On Fri, 2011-04-01 at 00:18 +0200, Michal Nazarewicz wrote:

On Thu, 31 Mar 2011 23:14:38 +0200, Dave Hansen wrote:

quoted

We BUG_ON() in bootmem.  Basically if we try to allocate an early-boot
structure and fail, we're screwed.  We can't keep running without an
inode hash, or a mem_map[].

This looks like it's going to at least get partially used in drivers, at
least from the examples.  Are these kinds of things that, if the driver
fails to load, that the system is useless and hosed?  Or, is it
something where we might limp along to figure out what went wrong before
we reboot?

Bug in the above place does not mean that we could not allocate memory.  It
means caller is broken.

Could you explain that a bit?

Is this a case where a device is mapped to a very *specific* range of
physical memory and no where else?  What are the reasons for not marking
it off limits at boot?  I also saw some bits of isolation and migration
in those patches.  Can't the migration fail?  

-- Dave