[PATCH 1/3] mm: Optimize pfn calculation in online_page()

[PATCH 1/3] mm: Optimize pfn calculation in online_page()

[Daniel Kiper]

If CONFIG_FLATMEM is enabled pfn is calculated in online_page()
more than once. It is possible to optimize that and use value
established at beginning of that function.

Signed-off-by: Daniel Kiper <dkiper@net-space.pl>
---
 mm/memory_hotplug.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 321fc74..f0651ae 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -375,7 +375,7 @@ void online_page(struct page *page)
 #endif
 
 #ifdef CONFIG_FLATMEM
-	max_mapnr = max(page_to_pfn(page), max_mapnr);
+	max_mapnr = max(pfn, max_mapnr);
 #endif
 
 	ClearPageReserved(page);
-- 
1.5.6.5

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Re: [PATCH 1/3] mm: Optimize pfn calculation in online_page()

[Dave Hansen]

On Mon, 2011-03-28 at 11:23 +0200, Daniel Kiper wrote:
> If CONFIG_FLATMEM is enabled pfn is calculated in online_page()
> more than once. It is possible to optimize that and use value
> established at beginning of that function.
> 
> Signed-off-by: Daniel Kiper <dkiper@net-space.pl> 

Looks sensible to me.

Acked-by: Dave Hansen <dave@linux.vnet.ibm.com

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Re: [PATCH 1/3] mm: Optimize pfn calculation in online_page()

[David Rientjes]

On Mon, 28 Mar 2011, Daniel Kiper wrote:

> If CONFIG_FLATMEM is enabled pfn is calculated in online_page()
> more than once. It is possible to optimize that and use value
> established at beginning of that function.
> 
> Signed-off-by: Daniel Kiper <dkiper@net-space.pl>

Acked-by: David Rientjes <rientjes@google.com>

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Re: [PATCH 1/3] mm: Optimize pfn calculation in online_page()

[Jesper Juhl]

On Mon, 28 Mar 2011, Daniel Kiper wrote:

> If CONFIG_FLATMEM is enabled pfn is calculated in online_page()
> more than once. It is possible to optimize that and use value
> established at beginning of that function.
> 
> Signed-off-by: Daniel Kiper <dkiper@net-space.pl>

This looks sane to me.

Reviewed-by: Jesper Juhl <jj@chaosbits.net>


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