diff options
| -rw-r--r-- | Documentation/cgroups/memory.txt | 40 | ||||
| -rw-r--r-- | init/Kconfig | 11 | ||||
| -rw-r--r-- | mm/memcontrol.c | 105 |
3 files changed, 149 insertions, 7 deletions
diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt index cc0ebc5..f245324 100644 --- a/Documentation/cgroups/memory.txt +++ b/Documentation/cgroups/memory.txt @@ -44,8 +44,9 @@ Features: - oom-killer disable knob and oom-notifier - Root cgroup has no limit controls. - Kernel memory and Hugepages are not under control yet. We just manage - pages on LRU. To add more controls, we have to take care of performance. + Hugepages is not under control yet. We just manage pages on LRU. To add more + controls, we have to take care of performance. Kernel memory support is work + in progress, and the current version provides basically functionality. Brief summary of control files. @@ -56,8 +57,11 @@ Brief summary of control files. (See 5.5 for details) memory.memsw.usage_in_bytes # show current res_counter usage for memory+Swap (See 5.5 for details) + memory.kmem.usage_in_bytes # show current res_counter usage for kmem only. + (See 2.7 for details) memory.limit_in_bytes # set/show limit of memory usage memory.memsw.limit_in_bytes # set/show limit of memory+Swap usage + memory.kmem.limit_in_bytes # if allowed, set/show limit of kernel memory memory.failcnt # show the number of memory usage hits limits memory.memsw.failcnt # show the number of memory+Swap hits limits memory.max_usage_in_bytes # show max memory usage recorded @@ -72,6 +76,9 @@ Brief summary of control files. memory.oom_control # set/show oom controls. memory.numa_stat # show the number of memory usage per numa node + memory.independent_kmem_limit # select whether or not kernel memory limits are + independent of user limits + 1. History The memory controller has a long history. A request for comments for the memory @@ -255,6 +262,35 @@ When oom event notifier is registered, event will be delivered. per-zone-per-cgroup LRU (cgroup's private LRU) is just guarded by zone->lru_lock, it has no lock of its own. +2.7 Kernel Memory Extension (CONFIG_CGROUP_MEM_RES_CTLR_KMEM) + +With the Kernel memory extension, the Memory Controller is able to limit +the amount of kernel memory used by the system. Kernel memory is fundamentally +different than user memory, since it can't be swapped out, which makes it +possible to DoS the system by consuming too much of this precious resource. + +Some kernel memory resources may be accounted and limited separately from the +main "kmem" resource. For instance, a slab cache that is considered important +enough to be limited separately may have its own knobs. + +Kernel memory limits are not imposed for the root cgroup. Usage for the root +cgroup may or may not be accounted. + +Memory limits as specified by the standard Memory Controller may or may not +take kernel memory into consideration. This is achieved through the file +memory.independent_kmem_limit. A Value different than 0 will allow for kernel +memory to be controlled separately. + +When kernel memory limits are not independent, the limit values set in +memory.kmem files are ignored. + +Currently no soft limit is implemented for kernel memory. It is future work +to trigger slab reclaim when those limits are reached. + +2.7.1 Current Kernel Memory resources accounted + +None + 3. User Interface 0. Configuration diff --git a/init/Kconfig b/init/Kconfig index 43298f9..b8930d5 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -689,6 +689,17 @@ config CGROUP_MEM_RES_CTLR_SWAP_ENABLED For those who want to have the feature enabled by default should select this option (if, for some reason, they need to disable it then swapaccount=0 does the trick). +config CGROUP_MEM_RES_CTLR_KMEM + bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)" + depends on CGROUP_MEM_RES_CTLR && EXPERIMENTAL + default n + help + The Kernel Memory extension for Memory Resource Controller can limit + the amount of memory used by kernel objects in the system. Those are + fundamentally different from the entities handled by the standard + Memory Controller, which are page-based, and can be swapped. Users of + the kmem extension can use it to guarantee that no group of processes + will ever exhaust kernel resources alone. config CGROUP_PERF bool "Enable perf_event per-cpu per-container group (cgroup) monitoring" diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 