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![Tejun Heo](/assets/img/avatar_default.png)
cftype->write_string() just passes on the writeable buffer from kernfs and there's no reason to add const restriction on the buffer. The only thing const achieves is unnecessarily complicating parsing of the buffer. Drop const from @buffer. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: Daniel Borkmann <dborkman@redhat.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
225 lines
5.4 KiB
C
225 lines
5.4 KiB
C
#include <net/tcp.h>
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#include <net/tcp_memcontrol.h>
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#include <net/sock.h>
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#include <net/ip.h>
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#include <linux/nsproxy.h>
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#include <linux/memcontrol.h>
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#include <linux/module.h>
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int tcp_init_cgroup(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
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{
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/*
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* The root cgroup does not use res_counters, but rather,
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* rely on the data already collected by the network
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* subsystem
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*/
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struct res_counter *res_parent = NULL;
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struct cg_proto *cg_proto, *parent_cg;
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struct mem_cgroup *parent = parent_mem_cgroup(memcg);
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cg_proto = tcp_prot.proto_cgroup(memcg);
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if (!cg_proto)
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return 0;
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cg_proto->sysctl_mem[0] = sysctl_tcp_mem[0];
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cg_proto->sysctl_mem[1] = sysctl_tcp_mem[1];
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cg_proto->sysctl_mem[2] = sysctl_tcp_mem[2];
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cg_proto->memory_pressure = 0;
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cg_proto->memcg = memcg;
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parent_cg = tcp_prot.proto_cgroup(parent);
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if (parent_cg)
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res_parent = &parent_cg->memory_allocated;
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res_counter_init(&cg_proto->memory_allocated, res_parent);
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percpu_counter_init(&cg_proto->sockets_allocated, 0);
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return 0;
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}
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EXPORT_SYMBOL(tcp_init_cgroup);
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void tcp_destroy_cgroup(struct mem_cgroup *memcg)
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{
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struct cg_proto *cg_proto;
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cg_proto = tcp_prot.proto_cgroup(memcg);
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if (!cg_proto)
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return;
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percpu_counter_destroy(&cg_proto->sockets_allocated);
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}
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EXPORT_SYMBOL(tcp_destroy_cgroup);
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static int tcp_update_limit(struct mem_cgroup *memcg, u64 val)
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{
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struct cg_proto *cg_proto;
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int i;
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int ret;
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cg_proto = tcp_prot.proto_cgroup(memcg);
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if (!cg_proto)
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return -EINVAL;
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if (val > RES_COUNTER_MAX)
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val = RES_COUNTER_MAX;
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ret = res_counter_set_limit(&cg_proto->memory_allocated, val);
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if (ret)
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return ret;
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for (i = 0; i < 3; i++)
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cg_proto->sysctl_mem[i] = min_t(long, val >> PAGE_SHIFT,
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sysctl_tcp_mem[i]);
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if (val == RES_COUNTER_MAX)
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clear_bit(MEMCG_SOCK_ACTIVE, &cg_proto->flags);
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else if (val != RES_COUNTER_MAX) {
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/*
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* The active bit needs to be written after the static_key
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* update. This is what guarantees that the socket activation
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* function is the last one to run. See sock_update_memcg() for
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* details, and note that we don't mark any socket as belonging
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* to this memcg until that flag is up.
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*
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* We need to do this, because static_keys will span multiple
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* sites, but we can't control their order. If we mark a socket
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* as accounted, but the accounting functions are not patched in
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* yet, we'll lose accounting.
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*
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* We never race with the readers in sock_update_memcg(),
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* because when this value change, the code to process it is not
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* patched in yet.
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*
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* The activated bit is used to guarantee that no two writers
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* will do the update in the same memcg. Without that, we can't
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* properly shutdown the static key.
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*/
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if (!test_and_set_bit(MEMCG_SOCK_ACTIVATED, &cg_proto->flags))
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static_key_slow_inc(&memcg_socket_limit_enabled);
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set_bit(MEMCG_SOCK_ACTIVE, &cg_proto->flags);
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}
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return 0;
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}
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static int tcp_cgroup_write(struct cgroup_subsys_state *css, struct cftype *cft,
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char *buffer)
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{
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struct mem_cgroup *memcg = mem_cgroup_from_css(css);
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unsigned long long val;
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int ret = 0;
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switch (cft->private) {
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case RES_LIMIT:
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/* see memcontrol.c */
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ret = res_counter_memparse_write_strategy(buffer, &val);
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if (ret)
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break;
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ret = tcp_update_limit(memcg, val);
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break;
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default:
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ret = -EINVAL;
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break;
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}
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return ret;
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}
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static u64 tcp_read_stat(struct mem_cgroup *memcg, int type, u64 default_val)
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{
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struct cg_proto *cg_proto;
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cg_proto = tcp_prot.proto_cgroup(memcg);
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if (!cg_proto)
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return default_val;
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return res_counter_read_u64(&cg_proto->memory_allocated, type);
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}
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static u64 tcp_read_usage(struct mem_cgroup *memcg)
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{
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struct cg_proto *cg_proto;
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cg_proto = tcp_prot.proto_cgroup(memcg);
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if (!cg_proto)
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return atomic_long_read(&tcp_memory_allocated) << PAGE_SHIFT;
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return res_counter_read_u64(&cg_proto->memory_allocated, RES_USAGE);
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}
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static u64 tcp_cgroup_read(struct cgroup_subsys_state *css, struct cftype *cft)
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{
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struct mem_cgroup *memcg = mem_cgroup_from_css(css);
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u64 val;
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switch (cft->private) {
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case RES_LIMIT:
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val = tcp_read_stat(memcg, RES_LIMIT, RES_COUNTER_MAX);
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break;
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case RES_USAGE:
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val = tcp_read_usage(memcg);
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break;
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case RES_FAILCNT:
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case RES_MAX_USAGE:
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val = tcp_read_stat(memcg, cft->private, 0);
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break;
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default:
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BUG();
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}
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return val;
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}
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static int tcp_cgroup_reset(struct cgroup_subsys_state *css, unsigned int event)
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{
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struct mem_cgroup *memcg;
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struct cg_proto *cg_proto;
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memcg = mem_cgroup_from_css(css);
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cg_proto = tcp_prot.proto_cgroup(memcg);
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if (!cg_proto)
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return 0;
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switch (event) {
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case RES_MAX_USAGE:
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res_counter_reset_max(&cg_proto->memory_allocated);
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break;
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case RES_FAILCNT:
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res_counter_reset_failcnt(&cg_proto->memory_allocated);
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break;
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}
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return 0;
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}
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static struct cftype tcp_files[] = {
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{
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.name = "kmem.tcp.limit_in_bytes",
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.write_string = tcp_cgroup_write,
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.read_u64 = tcp_cgroup_read,
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.private = RES_LIMIT,
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},
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{
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.name = "kmem.tcp.usage_in_bytes",
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.read_u64 = tcp_cgroup_read,
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.private = RES_USAGE,
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},
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{
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.name = "kmem.tcp.failcnt",
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.private = RES_FAILCNT,
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.trigger = tcp_cgroup_reset,
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.read_u64 = tcp_cgroup_read,
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},
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{
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.name = "kmem.tcp.max_usage_in_bytes",
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.private = RES_MAX_USAGE,
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.trigger = tcp_cgroup_reset,
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.read_u64 = tcp_cgroup_read,
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},
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{ } /* terminate */
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};
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static int __init tcp_memcontrol_init(void)
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{
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WARN_ON(cgroup_add_cftypes(&memory_cgrp_subsys, tcp_files));
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return 0;
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}
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__initcall(tcp_memcontrol_init);
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