On Sun, Jul 15, 2007 at 02:33:32PM +0200, Rafael J. Wysocki wrote: (snip) Many of these assumptions are based on the assumption that we want to save a full image of RAM. I'm not convinced that this is true. The two things that we need are application state and hardware state. Application state can clearly be saved without kernel involvement (though restoring some of it may need some help from the kernel...), so hardware state is a more interesting question. The obvious argument for saving the entirity of memory is that we have no mechanism for picking apart hardware state from any other part of the kernel. In reality, we're looking at implementing a set of hibernation operations anyway - it would be possible to utilise those to save as much state as needed. You also get fringe benefits, like being able to freeze a process that's accessing a piece of flaky hardware, swap the card out (assuming hotplug PCI), restore some amount of state and then let the process continue. I appreciate that this suggestion sounds kind of fragile and complicated, but I think that's true of most descriptions of suspend to disk :) The main benefit is that it means we can use the hibernation infrastructure for other purposes (checkpointing, swapping hardware, that kind of thing) and reduce the damage caused by users doing seemingly reasonable things (like suspending Linux, booting Windows and then writing to a shared partition...). -- Matthew Garrett | mjg59@xxxxxxxxxxxxx _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
