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Date:   Thu, 27 Jan 2022 13:26:26 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Tao Zhou <tao.zhou@linux.dev>
Cc:     mingo@redhat.com, tglx@linutronix.de, juri.lelli@redhat.com,
        vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
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        linux-mm@kvack.org, linux-api@vger.kernel.org, x86@kernel.org,
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        jannh@google.com, tdelisle@uwaterloo.ca, mark.rutland@arm.com,
        posk@posk.io
Subject: Re: [RFC][PATCH v2 5/5] sched: User Mode Concurency Groups
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References: <20220120155517.066795336@infradead.org>
 <20220120160822.914418096@infradead.org>
 <Ye67uQa4CwUuQJVY@geo.homenetwork>
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On Mon, Jan 24, 2022 at 10:46:17PM +0800, Tao Zhou wrote:
> > +/**
> > + * sys_umcg_wait: transfer running context
> > + *
> > + * Called like:
> > + *
> > + *	self->state = UMCG_TASK_RUNNABLE | UMCG_TF_COND_WAIT;
> > + *	...
> > + *	sys_umcg_wait(0, time);
> > + *
> > + * The syscall will clear TF_COND_WAIT and wait until state becomes RUNNING.
> > + * The code '...' must not contain syscalls
> > + *
> > + * If self->next_tid is set and indicates a valid UMCG task with RUNNABLE state
> > + * that task will be made RUNNING and woken -- transfering the running context
> > + * to that task. In this case self->next_tid is modified with TID_RUNNING to
> > + * indicate self->next_tid is consumed.
> > + *
> > + * If self->next has TID_RUNNING set, it is validated the related task has
> 
> /self->next/self->next_tid/

Yeah, there's more of that, I'll be sure to go re-read all the comments.