From: Peter Zijlstra <peterz@infradead.org>
To: Waiman Long <longman@redhat.com>
Cc: Nicholas Piggin <npiggin@gmail.com>,
Arnd Bergmann <arnd@arndb.de>, Borislav Petkov <bp@alien8.de>,
Davidlohr Bueso <dave@stgolabs.net>,
linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will.deacon@arm.com>,
x86@kernel.org
Subject: Re: [PATCH 2/2] locking/pvqspinlock: Optionally store lock holder cpu into lock
Date: Tue, 14 Jul 2020 11:01:26 +0200 [thread overview]
Message-ID: <20200714090126.GR10769@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <e850b327-d747-fbe8-95db-4e2fbb1d7871@redhat.com>
On Mon, Jul 13, 2020 at 10:48:00PM -0400, Waiman Long wrote:
> Storing the cpu number into the lock can be useful for other reason too. It
> is not totally related to PPC support.
Well, the thing you did only works for 'small' (<253 CPU) systems.
There's a number of Power systems that's distinctly larger than that. So
it simply cannot work as anything other than a suggestion/hint. It must
not be a correctness thing.
next prev parent reply other threads:[~2020-07-14 9:01 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-11 18:21 [PATCH 0/2] locking/qspinlock: Allow lock to store lock holder cpu number Waiman Long
2020-07-11 18:21 ` [PATCH 1/2] locking/qspinlock: Store lock holder cpu in lock if feasible Waiman Long
2020-07-12 17:33 ` Peter Zijlstra
2020-07-11 18:21 ` [PATCH 2/2] locking/pvqspinlock: Optionally store lock holder cpu into lock Waiman Long
2020-07-12 17:34 ` Peter Zijlstra
2020-07-12 23:05 ` Waiman Long
2020-07-13 4:17 ` Nicholas Piggin
2020-07-14 2:48 ` Waiman Long
2020-07-14 9:01 ` Peter Zijlstra [this message]
2020-07-15 16:33 ` Waiman Long
2020-07-13 9:21 ` Peter Zijlstra
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