Re: [linux-pm] [PATCH] Remove process freezer from suspend to RAMpathway

[Alan Stern]

On Tue, 3 Jul 2007, Matthew Garrett wrote:

> On Tue, Jul 03, 2007 at 12:03:33PM -0400, Alan Stern wrote:
> > On Tue, 3 Jul 2007, Matthew Garrett wrote:
> > 
> > > Suspend to RAM on a machine with / on a fuse filesystem turns out to be 
> > > a screaming nightmare - either the suspend fails because syslog (for 
> > > instance) can't be frozen, or the machine deadlocks for some other 
> > > reason I haven't tracked down. We could "fix" fuse, or alternatively we 
> > > could do what we do for suspend to RAM on other platforms (PPC and APM) 
> > > and just not use the freezer.
> > 
> > Quite apart from the sync() matter, _any_ synchronous call to a FUSE 
> > filesystem during STR will cause trouble.  Even if the user task 
> > implementing the filesystem isn't frozen, when it tries to carry out 
> > some I/O to a suspended device it will either:
> > 
> > 	block until the system wakes up, or
> 
> For the suspend to RAM case, that sounds absolutely fine.

It's not so good when your suspend process has to wait for the call to 
complete!

Alan Stern

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