diff mbox series

[RFC,for,4.14,1/2] membarrier: Remove unused code for architectures without membarrier hooks

Message ID 20171005223327.3500-1-mathieu.desnoyers@efficios.com (mailing list archive)
State Not Applicable
Headers show
Series [RFC,for,4.14,1/2] membarrier: Remove unused code for architectures without membarrier hooks | expand

Commit Message

Mathieu Desnoyers Oct. 5, 2017, 10:33 p.m. UTC 
Architectures without membarrier hooks don't need to emit the
empty membarrier_arch_switch_mm() static inline when
CONFIG_MEMBARRIER=y.

Adapt the CONFIG_MEMBARRIER=n counterpart to only emit the empty
membarrier_arch_switch_mm() for architectures with membarrier hooks.

Reported-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: Andrew Hunter <ahh@google.com>
CC: Maged Michael <maged.michael@gmail.com>
CC: gromer@google.com
CC: Avi Kivity <avi@scylladb.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Michael Ellerman <mpe@ellerman.id.au>
CC: Dave Watson <davejwatson@fb.com>
CC: Alan Stern <stern@rowland.harvard.edu>
CC: Will Deacon <will.deacon@arm.com>
CC: Andy Lutomirski <luto@kernel.org>
CC: Ingo Molnar <mingo@redhat.com>
CC: Alexander Viro <viro@zeniv.linux.org.uk>
CC: linuxppc-dev@lists.ozlabs.org
CC: linux-arch@vger.kernel.org
---
 include/linux/sched/mm.h | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

Comments

Paul E. McKenney Oct. 6, 2017, 9:08 p.m. UTC | #1 
On Thu, Oct 05, 2017 at 06:33:26PM -0400, Mathieu Desnoyers wrote:
> Architectures without membarrier hooks don't need to emit the
> empty membarrier_arch_switch_mm() static inline when
> CONFIG_MEMBARRIER=y.
> 
> Adapt the CONFIG_MEMBARRIER=n counterpart to only emit the empty
> membarrier_arch_switch_mm() for architectures with membarrier hooks.
> 
> Reported-by: Nicholas Piggin <npiggin@gmail.com>
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Queued for further review and testing, targeting v4.15.  Please let me
know if you need it sooner.

							Thanx, Paul

> CC: Peter Zijlstra <peterz@infradead.org>
> CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> CC: Boqun Feng <boqun.feng@gmail.com>
> CC: Andrew Hunter <ahh@google.com>
> CC: Maged Michael <maged.michael@gmail.com>
> CC: gromer@google.com
> CC: Avi Kivity <avi@scylladb.com>
> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> CC: Paul Mackerras <paulus@samba.org>
> CC: Michael Ellerman <mpe@ellerman.id.au>
> CC: Dave Watson <davejwatson@fb.com>
> CC: Alan Stern <stern@rowland.harvard.edu>
> CC: Will Deacon <will.deacon@arm.com>
> CC: Andy Lutomirski <luto@kernel.org>
> CC: Ingo Molnar <mingo@redhat.com>
> CC: Alexander Viro <viro@zeniv.linux.org.uk>
> CC: linuxppc-dev@lists.ozlabs.org
> CC: linux-arch@vger.kernel.org
> ---
>  include/linux/sched/mm.h | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
> index d5a9ab8f3836..b2767ecb21a8 100644
> --- a/include/linux/sched/mm.h
> +++ b/include/linux/sched/mm.h
> @@ -215,10 +215,6 @@ static inline void memalloc_noreclaim_restore(unsigned int flags)
>  #ifdef CONFIG_ARCH_HAS_MEMBARRIER_HOOKS
>  #include <asm/membarrier.h>
>  #else
> -static inline void membarrier_arch_switch_mm(struct mm_struct *prev,
> -		struct mm_struct *next, struct task_struct *tsk)
> -{
> -}
>  static inline void membarrier_arch_fork(struct task_struct *t,
>  		unsigned long clone_flags)
>  {
> @@ -247,10 +243,12 @@ static inline void membarrier_execve(struct task_struct *t)
>  	membarrier_arch_execve(t);
>  }
>  #else
> +#ifdef CONFIG_ARCH_HAS_MEMBARRIER_HOOKS
>  static inline void membarrier_arch_switch_mm(struct mm_struct *prev,
>  		struct mm_struct *next, struct task_struct *tsk)
>  {
>  }
> +#endif
>  static inline void membarrier_fork(struct task_struct *t,
>  		unsigned long clone_flags)
>  {
> -- 
> 2.11.0
>
Mathieu Desnoyers Oct. 6, 2017, 9:53 p.m. UTC | #2 
----- On Oct 6, 2017, at 5:08 PM, Paul E. McKenney paulmck@linux.vnet.ibm.com wrote:

> On Thu, Oct 05, 2017 at 06:33:26PM -0400, Mathieu Desnoyers wrote:
>> Architectures without membarrier hooks don't need to emit the
>> empty membarrier_arch_switch_mm() static inline when
>> CONFIG_MEMBARRIER=y.
>> 
>> Adapt the CONFIG_MEMBARRIER=n counterpart to only emit the empty
>> membarrier_arch_switch_mm() for architectures with membarrier hooks.
>> 
>> Reported-by: Nicholas Piggin <npiggin@gmail.com>
>> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> 
> Queued for further review and testing, targeting v4.15.  Please let me
> know if you need it sooner.

