Re: [linux-pm] Re: hibernation/snapshot design [was Re: [PATCH] Remove process freezer from suspend to RAM pathway]

Paul Mackerras
2007-07-10T01:56:58Z

Nigel Cunningham writes:

> (Finally catching up on emails since Saturday!)

Yes, I know what you mean; I was occupied with other work stuff on
Friday and not well on Saturday, and by that stage there was a backlog
of about 500 emails for me to wade through... :/

> The freezer is also essential for doing a full image of memory - you
> have to be able to guarantee that some of the image won't change in
> order to be able to write it out before the atomic copy. Of course the
> freezer alone isn't enough, but it solves 95% of the issue.

Sure. As I pointed out in another email, it's unrealistic to expect
the freezer to be able to stop everything in a state where any
arbitrary mutex is free. But as long as you don't need to do anything
that depends on getting a mutex while the system is frozen, there
should be no problem.

Paul.