From: Waiman Long <longman@redhat.com>
To: Nicholas Piggin <npiggin@gmail.com>,
Peter Zijlstra <peterz@infradead.org>
Cc: linux-arch@vger.kernel.org, Will Deacon <will@kernel.org>,
Boqun Feng <boqun.feng@gmail.com>,
linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org,
virtualization@lists.linux-foundation.org,
Ingo Molnar <mingo@redhat.com>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v3 0/6] powerpc: queued spinlocks and rwlocks
Date: Thu, 23 Jul 2020 10:29:05 -0400 [thread overview]
Message-ID: <af825bce-ecf3-66e4-ad63-a844dbd2e775@redhat.com> (raw)
In-Reply-To: <1595510571.u39qfc8d1o.astroid@bobo.none>
On 7/23/20 9:30 AM, Nicholas Piggin wrote:
>> I would prefer to extract out the pending bit handling code out into a
>> separate helper function which can be overridden by the arch code
>> instead of breaking the slowpath into 2 pieces.
> You mean have the arch provide a queued_spin_lock_slowpath_pending
> function that the slow path calls?
>
> I would actually prefer the pending handling can be made inline in
> the queued_spin_lock function, especially with out-of-line locks it
> makes sense to put it there.
>
> We could ifdef out queued_spin_lock_slowpath_queue if it's not used,
> then __queued_spin_lock_slowpath_queue would be inlined into the
> caller so there would be no split?
The pending code is an optimization for lightly contended locks. That is
why I think it is appropriate to extract it into a helper function and
mark it as such.
You can certainly put the code in the arch's spin_lock code, you just
has to override the generic pending code by a null function.
Cheers,
Longman
next prev parent reply other threads:[~2020-07-23 14:32 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-06 4:35 [PATCH v3 0/6] powerpc: queued spinlocks and rwlocks Nicholas Piggin
2020-07-06 4:35 ` [PATCH v3 1/6] powerpc/powernv: must include hvcall.h to get PAPR defines Nicholas Piggin
2020-07-09 10:05 ` Michael Ellerman
2020-07-06 4:35 ` [PATCH v3 2/6] powerpc/pseries: move some PAPR paravirt functions to their own file Nicholas Piggin
2020-07-09 10:11 ` Michael Ellerman
2020-07-06 4:35 ` [PATCH v3 3/6] powerpc: move spinlock implementation to simple_spinlock Nicholas Piggin
2020-07-09 10:15 ` Michael Ellerman
2020-07-06 4:35 ` [PATCH v3 4/6] powerpc/64s: implement queued spinlocks and rwlocks Nicholas Piggin
2020-07-09 10:20 ` Michael Ellerman
2020-07-09 10:33 ` Peter Zijlstra
2020-07-23 14:37 ` Michal Suchánek
2020-07-06 4:35 ` [PATCH v3 5/6] powerpc/pseries: implement paravirt qspinlocks for SPLPAR Nicholas Piggin
2020-07-09 10:53 ` Michael Ellerman
2020-07-09 11:03 ` Peter Zijlstra
2020-07-09 16:06 ` Waiman Long
2020-07-23 14:00 ` Peter Zijlstra
2020-07-23 18:32 ` Waiman Long
2020-07-23 18:47 ` peterz
2020-07-23 19:04 ` Waiman Long
2020-07-23 19:58 ` peterz
2020-07-23 20:30 ` Segher Boessenkool
2020-07-23 21:58 ` Waiman Long
2020-07-24 8:16 ` Will Deacon
2020-07-24 19:10 ` Waiman Long
2020-07-25 3:02 ` Waiman Long
2020-07-25 17:26 ` Peter Zijlstra
2020-07-25 17:36 ` Waiman Long
2020-07-23 14:09 ` Nicholas Piggin
2020-07-06 4:35 ` [PATCH v3 6/6] powerpc/qspinlock: optimised atomic_try_cmpxchg_lock that adds the lock hint Nicholas Piggin
2020-07-06 18:39 ` [PATCH v3 0/6] powerpc: queued spinlocks and rwlocks Waiman Long
2020-07-07 5:57 ` Nicholas Piggin
2020-07-08 3:33 ` Waiman Long
2020-07-08 5:10 ` Nicholas Piggin
2020-07-08 23:50 ` Waiman Long
2020-07-08 23:58 ` Waiman Long
2020-07-08 8:32 ` Peter Zijlstra
2020-07-08 23:53 ` Waiman Long
2020-07-08 8:41 ` Peter Zijlstra
2020-07-08 23:54 ` Waiman Long
2020-07-09 8:31 ` Peter Zijlstra
2020-07-21 11:20 ` Nicholas Piggin
2020-07-21 11:08 ` Nicholas Piggin
2020-07-21 14:36 ` Waiman Long
2020-07-23 13:30 ` Nicholas Piggin
2020-07-23 14:29 ` Waiman Long [this message]
2020-07-23 16:12 ` Nicholas Piggin
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