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Date:   Wed, 10 Apr 2019 10:22:54 -0700
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.deacon@arm.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        linux-kernel@vger.kernel.org, x86@kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Tim Chen <tim.c.chen@linux.intel.com>
Subject: Re: [PATCH-tip v2 06/12] locking/rwsem: Wake up almost all readers
 in wait queue
Message-ID: <20190410172254.ivgcgehjhqgwjtda@linux-r8p5>
References: <20190405192115.17416-1-longman@redhat.com>
 <20190405192115.17416-7-longman@redhat.com>
 <20190410165013.njy5bg32pxq6syyr@linux-r8p5>
 <114e3bc3-3b66-4a50-d422-6a477d85fa72@redhat.com>
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On Wed, 10 Apr 2019, Waiman Long wrote:
>There are 2 major reasons why there is a limit.
>
>1) It will be unfair to the task that needs to spend so much of its own
>CPU time to wake up too many readers.

This has never been a problem before.

>2) I want to avoid the extreme case that there are more than 32k readers
>in the wait queue and make the count overflow.

But in this case the readers are already on the queue.

Thanks,
Davidlohr