From: Peter Zijlstra <peterz@infradead.org>
To: Peter Oskolkov <posk@posk.io>
Cc: mingo@redhat.com, tglx@linutronix.de, juri.lelli@redhat.com,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
bristot@redhat.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, linux-api@vger.kernel.org, x86@kernel.org,
pjt@google.com, posk@google.com, avagin@google.com,
jannh@google.com, tdelisle@uwaterloo.ca
Subject: Re: [RFC][PATCH 3/3] sched: User Mode Concurency Groups
Date: Mon, 17 Jan 2022 14:04:54 +0100 [thread overview]
Message-ID: <YeVpdj/OP+qfAztn@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20211221171900.GA580323@dev-hv>
On Tue, Dec 21, 2021 at 05:19:00PM +0000, Peter Oskolkov wrote:
> On Tue, Dec 14, 2021 at 09:44:48PM +0100, Peter Zijlstra wrote:
> > +static struct task_struct *umcg_get_task(u32 tid)
> > +{
> > + struct task_struct *tsk = NULL;
> > +
> > + if (tid) {
> > + rcu_read_lock();
> > + tsk = find_task_by_vpid(tid);
> > + if (tsk && current->mm == tsk->mm && tsk->umcg_task)
>
> This essentially limits all operations to a single mm/process.
> Fine for now, but a fast remote context switch is also a valid use
> case. It is not directly related to userspace scheduling, so I'm
> just mentioning it here. Maybe server-to-server cross-process
> context switches should be allowed for the same user/cgroup? (Again,
> this is for later to consider).
Doing cross-address-space UMCG will be a massive effort, too much
(pretty much everything) in this implementation assumes things are
directly addressable.
> > + get_task_struct(tsk);
> > + else
> > + tsk = NULL;
> > + rcu_read_unlock();
> > + }
> > +
> > + return tsk;
> > +}
next prev parent reply other threads:[~2022-01-17 13:05 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-14 20:44 [RFC][PATCH 0/3] sched: User Managed Concurrency Groups Peter Zijlstra
2021-12-14 20:44 ` [RFC][PATCH 1/3] sched/umcg: add WF_CURRENT_CPU and externise ttwu Peter Zijlstra
2021-12-14 20:44 ` [RFC][PATCH 2/3] x86/uaccess: Implement unsafe_try_cmpxchg_user() Peter Zijlstra
2021-12-20 17:30 ` Sean Christopherson
2021-12-21 11:17 ` Peter Zijlstra
2021-12-14 20:44 ` [RFC][PATCH 3/3] sched: User Mode Concurency Groups Peter Zijlstra
2021-12-21 17:19 ` Peter Oskolkov
2022-01-14 14:09 ` Peter Zijlstra
2022-01-14 15:16 ` Peter Zijlstra
2022-01-14 17:15 ` Peter Zijlstra
2022-01-17 11:35 ` Peter Zijlstra
2022-01-17 12:22 ` Peter Zijlstra
2022-01-17 12:12 ` Peter Zijlstra
2022-01-18 10:09 ` Peter Zijlstra
2022-01-18 18:19 ` Peter Oskolkov
2022-01-19 8:47 ` Peter Zijlstra
2022-01-19 17:33 ` Peter Oskolkov
2022-01-19 8:51 ` Peter Zijlstra
2022-01-19 8:59 ` Peter Zijlstra
2022-01-19 17:52 ` Peter Oskolkov
2022-01-20 10:37 ` Peter Zijlstra
2022-01-17 13:04 ` Peter Zijlstra [this message]
2021-12-24 11:27 ` Peter Zijlstra
2021-12-14 21:00 ` [RFC][PATCH 0/3] sched: User Managed Concurrency Groups Peter Zijlstra
2021-12-15 3:46 ` Peter Oskolkov
2021-12-15 10:06 ` Peter Zijlstra
2021-12-15 13:03 ` Peter Zijlstra
2021-12-15 17:56 ` Peter Oskolkov
2021-12-15 18:18 ` Peter Zijlstra
2021-12-15 19:49 ` Peter Oskolkov
2021-12-15 22:25 ` Peter Zijlstra
2021-12-15 23:26 ` Peter Oskolkov
2021-12-16 13:23 ` Thomas Gleixner
2021-12-15 18:25 ` Peter Zijlstra
2021-12-15 21:04 ` Peter Oskolkov
2021-12-15 23:16 ` Peter Zijlstra
2021-12-15 23:31 ` Peter Oskolkov
2021-12-15 10:44 ` Peter Zijlstra
2021-12-15 13:49 ` Matthew Wilcox
2021-12-15 17:54 ` Peter Zijlstra
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