From: Christian Brauner <christian.brauner@ubuntu.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: linux-kernel@vger.kernel.org,
Christian Brauner <christian@brauner.io>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Kees Cook <keescook@chromium.org>,
Sargun Dhillon <sargun@sargun.me>,
Aleksa Sarai <cyphar@cyphar.com>,
linux-kselftest@vger.kernel.org,
Josh Triplett <josh@joshtriplett.org>,
Jens Axboe <axboe@kernel.dk>,
linux-api@vger.kernel.org, Jann Horn <jannh@google.com>
Subject: Re: [PATCH v2 2/4] exit: support non-blocking pidfds
Date: Thu, 3 Sep 2020 17:38:47 +0200 [thread overview]
Message-ID: <20200903153847.zvi5dzwj6v4eap6i@wittgenstein> (raw)
In-Reply-To: <20200903142241.GI4386@redhat.com>
On Thu, Sep 03, 2020 at 04:22:42PM +0200, Oleg Nesterov wrote:
> On 09/02, Christian Brauner wrote:
> >
> > It also makes the API more consistent and uniform. In essence, waitid() is
> > treated like a read on a non-blocking pidfd or a recvmsg() on a non-blocking
> > socket.
> > With the addition of support for non-blocking pidfds we support the same
> > functionality that sockets do. For sockets() recvmsg() supports MSG_DONTWAIT
> > for pidfds waitid() supports WNOHANG.
>
> What I personally do not like is that waitid(WNOHANG) returns zero or EAGAIN
> depending on f_flags & O_NONBLOCK... This doesn't match recvmsg(MSG_DONTWAIT)
> and doesn't look consistent to me.
It's not my favorite thing either but async event loops are usually
modeled around EAGAIN so I think this has benefits. Josh can speak more
to that.
Christian
next prev parent reply other threads:[~2020-09-03 15:38 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-02 10:21 [PATCH v2 0/4] Support non-blocking pidfds Christian Brauner
2020-09-02 10:21 ` [PATCH v2 1/4] pidfd: support PIDFD_NONBLOCK in pidfd_open() Christian Brauner
2020-09-03 14:31 ` Oleg Nesterov
2020-09-03 14:58 ` Oleg Nesterov
2020-09-03 15:25 ` Christian Brauner
2020-09-03 23:50 ` Josh Triplett
2020-09-02 10:21 ` [PATCH v2 2/4] exit: support non-blocking pidfds Christian Brauner
2020-09-03 14:22 ` Oleg Nesterov
2020-09-03 15:38 ` Christian Brauner [this message]
2020-09-03 23:54 ` Josh Triplett
2020-09-03 23:56 ` Josh Triplett
2020-09-04 10:29 ` Christian Brauner
2020-09-02 10:21 ` [PATCH v2 3/4] tests: port pidfd_wait to kselftest harness Christian Brauner
2020-09-02 10:21 ` [PATCH v2 4/4] tests: add waitid() tests for non-blocking pidfds Christian Brauner
2020-09-03 23:58 ` [PATCH v2 0/4] Support " Josh Triplett
2020-09-04 10:30 ` Christian Brauner
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