Re: [PATCH 0/4] Memory controller soft limit patches (v4)

From: KAMEZAWA Hiroyuki
Date: Fri Mar 06 2009 - 04:56:18 EST


On Fri, 06 Mar 2009 14:53:23 +0530
Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote:

>
> From: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
>
> New Feature: Soft limits for memory resource controller.
>
> Changelog v4...v3
> 1. Adopted suggestions from Kamezawa to do a per-zone-per-node reclaim
> while doing soft limit reclaim. We don't record priorities while
> doing soft reclaim
> 2. Some of the overheads associated with soft limits (like calculating
> excess each time) is eliminated
> 3. The time_after(jiffies, 0) bug has been fixed
> 4. Tasks are throttled if the mem cgroup they belong to is being soft reclaimed
> and at the same time tasks are increasing the memory footprint and causing
> the mem cgroup to exceed its soft limit.
>
I don't think this "4" is necessary.


> Changelog v3...v2
> 1. Implemented several review comments from Kosaki-San and Kamezawa-San
> Please see individual changelogs for changes
>
> Changelog v2...v1
> 1. Soft limits now support hierarchies
> 2. Use spinlocks instead of mutexes for synchronization of the RB tree
>
> Here is v4 of the new soft limit implementation. Soft limits is a new feature
> for the memory resource controller, something similar has existed in the
> group scheduler in the form of shares. The CPU controllers interpretation
> of shares is very different though.
>
> Soft limits are the most useful feature to have for environments where
> the administrator wants to overcommit the system, such that only on memory
> contention do the limits become active. The current soft limits implementation
> provides a soft_limit_in_bytes interface for the memory controller and not
> for memory+swap controller. The implementation maintains an RB-Tree of groups
> that exceed their soft limit and starts reclaiming from the group that
> exceeds this limit by the maximum amount.
>
> If there are no major objections to the patches, I would like to get them
> included in -mm.
>
You got Nack from me, again ;) And you know why.
I'll post my one later, I hope that one will be good input for you.

Thanks,
-Kame


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