On Thu, 7 Dec 2006, Jeremy Fitzhardinge wrote: > You can also deal with memory hotplug by adding a Xen-style > pseudo-physical vs machine address abstraction. This doesn't help with > making space for contiguous allocations, but it does allow you to move > "physical" pages from one machine page to another if you want to. The > paravirt ops infrastructure has already appeared in -git, and I'll soon > have patches to allow Xen's paravirtualized mmu mode to work with it, > which is a superset of what would be required to implement movable pages > for hotpluggable memory. > > (I don't know if you actually want to consider this approach; I'm just > pointing out that it definitely a bad idea to conflate the two problems > of memory fragmentation and hotplug.)
The same can be done using the virtual->physical mappings that exist on many platforms for the kernel address space (ia64 dynamically calculates those, x86_64 uses a page table with 2M pages for mapping the kernel). The problem is that the 1-1 mapping between physical and virtual addresses will have to be (at least partially) sacrificed which may lead to complications with DMA devices. - 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/
