Re: [HMM 02/15] mm/hmm: heterogeneous memory management (HMM for short) v4

[Jerome Glisse]

On Wed, May 31, 2017 at 12:10:24PM +1000, Balbir Singh wrote:
> On Wed, 24 May 2017 13:20:11 -0400
> Jérôme Glisse <jglisse@xxxxxxxxxx> wrote:
> 
> > HMM provides 3 separate types of functionality:
> >     - Mirroring: synchronize CPU page table and device page table
> >     - Device memory: allocating struct page for device memory
> >     - Migration: migrating regular memory to device memory
> > 
> > This patch introduces some common helpers and definitions to all of
> > those 3 functionality.
> > 
> > Changed since v3:
> >   - Unconditionaly build hmm.c for static keys
> > Changed since v2:
> >   - s/device unaddressable/device private
> > Changed since v1:
> >   - Kconfig logic (depend on x86-64 and use ARCH_HAS pattern)
> > 
> > Signed-off-by: Jérôme Glisse <jglisse@xxxxxxxxxx>
> > Signed-off-by: Evgeny Baskakov <ebaskakov@xxxxxxxxxx>
> > Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>
> > Signed-off-by: Mark Hairgrove <mhairgrove@xxxxxxxxxx>
> > Signed-off-by: Sherry Cheung <SCheung@xxxxxxxxxx>
> > Signed-off-by: Subhash Gutti <sgutti@xxxxxxxxxx>
> > ---
> 
> It would be nice to explain a bit of how hmm_pfn_t bits work with pfn
> and find out what we need from an arch to support HMM.
> 

This is only needed for HMM_MIRROR feature so you do not care about it
for powerpc

Jérôme