On Tue, Oct 27, 2020 at 10:41:33AM +1100, Gavin Shan wrote:
> On 10/27/20 1:44 AM, Will Deacon wrote:
> > For consistency with the rest of the stage-2 page-table page allocations
> > (performing using a kvm_mmu_memory_cache), ensure that __GFP_ACCOUNT is
> > included in the GFP flags for the PGD pages.
> > 
> > Cc: Marc Zyngier <[email protected]>
> > Cc: Quentin Perret <[email protected]>
> > Signed-off-by: Will Deacon <[email protected]>
> > ---
> >   arch/arm64/kvm/hyp/pgtable.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> 
> The patch itself looks good to me:
> 
> Reviewed-by: Gavin Shan <[email protected]>
> 
> Another question is why the page-table pages for hyp mode aren't
> allocated with __GFP_ACCOUNT in kvm_pgtable_hyp_init and hyp_map_walker()?
> The page-table pages for host or guest are allocated with GFP_PGTABLE_USER
> in alloc_pte_one().
> 
> #define GFP_PGTABLE_USER      (GFP_PGTABLE_KERNEL | __GFP_ACCOUNT)
> #define GFP_PGTABLE_KERNEL    (GFP_KERNEL | __GFP_ZERO)

I think because the guest pages are allocated as a direct result of the VMM,
whereas I tend to think of the hyp page-tables more like kernel page-tables
(which aren't accounted afaik: see GFP_PGTABLE_USER vs GFP_PGTABLE_KERNEL).

Will
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