Re: [PATCH] locking/atomics: Simplify the op definitions in atomic.h some more

[Palmer Dabbelt]

On Sun, 06 May 2018 07:57:27 PDT (-0700), mi...@kernel.org wrote:
>
> * Andrea Parri  wrote:
>
>> Hi Ingo,
>>
>> > From 5affbf7e91901143f84f1b2ca64f4afe70e210fd Mon Sep 17 00:00:00 2001
>> > From: Ingo Molnar 
>> > Date: Sat, 5 May 2018 10:23:23 +0200
>> > Subject: [PATCH] locking/atomics: Simplify the op definitions in atomic.h 
>> > some more
>> >
>> > Before:
>> >
>> >  #ifndef atomic_fetch_dec_relaxed
>> >  # ifndef atomic_fetch_dec
>> >  #  define atomic_fetch_dec(v) atomic_fetch_sub(1, (v))
>> >  #  define atomic_fetch_dec_relaxed(v) 
>> > atomic_fetch_sub_relaxed(1, (v))
>> >  #  define atomic_fetch_dec_acquire(v) 
>> > atomic_fetch_sub_acquire(1, (v))
>> >  #  define atomic_fetch_dec_release(v) 
>> > atomic_fetch_sub_release(1, (v))
>> >  # else
>> >  #  define atomic_fetch_dec_relaxedatomic_fetch_dec
>> >  #  define atomic_fetch_dec_acquireatomic_fetch_dec
>> >  #  define atomic_fetch_dec_releaseatomic_fetch_dec
>> >  # endif
>> >  #else
>> >  # ifndef atomic_fetch_dec_acquire
>> >  #  define atomic_fetch_dec_acquire(...)   
>> > __atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
>> >  # endif
>> >  # ifndef atomic_fetch_dec_release
>> >  #  define atomic_fetch_dec_release(...)   
>> > __atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
>> >  # endif
>> >  # ifndef atomic_fetch_dec
>> >  #  define atomic_fetch_dec(...)   
>> > __atomic_op_fence(atomic_fetch_dec, __VA_ARGS__)
>> >  # endif
>> >  #endif
>> >
>> > After:
>> >
>> >  #ifndef atomic_fetch_dec_relaxed
>> >  # ifndef atomic_fetch_dec
>> >  #  define atomic_fetch_dec(v) atomic_fetch_sub(1, (v))
>> >  #  define atomic_fetch_dec_relaxed(v) 
>> > atomic_fetch_sub_relaxed(1, (v))
>> >  #  define atomic_fetch_dec_acquire(v) 
>> > atomic_fetch_sub_acquire(1, (v))
>> >  #  define atomic_fetch_dec_release(v) 
>> > atomic_fetch_sub_release(1, (v))
>> >  # else
>> >  #  define atomic_fetch_dec_relaxedatomic_fetch_dec
>> >  #  define atomic_fetch_dec_acquireatomic_fetch_dec
>> >  #  define atomic_fetch_dec_releaseatomic_fetch_dec
>> >  # endif
>> >  #else
>> >  # ifndef atomic_fetch_dec
>> >  #  define atomic_fetch_dec(...)   
>> > __atomic_op_fence(atomic_fetch_dec, __VA_ARGS__)
>> >  #  define atomic_fetch_dec_acquire(...)   
>> > __atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
>> >  #  define atomic_fetch_dec_release(...)   
>> > __atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
>> >  # endif
>> >  #endif
>> >
>> > The idea is that because we already group these APIs by certain defines
>> > such as atomic_fetch_dec_relaxed and atomic_fetch_dec in the primary
>> > branches - we can do the same in the secondary branch as well.
>> >
>> > ( Also remove some unnecessarily duplicate comments, as the API
>> >   group defines are now pretty much self-documenting. )
>> >
>> > No change in functionality.
>> >
>> > Cc: Peter Zijlstra 
>> > Cc: Linus Torvalds 
>> > Cc: Andrew Morton 
>> > Cc: Thomas Gleixner 
>> > Cc: Paul E. McKenney 
>> > Cc: Will Deacon 
>> > Cc: linux-kernel@vger.kernel.org
>> > Signed-off-by: Ingo Molnar 
>>
>> This breaks compilation on RISC-V. (For some of its atomics, the arch
>> currently defines the _relaxed and the full variants and it relies on
>> the generic definitions for the _acquire and the _release variants.)
>
> I don't have cross-compilation for RISC-V, which is a relatively new arch.
> (Is there any RISC-V set of cross-compilation tools on kernel.org somewhere?)

Arnd added RISC-V to the cross compiler list a month or two ago when he updated 
them all.  I use the "make.cross" script from the Intel test robot, which will 
fetch the cross compilers for you.  It looks like I made a Git Hub pull request 
to update the script for RISC-V, it fetches from kernel.org


https://github.com/palmer-dabbelt/lkp-tests/blob/e14f4236ccd0572f4b87ffd480fecefee412dedc/sbin/make.cross
http://cdn.kernel.org/pub/tools/crosstool/files/bin/

http://cdn.kernel.org/pub/tools/crosstool/files/bin/x86_64/7.3.0/x86_64-gcc-7.3.0-nolibc_riscv64-linux.tar.gz

> Could you please send a patch that defines those variants against Linus's 
> tree,
> like the PowerPC patch that does something similar:
>
>   0476a632cb3a: locking/atomics/powerpc: Move cmpxchg helpers to 
> asm/cmpxchg.h and define the full set of cmpxchg APIs
>
> ?
>
> ... and I'll integrate it into the proper place to make it all bisectable, 
> etc.

