Re: Deleting an element from a free_list?

Re: Deleting an element from a free_list?

[frankeh]

NO, it will NOT prevent the kernel of allocating these blocks. They have to
be properly marked in the
bitmaps of the buddy algorithm...
You basically have to do what alloc_pages() does !!
If you know the addresses upfront at boottime ... you might screw around
with the reserve_bootmem or the
BIOS E820 bootmem map.....  (assuming you are sitting on an x86 box).

-- Hubertus

Timur Tabi <ttabi@interactivesi.com>@kvack.org on 06/27/2000 02:46:43 PM

Sent by:  owner-linux-mm@kvack.org


To:   Linux MM mailing list <linux-mm@kvack.org>
cc:
Subject:  Deleting an element from a free_list?



free_area[x].free_list.next points to the head of a linked list of free
blocks
of order x (2^x contiguous pages).  If I simply remove one element from one
of
these linked lists, using function list_del() in list.h, does that
effectively
remove that block from the free list and hence prevent the kernel from
allocating those blocks of memory to anyone else?  This is assuming that I
never
ever plan to "unallocate" those blocks of memory.  Will I need to also
update
the corresponding mem_map_t structures by doing something like setting the
usage
count to 1 or setting some bits in the flags field?



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Timur Tabi - ttabi@interactivesi.com
Interactive Silicon - http://www.interactivesi.com

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Re: Deleting an element from a free_list?

[Timur Tabi]

** Reply to message from frankeh@us.ibm.com on Tue, 27 Jun 2000 14:55:15 -0400


> NO, it will NOT prevent the kernel of allocating these blocks. They have to
> be properly marked in the
> bitmaps of the buddy algorithm...

Damn, I knew I was forgetting something.

> You basically have to do what alloc_pages() does !!

*sigh* back to the source ...




--
Timur Tabi - ttabi@interactivesi.com
Interactive Silicon - http://www.interactivesi.com

When replying to a mailing-list message, please don't cc: me, because then I'll just get two copies of the same message.
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Deleting an element from a free_list?

[Timur Tabi]

free_area[x].free_list.next points to the head of a linked list of free blocks
of order x (2^x contiguous pages).  If I simply remove one element from one of
these linked lists, using function list_del() in list.h, does that effectively
remove that block from the free list and hence prevent the kernel from
allocating those blocks of memory to anyone else?  This is assuming that I never
ever plan to "unallocate" those blocks of memory.  Will I need to also update
the corresponding mem_map_t structures by doing something like setting the usage
count to 1 or setting some bits in the flags field?



--
Timur Tabi - ttabi@interactivesi.com
Interactive Silicon - http://www.interactivesi.com

When replying to a mailing-list message, please don't cc: me, because then I'll just get two copies of the same message.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux.eu.org/Linux-MM/