linux-kernel - [RFC][PATCH 0/4] Memory controller soft limit patches (v2)

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Message-Id: <20090216110844.29795.17804.sendpatchset@localhost.localdomain>
Date:	Mon, 16 Feb 2009 16:38:44 +0530
From:	Balbir Singh <balbir@...ux.vnet.ibm.com>
To:	linux-mm@...ck.org
Cc:	Sudhir Kumar <skumar@...ux.vnet.ibm.com>,
	YAMAMOTO Takashi <yamamoto@...inux.co.jp>,
	Bharata B Rao <bharata@...ibm.com>,
	Paul Menage <menage@...gle.com>, lizf@...fujitsu.com,
	linux-kernel@...r.kernel.org,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	David Rientjes <rientjes@...gle.com>,
	Pavel Emelianov <xemul@...nvz.org>,
	Dhaval Giani <dhaval@...ux.vnet.ibm.com>,
	Balbir Singh <balbir@...ux.vnet.ibm.com>,
	Rik van Riel <riel@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
Subject: [RFC][PATCH 0/4] Memory controller soft limit patches (v2)

From: Balbir Singh <balbir@...ux.vnet.ibm.com>

Changelog v2...v1
1. Soft limits now support hierarchies
2. Use spinlocks instead of mutexes for synchronization of the RB tree

Here is v2 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. We'll compare shares and soft limits
below.

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.

This is an RFC implementation and is not meant for inclusion

TODOs

1. The current implementation maintains the delta from the soft limit
   and pushes back groups to their soft limits, a ratio of delta/soft_limit
   is more useful
2. It would be nice to have more targetted reclaim (in terms of pages to
   recalim) interface. So that groups are pushed back, close to their soft
   limits.

Tests
-----

I've run two memory intensive workloads with differing soft limits and
seen that they are pushed back to their soft limit on contention. Their usage
was their soft limit plus additional memory that they were able to grab
on the system.

Please review, comment.

Series
------

memcg-soft-limit-documentation.patch
memcg-add-soft-limit-interface.patch
memcg-organize-over-soft-limit-groups.patch
memcg-soft-limit-reclaim-on-contention.patch
---

 0 files changed, 0 insertions(+), 0 deletions(-)

-- 
	Balbir
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