Sorry, I got buried in email again.  Did this get merged, or is there a current 
version of the patch set I should look at?

Re: [PATCH] locking/atomics: Simplify the op definitions in atomic.h some more

[Palmer Dabbelt]

On Sun, 06 May 2018 07:57:27 PDT (-0700), mi...@kernel.org wrote:
>
> * Andrea Parri  wrote:
>
>> Hi Ingo,
>>
>> > From 5affbf7e91901143f84f1b2ca64f4afe70e210fd Mon Sep 17 00:00:00 2001
>> > From: Ingo Molnar 
>> > Date: Sat, 5 May 2018 10:23:23 +0200
>> > Subject: [PATCH] locking/atomics: Simplify the op definitions in atomic.h 
>> > some more
>> >
>> > Before:
>> >
>> >  #ifndef atomic_fetch_dec_relaxed
>> >  # ifndef atomic_fetch_dec
>> >  #  define atomic_fetch_dec(v) atomic_fetch_sub(1, (v))
>> >  #  define atomic_fetch_dec_relaxed(v) 
>> > atomic_fetch_sub_relaxed(1, (v))
>> >  #  define atomic_fetch_dec_acquire(v) 
>> > atomic_fetch_sub_acquire(1, (v))
>> >  #  define atomic_fetch_dec_release(v) 
>> > atomic_fetch_sub_release(1, (v))
>> >  # else
>> >  #  define atomic_fetch_dec_relaxedatomic_fetch_dec
>> >  #  define atomic_fetch_dec_acquireatomic_fetch_dec
>> >  #  define atomic_fetch_dec_releaseatomic_fetch_dec
>> >  # endif
>> >  #else
>> >  # ifndef atomic_fetch_dec_acquire
>> >  #  define atomic_fetch_dec_acquire(...)   
>> > __atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
>> >  # endif
>> >  # ifndef atomic_fetch_dec_release
>> >  #  define atomic_fetch_dec_release(...)   
>> > __atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
>> >  # endif
>> >  # ifndef atomic_fetch_dec
>> >  #  define atomic_fetch_dec(...)   
>> > __atomic_op_fence(atomic_fetch_dec, __VA_ARGS__)
>> >  # endif
>> >  #endif
>> >
>> > After:
>> >
>> >  #ifndef atomic_fetch_dec_relaxed
>> >  # ifndef atomic_fetch_dec
>> >  #  define atomic_fetch_dec(v) atomic_fetch_sub(1, (v))
>> >  #  define atomic_fetch_dec_relaxed(v) 
>> > atomic_fetch_sub_relaxed(1, (v))
>> >  #  define atomic_fetch_dec_acquire(v) 
>> > atomic_fetch_sub_acquire(1, (v))
>> >  #  define atomic_fetch_dec_release(v) 
>> > atomic_fetch_sub_release(1, (v))
>> >  # else
>> >  #  define atomic_fetch_dec_relaxedatomic_fetch_dec
>> >  #  define atomic_fetch_dec_acquireatomic_fetch_dec
>> >  #  define atomic_fetch_dec_releaseatomic_fetch_dec
>> >  # endif
>> >  #else
>> >  # ifndef atomic_fetch_dec
>> >  #  define atomic_fetch_dec(...)   
>> > __atomic_op_fence(atomic_fetch_dec, __VA_ARGS__)
>> >  #  define atomic_fetch_dec_acquire(...)   
>> > __atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
>> >  #  define atomic_fetch_dec_release(...)   
>> > __atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
>> >  # endif
>> >  #endif
>> >
>> > The idea is that because we already group these APIs by certain defines
>> > such as atomic_fetch_dec_relaxed and atomic_fetch_dec in the primary
>> > branches - we can do the same in the secondary branch as well.
>> >
>> > ( Also remove some unnecessarily duplicate comments, as the API
>> >   group defines are now pretty much self-documenting. )
>> >
>> > No change in functionality.
>> >
>> > Cc: Peter Zijlstra 
>> > Cc: Linus Torvalds 
>> > Cc: Andrew Morton 
>> > Cc: Thomas Gleixner 
>> > Cc: Paul E. McKenney 
>> > Cc: Will Deacon 
>> > Cc: linux-kernel@vger.kernel.org
>> > Signed-off-by: Ingo Molnar 
>>
>> This breaks compilation on RISC-V. (For some of its atomics, the arch
>> currently defines the _relaxed and the full variants and it relies on
>> the generic definitions for the _acquire and the _release variants.)
>
> I don't have cross-compilation for RISC-V, which is a relatively new arch.
> (Is there any RISC-V set of cross-compilation tools on kernel.org somewhere?)

Arnd added RISC-V to the cross compiler list a month or two ago when he updated 
them all.  I use the "make.cross" script from the Intel test robot, which will 
fetch the cross compilers for you.  It looks like I made a Git Hub pull request 
to update the script for RISC-V, it fetches from kernel.org


https://github.com/palmer-dabbelt/lkp-tests/blob/e14f4236ccd0572f4b87ffd480fecefee412dedc/sbin/make.cross
http://cdn.kernel.org/pub/tools/crosstool/files/bin/

http://cdn.kernel.org/pub/tools/crosstool/files/bin/x86_64/7.3.0/x86_64-gcc-7.3.0-nolibc_riscv64-linux.tar.gz

> Could you please send a patch that defines those variants against Linus's 
> tree,
> like the PowerPC patch that does something similar:
>
>   0476a632cb3a: locking/atomics/powerpc: Move cmpxchg helpers to 
> asm/cmpxchg.h and define the full set of cmpxchg APIs
>
> ?
>
> ... and I'll integrate it into the proper place to make it all bisectable, 
> etc.

