Re: [PATCH] x86_64: Fix partial page check to ensure unusable memoryis not being marked usable.

From: Mel Gorman
Date: Fri Nov 10 2006 - 05:04:36 EST


On Thu, 9 Nov 2006, Aaron Durbin wrote:

Fix partial page check in e820_register_active_regions to ensure
partial pages are
not being marked as active in the memory pool.

Signed-off-by: Aaron Durbin <adurbin@xxxxxxxxxx>


Acked-by: Mel Gorman <mel@xxxxxxxxxxxx>

This bug is in 2.6.19-rc5 and the patch will be needed for 2.6.19.

Thanks Aaron.

---
This was causing a machine to reboot w/ an area in the e820 that was less
than the page size because the upper address was being use to mark a hole as
active in the memory pool.

arch/x86_64/kernel/e820.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86_64/kernel/e820.c b/arch/x86_64/kernel/e820.c
index a75c829..855b561 100644
--- a/arch/x86_64/kernel/e820.c
+++ b/arch/x86_64/kernel/e820.c
@@ -278,7 +278,7 @@ e820_register_active_regions(int nid, un
>> PAGE_SHIFT;

/* Skip map entries smaller than a page */
- if (ei_startpfn > ei_endpfn)
+ if (ei_startpfn >= ei_endpfn)
continue;

/* Check if end_pfn_map should be updated */
--
1.4.2.GIT


--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab
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