6aff93c..9fbcff7 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -227,6 +227,10 @@ struct mem_cgroup { */ struct res_counter memsw; /* + * the counter to account for kmem usage. + */ + struct res_counter kmem; + /* * Per cgroup active and inactive list, similar to the * per zone LRU lists. */ @@ -277,6 +281,11 @@ struct mem_cgroup { */ unsigned long move_charge_at_immigrate; /* + * Should kernel memory limits be stabilished independently + * from user memory ? + */ + int kmem_independent_accounting; + /* * percpu counter. */ struct mem_cgroup_stat_cpu *stat; @@ -344,9 +353,14 @@ enum charge_type { }; /* for encoding cft->private value on file */ -#define _MEM (0) -#define _MEMSWAP (1) -#define _OOM_TYPE (2) + +enum mem_type { + _MEM = 0, + _MEMSWAP, + _OOM_TYPE, + _KMEM, +}; + #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val)) #define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff) #define MEMFILE_ATTR(val) ((val) & 0xffff) @@ -3848,10 +3862,17 @@ static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap) u64 val; if (!mem_cgroup_is_root(memcg)) { + val = 0; +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM + if (!memcg->kmem_independent_accounting) + val = res_counter_read_u64(&memcg->kmem, RES_USAGE); +#endif if (!swap) - return res_counter_read_u64(&memcg->res, RES_USAGE); + val += res_counter_read_u64(&memcg->res, RES_USAGE); else - return res_counter_read_u64(&memcg->memsw, RES_USAGE); + val += res_counter_read_u64(&memcg->memsw, RES_USAGE); + + return val; } val = mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_CACHE); @@ -3884,6 +3905,11 @@ static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft) else val = res_counter_read_u64(&memcg->memsw, name); break; +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM + case _KMEM: + val = res_counter_read_u64(&memcg->kmem, name); + break; +#endif default: BUG(); break; @@ -4612,6 +4638,69 @@ static int mem_control_numa_stat_open(struct inode *unused, struct file *file) } #endif /* CONFIG_NUMA */ +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM +static u64 kmem_limit_independent_read(struct cgroup *cgroup, struct cftype *cft) +{ + return mem_cgroup_from_cont(cgroup)->kmem_independent_accounting; +} + +static int kmem_limit_independent_write(struct cgroup *cgroup, struct cftype *cft, + u64 val) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgroup); + struct mem_cgroup *parent = parent_mem_cgroup(memcg); + + val = !!val; + + /* + * This follows the same hierarchy restrictions than + * mem_cgroup_hierarchy_write() + */ + if (!parent || !parent->use_hierarchy) { + if (list_empty(&cgroup->children)) + memcg->kmem_independent_accounting = val; + else + return -EBUSY; + } + else + return -EINVAL; + + return 0; +} +static struct cftype kmem_cgroup_files[] = { + { + .name = "independent_kmem_limit", + .read_u64 = kmem_limit_independent_read, + .write_u64 = kmem_limit_independent_write, + }, + { + .name = "kmem.usage_in_bytes", + .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE), + .read_u64 = mem_cgroup_read, + }, + { + .name = "kmem.limit_in_bytes", + .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT), + .read_u64 = mem_cgroup_read, + }, +}; + +static int register_kmem_files(struct cgroup *cont, struct cgroup_subsys *ss) +{ + int ret = 0; + + ret = cgroup_add_files(cont, ss, kmem_cgroup_files, + ARRAY_SIZE(kmem_cgroup_files)); + return ret; +}; + +#else +static int register_kmem_files(struct cgroup *cont, struct cgroup_subsys *ss) +{ + return 0; +} +#endif + static struct cftype mem_cgroup_files[] = { { .name = "usage_in_bytes", @@ -4925,6 +5014,7 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) if (parent && parent->use_hierarchy) { res_counter_init(&memcg->res, &parent->res); res_counter_init(&memcg->memsw, &parent->memsw); + res_counter_init(&memcg->kmem, &parent->kmem); /* * We increment refcnt of the parent to ensure that we can * safely access it on res_counter_charge/uncharge. @@ -4935,6 +5025,7 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) } else { res_counter_init(&memcg->res, NULL); res_counter_init(&memcg->memsw, NULL); + res_counter_init(&memcg->kmem, NULL); } memcg->last_scanned_child = 0; memcg->last_scanned_node = MAX_NUMNODES; @@ -4978,6 +5069,10 @@ static int mem_cgroup_populate(struct cgroup_subsys *ss, if (!ret) ret = register_memsw_files(cont, ss); + + if (!ret) + ret = register_kmem_files(cont, ss); + return ret; } |