Re: [RFC] userland swsusp

From: Pavel Machek
Date: Wed Nov 16 2005 - 14:20:01 EST


> > This is prototype of userland swsusp. I'd like kernel parts to go in,
> > probably for 2.6.16. Now, I'm not sure about the interface, ioctls are
> > slightly ugly, OTOH it would be probably overkill to introduce
> > syscalls just for this. (I'll need to add an ioctl for freeing memory
> > in future).
> I'm curious on the restrictions the userspace part would have to accept.
> Can /usr/swsusp.c write to a file? Currently, you allow it, but I doubt

No. Writing to file would trash the filesystem. But you can bmap the file,
then write to the block device.

> whether it would be wise to write to a file after you've snapshotted
> kernel's filesystem state. OTOH, I don't want to reserve a partition just
> for the image. Can userspace allocate memory after ioctl(SYS_FREEZE)?

Better avoid memory allocation.

> I have userspace supported encryption of the image in mind.

Yes, that should be feasible.
64 bytes from icmp_seq=28 ttl=51 time=448769.1 ms

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