[Devel] [patch rh7] free shows used=0 inside centos7 CT

[Konstantin Khorenko]

Andrey,

please _carefully_ review what is shown in /proc/meminfo inside our CTs, how it corresponds to host reports, how mainstream kernel reports and
finally review the patch.

Thank you.

--
Best regards,

Konstantin Khorenko,
Virtuozzo Linux Kernel Team

On 12/04/2015 08:16 PM, Vasily Averin wrote:
> Customer reports that free or top command inside Centos7 CT shows 0 memory used
>
> free from procps-ng-3.3.10-3.el7 uses /proc/meminfo output and calculates
> used = total - free - buffers - cache - slab
>
> However kernel in some cases calculates "Cached" value in meminfo output by using
> the same formula:
> cached = total - free - slab (where buffers = 0)
>
> Alternative calculation of cached value does not work  this time becasue
> additional UB_SHMPAGES.held argument added to work-around
> "negative cached" problem in previous version of free/procps-ng
> see PSBM-29352 and http://kb.sp.parallels.com/en/123422
>
> However free output was changed some time ago and this old issue is not actual now.
> https://gitlab.com/procps-ng/procps/commit/2f96eef7f86a12b81badef1c91ec2d503ae4029d
> library: reverting tmpfs subtraction from cached (18-FEB-2014)
>
> Therefore we're going to revert patch for previous issue
> and believe that it resolves current problem too.
>
> https://jira.sw.ru/browse/PSBM-42024
> Signed-off-by: Vasily Averin <vvs at virtuozzo.com>
>