Messages in this thread Patch in this message | | | Date | Wed, 6 Jan 2016 19:11:41 -0500 | From | Dave Jones <> | Subject | Re: weird DirectMap2M accounting. |
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On Wed, Jan 06, 2016 at 06:55:27PM -0500, Dave Jones wrote: > I just spotted this in /proc/meminfo on an old Core2 machine with 4G. > > DirectMap2M: 18446744073709543424 kB > > Looks like we subtracted 8192 from 0 somewhere. > > Should split_page_count() be checking that direct_pages_count > 0 ?
Ok, this diff makes that number print out as 0.
If this looks ok, I'll submit it properly, though I'd like to better understand what's happening here. Shouldn't I have 2M pages ?
Dave
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index a3137a4feed1..ff0e0c6c350e 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -66,6 +66,9 @@ void update_page_count(int level, unsigned long pages) static void split_page_count(int level) { + if (direct_pages_count[level] == 0) + return; + direct_pages_count[level]--; direct_pages_count[level - 1] += PTRS_PER_PTE; }
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