Re: [patch] mm: recheck lock rlim after f_op->mmap() method

[Hugh Dickins]

On Tue, 10 Jul 2007, Dmitry Monakhov wrote:
> On 18:27 ÐÑÑ 10 ÐÑÐ     , Hugh Dickins wrote:
> > Or would this simpler patch be the right one?  I suspect the
> > mspec driver only says VM_LOCKED because of a deep-seated but
> > irrational fear that its pages might fall into reclaim.
> No mspec is not the only one :( , in my case it was fglrx (ati driver).

Ah, then fglrx is wrong too.  We don't want to check locked_vm,
but we don't much want it to wrap negative later.  Perhaps we
should mask VM_LOCKED off, perhaps we should BUG, perhaps we
should ask ATI/AMD to change it (a BUG would be persuasive ;)

> BTW: where is comment about it in do_mmap_pgoff:  

Sorry, I don't understand.  You'd like a comment saying which flags
the driver may change and which it may not?  Hmmm... not today.

> 	/* Can addr have changed??
> 	 *
> 	 * Answer: Yes, several device drivers can do
> 	 * it in their
> 	 *         f_op->mmap method. -DaveM
> 	 */
> 	addr = vma->vm_start;
> 	pgoff = vma->vm_pgoff;
> 	vm_flags = vma->vm_flags;

Hugh