This config option dictates whether or not kernel memory in the
root cgroup should be accounted.
This may be useful in an environment where everything is supposed to be
in a cgroup and accounted for. Large amounts of kernel memory in the
root cgroup would indicate problems with memory isolation or accounting.
Signed-off-by: Suleiman Souhlal <sulei...@google.com>
---
init/Kconfig | 8 ++++++++
mm/memcontrol.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 52 insertions(+), 0 deletions(-)
diff --git a/init/Kconfig b/init/Kconfig
index 3f42cd6..a119270 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -714,6 +714,14 @@ config CGROUP_MEM_RES_CTLR_KMEM
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_MEM_RES_CTLR_KMEM_ACCT_ROOT
+ bool "Root Cgroup Kernel Memory Accounting (EXPERIMENTAL)"
+ depends on CGROUP_MEM_RES_CTLR_KMEM
+ default n
+ help
+ Account for kernel memory used by the root cgroup. This may be useful
+ to know how much kernel memory isn't currently accounted to any
+ cgroup.
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 6a475ed..d4cdb8e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -61,6 +61,10 @@ struct cgroup_subsys mem_cgroup_subsys __read_mostly;
#define MEM_CGROUP_RECLAIM_RETRIES 5
struct mem_cgroup *root_mem_cgroup __read_mostly;
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM_ACCT_ROOT
+atomic64_t pre_memcg_kmem_bytes; /* kmem usage before memcg is enabled */
+#endif
+
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
/* Turned on only when memory cgroup is enabled && really_do_swap_account = 1
*/
int do_swap_account __read_mostly;
@@ -5643,6 +5647,13 @@ memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp,
long long delta)
if (memcg)
ret = res_counter_charge(&memcg->kmem_bytes, delta, &fail_res);
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM_ACCT_ROOT
+ else if (root_mem_cgroup != NULL)
+ ret = res_counter_charge(&root_mem_cgroup->kmem_bytes, delta,
+ &fail_res);
+ else
+ atomic64_add(delta, &pre_memcg_kmem_bytes);
+#endif
return ret;
}
@@ -5668,6 +5679,12 @@ memcg_uncharge_kmem(struct mem_cgroup *memcg, long long
delta)
if (memcg)
res_counter_uncharge(&memcg->kmem_bytes, delta);
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM_ACCT_ROOT
+ else if (root_mem_cgroup != NULL)
+ res_counter_uncharge(&root_mem_cgroup->kmem_bytes, delta);
+ else
+ atomic64_sub(delta, &pre_memcg_kmem_bytes);
+#endif
if (memcg && !memcg->independent_kmem_limit)
res_counter_uncharge(&memcg->res, delta);
@@ -5953,7 +5970,12 @@ memcg_slab_move(struct mem_cgroup *memcg)
cachep = rcu_access_pointer(memcg->slabs[i]);
if (cachep != NULL) {
rcu_assign_pointer(memcg->slabs[i], NULL);
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM_ACCT_ROOT
+ cachep->memcg = root_mem_cgroup;
+#else
cachep->memcg = NULL;
+#endif
/* The space for this is already allocated */
strcat((char *)cachep->name, "dead");
@@ -5991,6 +6013,15 @@ memcg_kmem_init(struct mem_cgroup *memcg, struct
mem_cgroup *parent)
memcg_slab_init(memcg);
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM_ACCT_ROOT
+ if (memcg == root_mem_cgroup) {
+ long kmem_bytes;
+
+ kmem_bytes = atomic64_xchg(&pre_memcg_kmem_bytes, 0);
+ memcg->kmem_bytes.usage = kmem_bytes;
+ }
+#endif
+
atomic64_set(&memcg->kmem_bypassed, 0);
memcg->independent_kmem_limit = 0;
}
@@ -6010,6 +6041,19 @@ memcg_kmem_move(struct mem_cgroup *memcg)
spin_unlock_irqrestore(&memcg->kmem_bytes.lock, flags);
if (!memcg->independent_kmem_limit)
res_counter_uncharge(&memcg->res, kmem_bytes);
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM_ACCT_ROOT
+ {
+ struct res_counter *dummy;
+ int err;
+
+ /* Can't fail because it's the root cgroup */
+ err = res_counter_charge(&root_mem_cgroup->kmem_bytes,
+ kmem_bytes, &dummy);
+ err = res_counter_charge(&root_mem_cgroup->res, kmem_bytes,
+ &dummy);
+ }
+#endif
}
#else /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
static void
--
1.7.7.3
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