Re: [PATCH 2/2] Fold numa_maps into mempolicy.c

[Andi Kleen <ak@suse.de>]

On Wednesday 16 November 2005 08:10, Paul Jackson wrote:
> Christoph wrote:
> > + * Must hold mmap_sem until memory pointer is no longer in use
> > + * or be called from the current task.
> > + */
> > +struct mempolicy *get_vma_policy(struct task_struct *task,
> 
> Twenty (well, four) questions time.
> 
> Hmmm ... is that true - that get_vma_policy() can be called for the
> current task w/o holding mmap_sem?

Yes, e.g. when vma is NULL.

> Is there any call to get_vma_policy() made that isn't holding mmap_sem?

There are some callers of alloc_page_vma with NULL vma yes

> Except for /proc output, is there any call to get_vma_policy made on any
> task other than current?

In the original version there wasn't any. I still think it's a mistake
to allow it for /proc, unfortunately the patch went in.

> What does "until memory pointer is no longer in use" mean?

mempolicy is no longer in use or you took a reference.


-Andi
 

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