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Date: Mon, 9 Oct 2017 08:52:43 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Yury Norov <ynorov@caviumnetworks.com>
Cc: Will Deacon <will.deacon@arm.com>, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, Jeremy.Linton@arm.com,
        mingo@redhat.com, longman@redhat.com, boqun.feng@gmail.com,
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Subject: Re: [PATCH v2 0/5] Switch arm64 over to qrwlock
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 <20171008213052.ojyxpr56d2ypscjy@yury-thinkpad>
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On Mon, Oct 09, 2017 at 12:30:52AM +0300, Yury Norov wrote:
> The bottomline of discussion [1] was that queued locks are more
> effective when SoC has many CPUs. And 4 is not many.

qspinlock, yes. qrwlock not, as it fully depends on arch_spinlock_t for
the queueing. qrwlock is just a generic rwlock_t implementation.