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SubjectRe: [PATCH] kernel/freezer.c : Removing extra checking.
On Sat 2008-12-06 17:52:57, Rafael J. Wysocki wrote:
> On Saturday, 6 of December 2008, Rakib Mullick wrote:
> > On 12/6/08, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> > > On Saturday, 6 of December 2008, Rakib Mullick wrote:
> > > > Impact: Reduces an extra checking.
> > > >
> > > > Following patch removes an extra checking. We can remove it since, the
> > > > current task is frozen. If the current task is not frozen, then it
> > > > will return from __else__ condition of freezing(current) check. So,
> > > > the check becames unnecessary. It also reduces 32 bytes of text space
> > > > on my x86 (32 bit) system.
> > >
> > >
> > > What will happen with this patch applied when a task is woken up for some
> > > reason other than thawing?
> > thawing is usually used for woken up a frozzen process. Would you
> > please tell me what are the other ways to woken up a frozzen process?
> > Am I missing anything ?
>
> Well, in theory the process can be woken up for another reason.

...like pending signal...

> I don't have any particular examples in mind, but in this case the burden is
> yours to show that it won't happen and to say why exactly you think so in the
> changelog, because this is the very reason why the code has been written this
> way in the first place.
>
> Thanks,
> Rafael
>
>
> > > > Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
> > > >
> > > > --- linux-2.6-orig/kernel/freezer.c 2008-12-05 19:53:45.000000000 +0600
> > > > +++ linux-2.6/kernel/freezer.c 2008-12-05 19:55:40.000000000 +0600
> > > > @@ -46,8 +46,6 @@ void refrigerator(void)
> > > >
> > > > for (;;) {
> > > > set_current_state(TASK_UNINTERRUPTIBLE);
> > > > - if (!frozen(current))
> > > > - break;
> > > > schedule();
> > > > }
> > > > pr_debug("%s left refrigerator\n", current->comm);
> > >

Plus this looks like infinite loop after your change. Have you tested
it?


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