From: Oleg Nesterov <oleg@redhat.com>
To: David Vernet <void@manifault.com>
Cc: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
vincent.guittot@linaro.org, rostedt@goodmis.org,
bsegall@google.com, mgorman@suse.de, bristot@redhat.com,
vschneid@redhat.com, kernel-team@meta.com,
torvalds@linux-foundation.org, ebiederm@xmission.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] tasks: Extract rcu_users out of union
Date: Fri, 17 Feb 2023 11:25:21 +0100 [thread overview]
Message-ID: <20230217102521.GA27682@redhat.com> (raw)
In-Reply-To: <Y+54c0YvXcMIFva4@maniforge>
On 02/16, David Vernet wrote:
>
> On Thu, Feb 16, 2023 at 09:04:59AM +0100, Oleg Nesterov wrote:
> >
> > > a task that's successfully looked
> > > up in e.g. the pid_list with find_task_by_pid_ns(), can always have a
> > > 'usage' reference acquired on them, as it's guaranteed to be >
> > > 0 until after the next gp.
> >
> > Yes. So it seems you need another key-to-task_struct map with rcu-safe
> > lookup/get and thus the add() method needs inc_not_zero(task->rcu_users) ?
>
> Yes, exactly.
OK, in this case I agree, inc_not_zero(rcu_users) makes sense and thus we need
this patch.
Just I was confused by the previous part of the changelog due to my bad English.
Thanks,
Oleg.
next prev parent reply other threads:[~2023-02-17 10:26 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-15 23:30 [PATCH] tasks: Extract rcu_users out of union David Vernet
2023-02-16 8:04 ` Oleg Nesterov
2023-02-16 18:39 ` David Vernet
2023-02-17 10:25 ` Oleg Nesterov [this message]
2023-02-27 16:11 ` David Vernet
2023-03-07 17:19 ` David Vernet
2023-03-08 18:29 ` Oleg Nesterov
2023-03-09 0:55 ` Alexei Starovoitov
2023-03-13 19:59 ` Alexei Starovoitov
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