Commit 4b1327be authored by Wei Wang's avatar Wei Wang Committed by David S. Miller
Browse files

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



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: default avatarWei Wang <weiwan@google.com>
Reviewed-by: default avatarShakeel Butt <shakeelb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ab44035d

include/linux/memcontrol.h

+2 −1
Original line number Diff line number Diff line
@@ -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;

include/net/sock.h

+5 −0
Original line number Diff line number Diff line
@@ -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;

mm/memcontrol.c

+11 −13
Original line number Diff line number Diff line
@@ -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;

}

net/core/sock.c

+12 −4
Original line number Diff line number Diff line
@@ -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 @@ int __sk_mem_raise_allocated(struct sock *sk, int size, int amt, int kind) 
		/* 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;

net/ipv4/inet_connection_sock.c

+2 −1
Original line number Diff line number Diff line
@@ -534,7 +534,8 @@ struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern) 
				   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);

	}