Re: [PATCH v1 0/4]mm: convert totalram_pages, totalhigh_pages and managed pages to atomic

Arun KS
2018-11-07T06:19:47Z

On 2018-11-07 05:52, Andrew Morton wrote:
> On Fri, 26 Oct 2018 16:30:58 +0530 Arun KS <arunks@codeaurora.org>
> wrote:
>
>> This series convert totalram_pages, totalhigh_pages and
>> zone->managed_pages to atomic variables.
>
> The whole point appears to be removal of managed_page_count_lock, yes?
>
> Why? What is the value of this patchset? If "performance" then are
> any
> measurements available?

Hello Andrew,

https://patchwork.kernel.org/patch/10670787/
In version 2, I have added motivation behind this conversion. Pasting
same here,

totalram_pages, zone->managed_pages and totalhigh_pages updates are
protected by managed_page_count_lock, but readers never care about it.
Convert these variables to atomic to avoid readers potentially seeing a
store tear. I don't think we have a performance improvement here.

Regards,
Arun