_to_j
static inline cputime_t cputime_to_scaled(const cputime_t ct)
{
if (cpu_has_feature(CPU_FTR_SPURR)
- __get_cpu_var(cputime_last_delta))
+ __this_cpu_read(cputime_last_delta))
return (__force u64) ct *
- __get_cpu_var(cputime_scaled_last_delta) /
- __get_cpu_var(cputime_last_delta);
+ __this_cpu_read(cputime_scaled_last_delta) /
+ __this_cpu_read(cputime_last_delta);
return ct;
}
Index: linux/arch/powerpc/include/asm/hardirq.h
===
--- linux.orig/arch/powerpc/include/asm/hardirq.h 2013-08-22
14:56:47.939059652 -0500
+++ linux/arch/powerpc/include/asm/hardirq.h2013-08-22 14:56:47.935059693
-0500
@@ -19,7 +19,7 @@ DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpust
#define __ARCH_IRQ_STAT
-#define local_softirq_pending()
__get_cpu_var(irq_stat).__softirq_pending
+#define local_softirq_pending()
__this_cpu_read(irq_stat.__softirq_pending)
static inline void ack_bad_irq(unsigned int irq)
{
Index: linux/arch/powerpc/include/asm/tlbflush.h
===
--- linux.orig/arch/powerpc/include/asm/tlbflush.h 2013-08-22
14:56:47.939059652 -0500
+++ linux/arch/powerpc/include/asm/tlbflush.h 2013-08-22 14:56:47.935059693
-0500
@@ -107,14 +107,14 @@ extern void __flush_tlb_pending(struct p
static inline void arch_enter_lazy_mmu_mode(void)
{
- struct ppc64_tlb_batch *batch = __get_cpu_var(ppc64_tlb_batch);
+ struct ppc64_tlb_batch *batch = this_cpu_ptr(ppc64_tlb_batch);
batch-active = 1;
}
static inline void arch_leave_lazy_mmu_mode(void)
{
- struct ppc64_tlb_batch *batch = __get_cpu_var(ppc64_tlb_batch);
+ struct ppc64_tlb_batch *batch = this_cpu_ptr(ppc64_tlb_batch);
if (batch-index)
