Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754710AbZAGSlo (ORCPT ); Wed, 7 Jan 2009 13:41:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755916AbZAGSlT (ORCPT ); Wed, 7 Jan 2009 13:41:19 -0500 Received: from e28smtp01.in.ibm.com ([59.145.155.1]:52757 "EHLO e28smtp01.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755415AbZAGSlS (ORCPT ); Wed, 7 Jan 2009 13:41:18 -0500 From: Balbir Singh To: Andrew Morton Cc: Sudhir Kumar , YAMAMOTO Takashi , Paul Menage , lizf@cn.fujitsu.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, David Rientjes , Pavel Emelianov , Balbir Singh , KAMEZAWA Hiroyuki Date: Thu, 08 Jan 2009 00:11:16 +0530 Message-Id: <20090107184116.18062.8379.sendpatchset@localhost.localdomain> In-Reply-To: <20090107184110.18062.41459.sendpatchset@localhost.localdomain> References: <20090107184110.18062.41459.sendpatchset@localhost.localdomain> Subject: [RFC][PATCH 1/4] Memory controller soft limit documentation Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1889 Lines: 57 From: Balbir Singh Add documentation for soft limit feature support. Signed-off-by: Balbir Singh --- Documentation/controllers/memory.txt | 28 ++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-) diff -puN Documentation/controllers/memory.txt~memcg-soft-limit-documentation Documentation/controllers/memory.txt --- a/Documentation/controllers/memory.txt~memcg-soft-limit-documentation +++ a/Documentation/controllers/memory.txt @@ -360,7 +360,33 @@ cgroups created below it. NOTE2: This feature can be enabled/disabled per subtree. -7. TODO +7. Soft limits + +Soft limits allow for greater sharing of memory. The idea behind soft limits +is to allow control groups to use as much of the memory as needed, provided + +a. There is no memory contention +b. They do not exceed their hard limit + +When the system detects memory contention (through do_try_to_free_pages(), +while allocating), control groups are pushed back to their soft limits if +possible. If the soft limit of each control group is very high, they are +pushed back as much as possible to make sure that one control group does not +starve the others. + +7.1 Interface + +Soft limits can be setup by using the following commands (in this example we +assume a soft limit of 256 megabytes) + +# echo 256M > memory.soft_limit_in_bytes + +If we want to change this to 1G, we can at any time use + +# echo 1G > memory.soft_limit_in_bytes + + +8. TODO 1. Add support for accounting huge pages (as a separate controller) 2. Make per-cgroup scanner reclaim not-shared pages first _ -- Balbir -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/