Re: [RFC 12/18] limits: track RLIMIT_MEMLOCK actual max

[Alex Williamson <alex.williamson@redhat.com>]

On Mon, 13 Jun 2016 22:44:19 +0300
Topi Miettinen <toiwoton@gmail.com> wrote:

> Track maximum size of locked memory, presented in /proc/self/limits.
> 
> Signed-off-by: Topi Miettinen <toiwoton@gmail.com>
> ---
>  arch/ia64/kernel/perfmon.c                 |  1 +
>  arch/powerpc/kvm/book3s_64_vio.c           |  1 +
>  arch/powerpc/mm/mmu_context_iommu.c        |  1 +
>  drivers/infiniband/core/umem.c             |  1 +
>  drivers/infiniband/hw/hfi1/user_pages.c    |  1 +
>  drivers/infiniband/hw/qib/qib_user_pages.c |  1 +
>  drivers/infiniband/hw/usnic/usnic_uiom.c   |  2 ++
>  drivers/misc/mic/scif/scif_rma.c           |  1 +
>  drivers/vfio/vfio_iommu_spapr_tce.c        |  2 ++
>  drivers/vfio/vfio_iommu_type1.c            |  2 ++
>  include/linux/sched.h                      | 10 ++++++++--
>  kernel/bpf/syscall.c                       |  6 ++++++
>  kernel/events/core.c                       |  1 +
>  mm/mlock.c                                 |  7 +++++++
>  mm/mmap.c                                  |  3 +++
>  mm/mremap.c                                |  3 +++
>  16 files changed, 41 insertions(+), 2 deletions(-)
...  
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 2ba1942..4c6e7a3 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -312,6 +312,8 @@ static long vfio_pin_pages(unsigned long vaddr, long npage,
>  		}
>  	}
>  
> +	bump_rlimit(RLIMIT_MEMLOCK, (current->mm->locked_vm + i) << PAGE_SHIFT);
> +
>  	if (!rsvd)
>  		vfio_lock_acct(i);
>  


Not all cases passing through here bump rlimit (see: rsvd), there's an
entire case above the other end of this closing bracket that does bump
rlimit but returns before here, and I wonder why we wouldn't just do
this in our vfio_lock_acct() accounting function anyway.  Thanks,

Alex