Re: [PATCH v9 12/12] mm: stop zeroing memory during allocation in vmemmap

[Pasha Tatashin]

Hi Michal,

I decided not to merge these two patches, because in addition to sparc 
optimization move, we have this dependancies:

mm: zero reserved and unavailable struct pages

must be before

mm: stop zeroing memory during allocation in vmemmap.

Otherwise, we can end-up with struct pages that are not zeroed properly.

However, the first patch depends on
mm: zero struct pages during initialization

As it uses mm_zero_struct_page().

Pasha


On 10/03/2017 11:34 AM, Pasha Tatashin wrote:
> On 10/03/2017 09:19 AM, Michal Hocko wrote:
> > On Wed 20-09-17 16:17:14, Pavel Tatashin wrote:
> > > vmemmap_alloc_block() will no longer zero the block, so zero memory
> > > at its call sites for everything except struct pages. Struct page 
> > > memory
> > > is zero'd by struct page initialization.
> > >
> > > Replace allocators in sprase-vmemmap to use the non-zeroing version. So,
> > > we will get the performance improvement by zeroing the memory in 
> > > parallel
> > > when struct pages are zeroed.
> >
> > Is it possible to merge this patch with 
> > http://lkml.kernel.org/r/20170920201714.19817-7-pasha.tatashin@xxxxxxxxxx
>
> Yes, I will do that. It would also require re-arranging
> [PATCH v9 07/12] sparc64: optimized struct page zeroing
> optimization to come after this patch.
>
> Pasha