Re: objrmap-core-1 (rmap removal for file mappings to avoid 4:4 in<=16G machines)

[Arjan van de Ven]

> . Basically without
> this fix it's like 2.6 is running w/o pte-highmem. 700 tasks with 2.7G
> of shm mapped each would run the box out of zone-normal even with 4:4.
> With 3:1 100 tasks would be enough. Math is easy:
> 
> 	2.7*1024*1024*1024/4096*8*100/1024/1024/1024
> 	2.7*1024*1024*1024/4096*8*700/1024/1024/1024


not saying your patch is not useful or anything,but there is a less
invasive shortcut possible. Oracle wants to mlock() its shared area, and
for mlock()'d pages we don't need a pte chain *at all*. So we could get
rid of a lot of this overhead that way.

Now your patch might well be useful for a lot of other reasons too, but
if this is the only one there are potential less invasive solutions for
2.6.

Attachment: signature.asc
Description: This is a digitally signed message part