Re: [PATCH] MIPS: fix pfn_valid() for FLAGMEM

[Wu Zhangjin <wuzhangjin@gmail.com>]

On Thu, 2009-10-08 at 16:42 +0200, Ralf Baechle wrote:
> On Thu, Oct 08, 2009 at 04:57:32PM +0800, Wu Zhangjin wrote:
> 
> > When CONFIG_FLAGMEM enabled, STD/Hiberation will fail on YeeLoong
> > laptop, This patch fix it:
> > 
> > if pfn is between min_low_pfn and max_mapnr, the old pfn_valid() will
> > return TRUE, but in reality, if the memory is not continuous, it should
> > be false. for example:
> 
> Hm...  All that pfn_valid() indicates is that a page frame number is valid
> to index a pfn.  That is that a pfn is valid to index the mem_map array.
> 
> > $ cat /proc/iomem | grep "System RAM"
> > 00000000-0fffffff : System RAM
> > 90000000-bfffffff : System RAM
> > 
> > as we can see, it is not continuous, so, some of the memory is not valid
> > but regarded as valid by pfn_valid(), and at last make STD/Hibernate
> > fail when shrinking a too large number of invalid memory.
> > 
> > Here, we fix it via checking pfn is in the "System RAM" or not, if yes,
> > return TRUE.
> 
> Are the non-memory parts marked as reserved?
> 
No, so, is that a need to mark them?

Regrads,
	Wu Zhangjin