From: Jiri Kosina <jkosina@suse.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: ksummit-discuss@lists.linuxfoundation.org
Subject: Re: [Ksummit-discuss] [TECH TOPIC] giving freezer well-defined semantics
Date: Tue, 7 Jul 2015 23:13:01 +0200 (CEST) [thread overview]
Message-ID: <alpine.LNX.2.00.1507072307110.10183@pobox.suse.cz> (raw)
In-Reply-To: <4541757.2i2CVNfqPd@vostro.rjw.lan>
On Tue, 7 Jul 2015, Rafael J. Wysocki wrote:
> > Currently, the freezer has rather random semantics and there is no
> > rigorous definition that would provide clear guidance which kernel threads
> > should be freezable (and what rules they have to follow if they are).
>
> That's with respect to kernel threads, right?
Yeah, sorry for not being verbose enough. I have been buried in kthread
interactions with the rest of the kernel for too long, so my world view is
now a bit distorted.
Yes, this is purely related to try_to_freeze() in !PF_NOFREEZE kernel
threads.
> The primary purpose of the freezer is to get user space out of the way
> and at least in principle there should be no fundamental need to freeze
> any kernel threads.
Except those which are needed for hibernation image I/O. Which is
difficult to pre-categorize in a rigorous way.
You need some parts of VM for that. You need the underlying block
device. You name it.
--
Jiri Kosina
SUSE Labs
next prev parent reply other threads:[~2015-07-07 21:13 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-07 20:42 Jiri Kosina
2015-07-07 21:32 ` Rafael J. Wysocki
2015-07-07 21:13 ` Jiri Kosina [this message]
2015-07-07 23:12 ` Rafael J. Wysocki
2015-07-08 8:16 ` Jiri Kosina
2015-07-08 21:55 ` Rafael J. Wysocki
2015-07-09 11:25 ` Jan Kara
2015-07-10 0:18 ` Rafael J. Wysocki
2015-07-11 5:22 ` Benjamin Herrenschmidt
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