Hi,
I wanted to know about the impact of changing PAGE_ALLOC_COSTLY_ORDER value
from 3 to 2.
This macro is defined in include/linux/mmzone.h
#define PAGE_ALLOC_COSTLY_ORDER 3
As I know this value should never be changed irrespective of the type of the
system.
Is it good to change this value for RAM size: 512MB, 256MB or 128MB?
If anybody have changed this value and experience any kind of problem or
benefits please let us know.
We noticed that for one of the Android product with 512MB RAM, the
PAGE_ALLOC_COSTLY_ORDER was set to 2.
We could not figure out why this value was decreased from 3 to 2.
As per my analysis, I observed that kmalloc fails little early, if we change
this value to 2.
This is also visible from the _slowpath_ in page_alloc.c
Apart from this we could not find any other impact.
If anybody is aware of any other impact, please let us know.
Thank you!
Regards,
Pintu Kumar
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