socket: initial cgroup code.

The goal of this work is to move the memory pressure tcp
controls to a cgroup, instead of just relying on global
conditions.

To avoid excessive overhead in the network fast paths,
the code that accounts allocated memory to a cgroup is
hidden inside a static_branch(). This branch is patched out
until the first non-root cgroup is created. So when nobody
is using cgroups, even if it is mounted, no significant performance
penalty should be seen.

This patch handles the generic part of the code, and has nothing
tcp-specific.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujtsu.com>
CC: Kirill A. Shutemov <kirill@shutemov.name>
CC: David S. Miller <davem@davemloft.net>
CC: Eric W. Biederman <ebiederm@xmission.com>
CC: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index f2453241142b5bc5fd4b62b83e7fe622939c8121..23a8dc5319a3de958f0e798f8ba7c9a58203ca07 100644 (file)
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -289,7 +289,9 @@ to trigger slab reclaim when those limits are reached.
 
 2.7.1 Current Kernel Memory resources accounted
 
-None
+* sockets memory pressure: some sockets protocols have memory pressure
+thresholds. The Memory Controller allows them to be controlled individually
+per cgroup, instead of globally.
 
 3. User Interface
 

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index b87068a1a09ef84ece916a4a722ebf70e921d1c6..f15021b9f734bfb602542a4a88b920666db61d12 100644 (file)
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -85,6 +85,8 @@ extern struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page);
 extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
 extern struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm);
 
+extern struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg);
+
 static inline
 int mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *cgroup)
 {
@@ -381,5 +383,25 @@ mem_cgroup_print_bad_page(struct page *page)
 }
 #endif
 
+#ifdef CONFIG_INET
+enum {
+       UNDER_LIMIT,
+       SOFT_LIMIT,
+       OVER_LIMIT,
+};
+
+struct sock;
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+void sock_update_memcg(struct sock *sk);
+void sock_release_memcg(struct sock *sk);
+#else
+static inline void sock_update_memcg(struct sock *sk)
+{
+}
+static inline void sock_release_memcg(struct sock *sk)
+{
+}
+#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
+#endif /* CONFIG_INET */
 #endif /* _LINUX_MEMCONTROL_H */
 

diff --git a/include/net/sock.h b/include/net/sock.h
index ed0dbf034539b97a0c2e465b6131d0ac5ece53cc..d5eab256167cd2ed9cee6b08e63c79802f693863 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -54,6 +54,7 @@
 #include <linux/slab.h>
 #include <linux/uaccess.h>
 #include <linux/memcontrol.h>
+#include <linux/res_counter.h>
 
 #include <linux/filter.h>
 #include <linux/rculist_nulls.h>
@@ -168,6 +169,7 @@ struct sock_common {
        /* public: */
 };
 
+struct cg_proto;
 /**
   *    struct sock - network layer representation of sockets
   *    @__sk_common: shared layout with inet_timewait_sock
@@ -228,6 +230,7 @@ struct sock_common {
   *    @sk_security: used by security modules
   *    @sk_mark: generic packet mark
   *    @sk_classid: this socket's cgroup classid
+  *    @sk_cgrp: this socket's cgroup-specific proto data
   *    @sk_write_pending: a write to stream socket waits to start
   *    @sk_state_change: callback to indicate change in the state of the sock
   *    @sk_data_ready: callback to indicate there is data to be processed
@@ -342,6 +345,7 @@ struct sock {
 #endif
        __u32                   sk_mark;
        u32                     sk_classid;
+       struct cg_proto         *sk_cgrp;
        void                    (*sk_state_change)(struct sock *sk);
        void                    (*sk_data_ready)(struct sock *sk, int bytes);
        void                    (*sk_write_space)(struct sock *sk);
@@ -838,6 +842,37 @@ struct proto {
 #ifdef SOCK_REFCNT_DEBUG
        atomic_t                socks;
 #endif
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+       /*
+        * cgroup specific init/deinit functions. Called once for all
+        * protocols that implement it, from cgroups populate function.
+        * This function has to setup any files the protocol want to
+        * appear in the kmem cgroup filesystem.
+        */
+       int                     (*init_cgroup)(struct cgroup *cgrp,
+                                              struct cgroup_subsys *ss);
+       void                    (*destroy_cgroup)(struct cgroup *cgrp,
+                                                 struct cgroup_subsys *ss);
+       struct cg_proto         *(*proto_cgroup)(struct mem_cgroup *memcg);
+#endif
+};
+
+struct cg_proto {
+       void                    (*enter_memory_pressure)(struct sock *sk);
+       struct res_counter      *memory_allocated;      /* Current allocated memory. */
+       struct percpu_counter   *sockets_allocated;     /* Current number of sockets. */
+       int                     *memory_pressure;
+       long                    *sysctl_mem;
+       /*
+        * memcg field is used to find which memcg we belong directly
+        * Each memcg struct can hold more than one cg_proto, so container_of
+        * won't really cut.
+        *
+        * The elegant solution would be having an inverse function to
+        * proto_cgroup in struct proto, but that means polluting the structure
+        * for everybody, instead of just for memcg users.
+        */
+       struct mem_cgroup       *memcg;
 };
 
