Messages in this thread Patch in this message | | | From | Balbir Singh <> | Date | Sun, 02 Nov 2008 00:19:02 +0530 | Subject | [mm] [PATCH 4/4] Memory cgroup hierarchy feature selector |
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Don't enable multiple hierarchy support by default. This patch introduces a features element that can be set to enable the nested depth hierarchy feature. This feature can only be enabled when there is just one cgroup (the root cgroup).
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> ---
mm/memcontrol.c | 38 +++++++++++++++++++++++++++++++++++++- 1 file changed, 37 insertions(+), 1 deletion(-)
diff -puN mm/memcontrol.c~memcg-add-hierarchy-selector mm/memcontrol.c --- linux-2.6.28-rc2/mm/memcontrol.c~memcg-add-hierarchy-selector 2008-11-02 00:15:00.000000000 +0530 +++ linux-2.6.28-rc2-balbir/mm/memcontrol.c 2008-11-02 00:15:00.000000000 +0530 @@ -40,6 +40,9 @@ struct cgroup_subsys mem_cgroup_subsys __read_mostly; #define MEM_CGROUP_RECLAIM_RETRIES 5 +static unsigned long mem_cgroup_features; +#define MEM_CGROUP_FEAT_HIERARCHY 0x1 + /* * Statistics for memory cgroup. */ @@ -1080,6 +1083,31 @@ out: return ret; } +static u64 mem_cgroup_feature_read(struct cgroup *cont, struct cftype *cft) +{ + return mem_cgroup_features; +} + +static int mem_cgroup_feature_write(struct cgroup *cont, struct cftype *cft, + u64 val) +{ + int retval = 0; + struct cgroup *cgroup = init_mem_cgroup.css.cgroup; + + if (val & MEM_CGROUP_FEAT_HIERARCHY) { + if (list_empty(&cgroup->children)) + mem_cgroup_features |= MEM_CGROUP_FEAT_HIERARCHY; + else + retval = -EBUSY; + } else { + if (list_empty(&cgroup->children)) + mem_cgroup_features &= ~MEM_CGROUP_FEAT_HIERARCHY; + else + retval = -EBUSY; + } + return retval; +} + static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft) { return res_counter_read_u64(&mem_cgroup_from_cont(cont)->res, @@ -1214,6 +1242,11 @@ static struct cftype mem_cgroup_files[] .name = "stat", .read_map = mem_control_stat_show, }, + { + .name = "features", + .write_u64 = mem_cgroup_feature_write, + .read_u64 = mem_cgroup_feature_read, + }, }; static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) @@ -1292,7 +1325,10 @@ mem_cgroup_create(struct cgroup_subsys * return ERR_PTR(-ENOMEM); } - res_counter_init(&mem->res, parent ? &parent->res : NULL); + if ((mem_cgroup_features & MEM_CGROUP_FEAT_HIERARCHY) && parent) + res_counter_init(&mem->res, &parent->res); + else + res_counter_init(&mem->res, NULL); for_each_node_state(node, N_POSSIBLE) if (alloc_mem_cgroup_per_zone_info(mem, node)) _ -- Balbir
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