Messages in this thread | | | Date | Mon, 07 Apr 2014 12:42:40 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 2/3] x86: Define _PAGE_NUMA with unused physical address bits PMD and PTE levels |
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On 04/07/2014 12:36 PM, Cyrill Gorcunov wrote: > On Mon, Apr 07, 2014 at 12:27:10PM -0700, H. Peter Anvin wrote: >> On 04/07/2014 11:28 AM, Mel Gorman wrote: >>> >>> I had considered the soft-dirty tracking usage of the same bit. I thought I'd >>> be able to swizzle around it or a further worst case of having soft-dirty and >>> automatic NUMA balancing mutually exclusive. Unfortunately upon examination >>> it's not obvious how to have both of them share a bit and I suspect any >>> attempt to will break CRIU. In my current tree, NUMA_BALANCING cannot be >>> set if MEM_SOFT_DIRTY which is not particularly satisfactory. Next on the >>> list is examining if _PAGE_BIT_IOMAP can be used. >> >> Didn't we smoke the last user of _PAGE_BIT_IOMAP? > > Seems so, at least for non-kernel pages (not considering this bit references in > xen code, which i simply don't know but i guess it's used for kernel pages only). >
David Vrabel has a patchset which I presumed would be pulled through the Xen tree this merge window:
[PATCHv5 0/8] x86/xen: fixes for mapping high MMIO regions (and remove _PAGE_IOMAP)
That frees up this bit.
-hpa
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