 extern int proto_register(struct proto *prot, int alloc_slab);
@@ -856,7 +891,7 @@ static inline void sk_refcnt_debug_dec(struct sock *sk)
               sk->sk_prot->name, sk, atomic_read(&sk->sk_prot->socks));
 }
 
-static inline void sk_refcnt_debug_release(const struct sock *sk)
+inline void sk_refcnt_debug_release(const struct sock *sk)
 {
        if (atomic_read(&sk->sk_refcnt) != 1)
                printk(KERN_DEBUG "Destruction of the %s socket %p delayed, refcnt=%d\n",
@@ -868,6 +903,24 @@ static inline void sk_refcnt_debug_release(const struct sock *sk)
 #define sk_refcnt_debug_release(sk) do { } while (0)
 #endif /* SOCK_REFCNT_DEBUG */
 
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+extern struct jump_label_key memcg_socket_limit_enabled;
+static inline struct cg_proto *parent_cg_proto(struct proto *proto,
+                                              struct cg_proto *cg_proto)
+{
+       return proto->proto_cgroup(parent_mem_cgroup(cg_proto->memcg));
+}
+#define mem_cgroup_sockets_enabled static_branch(&memcg_socket_limit_enabled)
+#else
+#define mem_cgroup_sockets_enabled 0
+static inline struct cg_proto *parent_cg_proto(struct proto *proto,
+                                              struct cg_proto *cg_proto)
+{
+       return NULL;
+}
+#endif
+
+
 static inline bool sk_has_memory_pressure(const struct sock *sk)
 {
        return sk->sk_prot->memory_pressure != NULL;
@@ -877,6 +930,10 @@ static inline bool sk_under_memory_pressure(const struct sock *sk)
 {
        if (!sk->sk_prot->memory_pressure)
                return false;
+
+       if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
+               return !!*sk->sk_cgrp->memory_pressure;
+
        return !!*sk->sk_prot->memory_pressure;
 }
 
@@ -884,52 +941,136 @@ static inline void sk_leave_memory_pressure(struct sock *sk)
 {
        int *memory_pressure = sk->sk_prot->memory_pressure;
 
-       if (memory_pressure && *memory_pressure)
+       if (!memory_pressure)
+               return;
+
+       if (*memory_pressure)
                *memory_pressure = 0;
+
+       if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
+               struct cg_proto *cg_proto = sk->sk_cgrp;
+               struct proto *prot = sk->sk_prot;
+
+               for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
+                       if (*cg_proto->memory_pressure)
+                               *cg_proto->memory_pressure = 0;
+       }
+
 }
 
 static inline void sk_enter_memory_pressure(struct sock *sk)
 {
-       if (sk->sk_prot->enter_memory_pressure)
-               sk->sk_prot->enter_memory_pressure(sk);
+       if (!sk->sk_prot->enter_memory_pressure)
+               return;
+
+       if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
+               struct cg_proto *cg_proto = sk->sk_cgrp;
+               struct proto *prot = sk->sk_prot;
+
+               for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
+                       cg_proto->enter_memory_pressure(sk);
+       }
+
+       sk->sk_prot->enter_memory_pressure(sk);
 }
 
 static inline long sk_prot_mem_limits(const struct sock *sk, int index)
 {
        long *prot = sk->sk_prot->sysctl_mem;
+       if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
+               prot = sk->sk_cgrp->sysctl_mem;
        return prot[index];
 }
 
