Re: reserved pages and zero pages question

[Thiemo Seufer <ths@networkno.de>]

pulsar@kpsws.com wrote:
> Hi,
> 
> In my kernel startup I see the memory usage printed as:
> 
> Memory: 125312k/131072k available (1977k kernel code, 5648k reserved, 287k
> data, 1664k init, 0k highmem)
> 
> I wonder where the reserved pages are used for and how we can minimize it
> for small memory systems.

Most of that is the ramdisk you included. :-)  It normally given back
once the ramdisk is decompressed.

> In my search I see that in arcm/mips/mm/init.c there are zero-pages
> allocated and put to reserved.
> 
> Where are the zero pages used for and can we do without ?

They provide a clean zeroed page which gets mapped read-only (probably
for copy-on-write). You can't do without.


Thiemo