Re: missing madvise functionality

Eric Dumazet
2007-04-04T11:54:58Z

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.