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Date:   Mon, 7 Dec 2020 19:53:14 -0800
From:   Davidlohr Bueso <dave@stgolabs.net>
To:     Waiman Long <longman@redhat.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
        linux-kernel@vger.kernel.org, Phil Auld <pauld@redhat.com>
Subject: Re: [PATCH 3/5] locking/rwsem: Enable reader optimistic lock stealing
Message-ID: <20201208035314.rwz72kgn5apr2whm@linux-p48b>
References: <20201118030429.23017-1-longman@redhat.com>
 <20201118030429.23017-4-longman@redhat.com>
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On Tue, 17 Nov 2020, Waiman Long wrote:

>If the optimistic spinning queue is empty and the rwsem does not have
>the handoff or write-lock bits set, it is actually not necessary to
>call rwsem_optimistic_spin() to spin on it. Instead, it can steal the
>lock directly as its reader bias is in the count already.  If it is
>the first reader in this state, it will try to wake up other readers
>in the wait queue.
>
>Signed-off-by: Waiman Long <longman@redhat.com>

Reviewed-by: Davidlohr Bueso <dbueso@suse.de>