Hi Paul,

Given that the following patch in this patchset (2/2)
"Fix: membarrier: Handle CLONE_VM + !CLONE_THREAD correctly on powerpc"
is based on this patch, and that the fix needs to go into 4.14,
I would recommend queuing both patches for 4.14 is possible.

Otherwise I could try swapping the order of the two patches if
needed, but since both are touching nearby code areas, rebasing
is not straightforward.

Thanks,

Mathieu

> 
>							Thanx, Paul
> 
>> CC: Peter Zijlstra <peterz@infradead.org>
>> CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
>> CC: Boqun Feng <boqun.feng@gmail.com>
>> CC: Andrew Hunter <ahh@google.com>
>> CC: Maged Michael <maged.michael@gmail.com>
>> CC: gromer@google.com
>> CC: Avi Kivity <avi@scylladb.com>
>> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>> CC: Paul Mackerras <paulus@samba.org>
>> CC: Michael Ellerman <mpe@ellerman.id.au>
>> CC: Dave Watson <davejwatson@fb.com>
>> CC: Alan Stern <stern@rowland.harvard.edu>
>> CC: Will Deacon <will.deacon@arm.com>
>> CC: Andy Lutomirski <luto@kernel.org>
>> CC: Ingo Molnar <mingo@redhat.com>
>> CC: Alexander Viro <viro@zeniv.linux.org.uk>
>> CC: linuxppc-dev@lists.ozlabs.org
>> CC: linux-arch@vger.kernel.org
>> ---
>>  include/linux/sched/mm.h | 6 ++----
>>  1 file changed, 2 insertions(+), 4 deletions(-)
>> 
>> diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
>> index d5a9ab8f3836..b2767ecb21a8 100644
>> --- a/include/linux/sched/mm.h
>> +++ b/include/linux/sched/mm.h
>> @@ -215,10 +215,6 @@ static inline void memalloc_noreclaim_restore(unsigned int
>> flags)
>>  #ifdef CONFIG_ARCH_HAS_MEMBARRIER_HOOKS
>>  #include <asm/membarrier.h>
>>  #else
>> -static inline void membarrier_arch_switch_mm(struct mm_struct *prev,
>> -		struct mm_struct *next, struct task_struct *tsk)
>> -{
>> -}
>>  static inline void membarrier_arch_fork(struct task_struct *t,
>>  		unsigned long clone_flags)
>>  {
>> @@ -247,10 +243,12 @@ static inline void membarrier_execve(struct task_struct
>> *t)
>>  	membarrier_arch_execve(t);
>>  }
>>  #else
>> +#ifdef CONFIG_ARCH_HAS_MEMBARRIER_HOOKS
>>  static inline void membarrier_arch_switch_mm(struct mm_struct *prev,
>>  		struct mm_struct *next, struct task_struct *tsk)
>>  {
>>  }
>> +#endif
>>  static inline void membarrier_fork(struct task_struct *t,
>>  		unsigned long clone_flags)
>>  {
>> --
>> 2.11.0
diff mbox series

Patch

diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index d5a9ab8f3836..b2767ecb21a8 100644
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -215,10 +215,6 @@  static inline void memalloc_noreclaim_restore(unsigned int flags)
 #ifdef CONFIG_ARCH_HAS_MEMBARRIER_HOOKS
 #include <asm/membarrier.h>
 #else
-static inline void membarrier_arch_switch_mm(struct mm_struct *prev,
-		struct mm_struct *next, struct task_struct *tsk)
-{
-}
 static inline void membarrier_arch_fork(struct task_struct *t,
 		unsigned long clone_flags)
 {
@@ -247,10 +243,12 @@  static inline void membarrier_execve(struct task_struct *t)
 	membarrier_arch_execve(t);
 }
 #else
+#ifdef CONFIG_ARCH_HAS_MEMBARRIER_HOOKS
 static inline void membarrier_arch_switch_mm(struct mm_struct *prev,
 		struct mm_struct *next, struct task_struct *tsk)
 {
 }
+#endif
 static inline void membarrier_fork(struct task_struct *t,
 		unsigned long clone_flags)
 {