Re: [PATCH kernel v9 22/32] powerpc/powernv: Implement multilevel TCE tables

2015-05-05 Thread David Gibson
On Fri, May 01, 2015 at 07:48:49PM +1000, Alexey Kardashevskiy wrote: > On 04/29/2015 03:04 PM, David Gibson wrote: > >On Sat, Apr 25, 2015 at 10:14:46PM +1000, Alexey Kardashevskiy wrote: > >>TCE tables might get too big in case of 4K IOMMU pages and DDW enabled > >>on huge guests (hundreds of GB

Re: [PATCH kernel v9 22/32] powerpc/powernv: Implement multilevel TCE tables

2015-05-01 Thread Alexey Kardashevskiy
On 04/29/2015 03:04 PM, David Gibson wrote: On Sat, Apr 25, 2015 at 10:14:46PM +1000, Alexey Kardashevskiy wrote: TCE tables might get too big in case of 4K IOMMU pages and DDW enabled on huge guests (hundreds of GB of RAM) so the kernel might be unable to allocate contiguous chunk of physical m

Re: [PATCH kernel v9 22/32] powerpc/powernv: Implement multilevel TCE tables

2015-04-28 Thread David Gibson
On Sat, Apr 25, 2015 at 10:14:46PM +1000, Alexey Kardashevskiy wrote: > TCE tables might get too big in case of 4K IOMMU pages and DDW enabled > on huge guests (hundreds of GB of RAM) so the kernel might be unable to > allocate contiguous chunk of physical memory to store the TCE table. > > To add

[PATCH kernel v9 22/32] powerpc/powernv: Implement multilevel TCE tables

2015-04-25 Thread Alexey Kardashevskiy
TCE tables might get too big in case of 4K IOMMU pages and DDW enabled on huge guests (hundreds of GB of RAM) so the kernel might be unable to allocate contiguous chunk of physical memory to store the TCE table. To address this, POWER8 CPU (actually, IODA2) supports multi-level TCE tables, up to 5