| Date | Wed, 17 Apr 2019 11:00:06 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v4 08/16] locking/rwsem: Make rwsem_spin_on_owner() return owner state |
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On Sat, Apr 13, 2019 at 01:22:51PM -0400, Waiman Long wrote: > This patch modifies rwsem_spin_on_owner() to return four possible > values to better reflect the state of lock holder which enables us to > make a better decision of what to do next. > > In the special case that there is no active lock and the handoff bit > is set, optimistic spinning has to be stopped. > > Signed-off-by: Waiman Long <longman@redhat.com> > --- > kernel/locking/rwsem.c | 45 +++++++++++++++++++++++++++++++++++------- > 1 file changed, 38 insertions(+), 7 deletions(-) > > diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c > index aaab546a890d..2d6850c3e77b 100644 > --- a/kernel/locking/rwsem.c > +++ b/kernel/locking/rwsem.c > @@ -156,6 +156,11 @@ static inline bool is_rwsem_owner_spinnable(struct task_struct *owner) > return !((unsigned long)owner & RWSEM_ANONYMOUSLY_OWNED); > } > > +static inline bool is_rwsem_owner_reader(struct task_struct *owner) > +{ > + return (unsigned long)owner & RWSEM_READER_OWNED; > +}
Move this and the surrounding helpers into the RWSEM_SPIN_ON_OWNER block, it is only used there and that way all the code is together.
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