[Devel] [PATCH rh7 v2] x86: "pages zeroing on free" option introduced

[Vladimir Davydov]

On Wed, Nov 18, 2015 at 08:31:03PM +0400, Stanislav Kinsburskiy wrote:
> This patch add pages zeroing option to free_pages_prepare().
> It's disabled by default. To enable it one should add "zero-free-pages"
> kernel option to kernel boot parameters.
> Note, that kernel boot option handling and enabling of pages zeroing are
> divided. The reason for this is that static keys initialization can't be
> performed during kernel parameters parsing (can't specify, what is the exact
> reason, but kernel just doesn't boot, if static key is incremented on
> parameter callback). Because of this split, actual zeroing is enabled later
> during kernel boot, but still early enough.

> Another thing to notice, is that code is moved to a separate source file.
> The reason for this is to simplify rebases in future.

The last paragraph isn't true anymore :-)

> 
> https://jira.sw.ru/browse/PSBM-33071
> 
> v2: All the code was moved to mm/pages_alloc.c

Yeah, I like this more.

Reviewed-by: Vladimir Davydov <vdavydov at virtuozzo.com>

Come to think of it, with jump labels we can make it possible to flip
this feature at runtime via sysctl, but it's surely beyond the scope of
this patch.