From: Peter Oskolkov <posk@google.com>
To: Jann Horn <jannh@google.com>
Cc: Peter Oskolkov <posk@posk.io>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
Paul Turner <pjt@google.com>, Ben Segall <bsegall@google.com>,
Andrei Vagin <avagin@google.com>,
Thierry Delisle <tdelisle@uwaterloo.ca>
Subject: Re: [PATCH 3/4 v0.5] sched/umcg: RFC: implement UMCG syscalls
Date: Tue, 14 Sep 2021 09:51:28 -0700 [thread overview]
Message-ID: <CAPNVh5f6iaiYP8E2jKioirjJdwJDoJT-KHQLKjtgbr68H8-HxQ@mail.gmail.com> (raw)
In-Reply-To: <CAG48ez3Kd0sfKBi9CUSYDSd+ydkQ6H=zm2-iSB3jXHCyFvuWHw@mail.gmail.com>
On Wed, Sep 8, 2021 at 6:40 PM Jann Horn <jannh@google.com> wrote:
[...]
> I think umcg_idle_loop() should never be called from scheduler
> callbacks (meaning umcg_wq_worker_running()), only from UMCG syscalls.
I'm moving umcg_wq_worker_running() out of
core.c/sched_update_worker() and into
/kernel/entry/common.c/exit_to_user_mode_loop()
(and will rename the function appropriately).
It seems rescheduling/sleeping there is fine.
I'm not yet sure if this is all that is needed to deal with
UMCG_TF_PREEMPTED flag; but I don't expect to see
any locks held when the task truly returns to the userspace.
Maybe I'll need to set TIF_NOTIFY_RESUME in sched_update_worker()...
[...]
next prev parent reply other threads:[~2021-09-14 16:51 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-08 18:49 [PATCH 0/4 v0.5] sched/umcg: RFC UMCG patchset Peter Oskolkov
2021-09-08 18:49 ` [PATCH 1/4 v0.5] sched/umcg: add WF_CURRENT_CPU and externise ttwu Peter Oskolkov
2021-09-08 18:49 ` [PATCH 2/4 v0.5] sched/umcg: RFC: add userspace atomic helpers Peter Oskolkov
2021-09-08 23:38 ` Jann Horn
2021-09-09 1:16 ` Jann Horn
2021-09-09 19:06 ` Peter Oskolkov
2021-09-09 21:20 ` Jann Horn
2021-09-09 22:09 ` Peter Oskolkov
2021-09-09 23:13 ` Jann Horn
2021-09-14 16:52 ` Andy Lutomirski
2021-09-14 18:11 ` Peter Zijlstra
2021-09-14 18:40 ` Andy Lutomirski
2021-09-15 15:42 ` Peter Zijlstra
2021-09-15 16:50 ` Andy Lutomirski
2021-09-15 19:10 ` Peter Zijlstra
2021-09-14 8:07 ` Peter Zijlstra
2021-09-14 16:29 ` Peter Oskolkov
2021-09-14 18:04 ` Peter Zijlstra
2021-09-14 18:15 ` Peter Zijlstra
2021-09-14 18:29 ` Peter Oskolkov
2021-09-14 18:48 ` Peter Oskolkov
2021-09-08 18:49 ` [PATCH 3/4 v0.5] sched/umcg: RFC: implement UMCG syscalls Peter Oskolkov
2021-09-09 1:39 ` Jann Horn
2021-09-14 16:51 ` Peter Oskolkov [this message]
2021-09-08 18:49 ` [PATCH 4/4 v0.5] sched/umcg: add Documentation/userspace-api/umcg.rst Peter Oskolkov
2021-09-14 16:35 ` Tao Zhou
2021-09-14 16:57 ` Peter Oskolkov
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