Hi,
On Sunday, 4 February 2007 13:53, Pavel Machek wrote:
> Hi!
>
> > > > > o init/do_mounts_initrd.c line 57 handle_initrd().
> > > > > This looks to be short term anyway, so OK to leave.
> > > > > But does kernel_execve() clear PF_NOFREEZE?
> > > > >
> > > > > But it should be OK to freeze the init process when doing CPU
> > > > > hotplug ops, right?
> > > >
> > > > That looks bogus. If it is short term, it can as well live _without_
> > > > PF_NOFREEZE. Noone should suspend system at that stage, right?
> > >
> > > I agree that any attempt to freeze that early in boot would be
> > > at best an act of extreme bravery!
> >
> > This is needed so that the _resume_ works, when it's handled from the user land
> > by our resume tool. Currently, the resume code calls
> > freeze_processes() too.
>
> I do not understand... freeze_processes() always leaves curent process
> running... why is it needed?
IIRC, the do_linuxrc thread cannot be frozen (doesn't call try_to_freeze()),
so the freeze_processes() during the resume fails and the resume fails as a
result.
Still, I have an idea:
Instead of hunting for PF_NOFREEZE and wondering if the suspend/resume fails
when we remove them or replace them with try_to_freeze(), why don't we add
an "ignore_pf_nofreeze" argument to freeze_processes() and make it regard
_all_ tasks as if they haven't set PF_NOFREEZE when this "ignore_pf_nofreeze"
is set? Of course, additionally we'll have to make everyone call
try_to_freeze(), even if they set PF_NOFREEZE anyway.
Then, if freeze_processes() is called with "ignore_pf_nofreeze = 0", it will
work just as it does now. However, if it's called with
"ignore_pf_nofreeze = 1", it will try to make all prcesses enter the
refrigerator. The "ignore_pf_nofreeze = 0" version will be suitable for us
(ie. suspend etc.) and the "ignore_pf_nofreeze = 1" version will be suitable
for the CPU hotplug and such things.
You think?
Rafael
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