lkml.org 
[lkml]   [2000]   [Jan]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC] 2.3.39 zone balancing
On Thu, 13 Jan 2000, Rik van Riel wrote:

>On Wed, 12 Jan 2000, Kanoj Sarcar wrote:
>
>> --- mm/page_alloc.c Tue Jan 11 11:00:31 2000
>> +++ mm/page_alloc.c Tue Jan 11 23:59:35 2000
>> + cumulative += size;
>> + mask = (cumulative >> 7);
>> + if (mask < 1) mask = 1;
>> + zone->pages_low = mask*2;
>> + zone->pages_high = mask*3;
>> zone->low_on_memory = 0;
>
>I think that busier machines probably have a larger need
>for DMA memory than this code fragment will give us. I
>have the gut feeling that we'll want to keep about 512kB
>or more free in the lower 16MB of busy machines...
>
>(if only because such a large amount of free pages in
>such a small part of the address space will give us
>higher-order free pages)

That's only a workaround because the page-freeing mechanism is currently
not aware about fragmentation and about the order of the request we asked
for.

So such code shouldn't be wrote assuming the page-freeing is weak as now.

Supposing it's smart we don't need to take lots of memory free in the dma
zone to allow high order allocations to succeed.

Andrea


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:55    [W:0.106 / U:0.168 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site