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net-memcg: pass in gfp_t mask to mem_cgroup_charge_skmem()

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Add gfp_t mask as an input parameter to mem_cgroup_charge_skmem(),
to give more control to the networking stack and enable it to change
memcg charging behavior. In the future, the networking stack may decide
to avoid oom-kills when fallbacks are more appropriate.

One behavior change in mem_cgroup_charge_skmem() by this patch is to
avoid force charging by default and let the caller decide when and if
force charging is needed through the presence or absence of
__GFP_NOFAIL.

Signed-off-by: Wei Wang <weiwan@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Wei Wang 2021-08-17 12:40:03 -07:00 committed by David S. Miller
parent ab44035d30
commit 4b1327be9f
6 changed files with 34 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/linux/memcontrol.h
View File

@ -1581,7 +1581,8 @@ static inline void mem_cgroup_flush_foreign(struct bdi_writeback *wb)
#endif /* CONFIG_CGROUP_WRITEBACK */
struct sock;
bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages);
bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages,
gfp_t gfp_mask);
void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages);
#ifdef CONFIG_MEMCG
extern struct static_key_false memcg_sockets_enabled_key;

5
include/net/sock.h
View File

@ -2400,6 +2400,11 @@ static inline gfp_t gfp_any(void)
return in_softirq() ? GFP_ATOMIC : GFP_KERNEL;
}
static inline gfp_t gfp_memcg_charge(void)
{
return in_softirq() ? GFP_NOWAIT : GFP_KERNEL;
}
static inline long sock_rcvtimeo(const struct sock *sk, bool noblock)
{
return noblock ? 0 : sk->sk_rcvtimeo;

22
mm/memcontrol.c
View File

@ -7048,14 +7048,14 @@ void mem_cgroup_sk_free(struct sock *sk)
* mem_cgroup_charge_skmem - charge socket memory
* @memcg: memcg to charge
* @nr_pages: number of pages to charge
* @gfp_mask: reclaim mode
*
* Charges @nr_pages to @memcg. Returns %true if the charge fit within
* @memcg's configured limit, %false if the charge had to be forced.
* @memcg's configured limit, %false if it doesn't.
*/
bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages,
gfp_t gfp_mask)
{
gfp_t gfp_mask = GFP_KERNEL;
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
struct page_counter *fail;
@ -7063,21 +7063,19 @@ bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
memcg->tcpmem_pressure = 0;
return true;
}
page_counter_charge(&memcg->tcpmem, nr_pages);
memcg->tcpmem_pressure = 1;
if (gfp_mask & __GFP_NOFAIL) {
page_counter_charge(&memcg->tcpmem, nr_pages);
return true;
}
return false;
}
/* Don't block in the packet receive path */
if (in_softirq())
gfp_mask = GFP_NOWAIT;
if (try_charge(memcg, gfp_mask, nr_pages) == 0) {
mod_memcg_state(memcg, MEMCG_SOCK, nr_pages);
if (try_charge(memcg, gfp_mask, nr_pages) == 0)
return true;
}
try_charge(memcg, gfp_mask|__GFP_NOFAIL, nr_pages);
return false;
}

16
net/core/sock.c
View File

@ -2728,10 +2728,12 @@ int __sk_mem_raise_allocated(struct sock *sk, int size, int amt, int kind)
{
struct proto *prot = sk->sk_prot;
long allocated = sk_memory_allocated_add(sk, amt);
bool memcg_charge = mem_cgroup_sockets_enabled && sk->sk_memcg;
bool charged = true;
if (mem_cgroup_sockets_enabled && sk->sk_memcg &&
!(charged = mem_cgroup_charge_skmem(sk->sk_memcg, amt)))
if (memcg_charge &&
!(charged = mem_cgroup_charge_skmem(sk->sk_memcg, amt,
gfp_memcg_charge())))
goto suppress_allocation;
/* Under limit. */
@ -2785,16 +2787,22 @@ suppress_allocation:
/* Fail only if socket is _under_ its sndbuf.
* In this case we cannot block, so that we have to fail.
*/
if (sk->sk_wmem_queued + size >= sk->sk_sndbuf)
if (sk->sk_wmem_queued + size >= sk->sk_sndbuf) {
/* Force charge with __GFP_NOFAIL */
if (memcg_charge && !charged) {
mem_cgroup_charge_skmem(sk->sk_memcg, amt,
gfp_memcg_charge() | __GFP_NOFAIL);
}
return 1;
}
}
if (kind == SK_MEM_SEND || (kind == SK_MEM_RECV && charged))
trace_sock_exceed_buf_limit(sk, prot, allocated, kind);
sk_memory_allocated_sub(sk, amt);
if (mem_cgroup_sockets_enabled && sk->sk_memcg)
if (memcg_charge && charged)
mem_cgroup_uncharge_skmem(sk->sk_memcg, amt);
return 0;

3
net/ipv4/inet_connection_sock.c
View File

@ -534,7 +534,8 @@ out:
atomic_read(&newsk->sk_rmem_alloc));
mem_cgroup_sk_alloc(newsk);
if (newsk->sk_memcg && amt)
mem_cgroup_charge_skmem(newsk->sk_memcg, amt);
mem_cgroup_charge_skmem(newsk->sk_memcg, amt,
GFP_KERNEL | __GFP_NOFAIL);
release_sock(newsk);
}

3
net/ipv4/tcp_output.c
View File

@ -3373,7 +3373,8 @@ void sk_forced_mem_schedule(struct sock *sk, int size)
sk_memory_allocated_add(sk, amt);
if (mem_cgroup_sockets_enabled && sk->sk_memcg)
mem_cgroup_charge_skmem(sk->sk_memcg, amt);
mem_cgroup_charge_skmem(sk->sk_memcg, amt,
gfp_memcg_charge() | __GFP_NOFAIL);
}
/* Send a FIN. The caller locks the socket for us.