+static inline void memcg_memory_allocated_add(struct cg_proto *prot,
+                                             unsigned long amt,
+                                             int *parent_status)
+{
+       struct res_counter *fail;
+       int ret;
+
+       ret = res_counter_charge(prot->memory_allocated,
+                                amt << PAGE_SHIFT, &fail);
+
+       if (ret < 0)
+               *parent_status = OVER_LIMIT;
+}
+
+static inline void memcg_memory_allocated_sub(struct cg_proto *prot,
+                                             unsigned long amt)
+{
+       res_counter_uncharge(prot->memory_allocated, amt << PAGE_SHIFT);
+}
+
+static inline u64 memcg_memory_allocated_read(struct cg_proto *prot)
+{
+       u64 ret;
+       ret = res_counter_read_u64(prot->memory_allocated, RES_USAGE);
+       return ret >> PAGE_SHIFT;
+}
+
 static inline long
 sk_memory_allocated(const struct sock *sk)
 {
        struct proto *prot = sk->sk_prot;
+       if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
+               return memcg_memory_allocated_read(sk->sk_cgrp);
+
        return atomic_long_read(prot->memory_allocated);
 }
 
 static inline long
-sk_memory_allocated_add(struct sock *sk, int amt)
+sk_memory_allocated_add(struct sock *sk, int amt, int *parent_status)
 {
        struct proto *prot = sk->sk_prot;
+
+       if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
+               memcg_memory_allocated_add(sk->sk_cgrp, amt, parent_status);
+               /* update the root cgroup regardless */
+               atomic_long_add_return(amt, prot->memory_allocated);
+               return memcg_memory_allocated_read(sk->sk_cgrp);
+       }
+
        return atomic_long_add_return(amt, prot->memory_allocated);
 }
 
 static inline void
-sk_memory_allocated_sub(struct sock *sk, int amt)
+sk_memory_allocated_sub(struct sock *sk, int amt, int parent_status)
 {
        struct proto *prot = sk->sk_prot;
+
+       if (mem_cgroup_sockets_enabled && sk->sk_cgrp &&
+           parent_status != OVER_LIMIT) /* Otherwise was uncharged already */
+               memcg_memory_allocated_sub(sk->sk_cgrp, amt);
+
        atomic_long_sub(amt, prot->memory_allocated);
 }
 
 static inline void sk_sockets_allocated_dec(struct sock *sk)
 {
        struct proto *prot = sk->sk_prot;
+
+       if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
+               struct cg_proto *cg_proto = sk->sk_cgrp;
+
+               for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
+                       percpu_counter_dec(cg_proto->sockets_allocated);
+       }
+
        percpu_counter_dec(prot->sockets_allocated);
 }
 
 static inline void sk_sockets_allocated_inc(struct sock *sk)
 {
        struct proto *prot = sk->sk_prot;
+
+       if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
+               struct cg_proto *cg_proto = sk->sk_cgrp;
+
+               for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
+                       percpu_counter_inc(cg_proto->sockets_allocated);
+       }
+
        percpu_counter_inc(prot->sockets_allocated);
 }
 
@@ -938,6 +1079,9 @@ sk_sockets_allocated_read_positive(struct sock *sk)
 {
        struct proto *prot = sk->sk_prot;
 
+       if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
+               return percpu_counter_sum_positive(sk->sk_cgrp->sockets_allocated);
+
        return percpu_counter_sum_positive(prot->sockets_allocated);
 }
 

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 9fbcff71245ed429f58f6cb4eb3c4c81b7da3ee7..3de3901ae0a79b03c2b5d651bc7151576dbba2c9 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -379,7 +379,48 @@ enum mem_type {
 
 static void mem_cgroup_get(struct mem_cgroup *memcg);
 static void mem_cgroup_put(struct mem_cgroup *memcg);
-static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg);
+
+/* Writing them here to avoid exposing memcg's inner layout */
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+#ifdef CONFIG_INET
+#include <net/sock.h>
+
+static bool mem_cgroup_is_root(struct mem_cgroup *memcg);
+void sock_update_memcg(struct sock *sk)
+{
+       /* A socket spends its whole life in the same cgroup */
+       if (sk->sk_cgrp) {
+               WARN_ON(1);
+               return;
+       }
+       if (static_branch(&memcg_socket_limit_enabled)) {
+               struct mem_cgroup *memcg;
+
+               BUG_ON(!sk->sk_prot->proto_cgroup);
+
+               rcu_read_lock();
+               memcg = mem_cgroup_from_task(current);
+               if (!mem_cgroup_is_root(memcg)) {
+                       mem_cgroup_get(memcg);
+                       sk->sk_cgrp = sk->sk_prot->proto_cgroup(memcg);
+               }
+               rcu_read_unlock();
+       }
+}
+EXPORT_SYMBOL(sock_update_memcg);
+
+void sock_release_memcg(struct sock *sk)
+{
+       if (static_branch(&memcg_socket_limit_enabled) && sk->sk_cgrp) {
+               struct mem_cgroup *memcg;
+               WARN_ON(!sk->sk_cgrp->memcg);
+               memcg = sk->sk_cgrp->memcg;
+               mem_cgroup_put(memcg);
+       }
+}
+#endif /* CONFIG_INET */
+#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
+
 static void drain_all_stock_async(struct mem_cgroup *memcg);
 