Sorry, I got buried in email again.  Did this get merged, or is there a current 
version of the patch set I should look at?

Re: [PATCH] locking/atomics: Simplify the op definitions in atomic.h some more

[Andrea Parri]

On Sun, May 06, 2018 at 04:57:27PM +0200, Ingo Molnar wrote:
> 
> * Andrea Parri  wrote:
> 
> > Hi Ingo,
> > 
> > > From 5affbf7e91901143f84f1b2ca64f4afe70e210fd Mon Sep 17 00:00:00 2001
> > > From: Ingo Molnar 
> > > Date: Sat, 5 May 2018 10:23:23 +0200
> > > Subject: [PATCH] locking/atomics: Simplify the op definitions in atomic.h 
> > > some more
> > > 
> > > Before:
> > > 
> > >  #ifndef atomic_fetch_dec_relaxed
> > >  # ifndef atomic_fetch_dec
> > >  #  define atomic_fetch_dec(v)atomic_fetch_sub(1, (v))
> > >  #  define atomic_fetch_dec_relaxed(v)
> > > atomic_fetch_sub_relaxed(1, (v))
> > >  #  define atomic_fetch_dec_acquire(v)
> > > atomic_fetch_sub_acquire(1, (v))
> > >  #  define atomic_fetch_dec_release(v)
> > > atomic_fetch_sub_release(1, (v))
> > >  # else
> > >  #  define atomic_fetch_dec_relaxed   atomic_fetch_dec
> > >  #  define atomic_fetch_dec_acquire   atomic_fetch_dec
> > >  #  define atomic_fetch_dec_release   atomic_fetch_dec
> > >  # endif
> > >  #else
> > >  # ifndef atomic_fetch_dec_acquire
> > >  #  define atomic_fetch_dec_acquire(...)  
> > > __atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
> > >  # endif
> > >  # ifndef atomic_fetch_dec_release
> > >  #  define atomic_fetch_dec_release(...)  
> > > __atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
> > >  # endif
> > >  # ifndef atomic_fetch_dec
> > >  #  define atomic_fetch_dec(...)  
> > > __atomic_op_fence(atomic_fetch_dec, __VA_ARGS__)
> > >  # endif
> > >  #endif
> > > 
> > > After:
> > > 
> > >  #ifndef atomic_fetch_dec_relaxed
> > >  # ifndef atomic_fetch_dec
> > >  #  define atomic_fetch_dec(v)atomic_fetch_sub(1, (v))
> > >  #  define atomic_fetch_dec_relaxed(v)
> > > atomic_fetch_sub_relaxed(1, (v))
> > >  #  define atomic_fetch_dec_acquire(v)
> > > atomic_fetch_sub_acquire(1, (v))
> > >  #  define atomic_fetch_dec_release(v)
> > > atomic_fetch_sub_release(1, (v))
> > >  # else
> > >  #  define atomic_fetch_dec_relaxed   atomic_fetch_dec
> > >  #  define atomic_fetch_dec_acquire   atomic_fetch_dec
> > >  #  define atomic_fetch_dec_release   atomic_fetch_dec
> > >  # endif
> > >  #else
> > >  # ifndef atomic_fetch_dec
> > >  #  define atomic_fetch_dec(...)  
> > > __atomic_op_fence(atomic_fetch_dec, __VA_ARGS__)
> > >  #  define atomic_fetch_dec_acquire(...)  
> > > __atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
> > >  #  define atomic_fetch_dec_release(...)  
> > > __atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
> > >  # endif
> > >  #endif
> > > 
> > > The idea is that because we already group these APIs by certain defines
> > > such as atomic_fetch_dec_relaxed and atomic_fetch_dec in the primary
> > > branches - we can do the same in the secondary branch as well.
> > > 
> > > ( Also remove some unnecessarily duplicate comments, as the API
> > >   group defines are now pretty much self-documenting. )
> > > 
> > > No change in functionality.
> > > 
> > > Cc: Peter Zijlstra 
> > > Cc: Linus Torvalds 
> > > Cc: Andrew Morton 
> > > Cc: Thomas Gleixner 
> > > Cc: Paul E. McKenney 
> > > Cc: Will Deacon 
> > > Cc: linux-kernel@vger.kernel.org
> > > Signed-off-by: Ingo Molnar 
> > 
> > This breaks compilation on RISC-V. (For some of its atomics, the arch
> > currently defines the _relaxed and the full variants and it relies on
> > the generic definitions for the _acquire and the _release variants.)
> 
> I don't have cross-compilation for RISC-V, which is a relatively new arch.
> (Is there any RISC-V set of cross-compilation tools on kernel.org somewhere?)

I'm using the toolchain from:

  https://riscv.org/software-tools/

(adding Palmer and Albert in Cc:)


> 
> Could you please send a patch that defines those variants against Linus's 
> tree, 
> like the PowerPC patch that does something similar:
> 
>   0476a632cb3a: locking/atomics/powerpc: Move cmpxchg helpers to 
> asm/cmpxchg.h and define the full set of cmpxchg APIs
> 
> ?

Yes, please see below for a first RFC.

