Messages in this thread | | | Date | Fri, 9 Dec 2005 18:49:04 +0100 | From | Andi Kleen <> | Subject | Re: [discuss] Re: [patch 3/3] add x86-64 support for memory hot-add II |
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> In general SRAT has a hotplug memory bit so it's possible > to predict how much memory there will be in advance. Since > the overhead of the kernel page tables should be very > low I would prefer if you just used instead. > > (i.e. instead of extending the kernel mapping preallocate > the direct mapping and just clear the P bits) > > That should be much simpler.
Looking at it again - accessing SRAT currently relies on the direct mapping already. Untangling that would be possible, but require an bt_ioremap which would also add lots of code.
Ok I retract that objection. I guess your way is better for now.
In addition to the __cpuinit comment
+if (after_bootmem) spin_unlock(&init_mm.page_table_lock);
Conditional locking is evil. spinlocking in the boot case should just work too I think.
The EXPORTs should be probably EXPORT_SYMBOL_GPL.
With these changes it would look ok for me.
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