[PATCH v5 08/10] Display current tcp memory allocation in kmem cgroup

[Glauber Costa <glommer@parallels.com>]

This patch introduces kmem.tcp.failcnt file, living in the
kmem_cgroup filesystem. Following the pattern in the other
memcg resources, this files keeps a counter of how many times
allocation failed due to limits being hit in this cgroup.
The root cgroup will always show a failcnt of 0.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: David S. Miller <davem@davemloft.net>
CC: Hiroyouki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com>
CC: Eric W. Biederman <ebiederm@xmission.com>
---
 mm/memcontrol.c |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 51b5a55..9394224 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -517,6 +517,7 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
 			    const char *buffer);
 
 static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft);
+static int mem_cgroup_reset(struct cgroup *cont, unsigned int event);
 /*
  * We need those things internally in pages, so don't reuse
  * mem_cgroup_{read,write}
@@ -533,6 +534,12 @@ static struct cftype tcp_files[] = {
 		.read_u64 = mem_cgroup_read,
 		.private = MEMFILE_PRIVATE(_KMEM_TCP, RES_USAGE),
 	},
+	{
+		.name = "kmem.tcp.failcnt",
+		.private = MEMFILE_PRIVATE(_KMEM_TCP, RES_FAILCNT),
+		.trigger = mem_cgroup_reset,
+		.read_u64 = mem_cgroup_read,
+	},
 };
 
 static void tcp_create_cgroup(struct mem_cgroup *cg, struct cgroup_subsys *ss)
@@ -4134,6 +4141,8 @@ static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
 		if (mem_cgroup_is_root(mem)) {
 			if (name == RES_USAGE)
 				val = atomic_long_read(&tcp_memory_allocated) << PAGE_SHIFT;
+			else if (name == RES_FAILCNT)
+				val = 0;
 			else
 				val = RESOURCE_MAX;
 		} else
@@ -4251,6 +4260,10 @@ static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
 	case RES_FAILCNT:
 		if (type == _MEM)
 			res_counter_reset_failcnt(&mem->res);
+#if defined(CONFIG_CGROUP_MEM_RES_CTLR_KMEM) && defined(CONFIG_INET)
+		else if (type == _KMEM_TCP)
+			res_counter_reset_failcnt(&mem->tcp.tcp_memory_allocated);
+#endif
 		else
 			res_counter_reset_failcnt(&mem->memsw);
 		break;
-- 
1.7.6.4

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