(BTW, get_maintainer.pl says that that patch missed Benjamin, Paul, Michael
 and linuxppc-...@lists.ozlabs.org: FWIW, I'm Cc-ing the maintainers here.)

  Andrea


>From 411f05a44e0b53a435331b977ff864fba7501a95 Mon Sep 17 00:00:00 2001
From: Andrea Parri 
Date: Mon, 7 May 2018 10:59:20 +0200
Subject: [RFC PATCH] riscv/atomic: Defines _acquire/_release variants

In preparation for Ingo's renovation of the generic atomic.h header [1],
define the _acquire/_release variants in the arch's header.

No change in code generation.

[1] http://lkml.kernel.org/r/20180505081100.nsyrqrpzq2vd2...@gmail.com

Re: [PATCH] locking/atomics: Simplify the op definitions in atomic.h some more

[Andrea Parri]

On Sun, May 06, 2018 at 04:57:27PM +0200, Ingo Molnar wrote:
> 
> * Andrea Parri  wrote:
> 
> > Hi Ingo,
> > 
> > > From 5affbf7e91901143f84f1b2ca64f4afe70e210fd Mon Sep 17 00:00:00 2001
> > > From: Ingo Molnar 
> > > Date: Sat, 5 May 2018 10:23:23 +0200
> > > Subject: [PATCH] locking/atomics: Simplify the op definitions in atomic.h 
> > > some more
> > > 
> > > Before:
> > > 
> > >  #ifndef atomic_fetch_dec_relaxed
> > >  # ifndef atomic_fetch_dec
> > >  #  define atomic_fetch_dec(v)atomic_fetch_sub(1, (v))
> > >  #  define atomic_fetch_dec_relaxed(v)
> > > atomic_fetch_sub_relaxed(1, (v))
> > >  #  define atomic_fetch_dec_acquire(v)
> > > atomic_fetch_sub_acquire(1, (v))
> > >  #  define atomic_fetch_dec_release(v)
> > > atomic_fetch_sub_release(1, (v))
> > >  # else
> > >  #  define atomic_fetch_dec_relaxed   atomic_fetch_dec
> > >  #  define atomic_fetch_dec_acquire   atomic_fetch_dec
> > >  #  define atomic_fetch_dec_release   atomic_fetch_dec
> > >  # endif
> > >  #else
> > >  # ifndef atomic_fetch_dec_acquire
> > >  #  define atomic_fetch_dec_acquire(...)  
> > > __atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
> > >  # endif
> > >  # ifndef atomic_fetch_dec_release
> > >  #  define atomic_fetch_dec_release(...)  
> > > __atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
> > >  # endif
> > >  # ifndef atomic_fetch_dec
> > >  #  define atomic_fetch_dec(...)  
> > > __atomic_op_fence(atomic_fetch_dec, __VA_ARGS__)
> > >  # endif
> > >  #endif
> > > 
> > > After:
> > > 
> > >  #ifndef atomic_fetch_dec_relaxed
> > >  # ifndef atomic_fetch_dec
> > >  #  define atomic_fetch_dec(v)atomic_fetch_sub(1, (v))
> > >  #  define atomic_fetch_dec_relaxed(v)
> > > atomic_fetch_sub_relaxed(1, (v))
> > >  #  define atomic_fetch_dec_acquire(v)
> > > atomic_fetch_sub_acquire(1, (v))
> > >  #  define atomic_fetch_dec_release(v)
> > > atomic_fetch_sub_release(1, (v))
> > >  # else
> > >  #  define atomic_fetch_dec_relaxed   atomic_fetch_dec
> > >  #  define atomic_fetch_dec_acquire   atomic_fetch_dec
> > >  #  define atomic_fetch_dec_release   atomic_fetch_dec
> > >  # endif
> > >  #else
> > >  # ifndef atomic_fetch_dec
> > >  #  define atomic_fetch_dec(...)  
> > > __atomic_op_fence(atomic_fetch_dec, __VA_ARGS__)
> > >  #  define atomic_fetch_dec_acquire(...)  
> > > __atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
> > >  #  define atomic_fetch_dec_release(...)  
> > > __atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
> > >  # endif
> > >  #endif
> > > 
> > > The idea is that because we already group these APIs by certain defines
> > > such as atomic_fetch_dec_relaxed and atomic_fetch_dec in the primary
> > > branches - we can do the same in the secondary branch as well.
> > > 
> > > ( Also remove some unnecessarily duplicate comments, as the API
> > >   group defines are now pretty much self-documenting. )
> > > 
> > > No change in functionality.
> > > 
> > > Cc: Peter Zijlstra 
> > > Cc: Linus Torvalds 
> > > Cc: Andrew Morton 
> > > Cc: Thomas Gleixner 
> > > Cc: Paul E. McKenney 
> > > Cc: Will Deacon 
> > > Cc: linux-kernel@vger.kernel.org
> > > Signed-off-by: Ingo Molnar 
> > 
> > This breaks compilation on RISC-V. (For some of its atomics, the arch
> > currently defines the _relaxed and the full variants and it relies on
> > the generic definitions for the _acquire and the _release variants.)
> 
> I don't have cross-compilation for RISC-V, which is a relatively new arch.
> (Is there any RISC-V set of cross-compilation tools on kernel.org somewhere?)

I'm using the toolchain from:

  https://riscv.org/software-tools/

(adding Palmer and Albert in Cc:)


> 
> Could you please send a patch that defines those variants against Linus's 
> tree, 
> like the PowerPC patch that does something similar:
> 
>   0476a632cb3a: locking/atomics/powerpc: Move cmpxchg helpers to 
> asm/cmpxchg.h and define the full set of cmpxchg APIs
> 
> ?

