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authorGlauber Costa <glommer@parallels.com>2011-12-11 21:47:01 +0000
committerDavid S. Miller <davem@davemloft.net>2011-12-12 19:03:55 -0500
commite5671dfae59b165e2adfd4dfbdeab11ac8db5bda (patch)
treedaf5570e8da71934970daa4b2044c6f13ee98f9d
parent08e34eb14fe4cfd934b5c169a7682a969457c4ea (diff)
Basic kernel memory functionality for the Memory Controller
This patch lays down the foundation for the kernel memory component of the Memory Controller. As of today, I am only laying down the following files: * memory.independent_kmem_limit * memory.kmem.limit_in_bytes (currently ignored) * memory.kmem.usage_in_bytes (always zero) Signed-off-by: Glauber Costa <glommer@parallels.com> CC: Kirill A. Shutemov <kirill@shutemov.name> CC: Paul Menage <paul@paulmenage.org> CC: Greg Thelen <gthelen@google.com> CC: Johannes Weiner <jweiner@redhat.com> CC: Michal Hocko <mhocko@suse.cz> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--Documentation/cgroups/memory.txt40
-rw-r--r--init/Kconfig11
-rw-r--r--mm/memcontrol.c105
3 files changed, 149 insertions, 7 deletions
diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index cc0ebc5241b3..f2453241142b 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 43298f9810fb..b8930d5a8325 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 6aff93c98aca..9fbcff71245e 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;
}