Re: device model documentation 2/3

[Pavel Machek <pavel@suse.cz>]

Hi!

> > > SUSPEND_DISABLE tells the device to stop I/O transactions. When it
> > > stops transactions, or what it should do with unfinished transactions
> > > is a policy of the driver. After this call, the driver should not
> > > accept any other I/O requests.
> > 
> > Does this mean that memory allocations in the suspend/resume
> > implementations must be made with GFP_NOIO respectively
> > GFP_ATOMIC ?
> > It would seem so.
> 
> Why would you allocate memory on a resume transition? 
> 
> As for suspending, this is something that has been discussed a few times 
> before. No definitive decision has come out of it because it hasn't been 
> implemented yet. It hasn't been implemented yet because the infrastructure 
> isn't complete. It's real close, but still not quite there. 

swsusp works for me (tm). SO structure should be there ;-)

> Nonetheless, you have to do one of a couple things: use GFP_NOIO or
> special case the swap device(s) so they don't stop I/O when everything
> else does. (Of course, you have to eventually stop it)

Special casing swap is not enough -- you can well have memory full of data
for regular filesystem.

								Pavel

-- 
Philips Velo 1: 1"x4"x8", 300gram, 60, 12MB, 40bogomips, linux, mutt,
details at http://atrey.karlin.mff.cuni.cz/~pavel/velo/index.html.


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