Messages in this thread |  | | | From | Oliver Neukum <> | | Subject | Re: [linux-pm] Re: [PATCH] Remove process freezer from suspend to RAM pathway | | Date | Thu, 5 Jul 2007 10:24:22 +0200 |
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Am Donnerstag, 5. Juli 2007 schrieb Miklos Szeredi: > > > > 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.
Then this is a problem specific to fuse. You should teach fuse to block suspension while such operations are being performed.
Regards Oliver
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