From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758213Ab2FRKdk (ORCPT ); Mon, 18 Jun 2012 06:33:40 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:9335 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751864Ab2FRKdi (ORCPT ); Mon, 18 Jun 2012 06:33:38 -0400 From: Glauber Costa To: Cc: Pekka Enberg , Cristoph Lameter , David Rientjes , , , , , Frederic Weisbecker , Suleiman Souhlal , Glauber Costa , Pekka Enberg , Michal Hocko , Johannes Weiner , Randy Dunlap Subject: [PATCH v4 25/25] Documentation: add documentation for slab tracker for memcg Date: Mon, 18 Jun 2012 14:28:18 +0400 Message-Id: <1340015298-14133-26-git-send-email-glommer@parallels.com> X-Mailer: git-send-email 1.7.10.2 In-Reply-To: <1340015298-14133-1-git-send-email-glommer@parallels.com> References: <1340015298-14133-1-git-send-email-glommer@parallels.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In a separate patch, to aid reviewers. Signed-off-by: Glauber Costa CC: Christoph Lameter CC: Pekka Enberg CC: Michal Hocko CC: Kamezawa Hiroyuki CC: Johannes Weiner CC: Suleiman Souhlal CC: Randy Dunlap --- Documentation/cgroups/memory.txt | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt index 9b1067a..9ea82b5 100644 --- a/Documentation/cgroups/memory.txt +++ b/Documentation/cgroups/memory.txt @@ -74,6 +74,12 @@ Brief summary of control files. memory.kmem.tcp.limit_in_bytes # set/show hard limit for tcp buf memory memory.kmem.tcp.usage_in_bytes # show current tcp buf memory allocation + memory.kmem.limit_in_bytes # set/show hard limit for general kmem memory + memory.kmem.usage_in_bytes # show current general kmem memory allocation + memory.kmem.failcnt # show current number of kmem limit hits + memory.kmem.max_usage_in_bytes # show max kmem usage + memory.kmem.slabinfo # show cgroup-specific slab usage information + 1. History The memory controller has a long history. A request for comments for the memory @@ -270,6 +276,14 @@ cgroup may or may not be accounted. Currently no soft limit is implemented for kernel memory. It is future work to trigger slab reclaim when those limits are reached. +Kernel memory is not accounted until it is limited. Users that want to just +track kernel memory usage can set the limit value to a big enough value so +the limit is guaranteed to never hit. A kernel memory limit bigger than the +current memory limit will have this effect as well. + +This guarantes that this extension is backwards compatible to any previous +memory cgroup version. + 2.7.1 Current Kernel Memory resources accounted * sockets memory pressure: some sockets protocols have memory pressure @@ -278,6 +292,24 @@ per cgroup, instead of globally. * tcp memory pressure: sockets memory pressure for the tcp protocol. +* slab/kmalloc: + +When slab memory is tracked (memory.kmem.limit_in_bytes != -1ULL), both +memory.kmem.usage_in_bytes and memory.usage_in_bytes are updated. When +memory.kmem.limit_in_bytes is left alone, no tracking of slab caches takes +place. + +Because a slab page is shared among many tasks, it is not possible to take +any meaningful action upon task migration. Slabs created in a cgroup stay +around until the cgroup is destructed. Information about the slabs used +by the cgroup is displayed in the cgroup file memory.kmem.slabinfo. The format +of this file is and should remain compatible with /proc/slabinfo. + +Upon cgroup destruction, slabs that holds no live references are destructed. +Workers are fired to destroy the remaining caches as they objects are freed. + +Memory used by dead caches are shown in the proc file /proc/dead_slabinfo + 3. User Interface 0. Configuration @@ -286,6 +318,7 @@ a. Enable CONFIG_CGROUPS b. Enable CONFIG_RESOURCE_COUNTERS c. Enable CONFIG_CGROUP_MEM_RES_CTLR d. Enable CONFIG_CGROUP_MEM_RES_CTLR_SWAP (to use swap extension) +d. Enable CONFIG_CGROUP_MEM_RES_CTLR_KMEM (to use experimental kmem extension) 1. Prepare the cgroups (see cgroups.txt, Why are cgroups needed?) # mount -t tmpfs none /sys/fs/cgroup -- 1.7.10.2