Re: size of page table

[Abhishek SINHA <aby_sinha@yahoo.com>]

As i understand all the page tables descriptors are
stored in array mem_map. Each descriptor is less than
64 bytes long , mem_map requires about 4 Page frames
for 1 MB of RAM.also check out MAP_NR.

Correct guys ?
Abhishek
> 

--- Chandra G K Babu S <scgkiran@cse.iitk.ac.in>
wrote:
> 
> the answer is 8mb, may be that is a one level page
> table.
> the page size is 4kb (=4k * 1/8 = 1/2kB)
> 32 bits of virtual address divided as 23+9,
>  first 23 bits give the page number,
> the 9 bits give the index in a page. the page table
> have to
>  accomdate (2 pow 23) entries so the page table size
> is 8 mb.
> 
> i think this question ha nothing to do with the
> linux.
> any comments?
> 
> with regards,
> kiran
> On Mon, 6 Jan 2003, Rupa wrote:
> 
> > 
> > Actually this was the question asked in some exam.
> I do no how to calculate
> > size of page table. They had given 4 answers...
> > i)16mb ii)8mb
> > iii)2mb iv) 24mb
> > 
> > You have any idea?
> > 
> > Regards,
> > Rupa
> > ----- Original Message -----
> > From: "Raghu R. Arur" <rra2002@cs.columbia.edu>
> > To: "Rupa" <rupa.ramakrishna@ionidea.com>
> > Sent: Monday, January 06, 2003 11:47 AM
> > Subject: Re: size of page table
> > 
> > 
> > >
> > > Hi,
> > >
> > >  If you are talking about linux, the page table
> size is not related to the
> > > memory size (RAM size). page table is for per
> process and in linux each
> > > process will have 4GB of memory allocated. 3 GB
> for the user space and 1
> > > GB for the kernel space.
> > >
> > >  HTH,
> > > raghu
> > >
> > > On Mon, 6 Jan 2003, Rupa wrote:
> > >
> > > > Hello,
> > > >     I have small doubt regarding the sizeof
> page table. Consider a
> > machine with 64MB physical memory and a 32 bit
> virtual address space. If the
> > page size is 4kb, what is the approximate size of
> page table.?
> > > > Any help will be useful
> > > >
> > > > Rupa
> > > >
> > >
> > 
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