RE: bootmem ?

RE: bootmem ?

[Somshekar. C. Kadam - CTD, Chennai.]

hi Ravi,
    Thanks for ur response definately it helps me,
 
 but i want to know what is the value of node_boot_start as u said it is set
to zero means what does it mean boot node is located at 0th loaction fo ram 
is correct
regards 
som
-----Original Message-----
From: Ravi [mailto:kravi26@yahoo.com]
Sent: Friday, September 13, 2002 11:41 PM
To: Somshekar. C. Kadam - CTD, Chennai.
Cc: linux-mm@kvack.org
Subject: Re: bootmem ?



> struct bootmem_data
> unsigned long node_boot_start what for 
 
  node_boot_start always gets set to 0.
 
> void *node_bootmem_map what is this  for 
>
>  if i am right node_bootmem_map is a pointer to beginig of bitmap
> that is the end of kernel

  init_bootmem_core() creates a bitmap representing all pages available
to the bootmem allocator. To make sure this bitmap doesn't overwrite 
kernel text or data, the address beyond end of kernel is passed
to init_bootmem_core(). The location of this bitmap is stored in
node_bootmem_map.
  
 
>    what should be the value of node_boot_start 
 
>  i am having 32 mb ram 
>    my kernel is loaded from 0x400 after 1mb(including text data and
> bss) which is end of kernel 
> i am setting node_boot_start as the pouinter to bit map  storing 
> bitmap after the end of the kernel

 I didn't understand what you meant by that. Why do you have to set
node_boot_start? You just need to call init_bootmem() with the
right parameters - a safe address for creating the bootmem bitmap
and number of pages available to the bootmem allocator. 
  After initializing bootmem allocator, you have to make sure that
pages where kernel is loaded and the pages containing the bootmem
bitmap itself are marked reserved.

Hope this helps,
Ravi.

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Re: bootmem ?

[Ravi]

> struct bootmem_data
> unsigned long node_boot_start what for 
 
  node_boot_start always gets set to 0.
 
> void *node_bootmem_map what is this  for 
>
>  if i am right node_bootmem_map is a pointer to beginig of bitmap
> that is the end of kernel

  init_bootmem_core() creates a bitmap representing all pages available
to the bootmem allocator. To make sure this bitmap doesn't overwrite 
kernel text or data, the address beyond end of kernel is passed
to init_bootmem_core(). The location of this bitmap is stored in
node_bootmem_map.
  
 
>    what should be the value of node_boot_start 
 
>  i am having 32 mb ram 
>    my kernel is loaded from 0x400 after 1mb(including text data and
> bss) which is end of kernel 
> i am setting node_boot_start as the pouinter to bit map  storing 
> bitmap after the end of the kernel

 I didn't understand what you meant by that. Why do you have to set
node_boot_start? You just need to call init_bootmem() with the
right parameters - a safe address for creating the bootmem bitmap
and number of pages available to the bootmem allocator. 
  After initializing bootmem allocator, you have to make sure that
pages where kernel is loaded and the pages containing the bootmem
bitmap itself are marked reserved.

Hope this helps,
Ravi.

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Yahoo! News - Today's headlines
http://news.yahoo.com
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bootmem ?

[Somshekar. C. Kadam - CTD, Chennai.]

hi ,
 i am newbie to linux mm trying to understand bootmem allocator
struct bootmem_data
unsigned long node_boot_start what for 



void *node_bootmem_map what is this  for 

 if i am right 
           node_bootmem_map is apointer to beginig of bitmap that is the end
of kernel


   what should be the value of node_boot_start 

 i am having 32 mb ram 
 
   my kernel is loaded from 0x400 after 1mb(including text data and bss)
which is end of kernel 
 i am setting node_boot_start as the pouinter to bit map 
storing bitmap after the end of the kernel

what should be the value given to node_boot_start
whre should it be i am not clear 

 any idea pls 
thanks in advnce 

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