In a separate patch, to aid reviewers. Signed-off-by: Glauber Costa <glommer@xxxxxxxxxxxxx> CC: Christoph Lameter <cl@xxxxxxxxx> CC: Pekka Enberg <penberg@xxxxxxxxxxxxxx> CC: Michal Hocko <mhocko@xxxxxxx> CC: Kamezawa Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> CC: Johannes Weiner <hannes@xxxxxxxxxxx> CC: Suleiman Souhlal <suleiman@xxxxxxxxxx> CC: Randy Dunlap <rdunlap@xxxxxxxxxxxx> --- 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>