[xfs-masters] Re: freeze vs freezer

[Pavel Machek <pavel@xxxxxx>]

Hi!

> >>>>So how do you handle threads that are blocked on I/O or a lock  
> >>>>during the system freeze process, then?
> >>>
> >>>We wait until they can continue.
> >>
> >>So if I have a process blocked on an unavilable NFS mount, I can't
> >>suspend?
> >
> >That's correct, you can't.
> >
> >[And I know what you're going to say. ;-)]
> 
> Why exactly does suspend/hibernation depend on "TASK_INTERRUPTIBLE"  
> instead of a zero preempt_count()?  Really what we should do is just  
> iterate over all of the actual physical devices and tell each one  
> "Block new IO requests preemptably, finish pending DMA, put the  
> hardware in low-power mode, and prepare for suspend/hibernate".  As  
> long as each driver knows how to do those simple things we can have  
> an entirely consistent kernel image for both suspend and for  
> hibernation.

"each driver" means this is a lot of work. But yes, that is probably
way to go, and patch would be welcome.

-- 
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