lkml.org 
[lkml]   [2007]   [Jul]   [5]   [last100]   RSS Feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [linux-pm] Re: [PATCH] Remove process freezer from suspend to RAM pathway
FromMiklos Szeredi <>
DateThu, 05 Jul 2007 10:17:17 +0200
> > > I have discussed the benefits elsewhere.  As for the deadlocks -- do 
> > > you still observe them if you use the version of the freezer which 
> > > doesn't freeze kernel threads?
> > 
> > In general the only way to guarantee there are no deadlocks is to
> > construct the graph of dependencies between tasks.  Those dependencies
> > are not in practice observable from outside the tasks, so it is
> > virtually impossible to construct the graph.
> 
> In which way can user space tasks depend on each other in a way that
> allows a them members of that cycle to be in uninterruptible sleep?

 - process A calls rename() on a fuse fs
 - process B, the fuse server, starts to process the rename request
 - process B is frozen before it can reply

Now process A is unfreezable.  We cannot make rename() restartable,
hence it cannot be interruptible.

Miklos
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-07-05 10:21    [from the cache]
©2003-2008