Re: [PATCH v5 00/11] Introduce huge zero page

Kirill A. Shutemov
2012-11-15T07:28:50Z

[-- Attachment #1: Type: text/plain, Size: 1638 bytes --]

On Wed, Nov 14, 2012 at 01:33:42PM -0800, Andrew Morton wrote:
> On Wed, 7 Nov 2012 17:00:52 +0200
> "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> wrote:
>
> > Andrew, here's updated huge zero page patchset.
>
> There is still a distinct lack of reviewed-by's and acked-by's on this
> patchset.
>
> On 13 Sep, Andrea did indicate that he "reviewed the whole patchset and
> it looks fine to me". But that information failed to make it into the
> changelogs, which is bad.

As I said before, I had to drop Andrea's reviewed-by on rebase to
v3.7-rc1. I had to solve few not-that-trivial conflicts and I was not sure
if the reviewed-by is still applicable.

> I grabbed the patchset. I might hold it over until 3.9 depending on
> additional review/test feedback and upon whether Andrea can be
> persuaded to take another look at it all.
>
> I'm still a bit concerned over the possibility that some workloads will
> cause a high-frequency free/alloc/memset cycle on that huge zero page.
> We'll see how it goes...
>
> For this reason and for general ease-of-testing: can and should we add
> a knob which will enable users to disable the feature at runtime? That
> way if it causes problems or if we suspect it's causing problems, we
> can easily verify the theory and offer users a temporary fix.
>
> Such a knob could be a boot-time option, but a post-boot /proc thing
> would be much nicer.

Okay, I'll add sysfs knob.

BTW, we already have build time knob: just revert last two patches in the
series. It will bring lazy allocation instead of refcounting.

--
Kirill A. Shutemov

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 836 bytes --]