On Mon, Feb 11, 2019 at 11:35:24AM -0500, Waiman Long wrote:
> On 02/11/2019 06:58 AM, Peter Zijlstra wrote:
> > Which is clearly worse. Now we can write that as:
> >
> > int __down_read_trylock2(unsigned long *l)
> > {
> > long tmp = READ_ONCE(*l);
> >
> > while (tmp >= 0) {
> >
On 02/11/2019 06:58 AM, Peter Zijlstra wrote:
> Which is clearly worse. Now we can write that as:
>
> int __down_read_trylock2(unsigned long *l)
> {
> long tmp = READ_ONCE(*l);
>
> while (tmp >= 0) {
> if (try_cmpxchg(l, &tmp, tmp + 1))
>
On 02/11/2019 05:39 AM, Ingo Molnar wrote:
> * Ingo Molnar wrote:
>
>> Sounds good to me - I've merged this patch, will push it out after
>> testing.
> Based on Peter's feedback I'm delaying this - performance testing on at
> least one key ll/sc arch would be nice indeed.
>
> Thanks,
>
> I
On Sun, Feb 10, 2019 at 09:00:50PM -0500, Waiman Long wrote:
> +static inline int __down_read_trylock(struct rw_semaphore *sem)
> +{
> + long tmp;
> +
> + while ((tmp = atomic_long_read(&sem->count)) >= 0) {
> + if (tmp == atomic_long_cmpxchg_acquire(&sem->count, tmp,
> +
On Mon, Feb 11, 2019 at 10:40:44AM +0100, Peter Zijlstra wrote:
> On Mon, Feb 11, 2019 at 10:36:01AM +0100, Peter Zijlstra wrote:
> > On Sun, Feb 10, 2019 at 09:00:50PM -0500, Waiman Long wrote:
> > > +static inline int __down_read_trylock(struct rw_semaphore *sem)
> > > +{
> > > + long tmp;
> > >
* Will Deacon wrote:
> On Mon, Feb 11, 2019 at 11:39:27AM +0100, Ingo Molnar wrote:
> >
> > * Ingo Molnar wrote:
> >
> > > Sounds good to me - I've merged this patch, will push it out after
> > > testing.
> >
> > Based on Peter's feedback I'm delaying this - performance testing on at
> >
On Mon, Feb 11, 2019 at 11:39:27AM +0100, Ingo Molnar wrote:
>
> * Ingo Molnar wrote:
>
> > Sounds good to me - I've merged this patch, will push it out after
> > testing.
>
> Based on Peter's feedback I'm delaying this - performance testing on at
> least one key ll/sc arch would be nice inde
* Ingo Molnar wrote:
> Sounds good to me - I've merged this patch, will push it out after
> testing.
Based on Peter's feedback I'm delaying this - performance testing on at
least one key ll/sc arch would be nice indeed.
Thanks,
Ingo
On Mon, Feb 11, 2019 at 10:36:01AM +0100, Peter Zijlstra wrote:
> On Sun, Feb 10, 2019 at 09:00:50PM -0500, Waiman Long wrote:
> > +static inline int __down_read_trylock(struct rw_semaphore *sem)
> > +{
> > + long tmp;
> > +
> > + while ((tmp = atomic_long_read(&sem->count)) >= 0) {
> > +
On Sun, Feb 10, 2019 at 09:00:50PM -0500, Waiman Long wrote:
> diff --git a/kernel/locking/rwsem.h b/kernel/locking/rwsem.h
> index bad2bca..067e265 100644
> --- a/kernel/locking/rwsem.h
> +++ b/kernel/locking/rwsem.h
> @@ -32,6 +32,26 @@
> # define DEBUG_RWSEMS_WARN_ON(c)
> #endif
>
> +/*
> +
* Waiman Long wrote:
> On 02/10/2019 09:00 PM, Waiman Long wrote:
> > As the generic rwsem-xadd code is using the appropriate acquire and
> > release versions of the atomic operations, the arch specific rwsem.h
> > files will not be that much faster than the generic code as long as the
> > atom
On 02/10/2019 09:00 PM, Waiman Long wrote:
> As the generic rwsem-xadd code is using the appropriate acquire and
> release versions of the atomic operations, the arch specific rwsem.h
> files will not be that much faster than the generic code as long as the
> atomic functions are properly implement
As the generic rwsem-xadd code is using the appropriate acquire and
release versions of the atomic operations, the arch specific rwsem.h
files will not be that much faster than the generic code as long as the
atomic functions are properly implemented. So we can remove those arch
specific rwsem.h an
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