On Thursday, 12 July 2007 01:12, Al Boldi wrote: > Rafael J. Wysocki wrote: > > On Thursday, 12 July 2007 00:17, Al Boldi wrote: > > > Mark Lord wrote: > > > > Jeremy Maitin-Shepard wrote: > > > > > I'll certainly admit the kexec idea is vaporware currently, > > > > > > Your idea is starting to become a reality with this thread: > > > "[PATCH 0/2] Kexec jump: The first step to kexec base hibernation" > > > > > > > > but it does > > > > > differ in a significant way from freezer-based approaches, such that > > > > > I don't think it should be referred to as just another > > > > > implementation of a freezer. Specifically, it doesn't require that > > > > > the "old kernel" be in a "consistent" state to a greater extent than > > > > > suspend to ram; it is the case that all of the devices must be > > > > > quiesced or shut down to some extent, but doing this without races > > > > > and deadlocks (and without the freezer) is certainly very, very > > > > > similar to what needs to be done for suspend to ram, which will need > > > > > to be solved anyway. Unlike the existing hibernate approaches, > > > > > however, it will not be necessary to use any of the driver > > > > > infrastructure once switched to the "save image" kernel, and thus it > > > > > will not matter what locks are held, for instance. > > > > > > > > I really doubt that kexec(a special kernel) is going to solve anything > > > > here. The new kernel will have to initialize, probe for devices, etc. > > > > Which will take time. > > > > Which will slow down hibernate to an unacceptable degree. > > > > Right now, it (TuxOnIce) is *very* fast. > > > > Adding 10 seconds or so for reprobing/resetting/reiniting devices > > > > is not going to be useful. > > > > And modifying all of the drivers to *not* do their usual probe > > > > sequence sounds rather intrusive and is likely also a non-starter > > > > here. > > > > > > > > Or is it? > > > > > > Well, it's definitely less intrusive than readying drivers for the > > > freezer. > > > > There's nothing like this! > > Are you sure? > > # grep -i freeze drivers/*/* | wc -l > > gives: 297 > > Maybe you can clarify?
Yes, I can. For example, please have a look at 'struct ata_port_operations'. :-) The only direct relationship between the freezer and drivers is that some of them use kernel threads that call try_to_freeze() (and other freezer-related functions). Greetings, Rafael -- "Premature optimization is the root of all evil." - Donald Knuth - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