Yes, please see below for a first RFC.

(BTW, get_maintainer.pl says that that patch missed Benjamin, Paul, Michael
 and linuxppc-...@lists.ozlabs.org: FWIW, I'm Cc-ing the maintainers here.)

  Andrea


>From 411f05a44e0b53a435331b977ff864fba7501a95 Mon Sep 17 00:00:00 2001
From: Andrea Parri 
Date: Mon, 7 May 2018 10:59:20 +0200
Subject: [RFC PATCH] riscv/atomic: Defines _acquire/_release variants

In preparation for Ingo's renovation of the generic atomic.h header [1],
define the _acquire/_release variants in the arch's header.

No change in code generation.

[1] http://lkml.kernel.org/r/20180505081100.nsyrqrpzq2vd2...@gmail.com
http://lkml.kernel.org/r/20180505083635.622xmcvb42dw5...@gmail.com

Suggested-by: Ingo Molnar 
Signed-off-by: Andrea Parri 
Cc: Palmer Dabbelt 
Cc: Albert Ou 
Cc: Will Deacon 
Cc: Peter Zijlstra 
Cc: Boqun Feng 
Cc: linux-ri...@lists.infradead.org
---
 

Re: [PATCH] locking/atomics: Simplify the op definitions in atomic.h some more

[Ingo Molnar]

* Andrea Parri  wrote:

> Hi Ingo,
> 
> > From 5affbf7e91901143f84f1b2ca64f4afe70e210fd Mon Sep 17 00:00:00 2001
> > From: Ingo Molnar 
> > Date: Sat, 5 May 2018 10:23:23 +0200
> > Subject: [PATCH] locking/atomics: Simplify the op definitions in atomic.h 
> > some more
> > 
> > Before:
> > 
> >  #ifndef atomic_fetch_dec_relaxed
> >  # ifndef atomic_fetch_dec
> >  #  define atomic_fetch_dec(v)  atomic_fetch_sub(1, (v))
> >  #  define atomic_fetch_dec_relaxed(v)  
> > atomic_fetch_sub_relaxed(1, (v))
> >  #  define atomic_fetch_dec_acquire(v)  
> > atomic_fetch_sub_acquire(1, (v))
> >  #  define atomic_fetch_dec_release(v)  
> > atomic_fetch_sub_release(1, (v))
> >  # else
> >  #  define atomic_fetch_dec_relaxed atomic_fetch_dec
> >  #  define atomic_fetch_dec_acquire atomic_fetch_dec
> >  #  define atomic_fetch_dec_release atomic_fetch_dec
> >  # endif
> >  #else
> >  # ifndef atomic_fetch_dec_acquire
> >  #  define atomic_fetch_dec_acquire(...)
> > __atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
> >  # endif
> >  # ifndef atomic_fetch_dec_release
> >  #  define atomic_fetch_dec_release(...)
> > __atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
> >  # endif
> >  # ifndef atomic_fetch_dec
> >  #  define atomic_fetch_dec(...)
> > __atomic_op_fence(atomic_fetch_dec, __VA_ARGS__)
> >  # endif
> >  #endif
> > 
> > After:
> > 
> >  #ifndef atomic_fetch_dec_relaxed
> >  # ifndef atomic_fetch_dec
> >  #  define atomic_fetch_dec(v)  atomic_fetch_sub(1, (v))
> >  #  define atomic_fetch_dec_relaxed(v)  
> > atomic_fetch_sub_relaxed(1, (v))
> >  #  define atomic_fetch_dec_acquire(v)  
> > atomic_fetch_sub_acquire(1, (v))
> >  #  define atomic_fetch_dec_release(v)  
> > atomic_fetch_sub_release(1, (v))
> >  # else
> >  #  define atomic_fetch_dec_relaxed atomic_fetch_dec
> >  #  define atomic_fetch_dec_acquire atomic_fetch_dec
> >  #  define atomic_fetch_dec_release atomic_fetch_dec
> >  # endif
> >  #else
> >  # ifndef atomic_fetch_dec
> >  #  define atomic_fetch_dec(...)
> > __atomic_op_fence(atomic_fetch_dec, __VA_ARGS__)
> >  #  define atomic_fetch_dec_acquire(...)
> > __atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
> >  #  define atomic_fetch_dec_release(...)
> > __atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
> >  # endif
> >  #endif
> > 
> > The idea is that because we already group these APIs by certain defines
> > such as atomic_fetch_dec_relaxed and atomic_fetch_dec in the primary
> > branches - we can do the same in the secondary branch as well.
> > 
> > ( Also remove some unnecessarily duplicate comments, as the API
> >   group defines are now pretty much self-documenting. )
> > 
> > No change in functionality.
> > 
> > Cc: Peter Zijlstra 
> > Cc: Linus Torvalds 
> > Cc: Andrew Morton 
> > Cc: Thomas Gleixner 
> > Cc: Paul E. McKenney 
> > Cc: Will Deacon 
> > Cc: linux-kernel@vger.kernel.org
> > Signed-off-by: Ingo Molnar 
> 
> This breaks compilation on RISC-V. (For some of its atomics, the arch
> currently defines the _relaxed and the full variants and it relies on
> the generic definitions for the _acquire and the _release variants.)

I don't have cross-compilation for RISC-V, which is a relatively new arch.
(Is there any RISC-V set of cross-compilation tools on kernel.org somewhere?)

