[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] non-contiguous allocations
>>> On 18.04.11 at 20:45, Olaf Hering <olaf@xxxxxxxxx> wrote: > On Fri, Apr 01, George Dunlap wrote: > >> On Wed, 2011-03-30 at 19:04 +0100, Olaf Hering wrote: >> > Using the u16 means each cpu could in theory use up to 256MB as trace >> > buffer. However such a large allocation will currently fail on x86 due >> > to the MAX_ORDER limit. >> >> FWIW, I don't believe that there's any reason the allocations have to be >> contiguous any more. I kept them contiguous to minimize the changes to >> the moving parts near a release. But the new system has been pretty >> well tested now, so I think looking at non-contiguous allocations may be >> worthwhile. > > how do I allocate a few mfns and give them a virtual address? > I dont find a malloc like interface to allocate random pages. alloc_domheap_pages() followed by map_pages_to_xen() would be one way, if you pre-reserve virtual address space (suitable hence only for 64-bit and only if you can set a reasonable upper bound on the amount to want to map). Otherwise I think the only option is to introduce indirection (using the 1:1 mapping, and setting up an array of pointers). That may however be a little difficult if (and I think that's the case) data chunks aren't always of the same size (as then you need to deal with the roll-over into the next page). Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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