Messages in this thread | | | From | John Ogness <> | Subject | Re: [PATCH RFC v2 rcu 1/8] srcu: Convert ->srcu_lock_count and ->srcu_unlock_count to atomic | Date | Fri, 30 Sep 2022 22:43:43 +0206 |
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On 2022-09-30, "Paul E. McKenney" <paulmck@kernel.org> wrote: >> > - this_cpu_inc(ssp->sda->srcu_lock_count[idx]); >> > + this_cpu_inc(ssp->sda->srcu_lock_count[idx].counter); >> >> Is there any particular reason that you are directly modifying >> @counter instead of raw_cpu_ptr()+atomic_long_inc() that do you in >> __srcu_read_lock_nmisafe() of patch 2? > > Performance. From what I can see, this_cpu_inc() is way faster than > atomic_long_inc() on x86 and s390. Maybe also on loongarch. No idea > on arm64.
Yeah, that's what I figured. I just wanted to make sure.
FWIW, the rest of the series looks pretty straight forward to me.
John
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