Re: [PATCH 0/6] power: wire-up filesystem freeze/thaw with suspend/resume

[Christian Brauner <brauner@kernel.org>]

On Tue, Apr 01, 2025 at 04:14:07PM +0200, Peter Zijlstra wrote:
> On Tue, Apr 01, 2025 at 02:32:45AM +0200, Christian Brauner wrote:
> > The whole shebang can also be found at:
> > https://web.git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git/log/?h=work.freeze
> > 
> > I know nothing about power or hibernation. I've tested it as best as I
> > could. Works for me (TM).
> > 
> > I need to catch some actual sleep now...
> > 
> > ---
> > 
> > Now all the pieces are in place to actually allow the power subsystem to
> > freeze/thaw filesystems during suspend/resume. Filesystems are only
> > frozen and thawed if the power subsystem does actually own the freeze.
> 
> Urgh, I was relying on all kthreads to be freezable for live-patching:
> 
>   https://lkml.kernel.org/r/20250324134909.GA14718@noisy.programming.kicks-ass.net
> 
> So I understand the problem with freezing filesystems, but can't we
> leave the TASK_FREEZABLE in the kthreads? The way I understand it, the

Yeah, we can.

> power subsystem will first freeze the filesystems before it goes freeze
> threads anyway. So them remaining freezable should not affect anything,
> right?

Yes. I've dropped the other patches. I've discussed this later
downthread with Jan.
>