Re: [patch 6/6] mmu_notifier: Add invalidate_all()

Robin Holt
2008-01-29T16:32:18Z

What is the status of getting invalidate_all adjusted to indicate a need
to also call _release?

Thanks,
Robin

On Mon, Jan 28, 2008 at 12:28:46PM -0800, Christoph Lameter wrote:
> when a task exits we can remove all external pts at once. At that point the
> extern mmu may also unregister itself from the mmu notifier chain to avoid
> future calls.
>
> Note the complications because of RCU. Other processors may not see that the
> notifier was unlinked until a quiescent period has passed!
>
> Signed-off-by: Christoph Lameter <clameter@sgi.com>
>
> ---
> include/linux/mmu_notifier.h | 4 ++++
> mm/mmap.c | 1 +
> 2 files changed, 5 insertions(+)
>
> Index: linux-2.6/include/linux/mmu_notifier.h
> ===================================================================
> --- linux-2.6.orig/include/linux/mmu_notifier.h 2008-01-28 11:43:03.000000000 -0800
> +++ linux-2.6/include/linux/mmu_notifier.h 2008-01-28 12:21:33.000000000 -0800
> @@ -62,6 +62,10 @@ struct mmu_notifier_ops {
> struct mm_struct *mm,
> unsigned long address);
>
> + /* Dummy needed because the mmu_notifier() macro requires it */
> + void (*invalidate_all)(struct mmu_notifier *mn, struct mm_struct *mm,
> + int dummy);
> +
> /*
> * lock indicates that the function is called under spinlock.
> */
> Index: linux-2.6/mm/mmap.c
> ===================================================================
> --- linux-2.6.orig/mm/mmap.c 2008-01-28 11:47:53.000000000 -0800
> +++ linux-2.6/mm/mmap.c 2008-01-28 11:57:45.000000000 -0800
> @@ -2034,6 +2034,7 @@ void exit_mmap(struct mm_struct *mm)
> unsigned long end;
>
> /* mm's last user has gone, and its about to be pulled down */
> + mmu_notifier(invalidate_all, mm, 0);
> arch_exit_mmap(mm);
>
> lru_add_drain();
>
> --