Re: missing madvise functionality

Nick Piggin
2007-04-05T02:01:15Z

Eric Dumazet wrote:
> On Wed, 04 Apr 2007 20:05:54 +1000
> Nick Piggin <nickpiggin@yahoo.com.au> wrote:
>
>>>@@ -1638,7 +1652,7 @@ find_extend_vma(struct mm_struct * mm, u
>>> unsigned long start;
>>>
>>> addr &= PAGE_MASK;
>>>- vma = find_vma(mm,addr);
>>>+ vma = find_vma(mm,addr,&current->vmacache);
>>> if (!vma)
>>> return NULL;
>>> if (vma->vm_start <= addr)
>>
>>So now you can have current calling find_extend_vma on someone else's mm
>>but using their cache. So you're going to return current's vma, or current
>>is going to get one of mm's vmas in its cache :P
>
>
> This was not a working patch, just to throw the idea, since the answers I got showed I was not understood.
>
> In this case, find_extend_vma() should of course have one struct vm_area_cache * argument, like find_vma()
>
> One single cache on one mm is not scalable. oprofile badly hits it on a dual cpu config.

Oh, what sort of workload are you using to show this? The only reason that I
didn't submit my thread cache patches was that I didn't show a big enough
improvement.

--
SUSE Labs, Novell Inc.