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From: Kuniyuki Iwashima To: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Martin KaFai Lau Cc: John Fastabend , Stanislav Fomichev , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Neal Cardwell , Willem de Bruijn , Mina Almasry , Kuniyuki Iwashima , Kuniyuki Iwashima , bpf@vger.kernel.org, netdev@vger.kernel.org Content-Type: text/plain; charset="UTF-8" If net.core.memcg_exclusive is 1 when sk->sk_memcg is allocated, the socket is flagged with SK_MEMCG_EXCLUSIVE internally and skips the global per-protocol memory accounting. OTOH, for accept()ed child sockets, this flag is inherited from the listening socket in sk_clone_lock() and set in __inet_accept(). This is to preserve the decision by BPF which will be supported later. Given sk->sk_memcg can be accessed in the fast path, it would be preferable to place the flag field in the same cache line as sk->sk_memcg. However, struct sock does not have such a 1-byte hole. Let's store the flag in the lowest bit of sk->sk_memcg and check it in mem_cgroup_sk_exclusive(). Tested with a script that creates local socket pairs and send()s a bunch of data without recv()ing. Setup: # mkdir /sys/fs/cgroup/test # echo $$ >> /sys/fs/cgroup/test/cgroup.procs # sysctl -q net.ipv4.tcp_mem="1000 1000 1000" Without net.core.memcg_exclusive, charged to memcg & tcp_mem: # prlimit -n=524288:524288 bash -c "python3 pressure.py" & # cat /sys/fs/cgroup/test/memory.stat | grep sock sock 22642688 <-------------------------------------- charged to memcg # cat /proc/net/sockstat| grep TCP TCP: inuse 2006 orphan 0 tw 0 alloc 2008 mem 5376 <-- charged to tcp_mem # ss -tn | head -n 5 State Recv-Q Send-Q Local Address:Port Peer Address:Port ESTAB 2000 0 127.0.0.1:34479 127.0.0.1:53188 ESTAB 2000 0 127.0.0.1:34479 127.0.0.1:49972 ESTAB 2000 0 127.0.0.1:34479 127.0.0.1:53868 ESTAB 2000 0 127.0.0.1:34479 127.0.0.1:53554 # nstat | grep Pressure || echo no pressure TcpExtTCPMemoryPressures 1 0.0 With net.core.memcg_exclusive=1, only charged to memcg: # sysctl -q net.core.memcg_exclusive=1 # prlimit -n=524288:524288 bash -c "python3 pressure.py" & # cat /sys/fs/cgroup/test/memory.stat | grep sock sock 2757468160 <------------------------------------ charged to memcg # cat /proc/net/sockstat | grep TCP TCP: inuse 2006 orphan 0 tw 0 alloc 2008 mem 0 <- NOT charged to tcp_mem # ss -tn | head -n 5 State Recv-Q Send-Q Local Address:Port Peer Address:Port ESTAB 111000 0 127.0.0.1:36019 127.0.0.1:49026 ESTAB 110000 0 127.0.0.1:36019 127.0.0.1:45630 ESTAB 110000 0 127.0.0.1:36019 127.0.0.1:44870 ESTAB 111000 0 127.0.0.1:36019 127.0.0.1:45274 # nstat | grep Pressure || echo no pressure no pressure Signed-off-by: Kuniyuki Iwashima --- v8: Fix build failure when CONFIG_NET=n --- Documentation/admin-guide/sysctl/net.rst | 9 ++++++ include/net/netns/core.h | 3 ++ include/net/sock.h | 39 ++++++++++++++++++++++-- mm/memcontrol.c | 12 +++++++- net/core/sock.c | 1 + net/core/sysctl_net_core.c | 11 +++++++ net/ipv4/af_inet.c | 4 +++ 7 files changed, 76 insertions(+), 3 deletions(-) diff --git a/Documentation/admin-guide/sysctl/net.rst b/Documentation/admin-guide/sysctl/net.rst index 2ef50828aff1..7272194dcf45 100644 --- a/Documentation/admin-guide/sysctl/net.rst +++ b/Documentation/admin-guide/sysctl/net.rst @@ -212,6 +212,15 @@ mem_pcpu_rsv Per-cpu reserved forward alloc cache size in page units. Default 1MB per CPU. +memcg_exclusive +--------------- + +Skip charging socket buffers to the per-protocol global memory accounting +(controlled by net.ipv4.tcp_mem, etc) if they are already charged to the +cgroup memory controller ("sock" in memory.stat file). + +Default: 0 + rmem_default ------------ diff --git a/include/net/netns/core.h b/include/net/netns/core.h index 9b36f0ff0c20..ec511088e67d 100644 --- a/include/net/netns/core.h +++ b/include/net/netns/core.h @@ -16,6 +16,9 @@ struct netns_core { int sysctl_optmem_max; u8 sysctl_txrehash; u8 sysctl_tstamp_allow_data; +#ifdef CONFIG_MEMCG + u8 sysctl_memcg_exclusive; +#endif #ifdef CONFIG_PROC_FS struct prot_inuse __percpu *prot_inuse; diff --git a/include/net/sock.h b/include/net/sock.h index 66501ab670eb..0f597f4deaa3 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -2596,10 +2596,36 @@ static inline gfp_t gfp_memcg_charge(void) return in_softirq() ? GFP_ATOMIC : GFP_KERNEL; } +enum { + SK_MEMCG_EXCLUSIVE = (1UL << 0), + SK_MEMCG_FLAG_MAX = (1UL << 1), +}; + +#define SK_MEMCG_FLAG_MASK (SK_MEMCG_FLAG_MAX - 1) +#define SK_MEMCG_PTR_MASK ~SK_MEMCG_FLAG_MASK + #ifdef CONFIG_MEMCG static inline struct mem_cgroup *mem_cgroup_from_sk(const struct sock *sk) { - return sk->sk_memcg; + unsigned long val = (unsigned long)sk->sk_memcg; + + val &= SK_MEMCG_PTR_MASK; + return (struct mem_cgroup *)val; +} + +static inline void mem_cgroup_sk_set_flags(struct sock *sk, unsigned short flags) +{ + unsigned long val = (unsigned long)mem_cgroup_from_sk(sk); + + val |= flags; + sk->sk_memcg = (struct mem_cgroup *)val; +} + +static inline unsigned short mem_cgroup_sk_get_flags(const struct sock *sk) +{ + unsigned long val = (unsigned long)sk->sk_memcg; + + return val & SK_MEMCG_FLAG_MASK; } static inline bool mem_cgroup_sk_enabled(const struct sock *sk) @@ -2609,7 +2635,7 @@ static inline bool mem_cgroup_sk_enabled(const struct sock *sk) static inline bool mem_cgroup_sk_exclusive(const struct sock *sk) { - return false; + return mem_cgroup_sk_get_flags(sk) & SK_MEMCG_EXCLUSIVE; } static inline bool mem_cgroup_sk_under_memory_pressure(const struct sock *sk) @@ -2634,6 +2660,15 @@ static inline struct mem_cgroup *mem_cgroup_from_sk(const struct sock *sk) return NULL; } +static inline void mem_cgroup_sk_set_flags(struct sock *sk, unsigned short flags) +{ +} + +static inline unsigned short mem_cgroup_sk_get_flags(const struct sock *sk) +{ + return 0; +} + static inline bool mem_cgroup_sk_enabled(const struct sock *sk) { return false; diff --git a/mm/memcontrol.c b/mm/memcontrol.c index df3e9205c9e6..88028af8ac28 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4995,6 +4995,16 @@ void mem_cgroup_migrate(struct folio *old, struct folio *new) DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key); EXPORT_SYMBOL(memcg_sockets_enabled_key); +static void mem_cgroup_sk_set(struct sock *sk, struct mem_cgroup *memcg) +{ + sk->sk_memcg = memcg; + +#ifdef CONFIG_NET + if (READ_ONCE(sock_net(sk)->core.sysctl_memcg_exclusive)) + mem_cgroup_sk_set_flags(sk, SK_MEMCG_EXCLUSIVE); +#endif +} + void mem_cgroup_sk_alloc(struct sock *sk) { struct mem_cgroup *memcg; @@ -5013,7 +5023,7 @@ void mem_cgroup_sk_alloc(struct sock *sk) if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !memcg1_tcpmem_active(memcg)) goto out; if (css_tryget(&memcg->css)) - sk->sk_memcg = memcg; + mem_cgroup_sk_set(sk, memcg); out: rcu_read_unlock(); } diff --git a/net/core/sock.c b/net/core/sock.c index 814966309b0e..348e599c3fbc 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2519,6 +2519,7 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority) #ifdef CONFIG_MEMCG /* sk->sk_memcg will be populated at accept() time */ newsk->sk_memcg = NULL; + mem_cgroup_sk_set_flags(newsk, mem_cgroup_sk_get_flags(sk)); #endif cgroup_sk_clone(&newsk->sk_cgrp_data); diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index 8cf04b57ade1..c8b5fc3b8435 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -676,6 +676,17 @@ static struct ctl_table netns_core_table[] = { .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_ONE }, +#ifdef CONFIG_MEMCG + { + .procname = "memcg_exclusive", + .data = &init_net.core.sysctl_memcg_exclusive, + .maxlen = sizeof(u8), + .mode = 0644, + .proc_handler = proc_dou8vec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE + }, +#endif /* sysctl_core_net_init() will set the values after this * to readonly in network namespaces */ diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index c410eb525ebe..be27de94143c 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -758,12 +758,16 @@ void __inet_accept(struct socket *sock, struct socket *newsock, struct sock *new if (mem_cgroup_sockets_enabled && (!IS_ENABLED(CONFIG_IP_SCTP) || sk_is_tcp(newsk))) { gfp_t gfp = GFP_KERNEL | __GFP_NOFAIL; + unsigned short flags; + flags = mem_cgroup_sk_get_flags(newsk); mem_cgroup_sk_alloc(newsk); if (mem_cgroup_from_sk(newsk)) { int amt; + mem_cgroup_sk_set_flags(newsk, flags); + /* The socket has not been accepted yet, no need * to look at newsk->sk_wmem_queued. */ -- 2.51.0.384.g4c02a37b29-goog