Could you please send a patch that defines those variants against Linus's tree, 
like the PowerPC patch that does something similar:

  0476a632cb3a: locking/atomics/powerpc: Move cmpxchg helpers to asm/cmpxchg.h 
and define the full set of cmpxchg APIs

?

... and I'll integrate it into the proper place to make it all bisectable, etc.

Thanks,

Ingo

Re: [PATCH] locking/atomics: Simplify the op definitions in atomic.h some more

[Ingo Molnar]

* Andrea Parri  wrote:

> Hi Ingo,
> 
> > From 5affbf7e91901143f84f1b2ca64f4afe70e210fd Mon Sep 17 00:00:00 2001
> > From: Ingo Molnar 
> > Date: Sat, 5 May 2018 10:23:23 +0200
> > Subject: [PATCH] locking/atomics: Simplify the op definitions in atomic.h 
> > some more
> > 
> > Before:
> > 
> >  #ifndef atomic_fetch_dec_relaxed
> >  # ifndef atomic_fetch_dec
> >  #  define atomic_fetch_dec(v)  atomic_fetch_sub(1, (v))
> >  #  define atomic_fetch_dec_relaxed(v)  
> > atomic_fetch_sub_relaxed(1, (v))
> >  #  define atomic_fetch_dec_acquire(v)  
> > atomic_fetch_sub_acquire(1, (v))
> >  #  define atomic_fetch_dec_release(v)  
> > atomic_fetch_sub_release(1, (v))
> >  # else
> >  #  define atomic_fetch_dec_relaxed atomic_fetch_dec
> >  #  define atomic_fetch_dec_acquire atomic_fetch_dec
> >  #  define atomic_fetch_dec_release atomic_fetch_dec
> >  # endif
> >  #else
> >  # ifndef atomic_fetch_dec_acquire
> >  #  define atomic_fetch_dec_acquire(...)
> > __atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
> >  # endif
> >  # ifndef atomic_fetch_dec_release
> >  #  define atomic_fetch_dec_release(...)
> > __atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
> >  # endif
> >  # ifndef atomic_fetch_dec
> >  #  define atomic_fetch_dec(...)
> > __atomic_op_fence(atomic_fetch_dec, __VA_ARGS__)
> >  # endif
> >  #endif
> > 
> > After:
> > 
> >  #ifndef atomic_fetch_dec_relaxed
> >  # ifndef atomic_fetch_dec
> >  #  define atomic_fetch_dec(v)  atomic_fetch_sub(1, (v))
> >  #  define atomic_fetch_dec_relaxed(v)  
> > atomic_fetch_sub_relaxed(1, (v))
> >  #  define atomic_fetch_dec_acquire(v)  
> > atomic_fetch_sub_acquire(1, (v))
> >  #  define atomic_fetch_dec_release(v)  
> > atomic_fetch_sub_release(1, (v))
> >  # else
> >  #  define atomic_fetch_dec_relaxed atomic_fetch_dec
> >  #  define atomic_fetch_dec_acquire atomic_fetch_dec
> >  #  define atomic_fetch_dec_release atomic_fetch_dec
> >  # endif
> >  #else
> >  # ifndef atomic_fetch_dec
> >  #  define atomic_fetch_dec(...)
> > __atomic_op_fence(atomic_fetch_dec, __VA_ARGS__)
> >  #  define atomic_fetch_dec_acquire(...)
> > __atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
> >  #  define atomic_fetch_dec_release(...)
> > __atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
> >  # endif
> >  #endif
> > 
> > The idea is that because we already group these APIs by certain defines
> > such as atomic_fetch_dec_relaxed and atomic_fetch_dec in the primary
> > branches - we can do the same in the secondary branch as well.
> > 
> > ( Also remove some unnecessarily duplicate comments, as the API
> >   group defines are now pretty much self-documenting. )
> > 
> > No change in functionality.
> > 
> > Cc: Peter Zijlstra 
> > Cc: Linus Torvalds 
> > Cc: Andrew Morton 
> > Cc: Thomas Gleixner 
> > Cc: Paul E. McKenney 
> > Cc: Will Deacon 
> > Cc: linux-kernel@vger.kernel.org
> > Signed-off-by: Ingo Molnar 
> 
> This breaks compilation on RISC-V. (For some of its atomics, the arch
> currently defines the _relaxed and the full variants and it relies on
> the generic definitions for the _acquire and the _release variants.)

I don't have cross-compilation for RISC-V, which is a relatively new arch.
(Is there any RISC-V set of cross-compilation tools on kernel.org somewhere?)

Could you please send a patch that defines those variants against Linus's tree, 
like the PowerPC patch that does something similar:

  0476a632cb3a: locking/atomics/powerpc: Move cmpxchg helpers to asm/cmpxchg.h 
and define the full set of cmpxchg APIs

?

... and I'll integrate it into the proper place to make it all bisectable, etc.

