Commit-ID: c9e0d39126af9e338495b719e9d565ca9ebcd4c5
Gitweb: http://git.kernel.org/tip/c9e0d39126af9e338495b719e9d565ca9ebcd4c5
Author: Dave Jones <davej@xxxxxxxxxxxxxxxxx>
AuthorDate: Mon, 11 Jan 2016 12:04:28 -0500
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 12 Jan 2016 11:08:37 +0100
x86/mm/pat: Make split_page_count() check for empty levels to fix /proc/meminfo output
In CONFIG_PAGEALLOC_DEBUG=y builds, we disable 2M pages.
Unfortunatly when we split up mappings during boot,
split_page_count() doesn't take this into account, and
starts decrementing an empty direct_pages_count[] level.
This results in /proc/meminfo showing crazy things like:
DirectMap2M: 18446744073709543424 kB
Signed-off-by: Dave Jones <davej@xxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Luis R. Rodriguez <mcgrof@xxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Toshi Kani <toshi.kani@xxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/mm/pageattr.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 6000ad7..fc6a4c8 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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