Re: [RFC][PATCH -mm 2/3] freezer: Introduce freezer_flags

Rafael J. Wysocki
2007-04-23T22:54:57Z

On Tuesday, 24 April 2007 00:41, Gautham R Shenoy wrote:
> On Tue, Apr 24, 2007 at 12:40:17AM +0200, Rafael J. Wysocki wrote:
> > On Tuesday, 24 April 2007 00:23, Oleg Nesterov wrote:
> > > On 04/22, Rafael J. Wysocki wrote:
> > > >
> > > > Move all of the freezer-related flags to a separate field in task_struct and
> > > > introduce functions to operate them using set_bit() etc.
> > > >
> > > > [...snip...]
> > > >
> > > > --- linux-2.6.21-rc6-mm1.orig/kernel/fork.c 2007-04-22 19:37:42.000000000 +0200
> > > > +++ linux-2.6.21-rc6-mm1/kernel/fork.c 2007-04-22 20:55:01.000000000 +0200
> > > > @@ -922,7 +922,7 @@ static inline void copy_flags(unsigned l
> > > > {
> > > > unsigned long new_flags = p->flags;
> > > >
> > > > - new_flags &= ~(PF_SUPERPRIV | PF_NOFREEZE);
> > > > + new_flags &= ~PF_SUPERPRIV;
> > > > new_flags |= PF_FORKNOEXEC;
> > > > new_flags |= PF_STARTING;
> > > > p->flags = new_flags;
> > >
> > > OK, but you forgot to clear p->freezer_flags on copy_process()->dup_task_struct()
> > > path ?
> >
> > Yes, thanks for pointing that out.
>
> That reminds me, shouldn't we set the child's TFF_FREEZE flag if the parent
> is freezing or frozen?

Well, usually we'll want to freeze the child too in such cases, but I'm not
sure if that's always true.

Greetings,
Rafael