From: Russell King <[email protected]>
Oddly, max_low_pfn/max_pfn end up being the number of pages in the system,
rather than the maximum PFN on ARM. This doesn't seem to cause any problems,
so just add a note about it.
Signed-off-by: Russell King <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---
25-akpm/arch/arm/mm/init.c | 3 +++
1 files changed, 3 insertions(+)
diff -puN arch/arm/mm/init.c~arm-add-comment-about-max_low_pfn-max_pfn arch/arm/mm/init.c
--- 25/arch/arm/mm/init.c~arm-add-comment-about-max_low_pfn-max_pfn 2005-04-12 03:21:04.967381744 -0700
+++ 25-akpm/arch/arm/mm/init.c 2005-04-12 03:21:04.971381136 -0700
@@ -223,6 +223,9 @@ find_memend_and_nodes(struct meminfo *mi
* This doesn't seem to be used by the Linux memory
* manager any more. If we can get rid of it, we
* also get rid of some of the stuff above as well.
+ *
+ * Note: max_low_pfn and max_pfn reflect the number
+ * of _pages_ in the system, not the maximum PFN.
*/
max_low_pfn = memend_pfn - O_PFN_DOWN(PHYS_OFFSET);
max_pfn = memend_pfn - O_PFN_DOWN(PHYS_OFFSET);
_
I told rmk about this long time ago.
On 4/12/05, [email protected] <[email protected]> wrote:
>
> From: Russell King <[email protected]>
>
> Oddly, max_low_pfn/max_pfn end up being the number of pages in the system,
> rather than the maximum PFN on ARM. This doesn't seem to cause any problems,
> so just add a note about it.
>
> Signed-off-by: Russell King <[email protected]>
> Signed-off-by: Andrew Morton <[email protected]>
> ---
>
> 25-akpm/arch/arm/mm/init.c | 3 +++
> 1 files changed, 3 insertions(+)
>
> diff -puN arch/arm/mm/init.c~arm-add-comment-about-max_low_pfn-max_pfn arch/arm/mm/init.c
> --- 25/arch/arm/mm/init.c~arm-add-comment-about-max_low_pfn-max_pfn 2005-04-12 03:21:04.967381744 -0700
> +++ 25-akpm/arch/arm/mm/init.c 2005-04-12 03:21:04.971381136 -0700
> @@ -223,6 +223,9 @@ find_memend_and_nodes(struct meminfo *mi
> * This doesn't seem to be used by the Linux memory
> * manager any more. If we can get rid of it, we
> * also get rid of some of the stuff above as well.
> + *
> + * Note: max_low_pfn and max_pfn reflect the number
> + * of _pages_ in the system, not the maximum PFN.
> */
> max_low_pfn = memend_pfn - O_PFN_DOWN(PHYS_OFFSET);
> max_pfn = memend_pfn - O_PFN_DOWN(PHYS_OFFSET);
> _
--
Coywolf Qi Hunt
http://sosdg.org/~coywolf/
FYI
http://lkml.org/lkml/2004/6/29/57
On 4/13/05, Coywolf Qi Hunt <[email protected]> wrote:
> I told rmk about this long time ago.
>
> On 4/12/05, [email protected] <[email protected]> wrote:
> >
> > From: Russell King <[email protected]>
> >
> > Oddly, max_low_pfn/max_pfn end up being the number of pages in the system,
> > rather than the maximum PFN on ARM. This doesn't seem to cause any problems,
> > so just add a note about it.
> >
> > Signed-off-by: Russell King <[email protected]>
> > Signed-off-by: Andrew Morton <[email protected]>
> > ---
> >
> > 25-akpm/arch/arm/mm/init.c | 3 +++
> > 1 files changed, 3 insertions(+)
> >
> > diff -puN arch/arm/mm/init.c~arm-add-comment-about-max_low_pfn-max_pfn arch/arm/mm/init.c
> > --- 25/arch/arm/mm/init.c~arm-add-comment-about-max_low_pfn-max_pfn 2005-04-12 03:21:04.967381744 -0700
> > +++ 25-akpm/arch/arm/mm/init.c 2005-04-12 03:21:04.971381136 -0700
> > @@ -223,6 +223,9 @@ find_memend_and_nodes(struct meminfo *mi
> > * This doesn't seem to be used by the Linux memory
> > * manager any more. If we can get rid of it, we
> > * also get rid of some of the stuff above as well.
> > + *
> > + * Note: max_low_pfn and max_pfn reflect the number
> > + * of _pages_ in the system, not the maximum PFN.
> > */
> > max_low_pfn = memend_pfn - O_PFN_DOWN(PHYS_OFFSET);
> > max_pfn = memend_pfn - O_PFN_DOWN(PHYS_OFFSET);
> > _
>
> --
> Coywolf Qi Hunt
> http://sosdg.org/~coywolf/
>
--
Coywolf Qi Hunt
http://sosdg.org/~coywolf/
On Wed, Apr 13, 2005 at 11:10:35AM +0800, Coywolf Qi Hunt wrote:
> I told rmk about this long time ago.
The kernel is a mess of DMA masks and maximum PFNs which all assume
that memory always starts at zero, which I've mentioned before as
well.
I might see about fixing this up properly when it causes real
problems, but until then its better to document the behaviour.
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of: 2.6 Serial core