From: "Michal Koutný" <mkoutny@suse.com>
To: Tejun Heo <tj@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Vipin Sharma <vipinsh@google.com>,
seanjc@google.com, lizefan.x@bytedance.com, hannes@cmpxchg.org,
dmatlack@google.com, jiangshanlai@gmail.com, kvm@vger.kernel.org,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] KVM: Move VM's worker kthreads back to the original cgroups before exiting.
Date: Thu, 20 Jan 2022 16:05:02 +0100 [thread overview]
Message-ID: <20220120150502.GC27269@blackbody.suse.cz> (raw)
In-Reply-To: <YehY0z2vHYVZk52J@slm.duckdns.org>
On Wed, Jan 19, 2022 at 08:30:43AM -1000, Tejun Heo <tj@kernel.org> wrote:
> It'd be nicer if we can make kthread_stop() waiting more regular but I
> couldn't find a good existing place and routing the usual parent
> signaling might be too complicated. Anyone has better ideas?
The regular way is pictured in Paolo's diagram already, the
exit_notify/do_signal_parent -> wait4 path.
Actually, I can see that there exists already kernel_wait() and is used
by a UMH wrapper kthread. kthreadd issues ignore_signals() so (besides
no well defined point of signalling a kthread) the signal notification
is moot and only waking up the waiter is relevant. So kthread_stop()
could wait via kernel_wait() based on pid (extracted from task_struct).
Have I missed an obstacle?
Michal
next prev parent reply other threads:[~2022-01-20 15:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-22 22:53 [PATCH v2] KVM: Move VM's worker kthreads back to the original cgroups before exiting Vipin Sharma
[not found] ` <20211222225350.1912249-1-vipinsh-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2021-12-28 17:17 ` Sean Christopherson
[not found] ` <YctGtWzYcNP2iTaN-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2022-01-18 19:53 ` Vipin Sharma
2022-01-05 18:04 ` Michal Koutný
2022-01-18 20:25 ` Vipin Sharma
[not found] ` <CAHVum0e84nUcGtdPYQaJDQszKj-QVP5gM+nteBpSTaQ2sWYpmQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2022-01-18 20:39 ` Tejun Heo
2022-01-19 18:02 ` Paolo Bonzini
[not found] ` <7a0bc562-9f25-392d-5c05-9dbcd350d002-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2022-01-19 18:30 ` Tejun Heo
[not found] ` <YehY0z2vHYVZk52J-NiLfg/pYEd1N0TnZuCh8vA@public.gmane.org>
2022-01-19 18:49 ` Vipin Sharma
2022-01-19 19:05 ` Tejun Heo
2022-01-20 15:05 ` Michal Koutný [this message]
[not found] ` <20220120150502.GC27269-9OudH3eul5jcvrawFnH+a6VXKuFTiq87@public.gmane.org>
2022-02-16 17:37 ` Vipin Sharma
[not found] ` <CAHVum0fOP-2XcUcG3PqW08DY7CmpDroG6Fcv9KoD1FqLmGpB8w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2022-02-16 19:48 ` Paolo Bonzini
2022-02-25 17:37 ` Michal Koutný
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