Thanks,

Ingo

Re: [PATCH] locking/atomics: Simplify the op definitions in atomic.h some more

[Andrea Parri]

Hi Ingo,

> From 5affbf7e91901143f84f1b2ca64f4afe70e210fd Mon Sep 17 00:00:00 2001
> From: Ingo Molnar 
> Date: Sat, 5 May 2018 10:23:23 +0200
> Subject: [PATCH] locking/atomics: Simplify the op definitions in atomic.h 
> some more
> 
> Before:
> 
>  #ifndef atomic_fetch_dec_relaxed
>  # ifndef atomic_fetch_dec
>  #  define atomic_fetch_dec(v)atomic_fetch_sub(1, (v))
>  #  define atomic_fetch_dec_relaxed(v)
> atomic_fetch_sub_relaxed(1, (v))
>  #  define atomic_fetch_dec_acquire(v)
> atomic_fetch_sub_acquire(1, (v))
>  #  define atomic_fetch_dec_release(v)
> atomic_fetch_sub_release(1, (v))
>  # else
>  #  define atomic_fetch_dec_relaxed   atomic_fetch_dec
>  #  define atomic_fetch_dec_acquire   atomic_fetch_dec
>  #  define atomic_fetch_dec_release   atomic_fetch_dec
>  # endif
>  #else
>  # ifndef atomic_fetch_dec_acquire
>  #  define atomic_fetch_dec_acquire(...)  
> __atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
>  # endif
>  # ifndef atomic_fetch_dec_release
>  #  define atomic_fetch_dec_release(...)  
> __atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
>  # endif
>  # ifndef atomic_fetch_dec
>  #  define atomic_fetch_dec(...)  
> __atomic_op_fence(atomic_fetch_dec, __VA_ARGS__)
>  # endif
>  #endif
> 
> After:
> 
>  #ifndef atomic_fetch_dec_relaxed
>  # ifndef atomic_fetch_dec
>  #  define atomic_fetch_dec(v)atomic_fetch_sub(1, (v))
>  #  define atomic_fetch_dec_relaxed(v)
> atomic_fetch_sub_relaxed(1, (v))
>  #  define atomic_fetch_dec_acquire(v)
> atomic_fetch_sub_acquire(1, (v))
>  #  define atomic_fetch_dec_release(v)
> atomic_fetch_sub_release(1, (v))
>  # else
>  #  define atomic_fetch_dec_relaxed   atomic_fetch_dec
>  #  define atomic_fetch_dec_acquire   atomic_fetch_dec
>  #  define atomic_fetch_dec_release   atomic_fetch_dec
>  # endif
>  #else
>  # ifndef atomic_fetch_dec
>  #  define atomic_fetch_dec(...)  
> __atomic_op_fence(atomic_fetch_dec, __VA_ARGS__)
>  #  define atomic_fetch_dec_acquire(...)  
> __atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
>  #  define atomic_fetch_dec_release(...)  
> __atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
>  # endif
>  #endif
> 
> The idea is that because we already group these APIs by certain defines
> such as atomic_fetch_dec_relaxed and atomic_fetch_dec in the primary
> branches - we can do the same in the secondary branch as well.
> 
> ( Also remove some unnecessarily duplicate comments, as the API
>   group defines are now pretty much self-documenting. )
> 
> No change in functionality.
> 
> Cc: Peter Zijlstra 
> Cc: Linus Torvalds 
> Cc: Andrew Morton 
> Cc: Thomas Gleixner 
> Cc: Paul E. McKenney 
> Cc: Will Deacon 
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Ingo Molnar 

This breaks compilation on RISC-V. (For some of its atomics, the arch
currently defines the _relaxed and the full variants and it relies on
the generic definitions for the _acquire and the _release variants.)

  Andrea


> ---
>  include/linux/atomic.h | 312 
> ++---
>  1 file changed, 62 insertions(+), 250 deletions(-)
> 
> diff --git a/include/linux/atomic.h b/include/linux/atomic.h
> index 67aaafba256b..352ecc72d7f5 100644
> --- a/include/linux/atomic.h
> +++ b/include/linux/atomic.h
> @@ -71,98 +71,66 @@
>  })
>  #endif
>  
> -/* atomic_add_return_relaxed() et al: */
> -
>  #ifndef atomic_add_return_relaxed
>  # define atomic_add_return_relaxed   atomic_add_return
>  # define atomic_add_return_acquire   atomic_add_return
>  # define atomic_add_return_release   atomic_add_return
>  #else
> -# ifndef atomic_add_return_acquire
> -#  define atomic_add_return_acquire(...) 
> __atomic_op_acquire(atomic_add_return, __VA_ARGS__)
> -# endif
> -# ifndef atomic_add_return_release
> -#  define atomic_add_return_release(...) 
> __atomic_op_release(atomic_add_return, __VA_ARGS__)
> -# endif
>  # ifndef atomic_add_return
>  #  define atomic_add_return(...) 
> __atomic_op_fence(atomic_add_return, __VA_ARGS__)
> +#  define atomic_add_return_acquire(...) 
> __atomic_op_acquire(atomic_add_return, __VA_ARGS__)
> +#  define atomic_add_return_release(...) 
> __atomic_op_release(atomic_add_return, __VA_ARGS__)
>  # endif
>  #endif
>  
> -/* atomic_inc_return_relaxed() et al: */
> -
>  #ifndef atomic_inc_return_relaxed
>  # define atomic_inc_return_relaxed   atomic_inc_return
>  # define atomic_inc_return_acquire   atomic_inc_return
>  # define atomic_inc_return_release   atomic_inc_return
>  #else
> -# ifndef atomic_inc_return_acquire
> -#  define 

Re: [PATCH] locking/atomics: Simplify the op definitions in atomic.h some more

[Andrea Parri]

