Messages in this thread Patch in this message | | | Date | Fri, 28 Aug 2009 11:59:00 -0700 | From | "H. Peter Anvin" <> | Subject | PG_uncached, CONFIG_EXTENDED_PAGEFLAGS and !NUMA |
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Hi all,
I am looking at a patchset by Venkatesh Pallipadi which cleans up a lot of the corner cases in x86 PAT.
http://marc.info/?i=cover.1247162373.git.venkatesh.pallipadi@intel.com
This patchset pages PG_uncached available to other architectures than IA64 on an opt-in basis. Unfortunately, it means we run out of page flags on X86_32+PAE+SPARSEMEM.
Rather than increasing SECTION_SIZE_BITS further, it seems more reasonable to disable CONFIG_EXTENDED_PAGEFLAGS in this case:
diff --git a/mm/Kconfig b/mm/Kconfig index c948d4c..fe221c7 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -153,7 +153,7 @@ config MEMORY_HOTREMOVE # config PAGEFLAGS_EXTENDED def_bool y - depends on 64BIT || SPARSEMEM_VMEMMAP || !NUMA || !SPARSEMEM + depends on 64BIT || SPARSEMEM_VMEMMAP || !SPARSEMEM
# Heavily threaded applications may benefit from splitting the mm-wide
Dropping the !NUMA requirement here seems reasonable, since we already have generic code that handles removing the node number from the page flags when there are too many. We could make this an x86-specific change, but the above generic change would be cleaner in terms of Kconfig complexity. Would people object to this as a general change?
-hpa
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