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#include <net/tcp.h>
#include <net/tcp_memcontrol.h>
#include <net/sock.h>
#include <net/ip.h>
#include <linux/nsproxy.h>
#include <linux/memcontrol.h>
#include <linux/module.h>
int tcp_init_cgroup(struct mem_cgroup *memcg)
{
struct mem_cgroup *parent = parent_mem_cgroup(memcg);
struct page_counter *counter_parent = NULL;
/*
* The root cgroup does not use page_counters, but rather,
* rely on the data already collected by the network
* subsystem
*/
if (memcg == root_mem_cgroup)
return 0;
memcg->tcp_mem.memory_pressure = 0;
if (parent)
counter_parent = &parent->tcp_mem.memory_allocated;
page_counter_init(&memcg->tcp_mem.memory_allocated, counter_parent);
return 0;
}
void tcp_destroy_cgroup(struct mem_cgroup *memcg)
{
if (memcg == root_mem_cgroup)
return;
if (memcg->tcp_mem.active)
static_branch_dec(&memcg_sockets_enabled_key);
}
static int tcp_update_limit(struct mem_cgroup *memcg, unsigned long nr_pages)
{
int ret;
if (memcg == root_mem_cgroup)
return -EINVAL;
ret = page_counter_limit(&memcg->tcp_mem.memory_allocated, nr_pages);
if (ret)
return ret;
if (!memcg->tcp_mem.active) {
/*
* The active flag needs to be written after the static_key
* update. This is what guarantees that the socket activation
* function is the last one to run. See sock_update_memcg() for
* details, and note that we don't mark any socket as belonging
* to this memcg until that flag is up.
*
* We need to do this, because static_keys will span multiple
* sites, but we can't control their order. If we mark a socket
* as accounted, but the accounting functions are not patched in
* yet, we'll lose accounting.
*
* We never race with the readers in sock_update_memcg(),
* because when this value change, the code to process it is not
* patched in yet.
*/
static_branch_inc(&memcg_sockets_enabled_key);
memcg->tcp_mem.active = true;
}
return 0;
}
enum {
RES_USAGE,
RES_LIMIT,
RES_MAX_USAGE,
RES_FAILCNT,
};
static DEFINE_MUTEX(tcp_limit_mutex);
static ssize_t tcp_cgroup_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
unsigned long nr_pages;
int ret = 0;
buf = strstrip(buf);
switch (of_cft(of)->private) {
case RES_LIMIT:
/* see memcontrol.c */
ret = page_counter_memparse(buf, "-1", &nr_pages);
if (ret)
break;
mutex_lock(&tcp_limit_mutex);
ret = tcp_update_limit(memcg, nr_pages);
mutex_unlock(&tcp_limit_mutex);
break;
default:
ret = -EINVAL;
break;
}
return ret ?: nbytes;
}
static u64 tcp_cgroup_read(struct cgroup_subsys_state *css, struct cftype *cft)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
u64 val;
switch (cft->private) {
case RES_LIMIT:
if (memcg == root_mem_cgroup)
val = PAGE_COUNTER_MAX;
else
val = memcg->tcp_mem.memory_allocated.limit;
val *= PAGE_SIZE;
break;
case RES_USAGE:
if (memcg == root_mem_cgroup)
val = atomic_long_read(&tcp_memory_allocated);
else
val = page_counter_read(&memcg->tcp_mem.memory_allocated);
val *= PAGE_SIZE;
break;
case RES_FAILCNT:
if (memcg == root_mem_cgroup)
return 0;
val = memcg->tcp_mem.memory_allocated.failcnt;
break;
case RES_MAX_USAGE:
if (memcg == root_mem_cgroup)
return 0;
val = memcg->tcp_mem.memory_allocated.watermark;
val *= PAGE_SIZE;
break;
default:
BUG();
}
return val;
}
static ssize_t tcp_cgroup_reset(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg;
memcg = mem_cgroup_from_css(of_css(of));
if (memcg == root_mem_cgroup)
return nbytes;
switch (of_cft(of)->private) {
case RES_MAX_USAGE:
page_counter_reset_watermark(&memcg->tcp_mem.memory_allocated);
break;
case RES_FAILCNT:
memcg->tcp_mem.memory_allocated.failcnt = 0;
break;
}
return nbytes;
}
static struct cftype tcp_files[] = {
{
.name = "kmem.tcp.limit_in_bytes",
.write = tcp_cgroup_write,
.read_u64 = tcp_cgroup_read,
.private = RES_LIMIT,
},
{
.name = "kmem.tcp.usage_in_bytes",
.read_u64 = tcp_cgroup_read,
.private = RES_USAGE,
},
{
.name = "kmem.tcp.failcnt",
.private = RES_FAILCNT,
.write = tcp_cgroup_reset,
.read_u64 = tcp_cgroup_read,
},
{
.name = "kmem.tcp.max_usage_in_bytes",
.private = RES_MAX_USAGE,
.write = tcp_cgroup_reset,
.read_u64 = tcp_cgroup_read,
},
{ } /* terminate */
};
static int __init tcp_memcontrol_init(void)
{
WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, tcp_files));
return 0;
}
__initcall(tcp_memcontrol_init);
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