Hi Ingo,

> From 5affbf7e91901143f84f1b2ca64f4afe70e210fd Mon Sep 17 00:00:00 2001
> From: Ingo Molnar 
> Date: Sat, 5 May 2018 10:23:23 +0200
> Subject: [PATCH] locking/atomics: Simplify the op definitions in atomic.h 
> some more
> 
> Before:
> 
>  #ifndef atomic_fetch_dec_relaxed
>  # ifndef atomic_fetch_dec
>  #  define atomic_fetch_dec(v)atomic_fetch_sub(1, (v))
>  #  define atomic_fetch_dec_relaxed(v)
> atomic_fetch_sub_relaxed(1, (v))
>  #  define atomic_fetch_dec_acquire(v)
> atomic_fetch_sub_acquire(1, (v))
>  #  define atomic_fetch_dec_release(v)
> atomic_fetch_sub_release(1, (v))
>  # else
>  #  define atomic_fetch_dec_relaxed   atomic_fetch_dec
>  #  define atomic_fetch_dec_acquire   atomic_fetch_dec
>  #  define atomic_fetch_dec_release   atomic_fetch_dec
>  # endif
>  #else
>  # ifndef atomic_fetch_dec_acquire
>  #  define atomic_fetch_dec_acquire(...)  
> __atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
>  # endif
>  # ifndef atomic_fetch_dec_release
>  #  define atomic_fetch_dec_release(...)  
> __atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
>  # endif
>  # ifndef atomic_fetch_dec
>  #  define atomic_fetch_dec(...)  
> __atomic_op_fence(atomic_fetch_dec, __VA_ARGS__)
>  # endif
>  #endif
> 
> After:
> 
>  #ifndef atomic_fetch_dec_relaxed
>  # ifndef atomic_fetch_dec
>  #  define atomic_fetch_dec(v)atomic_fetch_sub(1, (v))
>  #  define atomic_fetch_dec_relaxed(v)
> atomic_fetch_sub_relaxed(1, (v))
>  #  define atomic_fetch_dec_acquire(v)
> atomic_fetch_sub_acquire(1, (v))
>  #  define atomic_fetch_dec_release(v)
> atomic_fetch_sub_release(1, (v))
>  # else
>  #  define atomic_fetch_dec_relaxed   atomic_fetch_dec
>  #  define atomic_fetch_dec_acquire   atomic_fetch_dec
>  #  define atomic_fetch_dec_release   atomic_fetch_dec
>  # endif
>  #else
>  # ifndef atomic_fetch_dec
>  #  define atomic_fetch_dec(...)  
> __atomic_op_fence(atomic_fetch_dec, __VA_ARGS__)
>  #  define atomic_fetch_dec_acquire(...)  
> __atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
>  #  define atomic_fetch_dec_release(...)  
> __atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
>  # endif
>  #endif
> 
> The idea is that because we already group these APIs by certain defines
> such as atomic_fetch_dec_relaxed and atomic_fetch_dec in the primary
> branches - we can do the same in the secondary branch as well.
> 
> ( Also remove some unnecessarily duplicate comments, as the API
>   group defines are now pretty much self-documenting. )
> 
> No change in functionality.
> 
> Cc: Peter Zijlstra 
> Cc: Linus Torvalds 
> Cc: Andrew Morton 
> Cc: Thomas Gleixner 
> Cc: Paul E. McKenney 
> Cc: Will Deacon 
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Ingo Molnar 

This breaks compilation on RISC-V. (For some of its atomics, the arch
currently defines the _relaxed and the full variants and it relies on
the generic definitions for the _acquire and the _release variants.)

  Andrea


> ---
>  include/linux/atomic.h | 312 
> ++---
>  1 file changed, 62 insertions(+), 250 deletions(-)
> 
> diff --git a/include/linux/atomic.h b/include/linux/atomic.h
> index 67aaafba256b..352ecc72d7f5 100644
> --- a/include/linux/atomic.h
> +++ b/include/linux/atomic.h
> @@ -71,98 +71,66 @@
>  })
>  #endif
>  
> -/* atomic_add_return_relaxed() et al: */
> -
>  #ifndef atomic_add_return_relaxed
>  # define atomic_add_return_relaxed   atomic_add_return
>  # define atomic_add_return_acquire   atomic_add_return
>  # define atomic_add_return_release   atomic_add_return
>  #else
> -# ifndef atomic_add_return_acquire
> -#  define atomic_add_return_acquire(...) 
> __atomic_op_acquire(atomic_add_return, __VA_ARGS__)
> -# endif
> -# ifndef atomic_add_return_release
> -#  define atomic_add_return_release(...) 
> __atomic_op_release(atomic_add_return, __VA_ARGS__)
> -# endif
>  # ifndef atomic_add_return
>  #  define atomic_add_return(...) 
> __atomic_op_fence(atomic_add_return, __VA_ARGS__)
> +#  define atomic_add_return_acquire(...) 
> __atomic_op_acquire(atomic_add_return, __VA_ARGS__)
> +#  define atomic_add_return_release(...) 
> __atomic_op_release(atomic_add_return, __VA_ARGS__)
>  # endif
>  #endif
>  
> -/* atomic_inc_return_relaxed() et al: */
> -
>  #ifndef atomic_inc_return_relaxed
>  # define atomic_inc_return_relaxed   atomic_inc_return
>  # define atomic_inc_return_acquire   atomic_inc_return
>  # define atomic_inc_return_release   atomic_inc_return
>  #else
> -# ifndef atomic_inc_return_acquire
> -#  define atomic_inc_return_acquire(...) 
> __atomic_op_acquire(atomic_inc_return, __VA_ARGS__)
> -# endif
> -# ifndef atomic_inc_return_release
> -#  define atomic_inc_return_release(...)