Date:   Thu, 11 Nov 2021 22:38:14 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Waiman Long <longman@redhat.com>
Cc:     Hillf Danton <hdanton@sina.com>,
        =?utf-8?B?6ams5oyv5Y2O?= <mazhenhua@xiaomi.com>,
        mingo <mingo@redhat.com>, will <will@kernel.org>,
        "boqun.feng" <boqun.feng@gmail.com>,
        linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [BUG]locking/rwsem: only clean RWSEM_FLAG_HANDOFF when already
 set
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On Thu, Nov 11, 2021 at 04:01:16PM -0500, Waiman Long wrote:

> > > +			if (has_handoff || (!waiter->rt_task &&
> > > +					    !time_after(jiffies, waiter->timeout)))
> > 
> > Does ->rt_task really help over rt_task(current) ? I suppose there's an
> > argument for locality, but that should be pretty much it, no?
> Waiting for the timeout may introduce too much latency for RT task. That is
> the only reason I am doing it. I can take it out if you think it is not
> necessary.

I meant simply calling rt_task(waiter->task) here, instead of mucking about
with the extra variable.