For the root cgroup (the whole system), we already have overcommit
accounting and control, so we can skip charging tasks in the root cgroup
to avoid overhead.
Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
---
mm/vm_cgroup.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/mm/vm_cgroup.c b/mm/vm_cgroup.c
index 6642f934540a..c871fecaab4c 100644
--- a/mm/vm_cgroup.c
+++ b/mm/vm_cgroup.c
@@ -1,6 +1,7 @@
#include <linux/cgroup.h>
#include <linux/res_counter.h>
#include <linux/mm.h>
+#include <linux/mman.h>
#include <linux/slab.h>
#include <linux/rcupdate.h>
#include <linux/shmem_fs.h>
@@ -65,6 +66,9 @@ static int vm_cgroup_do_charge(struct vm_cgroup *vmcg,
unsigned long val = nr_pages << PAGE_SHIFT;
struct res_counter *fail_res;
+ if (vm_cgroup_is_root(vmcg))
+ return 0;
+
return res_counter_charge(&vmcg->res, val, &fail_res);
}
@@ -73,6 +77,9 @@ static void vm_cgroup_do_uncharge(struct vm_cgroup *vmcg,
{
unsigned long val = nr_pages << PAGE_SHIFT;
+ if (vm_cgroup_is_root(vmcg))
+ return;
+
res_counter_uncharge(&vmcg->res, val);
}
@@ -159,6 +166,9 @@ static u64 vm_cgroup_read_u64(struct cgroup_subsys_state *css,
struct vm_cgroup *vmcg = vm_cgroup_from_css(css);
int memb = cft->private;
+ if (vm_cgroup_is_root(vmcg))
+ return vm_memory_committed() << PAGE_SHIFT;
+
return res_counter_read_u64(&vmcg->res, memb);
}
--
1.7.10.4
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