Dumbest question ever [LWN.net]

Dumbest question ever

Posted Aug 4, 2005 9:56 UTC (Thu) by rvfh (subscriber, #31018)
In reply to: A pair of suspend2 patches by NCunningham
Parent article: A pair of suspend2 patches

That's probably the dumbest question ever heard, but...
Why is it needed to flush dirty pages? Presumably, all pages are in the memory, which is going to be saved to disk anyway...
Why is it not possible to

stop all processes
tell all drivers to suspend (apart from hard-disk, of course)
copy memory contents and registers to disk
suspend system

Is there some document I could read about that so I'll ask more clever questions in the future?

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Dumbest question ever

Posted Aug 6, 2005 15:54 UTC (Sat) by fjalvingh (guest, #4803) [Link]

I think the reason would be:

Dirty pages can also be pages from the file system. Not flushing them would put the FS in an inconsistent state - i.e. the changes are not written. This would not be a problem IF the machine was brought up again from the hibernated state, but if that fails then you have a damaged file system..