On Sun, Jul 30, 2023 at 10:33:08PM -0400, guoren@xxxxxxxxxx wrote: > From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx> > > The arch_spin_value_unlocked would cause an unnecessary memory > access to the contended value. Although it won't cause a significant > performance gap in most architectures, the arch_spin_value_unlocked > argument contains enough information. Thus, remove unnecessary > atomic_read in arch_spin_value_unlocked(). > > The caller of arch_spin_value_unlocked() could benefit from this > change. Currently, the only caller is lockref. > > Signed-off-by: Guo Ren <guoren@xxxxxxxxxx> > Cc: Waiman Long <longman@xxxxxxxxxx> > Cc: David Laight <David.Laight@xxxxxxxxxx> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx> > --- > Changelog > V2: > - Fixup commit log with Waiman advice. > - Add Waiman comment in the commit msg. > --- > include/asm-generic/spinlock.h | 16 +++++++++------- > 1 file changed, 9 insertions(+), 7 deletions(-) Acked-by: Will Deacon <will@xxxxxxxxxx> It would be nice to see some numbers showing this actually helps, though. Will