 static struct mem_cgroup_per_zone *
@@ -4932,12 +4973,13 @@ static void mem_cgroup_put(struct mem_cgroup *memcg)
 /*
  * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
  */
-static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
+struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
 {
        if (!memcg->res.parent)
                return NULL;
        return mem_cgroup_from_res_counter(memcg->res.parent, res);
 }
+EXPORT_SYMBOL(parent_mem_cgroup);
 
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
 static void __init enable_swap_cgroup(void)

diff --git a/net/core/sock.c b/net/core/sock.c
index a3d4205e7238a9ab38f8302355a87415d3c82782..6a871b8fdd20eacab1ba49afb68c02e804e95e8f 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -111,6 +111,7 @@
 #include <linux/init.h>
 #include <linux/highmem.h>
 #include <linux/user_namespace.h>
+#include <linux/jump_label.h>
 
 #include <asm/uaccess.h>
 #include <asm/system.h>
@@ -142,6 +143,9 @@
 static struct lock_class_key af_family_keys[AF_MAX];
 static struct lock_class_key af_family_slock_keys[AF_MAX];
 
+struct jump_label_key memcg_socket_limit_enabled;
+EXPORT_SYMBOL(memcg_socket_limit_enabled);
+
 /*
  * Make lock validator output more readable. (we pre-construct these
  * strings build-time, so that runtime initialization of socket
@@ -1711,23 +1715,27 @@ int __sk_mem_schedule(struct sock *sk, int size, int kind)
        struct proto *prot = sk->sk_prot;
        int amt = sk_mem_pages(size);
        long allocated;
+       int parent_status = UNDER_LIMIT;
 
        sk->sk_forward_alloc += amt * SK_MEM_QUANTUM;
 
-       allocated = sk_memory_allocated_add(sk, amt);
+       allocated = sk_memory_allocated_add(sk, amt, &parent_status);
 
        /* Under limit. */
-       if (allocated <= sk_prot_mem_limits(sk, 0)) {
+       if (parent_status == UNDER_LIMIT &&
+                       allocated <= sk_prot_mem_limits(sk, 0)) {
                sk_leave_memory_pressure(sk);
                return 1;
        }
 
-       /* Under pressure. */
-       if (allocated > sk_prot_mem_limits(sk, 1))
+       /* Under pressure. (we or our parents) */
+       if ((parent_status > SOFT_LIMIT) ||
+                       allocated > sk_prot_mem_limits(sk, 1))
                sk_enter_memory_pressure(sk);
 
-       /* Over hard limit. */
-       if (allocated > sk_prot_mem_limits(sk, 2))
+       /* Over hard limit (we or our parents) */
+       if ((parent_status == OVER_LIMIT) ||
+                       (allocated > sk_prot_mem_limits(sk, 2)))
                goto suppress_allocation;
 
        /* guarantee minimum buffer size under pressure */
@@ -1774,7 +1782,7 @@ suppress_allocation:
        /* Alas. Undo changes. */
        sk->sk_forward_alloc -= amt * SK_MEM_QUANTUM;
 
-       sk_memory_allocated_sub(sk, amt);
+       sk_memory_allocated_sub(sk, amt, parent_status);
 
        return 0;
 }
@@ -1787,7 +1795,7 @@ EXPORT_SYMBOL(__sk_mem_schedule);
 void __sk_mem_reclaim(struct sock *sk)
 {
        sk_memory_allocated_sub(sk,
-                               sk->sk_forward_alloc >> SK_MEM_QUANTUM_SHIFT);
+                               sk->sk_forward_alloc >> SK_MEM_QUANTUM_SHIFT, 0);
        sk->sk_forward_alloc &= SK_MEM_QUANTUM - 1;
 
        if (sk_under_memory_pressure(sk) &&