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From: Oleg Nesterov <oleg@redhat.com>
To: Christian Brauner <brauner@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Tycho Andersen <tycho@tycho.pizza>,
	linux-api@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/2] pidfd: change pidfd_send_signal() to respect PIDFD_THREAD
Date: Sat, 10 Feb 2024 14:15:18 +0100	[thread overview]
Message-ID: <20240210131518.GC27557@redhat.com> (raw)
In-Reply-To: <20240210-dackel-getan-619c70fefa62@brauner>

On 02/10, Christian Brauner wrote:
>
> The question is what is more useful for userspace when they do:
> pidfd_send_signal(1234, PIDFD_SEND_PROCESS_GROUP)?
>
> (1) They either mean to signal a process group that is headed by 1234.

Yes, this is what I had in mind, see also another email from me.
Simple, clear, and matches kill(-1234).

> (2) Or they want to signal a process group of which 1234 is a member or
>     the leader.

Somehow I didn't even consider this option when I thought about
PIDFD_SIGNAL_PGRP...

> From a usability perspective (1) is a lot more restrictive because it
> requires @pidfd to refer to a process group leader.

Yes, but to be honest (2) doesn't fit my head. Probably simply because
I always had (1) in mind...

But I won't argue if you think that (2) has useful usecases.

Oleg.


  reply	other threads:[~2024-02-10 13:16 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-09 13:06 [PATCH v2 1/2] signal: add the "int si_code" arg to prepare_kill_siginfo() Oleg Nesterov
2024-02-09 13:06 ` [PATCH v2 2/2] pidfd: change pidfd_send_signal() to respect PIDFD_THREAD Oleg Nesterov
2024-02-09 15:11   ` Christian Brauner
2024-02-09 15:15   ` Christian Brauner
2024-02-09 15:43     ` Oleg Nesterov
2024-02-09 15:49       ` Christian Brauner
2024-02-09 15:56         ` Oleg Nesterov
2024-02-10 10:23           ` Christian Brauner
2024-02-10 12:30             ` Oleg Nesterov
2024-02-10 12:47               ` Oleg Nesterov
2024-02-10 12:54               ` Christian Brauner
2024-02-10 13:15                 ` Oleg Nesterov [this message]
2024-02-10 14:26                   ` Christian Brauner
2024-02-10 16:51                     ` Oleg Nesterov
2024-02-10 17:22                       ` Christian Brauner
2024-02-14 12:36                       ` Oleg Nesterov
2024-02-16 12:28                         ` Christian Brauner
2024-02-16 13:06                           ` Oleg Nesterov
2024-02-16 14:46                             ` Christian Brauner
2024-02-16 18:12                               ` Oleg Nesterov
2024-02-20  8:34                                 ` Christian Brauner
2024-02-20  9:02                                   ` Oleg Nesterov
2024-02-20  9:22                                     ` Christian Brauner
2024-02-20 11:00                                       ` Oleg Nesterov
2024-02-20 12:59                                         ` Christian Brauner
2024-02-20 16:22                                           ` Oleg Nesterov
2024-02-21  7:42                                             ` Christian Brauner
2024-02-21 12:55                                               ` Oleg Nesterov
2024-02-21 13:35                                                 ` Christian Brauner
2024-02-09 19:08   ` Tycho Andersen
2024-02-09 15:10 ` [PATCH v2 1/2] signal: add the "int si_code" arg to prepare_kill_siginfo() Christian Brauner
2024-02-09 16:13 ` Christian Brauner
2024-02-09 16:22 ` Eric W. Biederman
2024-02-09 16:39   ` Oleg Nesterov
2024-02-09 19:36     ` Christian Brauner
2024-02-09 19:53       ` Oleg Nesterov
2024-02-09 20:01       ` Tycho Andersen

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