From: Alexander Sverdlin <alexander.sverdlin@nokia.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Burton <paul.burton@imgtec.com>,
linux-mips@vger.kernel.org,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Will Deacon <will@kernel.org>, Boqun Feng <boqun.feng@gmail.com>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/6] MIPS: Octeon: qspinlock: Flush write buffer
Date: Thu, 28 Jan 2021 13:13:03 +0100 [thread overview]
Message-ID: <f8344f35-cdf1-ec3d-dcd0-7bfc392ef6e0@nokia.com> (raw)
In-Reply-To: <YBKha2GRFWyYp+Lz@hirez.programming.kicks-ass.net>
Hi!
On 28/01/2021 12:35, Peter Zijlstra wrote:
>> My point was that original MIPS spinlocks had this write-buffer-flush and
>> it got lost on the conversion to qspinlocks. The referenced commit just
>> allows to see the last MIPS-specific implementation before deletion.
> Hardware that needs a store-buffer flush after release is highly suspect
> and needs big and explicit comments. Not vague hints.
I have a feeling that you are not going to suggest the comments for the code
and one has to guess what is it you have in mind?
Do you think the proper approach would be to undelete MIPS spinlocks and
make these broken qspinlocks a configurable option for MIPS? I don't even
mind if they will be default option for those not interested in performance
or latency.
--
Best regards,
Alexander Sverdlin.
next prev parent reply other threads:[~2021-01-28 12:14 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-27 20:36 [PATCH 0/6] MIPS: qspinlock: Try to reduce reduce the spinlock regression Alexander A Sverdlin
2021-01-27 20:36 ` [PATCH 1/6] MIPS: Octeon: Implement __smp_store_release() Alexander A Sverdlin
2021-01-27 22:32 ` Peter Zijlstra
2021-01-28 7:27 ` Alexander Sverdlin
2021-01-28 11:33 ` Peter Zijlstra
2021-01-28 11:52 ` Alexander Sverdlin
2021-01-28 14:57 ` Peter Zijlstra
2021-01-28 15:15 ` Peter Zijlstra
2021-01-28 12:09 ` Alexander Sverdlin
2021-01-28 15:04 ` Peter Zijlstra
2021-01-27 20:36 ` [PATCH 2/6] MIPS: Implement atomic_cmpxchg_relaxed() Alexander A Sverdlin
2021-01-27 20:36 ` [PATCH 3/6] MIPS: Octeon: qspinlock: Flush write buffer Alexander A Sverdlin
2021-01-27 22:34 ` Peter Zijlstra
2021-01-28 7:29 ` Alexander Sverdlin
2021-01-28 11:35 ` Peter Zijlstra
2021-01-28 12:13 ` Alexander Sverdlin [this message]
2021-01-28 15:26 ` Peter Zijlstra
2021-01-27 20:36 ` [PATCH 4/6] MIPS: Octeon: qspinlock: Exclude mmiowb() Alexander A Sverdlin
2021-01-27 22:35 ` Peter Zijlstra
2021-01-27 20:36 ` [PATCH 5/6] MIPS: Provide {atomic_}xchg_relaxed() Alexander A Sverdlin
2021-01-27 20:36 ` [PATCH 6/6] MIPS: cmpxchg: Use cmpxchg_local() for {cmp_}xchg_small() Alexander A Sverdlin
2021-01-27 22:37 ` Peter Zijlstra
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