[PATCH 8/8] mm: memcontrol: introduce CONFIG_MEMCG_LEGACY_KMEM

Johannes Weiner
2015-12-08T18:35:12Z

Let the user know that CONFIG_MEMCG_KMEM does not apply to the cgroup2
interface. This also makes legacy-only code sections stand out better.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
---
include/linux/memcontrol.h | 4 ++--
init/Kconfig | 10 +++++++++-
mm/memcontrol.c | 16 ++++++++--------
net/ipv4/Makefile | 2 +-
4 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 80f38da..c6a5ed2 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -233,7 +233,7 @@ struct mem_cgroup {
*/
struct mem_cgroup_stat_cpu __percpu *stat;

-#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
+#if defined(CONFIG_MEMCG_LEGACY_KMEM) && defined(CONFIG_INET)
struct cg_proto tcp_mem;
#endif

@@ -873,7 +873,7 @@ extern struct static_key_false memcg_sockets_enabled_key;
#define mem_cgroup_sockets_enabled static_branch_unlikely(&memcg_sockets_enabled_key)
static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)
{
-#ifdef CONFIG_MEMCG_KMEM
+#ifdef CONFIG_MEMCG_LEGACY_KMEM
if (memcg->tcp_mem.memory_pressure)
return true;
#endif
diff --git a/init/Kconfig b/init/Kconfig
index f1af42d..e5e4971 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1040,10 +1040,13 @@ config MEMCG_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 MEMCG_LEGACY_KMEM
+ bool
config MEMCG_KMEM
- bool "Memory Resource Controller Kernel Memory accounting"
+ bool "Legacy Memory Resource Controller Kernel Memory accounting"
depends on MEMCG
depends on SLUB || SLAB
+ select MEMCG_LEGACY_KMEM
help
The Kernel Memory extension for Memory Resource Controller can limit
the amount of memory used by kernel objects in the system. Those are
@@ -1052,6 +1055,11 @@ config MEMCG_KMEM
the kmem extension can use it to guarantee that no group of processes
will ever exhaust kernel resources alone.

+ This option affects the ORIGINAL cgroup interface. The cgroup2 memory
+ controller includes important in-kernel memory consumers per default.
+
+ If you're using cgroup2, say N.
+
config CGROUP_HUGETLB
bool "HugeTLB Resource Controller for Control Groups"
depends on HUGETLB_PAGE
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d048137..c527767 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2959,7 +2959,7 @@ static void memcg_free_kmem(struct mem_cgroup *memcg)
}
}

-#ifdef CONFIG_MEMCG_KMEM
+#ifdef CONFIG_MEMCG_LEGACY_KMEM
static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
unsigned long limit)
{
@@ -2983,7 +2983,7 @@ static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
{
return -EINVAL;
}
-#endif /* CONFIG_MEMCG_KMEM */
+#endif /* CONFIG_MEMCG_LEGACY_KMEM */

/*
* The user of this function is...
@@ -3995,7 +3995,7 @@ static struct cftype mem_cgroup_legacy_files[] = {
.seq_show = memcg_numa_stat_show,
},
#endif
-#ifdef CONFIG_MEMCG_KMEM
+#ifdef CONFIG_MEMCG_LEGACY_KMEM
{
.name = "kmem.limit_in_bytes",
.private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
@@ -4220,7 +4220,7 @@ mem_cgroup_css_online(struct cgroup_subsys_state *css)
if (ret)
return ret;

-#ifdef CONFIG_MEMCG_KMEM
+#ifdef CONFIG_MEMCG_LEGACY_KMEM
ret = tcp_init_cgroup(memcg);
if (ret)
return ret;
@@ -4276,7 +4276,7 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css)

memcg_free_kmem(memcg);

-#ifdef CONFIG_MEMCG_KMEM
+#ifdef CONFIG_MEMCG_LEGACY_KMEM
tcp_destroy_cgroup(memcg);
#endif

@@ -5495,7 +5495,7 @@ void sock_update_memcg(struct sock *sk)
memcg = mem_cgroup_from_task(current);
if (memcg == root_mem_cgroup)
goto out;
-#ifdef CONFIG_MEMCG_KMEM
+#ifdef CONFIG_MEMCG_LEGACY_KMEM
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !memcg->tcp_mem.active)
goto out;
#endif
@@ -5524,7 +5524,7 @@ bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
{
gfp_t gfp_mask = GFP_KERNEL;

-#ifdef CONFIG_MEMCG_KMEM
+#ifdef CONFIG_MEMCG_LEGACY_KMEM
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
struct page_counter *counter;

@@ -5556,7 +5556,7 @@ bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
*/
void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
{
-#ifdef CONFIG_MEMCG_KMEM
+#ifdef CONFIG_MEMCG_LEGACY_KMEM
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
page_counter_uncharge(&memcg->tcp_mem.memory_allocated,
nr_pages);
diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index c29809f..bee5055 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -56,7 +56,7 @@ obj-$(CONFIG_TCP_CONG_SCALABLE) += tcp_scalable.o
obj-$(CONFIG_TCP_CONG_LP) += tcp_lp.o
obj-$(CONFIG_TCP_CONG_YEAH) += tcp_yeah.o
obj-$(CONFIG_TCP_CONG_ILLINOIS) += tcp_illinois.o
-obj-$(CONFIG_MEMCG_KMEM) += tcp_memcontrol.o
+obj-$(CONFIG_MEMCG_LEGACY_KMEM) += tcp_memcontrol.o
obj-$(CONFIG_NETLABEL) += cipso_ipv4.o

obj-$(CONFIG_XFRM) += xfrm4_policy.o xfrm4_state.o xfrm4_input.o \
--
2.6.3